THEE/“"3 This is to certify that the dissertation entitled BOND AND SLIP OF STEEL BARS IN FROZEN SAND presented by R IYADH M . ALWAHHAB has been accepted towards fulfillment of the requirements for Ph.D. degreein C'iV'll 8: Sanitary Engineering cw R,MM Major professor Date November l0, 1983 MSU is an Affirmative Action/Equal Opportunity Institution 0-12771 . ‘4... L”. I .W ‘ ' hMI—b ha a...“ -k__ - ‘ “i? ‘1‘“: \(~--. .. v." I" -- ’ i ". ”1% t‘ - :4 (1.1 ‘1'4' . 5““?41‘ L A 1. ‘. “(23' .- \_ _, .._‘.V_‘~. '2‘ C )‘h« L-" ’ w. ". -4 r- . 1n. \ .“ . , ' ; "i " ) 1 4,-5.3 '. .2 ‘ (7* l ‘ ., .-'. "u “A." I a “'7 ’{I'r‘ fl _ g. ‘ 3 {l t '5} ‘ #53} .;‘I‘,-..-\;./ .. if ..,, t “1.8 ":1'h; >1 .t‘. .‘a a 4‘1l',-'" 14 4 “EH” " J ‘1'.) {Lin - ~ g . - \u . V! ‘ A..... .v- a‘. Wv'w, J1-.. _‘__ BOND AND SLIP OF STEEL BARS IN FROZEN SAND by Riyadh M. Alwahhab A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Civil and Sanitary Engineering 1983 ABSTRACT BOND AND SLIP OF STEEL BARS IN FROZEN SAND By Riyadh M. Alwahhab Structural members (reinforcement, piles, ground anchors) embedded in frozen ground for the transfer and distribution of loads, tensile or compressive, involve load transfer at their common interface. Engineer— ing design requires prediction of both the short— and long—term adfreeze bond strength for a range of freezing temperatures and sand-volume fract— ions. The design method must account for surface type (steel, wood, con— crete), roughness, loading geometry, and the presence of any impurities in the sand—ice material. Adfreeze bond strength at the interface can be described as the shearing stress between the structural member and surround- ing frozen soil at failure. For steel bars embedded in frozen sand the adfreeze bond includes three components: ice adhesion to the bar, friction between the bar surface and sand particles, and mechanical interaction between frozen sand and the bar surface roughness. This experimental study involved measurement of the adfreeze bond components using model structural members (steel bars) embedded in frozen sand samples. Pullout loads, bar displacements, and temperatures were monitored for both constant displacement rate tests and constant load (cre- eP) tests. The observed behavior showed that initially ice adhesion combi- ned with friction prevents slip. Very small bar displacements (about 0.002 in.) characterize the start of tertiary creep for shearing stresses below those required for rupture of ice adhesion. After rupture and partial slip Riyadh M. Alwahhab a much smaller residual adfreeze bond controlled the pullout load. When a single lug was added to the bar, bearing action of frozen sand on the lug greatly increased the pullout load. Larger displacements with higher adfreeze bond strengths are associated with mobilization of mechanical interaction forces between the frozen sand and bar surface asperities. Lug spacing for maximum adfreeze bond was shown to be a function of pressure bulb overlap between lugs and formation of a void space behind lugs. Ex— perimental relations presented showed the dependence of creep displacement rates and/or adfreeze bond on lug size and spacing, sample dimensions, water impurities, bar surface roughness, temperature, sand volume fraction, and permitted development of empirical relationships for prediction of ad- freeze bond strength. TO MY FATHER WHO GAVE LOVE AND FATHERHOOD THEIR IDEAL MEANING T—f ACKNOWLEDGEMENT The author wishes to express a special appreciation to his major advisor, Dr. 0.B. Andersland, professor of Civil Engineering, for his encouragement, initiative, and aid throughout the author's doctoral studies and for his guidance during the preparation of this thesis. Thanks are also due the other members of the author's doctoral committee: Dr. R.K. Wen, Professor of Civil Engineering; Dr. G.L. Cloud, Professor of Metallurgy, Mechanics, and Materials Science; and Dr. C.O. Horgan, Professor of Metallurgy, Mechanics, and Materials Science. Sincere appreciation is also given to the author's father for his love and support throughout the author's studies. Thanks are also due the National Science Foundation, Division of Engineering Research, and the Department of Civil and Sanitary Engineering for their financial assistance which made this study possible at Michigan State University. The author also wishes to extend thanks to the Univer- sity of Technology in Baghdad for financial support. Special appreciation is also given to Margaret L. Cridge for her love, patience, and encouragement. Appreciation is also extended to the author's close friend, Dr. Saad M. Alhir and his family, for their moral support. LIST OF LIST OF LIST OF CHAPTER I. III. TABLE OF CONTENTS TABLES ...................... . . . FIGURES ................... . . . . SYMBOLS ........................ INTRODUCTION .................. . . . . . 1.1 Ground freezing ............... . . 1.2 Ground reinforcement ..... . .......... 1.3 Scope of investigation ............... REVIEW OF LITERATURE ................... Ice adhesion ............ . . . . . . . . Mechanical properties of frozen soil . . ...... Pile tests in frozen soils ............. 2 1 2 2 2.3 Pile tests in ice ............... 2 4 2 5 Circular footing in frozen soil ........... 2.6 Frozen soil beam tests ..... , ......... MATERIAL PROPERTIES AND SAMPLE PREPARATION ...... .. . 3.1 Steel rods ................. . . . . 3.2 Ice samples ........ . ...... . . . . . . 3.3 Sand-ice samples .................. EQUIPMENT AND TEST PROCEDURES . . . . . . . . . . . . 4.1 Equipment . . . . . . . . . . . . . . . . . . . 4.2 Test procedure . . . . . . . . . . . . . . . . EXPERIMENTAL RESULTS . . . . . . . . . . . . . . . . 5.1 Constant displacement rate tests . . . . . . . .1. Displacement (and loading) rate effects. 3%: .1 1 2 Temperature effect .............. 3 Bar size and sample height effects ...... 4 Lug size and shape effects .......... 78 8O 5.1.5 Bar surface roughness ...... . . . . 5.1.6 Water impurities and sand concentration . . 5.2 Constant load (creep) tests ........... 5.2.1 Load effect ........ . ..... . . 5.2.2 Temperature effect . . .......... 5.2.3 Lug size and position ........... 5.2.4 Sample diameter and sand concentration VI. ANALYSIS AND DISCUSSION ..... . .......... 6.1 Load transfer mechanisms ............. 6.1.1 Ice adhesion and sand friction ...... 6.1.2 Lug bearing ......... . ...... 6 1.2.1 Lug behavior in frozen sands . . 6.1.2.2 Lugs versus standard deformed bars 6.1.2.3 Long- -term lug bearing capacity. 6 1. 2. 4 Sample size and sand concentration 6 1. 2. 5 Lug bearing in ice ........ 6.2 Creep versus constant displacement rate tests 6.3 Correlation of experimental results ....... 6.3.1 Plain rods ................ 6 3 2 Deformed rods ............... 6.4 Theoretical predictions ............. 6.4.1 Bond for plain steel rods ......... 6.4.2 Load prediction based on cavity expansion theory .................. 6.4.3 Roughness criterion for steel rods 6.5 Applications ................... 6.5.1 Frozen soil reinforcement . . . . . . . . . 6.5.2 Pile or anchor capacity . . . . . . . . . . VII. SUMMARY AND CONCLUSION . . . . . . . . . . . . . . . . 7.1 Test procedures . . . . . ........ . . . 7. 2 Load transfer mechanisms ......... . . 7. 3 Applications--reinforcement, piles, anchors 7.4 Recommendations for future work ....... . . BIBLIOGRAPHY .................... . . . Page 82 84 176 187 191 192 194 197 198 199 200 202 206 207 209 212 214 215 218 264 264 265 267 269 271 vi Page APPENDIX—-Data .................. . . . . . 281 A. Constant displacement rate tests .......... 282 B. Constant stress (creep) tests ........... 317 Table 5.1 5.2 5.3 5.4 5.5 6.1 6.2 6.3 6.4 6.5 A—l A-2 A-3 LIST OF TABLES Page Title No. Physical properties of ice, frozen sand specimens, and steel rods for constant displacement rate test ....................... 97 Summary of test results for constant displacement rate tasts .................... 103 Temperature effect on the parameters used in Equations 5.1 to 5.4 ............... 108 Physical properties of ice, frozen sand specimens, and steel rods used in constant load (creep tests ...................... 109 Summary of test results for constant load (creep) tests ...................... 111 Comparison of frozen sand cohesion with the bond and lug bearing capacity ............... L Effect of lug size on creep rate and lug bearing in frozen sand at -10°C ............... 223 Values of "pseudo" instantaneous displacement a. and time to failure t at different loads for a 178 in. r lug in frozen sand ................ 29 Comparison of the n parameter from unconfined com— pression tests with that from bond tests . . . . . 226 Variation of ultimate load with rod surface roughness, 227 including lugs . . . . . . . . . . . ..... . . Data for ice samples I—l to 1-21 (Ice 1) ...... 282 Data for ice samples I—22 to 1-27 (Ice 2) ..... 287 Data for ice samples I-28 to I—32 (Ice 3) ..... vii Table No. A—4 B-l B-2 viii Title Data for frozen sand samples ........... Data for ice samples CI-l and CI—2 (Ice 3) . Data for frozen sand samples ........... Page 289 317 318 LIST OF FIGURES Figure Page No. Title No. 1.1 Frozen sand backfill with steel bars simulating a reinforced simple beam for partial support of a pipeline in areas of differential front heave action .................. . . . 5 1.2 Ground reinforcement ............... 6 2.1 Adhesive strength of ice to different materials as a function of temperature ....... . . . . 39 2.2 Effect of test type on the adhesive strength of ice to polystyrene surface (after Jellinek 1957 b) .................... 40 2.3 Constant-stress creep test: (a) basic creep curve; (b) true strain vs. time ............ 41 2.4 Creep strength vs. time to failure for frozen Ottawa sand at -3.850C (after Sayles, 1973) ...... 42 2.5 Volume concentration of Ottawa sand and peak strength (after Goughnour and Andersland, 1968) ..... 43 2.6 Results of strength testing on frozen soils at low confining stresses ............. . . 44 2.7 Effect of confining stress on the strength of ice and frozen soils . . . . . . . . . . . . . . . . 45 2.8 Effect of ice thickness and pile diameter on the ice adhesive strength (after Frederking, 1979) . 46 2.9 Adfreeze strength for piles in ice as a function of pile displacement rate (after Parameswaran, 1981) ..... ..... 47 2.10 Adfreeze strength, of silt—water slurry to an 8-in. diameter steel pipe pile, versus tempe— 48 rature (after Crory, 1963) ........... Figure No. 2.11 2.12 2.13 2.18 3.1 3.2 4.1 4.2 Title Definition of terms used in the bond analysis of a plain rod (pile) in frozen soil (after Johnston and Ladanyi, 1972) . . . ..... . ...... Variation of adfreeze strength of piles in frozen sand (solid lines) and contribution due to ice adhesion present in sand (dashed lines) with nominal pile displacement rate (after Parames— waran, 1981) .................. (a) Soil response to penetration by a flat cir- cular punch, (b) and (c) Notations for transformation of cavity expansion theory to a deep footing problem (after Ladanyi and Johnston, 1974) ................ Effect of footing depth on settlement of circular test plates in ice at -2.3°C (after Vyalov et al., 1973) ................... Results of a loading creep test on a circular plate (1.4 in. diameter, 18 in. deep) in frozen sand (after Ladanyi and Paquin, 1978) ..... Creep deflection at the center of frozen sand beams (after Klein and Jessberger, 1978) ....... Frozen Soil Beam; (a) Diagram of a Simply Supported Beam; (b) Stress Distribution (after Klein and Jessberger, 1978) ............... Deflection creep curves for simply supported beams of frozen sand at -10°C (after $00, 1983) . . . Equipment for pull«out tests including a frozen sand sample, steel rod with lug, and loading frame immersed in the circulating coolant . . . Bar configuration. (a) Plain rod. (b) Plain rod with 90 degree lug. (c) Lug with 45 degree face angle ................ . . . . . Diagram of test system for constant displacement rate tests ' 0 0 0 Q O O I O O i I V O U ' 1 C 0 Diagram of test system for constant load (creep) tests . . . . . . . . . . ........... Page No. 49 50 51 52 53 54 55 62 63 68 69 Figure _ _ Page No. . Title No. 5.1 Typical strip chart load and displacement records for plain steel rods in ice and sand—ice speci- mens ........... . .......... 118 5.2 Typical load-displacement curves at different loading rates for the bond of frozen sand (v5 = 64%) to a plain steel rod ........ 119 5.3 Effect of loading rate on the bond strength of frozen sand (v = 64%) to a 5/8 in. diameter plain steel rod at different temperatures . . . 120 5.4 Effect of nominal displacement rate on the bond strength of frozen sand (vS =64%) to a 5/8 in. diameter plain rod ............... 121 5.5 Typical load-displacement curves at different displacement rates for a plain rod with a single lug in frozen sand (v5 = 64%) ......... 122 5.6 Effect of displacement and loading rates on the ultimate lug capacity in frozen sand (vS — 64%) at —100c .................... 123 5.7 Typical load-displacement curves at different temperatures for a plain rod in frozen sand r = 64%) 124 ooooooooooooooooooo 5.8 Temperature effect on the bond strength of frozen sand (vS =64%) to a plain steel rod, at several loadingS rates ................. 125 5.9 Relationship between temperature and bond strength of frozen sand (v 64%) to a 5/8 in. plain rod, at several loading rates ............ 126 5.10 Comparison of strain hardening parameters, n based ' on constant loading rate and n' based on constant displacement rate, for 5/8 in. diameter plain rod in frozen sand (v5 = 64%) . . . . ........ 127 5.11 Temperature effect on the n parameter as defined by Equations 5.1 and 5. 3 . ............ 128 5.12 Relationship between temperature and the n parameter for a plain rod in frozen sand (vS =64%) . . . 129 5.13 Temperature effect on ice adhesion to a 5/8 in. diameter plain rod ........... . . . . . 130 Figure . Page No. T1tle No. 5.14 Typical load-displacement curves at different temperatures for a plain rod with lug in frozen sand (vS = 64%) .............. 131 5.15 Temperature effect on lug bearing, ultimate and "initial yield" loads, in frozen sand (vS = 64%) . 132 5.16 Effect of rod size (diameter) on the bond strength of frozen sand (v5 = 64%) to plain steel rods . . 133 5.17 Comparison of bond strength for two plain rod diameters in frozen sand (vS =64%) at several temperatures ................... 134 5.18 Relationship between the d/H ratio and bond strength of frozen sand (vS = 64%) to plain rods ..... 135 5.19 Effect of sample height on bond strength for plain steel rods in frozen sand (v5 = 64%) ....... 136 5.20 Load-displacement curves for a 3/8 in. steel rod with four lug sizes in frozen sand (vS = 64%) at —10 C 137 5.21 Load- -displacement curves for a standard deformed No.3 bar in frozen sand (vs — 64%) at —100C . . . 138 5.22 Effect of lug size (height) on the ultimate lug capacity in frozen sand (vS = 64%) ........ 139 5.23 Typical load- displacement curves for plain rods with two lug types, 450- -lug and 90°— lug, in frozen sand (vS 64%) ................. 140 5.24 Relationship between temperature and lug bearing capacity in frozen sand (v5 = 64% ........ 141 5.25 Roughness criterion (After Wright, 1955) ...... 142 5.26 Typical outputs for three types of steel surfaces as recorded on the strip chart, with a list of their properties . . ....... . ...... . . . . 143 5.27 Load- displacement curves for three types of steel finish, in frozen sand (vS =64%) at —10° C. . . . 144 5.28 Effect of surface roughness on the bond strength of frozen sand (vS = 64%) to plain steel rods . . . . 145 5.29 Bond strength dependence on ice sample preparation method ...................... 145 X111 Figure No_ T1tle 5.30 Bond strength dependence on water impurities for a 3/8 in. diameter plain rod in frozen sand (vS = 64%) at several temperatures .......... 5.31 Effect of sand fraction on bond strength for plain rods, peak and residual at —10°C ........ 5.32 Creep curves based on step loading a plain rod in frozen sand (vS = 64%) at -10°C ......... 5.33 Loading effect on the creep rate of a plain steel rod in frozen sand (vS = 64%) at -10C ..... 5.34 Creep curves for step loading of a plain 3/8 in. rod with a 1/8 in. lug height in frozen sand (vS = 64%) at —10°C .............. 5.35 Creep curves for step loading followed by unloading a plain rod with one lug in frozen sand VS=60 ........... . ....... 5.36 Loading effect on creep displacement rate of a plain rod with one lug in frozen sand (v5 = 64%) ...................... 5.37 Creep curves for a plain rod in frozen sand (v5 = 64%) Step loading procedure .......... 5.38 Temperature effect on creep rate of a plain rod in frozen sand (vS = 64%) ........... 5.39 Creep curves for step loading a plain rod with one 900 lug in frozen sand (v v5 = 64% ........ 5.40 Creep displacement rates for a plain steel 3/8 in. rod with a 1/8 in. lug in frozen sand vS = 64%) at four temperatures . . . . .......... 5.41 Effect of lug height on the creepO behavior of a plain steel 3/8 in. rod with 900 lugs in frozen sand (vS =64%) at -100 C ......... . . . 5.42 Creep curves for step loading a standard No.3 bar in frozen sand (vS —64%) at -10° C . . . . . 5.43 Load-displacement rate curve for a plain 3/8 in. steel rod with a 1/8 in. lug at different positions, in frozen sand (vS = 64%) at -10°C. . Figure . No. Title 5.44 Effect of sample diameter on creep rate of a plain 3/8 in. steel rod with a 1/8 in. lug in frozen sand (v5 = 64%) at —10°C ............ 5.45 Pull-out load dependence on soil cover for a plain steel 3/8 in. rod with a 1/8 in. lug in frozen sand (vS = 64%) ................. 5.46 Creep curves for step loading plain bars with a 1/8 lug in frozen sand at —10° C ......... 5.47 Creep curve for a plain 3/8 in. steel rod with a 1/8 in. lug in snow-ice (vS = 0) at -10°C . . . 5.48 Creep displacement rates for plain 3/8 in. steel rods with a 1/8 in. lug in frozen sand at -10°C and different sand volume concentrations . . . . 5.49 Load capacity dependence on sand concentration during creep for plain steel 3/8 in. rods with a 1/8 in. lug in frozen sands at —10°C ..... 5.50 Comparison of lug loads at different sand concen- tration for frozen sand at -10°C ........ 6.1 Temperature effect on ice adhesion to different materials .................... 6.2 Typical bond stress versus displacement curves for plain steel piles (rods) in frozen sands . . . 6.3 Variation of bond strength with the ratio d/H for ice and frozen sand (to piles of different materials) ................... 6.4 Comparison of bond strength for different pile types in frozen sandy soils ........... 6.5 Comparison of load-displacement curves for a plain steel rod in ice and frozen sand . . ...... 6.6 Comparison of ice adhesion and sand friction for a 3/8 in. plain steel rod embedded in ice and frozen sand ................... 6.7 Comparison of lug bearing, sand friction, and ice adhesion effects on the load—displacement curves for steel rods ................. Page No. 167 168 169 172 173 174 175 228 229 230 231 232 233 234 Figure No. 6.8 6.9 6.18 6.19 6.20 ri— XV Title Lug contribution for the initial bond rupture con— tribution at different temperatures ...... Comparison of ice adhesion, sand friction, and lug contribution for steel rods at different temperatures and ultimate conditions ..... Lug contribution to the ultimate pull—out capacity of a plain rod, with a single lug with different lug heights, in frozen sand ........... Comparison of frozen sand cohesion (at different temperatures) with the bond and lug bearing capacity .................... Relationship between lug bearing capacity and uniaxial compressive strength for frozen Wedron sand ...................... Comparison of lug behavior in frozen Wedron sand with that of a 1.4 in. diameter penetrometer in frozen quartz sand at —60C ........... Creep rate dependence on size (area) for lugs and punches .................... Pressure bulb overlap for consecutive lugs on a 3/8 in. diameter deformed bar ......... Time dependence of load relative to specified creep displacements, 6f, at -10°C for a 3/8 in.)rod with a 1/8 in. lug in frozen sand (v5 = 64% ...................... Sand volume fraction effect on the unconfined compressive strength of frozen Ottawa sand, and the lug bearing capacity in frozen Wedron sand. Bond strength for a plain rod in frozen sand, as a function of displacement rates, for creep tests and constant displacement rate tests. . Lug capacity comparisons, creep tests versus constant displacement rate tests, for different test conditions ................ Modified relationship between bond strength and the ratio d/H for plain steel rods in frozen sand (vS = 64%) ................ Page No. 235 236 237 238 242 243 244 245 246 247 Figure No. 6.21 6.22 6.23 6.24 6.25 6.26 6.27 6.28 6.29 6.30 6.32 6.33 6.34 xvi Title _____.____.__._____________________.______.._____ Bond strength of plain steel rods in frozen sand at —10°C as a function of sand fraction . Comparison of Equation 6.2 with experimental data for bond of plain rods in frozen sand (v5 = 64%) Lug pull-out capacity as a function of temperature for a displacement rate of 5 X 10'“ in./min. Effect of lug size (area) on bearing pressure . Lug capacity as a function of sand volume fraction for a creep rate of 5 X 10’“ in./min ...... Load versus instantaneous displacement for a 3/8 in. diameter rod with a 1/8 in. lug in frozen sand (v3 = 64%) at -1o°c ............ Time to 1 in. total displacement versus applied load, for a 3/8 in. rod with a 1/8 in. lug in frozen sand at —lO°C .............. Comparison of experimental bond strength with the theoretical predictions for a plain 5/8 in. diameter rod in frozen sand (v5 = 64%) at -10 C ..................... Comparison of n-values for bond tests with com— pression tests on frozen Wedron sand ...... Comparison of Equation 2.16 with experimental bond strength for a plain 5/8 in. diameter rod in frozen sand (vS = 64%) at -10°C ....... Load predictions based on cavity expansion theory for a single lug in frozen sand (v5 = 64%). . . Zone of crushed sand observed around the lug, at the end of creep tests ............. Correlation between profilometer and strip chart readings of aspirity heights for different steel surfaces ................. Roughness criterion (Figure 5.25) for a cold-. rolled steel bar extended to include 1 1/8 in. lug ...................... Page 248 249 250 251 252 253 254 259 260 261 xvii Figure Page No. Title No. 6.35 Ultimate pull-out capacity of steel rods in frozen sand (v = 64%) as a function of rod surface roughne s .................... 262 6.36 Conditions of equillibrium for a frozen sand beam reinforced with a plain steel rod ........ 263 xviii LIST OF SYMBOLS Rod, pile, or footing radius, (d or B)/2, Constant (Equation 5.5), Constant (Equation 2.16), or beam width (Equation 2.20), Constant (Equation 5.5), Constant (Equation 2.16), or soil cohesion, Long-term soil cohesion, Rod (or pile) diameter, Reinforcement depth in a frozen soil beam, Flow value, (1 + sin¢)/(1 — sin¢), Lug height, or frozen soil beam (cross-section) height, Constant (Equation 2.3), Constant (Equation 2.6), Exponent (Equation 5.1), Exponent (Equation 5.3), Strain-hardening parameter, l/m, 1/m', Confining stress, (01 + 03)/22 Cavity expansion pressure, Overburden (confining) pressure, Maximum shear stress, (01 - 03)/23 0* lug (or f°°ting) pressure, "Proof” lug Pressure at e = 0°C and éc = 0.0005 in./min. (Equation ’ xix "Proof“ lug pressure at temperature a and 3C = 0.0005 in./min. (Equation 6.4), Lug pressure, P1/A1, Pressure under the first lug in a deformed bar, Ultimate lug pressure, Pu/A], Radial dimension in a cylindrical or spherical coordinate system, Radius of a cylindrical plastic "cavity” "Cavity” radius at the elastic—plastic boundary, Radius of a spherical ”cavity” Footing settlement, Creep settlement rate, Time, Time to failure, Time parameter (Equation 2.1), Soil dependent parameter (Equation 2.1), exP(°o/Oi) Vertical soil displacement at distance r, Soil displacement at r=a, "Cavity" expansion displacement, Creep deflection at the center of a frozen soil beam, Deflection rate at the beam center, Sand volume fraction, Horizontal coordinate, Vertical coordinate, or lug position relative to the reaction plate, Neutral axis position in a frozen soil beam, Constant (Equation 2.7), Lug area, Rod area , P co C0 PC XX Footing Width, or equivalent footing width (= d + 2h), Sample diameter, Footing embeddment depth, Soil modulus of elasticity, Bond resisting force in tension zone, Soil resistance in compression zone, Resultant force in tension zone, (Fb + Ts), Sample height, Bond development length (embedded portion of rod in frozen sample or beam), Constant (Equation 2.9), U/R', OK, Length of a standard chord, Length of ”roughness" line, Total length of standard chords, Pull-out load, Loading rate, ”Proof” load for any lug height, at 3C = 0.0005 in./min. (Figure 5.4) Arbitrary loading rate, 1 lb./min. (Equation 5.1), “Proof” load at e = 0°C and 8C = 0.0005 in./min. (Figure 6.23), “Proof” load at temperature a and 8C = 0.0005 in./min. (Figure 6. Load from constant load (creep) tests, ”Initial yield" load for deformed rods, Lug load, Long-term lug load, Residual load for plain rods, Ultimate load, Load from constant 3, Radius of beam curvature, Universal gas constant, Maximum and minimum aspirity heights observed on the profilometer, Maximum and minimum aspirity heights as observed on the recorder strip chart, Temperature (0C or 0K), Soil resistance in tension zone Apparent activation energy, Displaced volume of soil under the footing, Displaced volume of an expanding ”cavity" Wedging angle under the footing, Angle of internal friction, Long—term angle of internal friction, Strain, Creep strain, Compression strain at the beam outer fiber, Failure strain, "Psuedo" instantaneous strain, Instantaneous plastic strain, Strain at the reinforcement level, Instantaneous strain, Strain rate, Creep strain rate, Arbitrary strain rate Major principal strain rate, —mma amocm mepcmcmmmwm mo mmmcm cw mam—mama m mo ucoaazm Ewm cmucomcmmc m mcwpm_:Ewm mama mepm apwz Ppwwxmma acmm :mNocm meucma Low Emma mfia flea cma pmmpm.i/K LAT .m>mma pmogm mo mpcmoq pm ampcoaasm Emma mnemormc< "Ill'l'rl|'l"'llil Emma mowimcmm :a:an:aaa:a mmoa mcwmmama flay Amv m>mmmam mmcm a pmoad m>mma pmocd mmmcmF mum compumm m \\\\ mo 0 “NU [\lrklli \\ \\ \K\ \\\\ \ x s \K . ... u .. . . .. .. . .. .... nrlnicma pmmpm . . a .. /—U:mm CQNOLL o b O o v . mW. mCPPmawa mmw .. ...: ...... ....M ”Junk... “33.4.13“. flu.fl.|..u.....u.. n... 13.114 .l........ n\\\ \ \\ \\\ l\¢ \\\\V\Dmomt:muc:ogw+ m \ \ Ch freeze pipe‘ 'GSL ll ///77— cu Frozen earth wall-— / . #5—- Steel H—beam / I 4'! L x” you! __ Large open ; g. 2&3 excavation / " / I m /'l ///’1// fill 'I / /'| ll! a II II (a) Cantilevered frozen earth Smooth pipe pile Figure 1.2: Corrugated pipe pile wall with H-beam reinforcement Permafrost t a? :2, (d) Screw anchor Ground Reinforcement conpl the l point Postu' consic gators Hosler uniroz I to at ‘ termini (Jenn 1960 a; EXPEFin Steel , muthe Strengt This in “99] ll CHAPTER II REVIEW OF LITERATURE 2.1 Ice Adhesion: Studies on the adhesive properties of ice normally deal with complex physico-chemical phenomenon. There are numerous papers in the literature which report on ice studies based on a fundamental view— point. The existence of a liquid-like layer on the ice surface was postulated by Faraday (1859; 1860). This concept has since undergone considerable attention. Experiments carried out by several investi— gators (Nakaya and Matsumoto, 1953; Hori, 1956; Jensen, 1956; and Hosler et al., 1957) offer strong evidence for the existence of an unfrozen transition liquid film on the ice surface. It is currently agreed that liquid-like water exists on ice down to at least -250C. However, it has been difficult to precisely de- termine the nature, and properties of this unfrozen water (Jellinek, 1967; Barnes et al., 1971). Jellinek (1957 a; 1957 b; 1960 a; 1960 b; 1960 c; 1970) carried out tensile and shear adhesion experiments on ice frozen to various surfaces including stainless steel, polystyrene, lucite, and fused quartz of varying surface roughness. These results, summarized in Figure 2.1, show the adhesive strength of ice to Various matenials as a function of temperature. This figure indicates that the adhesive strength of ice to stainless steel increases linearly with decreasing temperature until it becomes larg only i nte expe occu by H. The iinis rougl poly: 1957 obtai conti larger than the cohesive strength of ice. Cohesive type breaks (i.e. within the ice crystals) were observed only in the tensile experiments. Adhesive type breaks (i.e. at the interface between the ice and solid) were observed in the shear experiments. The transition from adhesion to cohesion appears to occur at about —14°C. These results are very similar to those reported by Hunsaker,et al. (1940) on the adhesion of ice to brass (Figure 2.1). The transition temperature in the latter case was close to —12°C. The adhesive shear strength was also strongly dependent on surface finish, with strength decreasing significantly with decreasing roughness. This is also shown in Figure 2.1, where the surface of the polystyrene plate was much "smoother" than the stainless steel surface. The adhesive strength obtained from tensile experiments (Jellinek, 1957 b) was observed to be about fifteen times greater than that obtained from shear experiments (Figure 2.2). To explain these results, Jellinek (1957 b) proposed that a continuous liquid-like transition layer exists between the ice and the material. For shear experiments, the adhesive strength was a function of the interfacial strength, and consisted of a viscous contribution from this thin film, as well as contribution due to surface roughness. For the tensile adhesion experiments, the measured strength was con- trolled by the ice cohesion as shown by the nature of the observed breaks (mostly cohesive). Jellinek proposed that the ice/solid interfacial strength was increased in the tensile mode due to the reinforcing effect of surface "tension" at the perimeter of the inten Ii unfroz proper induce to dis analys been c (1971) sisten Unfort nechan eXperi unifon 0f the caused (1957 r consisn 2-2 Me Mec Seviet are a f bOundar 0f Unfr Ariders] interfacial transitional water. If the two-dimensional liquid model for absorbed water in unfrozen soil were to be adopted (Martin, 1960), then these adhesive properties may be readily explained: while it was relatively easy to induce motions laterally parallel to the surface, it was very difficult to displace the absorbed water normal to the surface. Other tests and analyses related to the nature of the unfrozen water film in ice have been carried out. These are summarized by Jellinek (1967) and Barnes, et al. (1971). Generally, the results from these investigations are con- sistent with the concept of a liquid-like transitional film in ice. Unfortunately there are very few available data on this basic nechanical property of ice and there is a lot of scatter in the experimental results because of difficulty with control of the unifonnity of the ice structure. Further, the extreme sensitivity of the interfaces to any small impurities, such as solutes or gases, caused poor reproducibility of the experimental results. Jellinek (1957 b) duplicated each data point 12 times to obtain the reasonably consistent variation shown in Figure 2.1. 2.2 Mechanical Properties of Frozen Soil: Mechanical properties of frozen soils have been studied in the Soviet Union as early as 1920 (Tsytovich, 1975). Most frozen soils are a four—phase material; containing solid particles, ice, gas, and boundary water in equillibrium with ice (Vyalov, 1965). The amount of unfrozen water in frozen soil depends on the soil type (Dillon and Andersland, 1966), temperature (Nerseova and Tsytovich, 1963), grai pres uate llers facb rate 501 )1 corn coupe quart deper rUptu Press C0ntr in pa for c (Vial With 8 up (Obta' Primal and ii Anders IrIIIIIIIIII____________________________________——_ 10 grain-to—grain contact pressure (Tsytovich, 1975), and hydrostatic pressure (Chamberlain,et al., 1972). In frozen sands nearly all water is frozen at 0°C under atmospheric pressure, as reported by Nerseova and Tsytovich (1963) and Dillon and Andersland (1966). The mechanical properties of frozen soils are dependent on nany factors including tine, temperature, soil type, frozen and unfrozen water contents, ice content, etc. Owing to the varying nature of soils and experimental conditions, it is difficult to compare or correlate the data obtained by different authors. However, one can compare the results obtained for materials of the same type (such as quartz sands) tested under similar conditions. The strength of frozen soils may take on different meanings depending on the engineering problem. It includes the concept of rupture and that of excessive deformation (Andersland,et al., 1978). Pressure melting of ice at points of contact with soil particles contributes to plastic defbrmation of the pore ice and readjustment in particle arrangement. .This mechanism appears to be responsible for creep of frozen soil under constant stress and temperature (Vyalov, 1965; Andersland,et al., 1978). The increase in deformation with time, under constant stress and temperature, is represented by a typical creep curve in Figure 2.3 (a). After an initial strain eo (obtained immediately upon loading), the creep rate decreases over the primary stage, remains approximately constant during the secondary stage, and increases over the tertiary stage until terminated by rupture. Andersland (1963) and Vyalov (1963) attribute this creep behavior mainly partic unent (lysto 1965), streng theory an ang depend that f tenn s Salles Vyalov rePtesc Where 1 tr is 1 (01.031 t* equa to the change in soil structure, otherwise, the creep rate would have renained constant. Refreezing of liquid water is also considered to be a healing mechanism which contributes to the time-hardening process (i.e. decreasing creep rate) over the primary stage, Figure 2.3 (b). The strength of frozen soil develops from interparticle friction, particle interlocking, and cohesion. The latter is related to ice cementing of soil particles and from the shear strength of ice (Tystovich, 1958; Vyalov, 1965; Sayles, 1968). Tests by Vyalov (1959, 1965), Tsytovich (1966), and Sayles (1973) have shown that the shear strength of frozen soil can be described, using the Mohr—Coulomb failure theory, by a normal stress on the failure surface and two parameters; an angle of internal friction and cohesion. Time and temperature dependence is governed primarily by the cohesion. It is recognized that frozen soil has a high instantaneous strength and a smaller long— term strength. Test results (Figure 2.4) on Ottawa sand at -3.85°C by Sayles (1973) show a reasonable agreement with Vyalov's long-term strength. Vyalov (1959, 1963) suggested that the variation of strength can be represented by: 0' = 00 - 2 00 f lnE(tfl‘t*)/td] ln(tf/to) (2'1) where the parameters 00 and t0 depend on soil type and temperature, tf is the time to failure, of is the long-term strength and equals (01-03) as modified by Sayles (1973) to allow for triaxial conditions, t* equals exp (00/01) and °i is the instantaneous strength. Where ( Mdifi. frozen 12 For long-term strengths Vyalov (1963) stated that the quantity t* may be neglected. This appears to be applicable to frozen soils where either primary or secondary creep dominates the deformation behavior. Equation 2.1 with tf equal to infinity results in a long-term strength equal to zero, which is not consistent with the idea of con— tinuous strength at some finite time. Vyalov (1963) stated that the idea is purely conventional, but in practice, after some long period of time, the additional strength reduction is so insignificant and so slow that the reduction can be neglected in engineering calculations. Long- term strengths reported by Vyalov (1965) ranged from 18 to 37 percent of the instantaneous cohesion for a frozen sandy silt. Vyalov (1963) pointed out that with a stress level below the long-term strength the strain rate would not change to the stationary (or secondary) stage, but would remain in the primary stage where it continues to decrease until it becomes zero. If a = of, then the rate goes to zero, according to the following equation: Q. r4.» = E = 5 (0' 0r)“ (2.2) where u > 1 and g is the reciprocal of viscosity. Equation 2.2 is a modified version of the primary creep model Vyalov (1965) has proposed for frozen soils and which has been successfuly applied to various frozen soils by Sayles (1968, 1974) and others. In this model, the strain is expressed as: atA W (2.3) )k 6:8(t)=(w(e+e 0 where 6 equals -T, 90 is a reference temperature, usually 1°C, and in: Note thus hard iron When Proo 59) er 13 m, k, 1, m are soil parameters. By differentiating Equation 2.3 with respect to time, the strain rate é may be obtained: 8 = _%.( o k )l/m t(A—m)/m (2.4) m( 6 + 00) Note that the strain rate é decreases continuously with time, for A < m, thus confirming that Equation 2.3 represents the primary (strain and time hardening) creep model. The parameters in this equation may be obtained from a series of log-log curve fits based on experimental data. Secondary creep models for frozen soils have been proposed by Ladanyi (1972) based on work in metals by Hult (1966), Odqvist (1966) and others. One model is based on a power law which may be written as: $F-”=° (/ )" dt E 8c U Ocue (2.5) where “cue and n are creep parameters, both dependent on temperature. The proof stress 0 (Hult, 1966) is the uniaxial stress for an arbitrarily cue selected creep rate EC. Then, for a given material at a constant temperature, the total strain e(t) is: an=9+ 8 mm M'+té c= Where 8 f1's th Us Perletra Strengt‘ 32 for the cone and the wedge, statical considerations at failure give the pressure q as a function of the cavity expansion pressure Pi’ cohesion c, and the friction angle a. Ladanyi and Johnston (1974) indicated that in frozen soils the ultimate load is reached at a total settlement close to 10 percent of the punch diameter B. Also, the authors transformed cavity—expansion displacements ”i into footing settlements s, by equalizing the displaced volumes in both cases, i.e. VS=Vu in Figure 2.13 (c). This assumption implies that the frozen soil inside the "cavity” or the cone is perfectly plastic (incom- pressible). Using the generalized stress vs. strain rate relationship (for an incompressible von Mises material), the Mohr-Coulomb failure criterion, boundary and equillibrium conditions, Johnston and Ladanyi (1974) deduced the following relationship between the footing creep settlement rate s0 and the applied pressure q: éc = (éC/zogue)(3/2n)”o.IOB, po is the confining pressure, and c is the triaxial test cohesion and is given by (for ¢>0): c=ocue(ef/éctf)/2f% (2.19) where ef is the strain at failure, tf is the time to failure, and f is the flow value and equals (1+sin¢)/(1—sin¢). Using the same theory, Ladanyi (1976) has shown that the static penetration test can also be used in frozen soils to determine their strength parameters. A series of quasi-static and static (or incre site study with tip c resis leadi of pe with (1978 soil (Hoff that “P to numer aDDea compel effeci soils. avails 3990. settiE from C that w incremental loading) penetration tests were conducted at.a permafrost site near Thompson, Monitoba (T=~0.1OOC to -O.33°C). The field study included stress and penetration rate-controlled tests, performed with an electric penetrometer (1.4—in. dia.). The original conical tip of the penetrometer was replaced by a flat disc. The point resistance was plotted versus penetration rate on a log—log scale leading to a general power law relationship for the rate dependence of penetration resistance. The experimental data were in good agreement with the solution obtained from the cavity expansion theory. Nixon (1978) attempted two solutions; the Boussinesq solution for linear soil behavior, and a numerical solution based on Hoff's analogy (Hoff, 1954) to consider the soil non—linearity. Nixon (1978) showed that cavity expansion theory tends to over—predict settlement rates up to a factor of 2 for value of 13.5 the linear Boussinesq solution appears to over—predict settlement rates up to a factor of 3, in comparison to the two other methods. The depth of embeddment of the footing appears to have a similar effect on the settlement and bearing capacity as that in unfrozen soils. Although no theoretical solution of this problem is yet available (Ladanyi, 1981b), experimental data (Vyalov et al. 1973; Sego, 1980) show that the depth of burial reduces the total creep settlement to about one half when the relative depth D'/B increases from 0 to 1.25 (Figure 2.14). On the other hand, Sego (1980) observed that when a punch settles more than about 5 percent of its diameter, the dept buri 1980 1978 sett succ load test Lada Plan a sai rate (Figi tests tests Settl long mobil attai loadj then 34 the soil enters into a viscoplastic region and the effect of burial depth becomes much smaller. Under such conditions, no effect of burial depth was observed between Dl/B = 0.5 and 3.3 in ice (Sego, 1980) and between D'/B = 5 and 15 in frozen sand (Ladanyi and Paquin, 1978). ‘ Little information is available in the literature on the effect of loading history. Vyalov et al. (1973) presents information on the settlement of 6.3—in. (16 cm) diameter punches, loaded in five successive stages, on blocks of ice in Figure 2.14. In each stage the load was increased and kept constant for 10 days. Data in Figure 2.14 show that a steady—state settlement rate was attained in these tests after about 1 to 2 days. A similar conclusion was reached by Ladanyi and Paquin (1978) when analyzing the results of their deep plate (1.4'in. diameter circular punches) loading tests embedded in a saturated frozen sand. They observed that a constant settlement rate usually developed after 1 to 5 days under constant load . (Figure 2.15). The instantaneous settlement was negligible in such tests. It was also negligible in Ladanyi‘s (1976) static penetration tests on frozen silt. Ladanyi and Paquin (1978) found that the settlement rate remains a function of the loading history only as long as the penetration resistance of the soil is not completely mobilized, which happens after the total accumulated settlement attains about 1/3 the footing diameter. Beyond that settlement, the loading history effect appears to be erased and the settlement rate then depends only on the applied load, as long as the soil remains unc reu cons in i give visc 1966 stud abse work Jess unde Flgm 1976: CvaE on tt behav was t Prand Mende compu Both 35 unchanged. 2.6 Frozen Soil Beam Tests: To investigate the multiaxial stress state and to verify the results of analytical or numerical analyses based on properties or constitutive laws, it is convenient to simulate frozen soil structures in the laboratory. Examples of model piles and footings have been given in previous sections. Although analytical solutions for viscoelastic plain beams have been attempted (Hult, 1966; Odqvist, 1966) and also numerical solutions (Klein and Jessberger, 1978), model studies on frozen soil beams (plain or reinforced) are generally absent in the literature. An exception to this is the experimental work published by Meissner and Eckardt (1976), as quoted by Klein and Jessberger (1978), and more recently an experimental—analytical study undertaken by $00 (1983). An experimental creep curve for Emscher-Marl at —6°C is shown in Figure 2.16 for a frozen simply supported beam (Meissner and Eckhardt, 1976). The dashed lines represent the theoretical creep deflection curves, for Emscher-Marl at —10°C and Karlsrdher sand at —33°C, based on the finite element method of analysis. Identical stress-strain behavior was assumed in tension and compression. The uniaxial case was transformed to the multiaxial state of stress based on the Prandtl—Reuss equation and the von Mises flow rule (Hill, 1950; Mendelson, 1968). The finite element program was also used to compute the stress distribution across the beam depth, Figure 2.17. Both the deflection rates and the stress distribution were in close agr Odo Odc eni iai Few rai cre 36 ‘agreement with the analytical solution proposed by Hult (1966) and Odqvist (1966). The stress distribution can be evaluated analytically by satisfying the moment equillibrium equation given below (Hult, 1966; Odqvist, 1966): h‘ f o z(b dz) = O (2.20) o where ht b, and z are defined in Figure 2.17, and for identical soil behavior in tension and compression the neutral axis is located at the cross—section centroid, i.e. at 21 = h/2. Applying the elastic analog, in which the strain rate e is made equal to the elastic strain e, then 0 can be expressed as: o= ocue(e/éc)1/“ (2.21) The assumption of identical soil behavior in tension and com- pression does not appear to be always valid. Short-term creep tests on frozen silt, at -10°C, showed that the ratio of its compressive to tensile strength, oC/ot, was about 4 (Vyalov, 1965) at one hours time to failure. The ratio was deduced from parabolic Mbhr-Coulomb failure envelopes at different times to failure. For a 12-hour time to failure envelope, the ratio was reduced to about 3.5, thereafter remained almost constant. Hawkes and Mellor (1972) observed that the ratio oC/ot increased from unity at strain rates below 10’6 sec.'1, in creep tests, to about 8 at higher rates, in constant strain rate tests on polycrystalline ice at -7°C. This is because for higher rates, ten- sile strength ot changed very slightly as the strain rate é increased, while the compressive strength oc continued to increase (Ladanyi, 1981). stn axis at l ShOl Oven Brag whei Subs lnte 37 Haynes et al. (1975) reported that the ratio remained equal to one, for a frozen silt at -9.4°C, until the strain rates exceeded 10'3 sec.'1. After that, the ratio started to increase UP to about 3.5, with increasing brittleness in tension. Haynes and Karalius (1977) observed that the gap between the compressive and tensile strengths of frozen silt did not only increase with the increase in strain rate, but also with the decrease in temperatures. More recently, Bragg (1980) reported that the ratio oC/ot is about 5, obtained by extrapolation for frozen Nedron sand. Based on the foregoing observations, a frozen soil beam subjected to external bending moment may fail because of a weakness in tensile strength. Therefore, it can no longer be assumed that the neutral axis is located at the centroid of the beam cross-section, especially at high strain rates. In this case, the position of the neutral axis should be determined by satisfying the force equillibrium condition, over the beam cross-section, given below (Hult, 1966; Odqvist, 1966; Bragg, 1980): Fc = Ft (2.22) where FC is the resultant force in the compression zone, 30d 15 given AV: z . Fc=0f 1 ocue(e/eC)1/"(b d2) (2.23) Substituting Z/R for e, where R is the radius of beam curvature, and integrating gives: FC = (n b ocue/ 1+n)(1/ R ec)l/“ (21)1+1/" (Z 24) A similar expression may be derived, for the resultant fOrce Ft in the tension zone, with 21 replaced by (hLzl) in Equation 2.24. The creep par pre Equ bot and Sdt 38 parameters n, Ocue’ and go may not be the same in tension and com- pression. Substituting for FC and Ft by their corresponding expressions Equation 2.22 can be solved for 21. Note that R would cancel from both sides of Equation 2.22. 300 (1983) has included the effect of steel reinforcement (plain and deformed bars) in his experimental study. Frozen beams of saturated Wedron silica Sand (64 percent sand by volume) were tested at -10°C under step loadings maintained for 7 to 20 hours. The two types of steel reinforcement used included plain rods and rods with a single lug at each end. Preliminary data from his tests are summarized in Figure 2.18. As expected, the plain beam showed the largest deflection when compared to the reinforced beams under almost the same load. Although the ultimate load carrying capacity of the beam with the deformed rod was larger than that of the beam with the plain rod, the latter showed a smaller deflection and deflection rate than the beam with a deformed bar. A discussion of these findings relative to the results from the present study are included in Chapter VI. N:_0\Uv_ ..rz. wfiumcmium 0>wm®£u< ®U~ Ice Adhesive Strength, T1, kg/cm2 39 22 L’ I ' I I I l a 18 ._ [Ice/brass adhesion '(Hunsaker et al., 1940) I .— II at. 14, _ ' Ice/stainless steel ' l(Jellinek, 1957b ) __ I I ,l 10- I I l t’ I l w I 6 I I F I l 2 _ l V l lfit- l l ‘ Ice/polystyrene l (Jellinek, 1957b ) 0.5 L ’ + o -... 41..l..fl....1.1#141..l 0 -5 -10 -15 -20 —25 —30 Temperature, °C Figure 2.1: Adhesive strength of ice to different materials as a function of temperature. .5 $3.32.“: 4 NEU\@¥ Am. r 3 2 .Iflmtmxww ®>wm®£U< GUN 1 I \ 0.2 4O 7.0 [: 6.0 _ 5.0 ' N 5 _. \ C7) ‘5‘40— :5 :3 + From tensile experiments. Data E; showed strength dependence on 5 3 0 sample volume, cross-sectional i; area, and loading rate. (1) > 'S 2.0 G) I '0 < _ Cl) .2 1.0“ ‘7 0 5t— From shear experiments I 0025— 0 1I‘lllllllllllljl'lllllllllllll 0 -5 -10 ~15 -20 —25 —30 Temperature, °C Figure 2.2: Effect of test type on the adhesive strength of ice to polystyrene surface (after Jellinek, 1957 b 41 Rate e Strain (b) Time Figure 2.3: Constant—stress creep test: (a) basic creep curve; (b) true strain rate vs. time. r .+\ +\C._.\ i...” a tliwxx Ammrokw>npv @950 u MMF Rh 42 422 .828 28.23 9.35. E 2:8 2.35 :mNocw Low wL:_?m+ ou wE_u .m> cpmcmcpm ammcu ”v.m mczmrd .cPE .wp .mc:_wmd op wave omfi ONH ow ow o n u 1 — q u u 1 22.2.3: sorcflmoge ..... Awmwcw>mv wpmu “mob g <1- EdN ‘Eo—Io ‘uqfiuaaas daaug \\\> .AmomH .uchWLwc:< U:m_c:o:cm:oo memmv :bmcmcpm xama wee ucmm mzmppo do coepmcpcmocoo oE:_o> ”m.m magma; mE:_o> xa Ucmm “smegma om ow ON 0 _ _ _ . - oomw.m- we H-.ezee-ofixoo.mwsw D D oomo.mfin uh H-.eaee-oflxmm.fiufiw Demo.mfl-n H eiiiiiiiiii H-.ewse-ofixm©.mwfiw PdH ‘ssauas [etxv XPBd 1 do: . NX mo.» any no 1 3O " 25 - 20 — 44 Leena >0 .963qu 80—120 silica sand —24Oc c3=o.17MPas'1 Smith and ' . o ,= -l Cheatham 80 120 Slllca sand 16 C O 0.17MPas (1975) Unfrozen OWS 20—30 (grained) _3 _1 Alkire and Frozen OWS 20—30 —12 C 4.4x10 8 S=55% Andersland Frozen ows 20-30 —12°c 4.4x10‘3s‘1 S=97z (1973) Penn Sand 80—200 —8°c lO-Ss—l Perkins and Ruedrich (1973) ows 100—200 -1o°c 10‘3s'l Chamberlain et al. (1972) ows 2-30 -3.9°c 3xlO—3s—l Sayles (1974) OWS: Ottawa sand Penn: Pennsylvania sand S: Degree of saturation unfrozen sand I l l I 1 l n n l n n 1 n I 1 1 1 l 10 15 20 25 p: (01+o3 )/2, MPA Figure 2.6: Results of strength testing on frozen soils at low confining stresses UQM, .m_e0m :wNose use woe eo gaucwcpm web so mmwnpm acecemcoo we bummem ”m.m mesmen ea: .N\Ams+aev ”a com com OOH 3 . _ _ _ . . :1 AN AN ,4 fl < a . pFem mufid f r (_ tJ _ HHH O \— HH l—IH mm [OH mw escape it mm 0 I it o om Ammmfi ._w um gem—Lonamguv I HimMIQH oooH- oomloofi ucmm campuo mu Ammmfi .Fa pm :TMFLwnEmcuv H-mm-oH Doofi- p_em AN “wees maeeev Hiwv-ofixa.m oom.HH- wow Lm_:cmsw nu \u szomb HH H om d Paw ‘z/(€0+ID) EE .I AWWMVCXUwEL. 00H ASE 6:2qude (6:3 cpmcmbm $532 8.? 9t. :0 smqumE 3E ES 39335 our US powtm "md 8:5: as .N\e .N\aaeaEeee seen mos w e a N was w e a N n4- - q - - Jt _— _ u _ _ a — ”H HaO .aam\es m-ofixa.wn a UGO! H._. ,o - Ase cm on oewzv a . N.o 4 mnaOIAOm\UVNm.OH.H iv - - e.o - Ase omuev - e.o ea.mi eso.onee - - a w.o l . . . _ . .n . . . _ . . . OJ mg m o v N mg m o v N 3 EE .1 $853.2: 8H edw .1, ‘uifiuaaes aAsseupv 831 47 Afimmfi .cmcmmeEmsma ampemv mums “seamen—amen area mo cowpocze a ma woe a? moped com spmcmLum m~mmcwu< ”m.m weaned .:wE\EE .cm .pcmsmumfiamwa mea NIJWI muoH auofi muoH . fij.~... . _u..-q. q a —.....~ - q HO pompm . «\.mpmsucoo U \\m I. o.H U003 edw ‘11 ‘HlfiUGJlS azaaupv .m OH .e m1 a £HmC®LHW UNUOLuvU.‘ Adfreeze Strength, psi 10 20 3O 4O '50 \\ \ . \\ \\ \ _ \\ \ , \ \ \ . \ ‘\ \ \ \ \ —- \\ \(eLong-term strength \ \. \ \\ . \ ‘\ \\ \ \ \\ _ \ \ \ \\ ‘\\ \\ - \ \\~\ \ \Q—Ultimate strength _, \’ (10 Kips/day) \ \ \ \ \ \ \ h; 1 l l l _l \ A 32 30 28 26 Ground Temperature, °F Adfreeze strength, of silt-water slurry to an 8—in. diamter steel pipe pile, versus temperature (after Crory, 1963). Figure 2.10: 49 O \ /l ‘ <1" I“ ,-/’" /l du la ' ” I / v=du/dr /‘\\%assumed I l l l l l / load distribution I I I I I I I Z: P I t Loaded End .___J. dr Y‘ plan en. a @de \ Definition of terms used in the bond analysis of a plain rod (pile) in frozen soil (after Johnston and Ladanyi, 1972). Figure 2.11: .Afimmfi .cwgmzmmEmLma empemv mums “cmeuwFQmwv wpwa FMCWEo: 5pm: Amwce_ umcmmuv scam cw “commas :oemwcum woe Op mzv coeuznenpcou new Amm:__ ueFOmv teem :mwoce ce mm_ea mo cpmcwapm wwaLevm we cowpmwcm> ”NH.N enamel .CeE\EE .ouom pcmewanQmeo mFTQ 50 I 0 r4 mepmu «u.u muwaucoou \m.m l aeez- .<.< - Use- as a: ..... i 9N goo- we teem :mwocn Trill: pdw ‘uibuaais eZBBJJPV Flgu a a Elastic-plastic rc boundary; cylindrical —e4q ”cavity” I Advancing plastic zone Elastic—plastic boundary; spherical ”cavity” (a) B n S t ‘1 V 7 W .- IL I; 51.14% @9114 _ -Pntand> "\I ‘3'?“ / ‘ 1v t2 /;>\ ’/<:\ Vu l‘ a 1” K 43/ . . ~~ "J, P_i Semlfsp'berlcal Jig/i7,_7§§7 cav1ty (Not Tu. to a scale) 1 (b) (C) Figure 2.13: (a) Soil response to penetration by a flat circular punch, (b) and (c) notations for transformation of cavity expansion theory to a deep footing problem (after Ladanyi and Johnston, 1974). on: m.OwU rlIIIIIIIJHHMW 0.0 on: N.Dwo 52 Ammmfi ,._m we >ormz> empemv mom.m- um mu_ Ce mmpmfia ummw ce_:oceo we ucmEm_upmm co spawn mcepoom mo powwwm "QH.N enamel mzwn .mEeH om ow om om OH mNe.e eases meanest was me .e as as am mmwm u.m.~- we a\.e ma: o.ouc an: N.oua w.o mu ‘5 ‘1uawaiaiag Six 0 +£0..c0...++QV FELFC. Total Settlement, s, cm T= —6°C +q= 18.07 MPa = 21 83 hours s: 9.81x10'2 cm/min. 4.06 MPA 98.05 hours 1.83x10'4 cm/min. I a 7.57 MPa 48.05 hours 3 69x10'3 cm/min. —————— ‘*‘~13 80 MPa 24.52 ho rs ,r 20.92 MPa 3.09x10‘ cm/min. 3.75 hours 0.155 cm/min I l l l l l l 0 20 40 6O 80 Tine, hours Results of a loading creep test on a chtMarMam(14in.Mmmwm Min. deep) in frozen sand (after Ladanyi and Paquin, 1978). Figure 2.15: 54 com ae\ee m-onem.m (io\.\i ..E\EE muofixwamna o..l|.l.l. IIIII I.l..|ol..||.|.|. .Awmmfi .mecmnmmww use cew_¥ qummv mamas scam :mNoLe eo cwpcmu age we cove meso; .maeh cow cow \II \OI \\ _aez-amsum5m a Aesafi .aeaeeem see racemeazv Doe- Ammmfi .smmsmamqu new :wm_xv \\ Ucmm LOSDLm—Lflx ow_wwv awwco an.m mcsmeu QIIU'IIIII AIIO‘ we .pcwswawaxm “cmEmFm evened -1-- ; 0H mm ‘A ‘uoiioaliag EU 'mwX< FQLU.DOZ EOLns OUEMHWwQ Distance from Neutral Axis, cm ’N 55 P= 4kN(900 lbs) b: o 1 0.15 m ——-———————a> x AA] —— - 1‘ 1g /// I .Om J / (a) 6 .e_.._____‘g___Finite element 3 _. I 0 -3 — -6— l J J I 1 -400 -300 ~200 -100 O 100 200 300 400 (b) Normal Stress at x=0.475m, ox, psi Figure 2.17: Frozen Soil Beam; (a) Diagram of a Simply Supported Beam; (b) Stress Distribution (after Klein and Jessberger, 1978). a: r NIOHX A) I C0?U.UU~M¥.WQ .: GUM. Beam Deflection, v, x10“2 in. 56 I P P 10 .. Ix’T— “\\ 21/ 3%” / A :1] V A \5\ — I<—_>‘ H II 10" loll u 2.75" “We—+434 l— I<+——- 2L= 403——.———+>4 8 _ Rod (3/16"¢) Lug (1/16” ht.) I I I 6 .. II I I . I I Unreinforced Beam P= 205 lbs. - I (7: 0.002 in/hr. plain rod and lug 4 I3: 200 lbs. 8 v: 0.002 in/hr. ,_ E] E] El El Cl _ E] I [3 E] E! El E E! El '3 a E e o o 2 _ El '3 o 0 O O O E= 226 lbs. v= 0.001 in/hr. 0 l l l l l l l l I l l O 2 4 6 8 10 Time, t, hours Figure 2.18: Deflection creep curves for simply supported beams of frozen sand at -10°C (after $00, 1983). IOC fro USE CHAPTER III MATERIAL PROPERTIES AND SAMPLE PREPARATION 3.1 Steel Rods: For most ice samples, a plain cold—rolled steel rod, 5/8 in. diameter, was used. A few samples were tested with a 3/8 in. diameter rod for comparison. For sand—ice samples, several diameters ranging from 3/32, 6/32, 12/32, and 20/32 in. plain cold—rolled steel rods were used. All of these rods included a threaded portion at both ends which permitted easy attachment to an eye connector and hook at the bottom of the coolant bath and mounting of a displacement transducer at the upper l rod end (Figures 3.1 and 3.2 a). Lugs welded to the 3/8 in. diameter rod, shown in Figure 3.2 b, included heights, h, of 1/16, 2/16, and 3/16 in. and a length of 1/2 inch. Lug heights were limited to 3/16 in. so as to avoid a tensile failure in the 3/8 in. steel rod. Plain rods with a single lug are referred to as deformed bars. Lug face angles of 45 and 90 degrees, Figure 3.2 (c), were selected to provide preliminary information on wedging between the frozen sand and rod during pull-out. Rod surface roughness was considered by using three steel surface types: ground-finish steel with a roughness factor 0 of 90 percent, cold-rolled with p = 625%, and shot—blasted with p = 1489%. The latter type surface was prepared from the ground—finish steel by shot-blasting with commercially available, uniformly graded glass beads with all beads passing the No. 60 U.S. standard sieve and retained on 57 IN tes alh beti at1 ail Illa IIEQ 58 the No. 100 sieve (size range of 0.0058 in. to 0.0097 in.). Shot—blasting generally gave the steel surface a finely-textured grey color, whereas the ground-finish steel displayed an almost white, shiney and highly polished surface with minimum imperfections. The cold-rolled steel rod surface was dark grey with very fine spots due to some imperfections which originated during its manufacture. A standard deformed 3/8 in. diameter rod with lugs spaced at 0.3125 in. on centers was also used in several tests. The lug height for this rod was about 1/64 in. (0.015 in.). 3.2 Ice Samples: Three ice types used in this study are referred to as Ice(1), Ice(2), and Ice(3). For the first type, ice samples were prepared by pouring distilled water directly into a cylindrical split steel mold with a 6 in. inside diameter and 7 in. height. The water was poured to a height of 6 in. i 1/8 in., in four layers. Before that, the mold was first mounted on a 6 in. diameter by 1/2 in. high steel reaction plate. This plate was attached, by screws, to a rectangular aluminum reaction beam, 1 1/2 in. X 5 in. X 12 in., with a circular hole in the center to allow for the steel rod embedded in the pull-out specimens. Clearance between the rod and the hole for each rod size was maintained at 0.063 in. by use of a removable washer in the reaction plate. To prevent leakage a commercial putty was used to seal the mold at the edges and to minimize ice adhesion to the mold it was lined with a thin sheet of plastic saran wrap. All samples were frozen and stored in a freezer at close to -20°C for at least 12 hours. Directional freezing took place from the base upward and from the sides radially to the in: on san huh WEI ire bini SllOI snow and nomi IOe Ion“ sawp diff ice Cool; samp‘ Perm! Place 59 the center. The sample top was covered with a one inch layer of styrofoam insulation to minimize sample damage due to delayed volume expansion caused by change of water to ice in the central core of the sample. Ice samples prepared in this way were clear with few or no entrapped air bubbles. After removal from the mold, rubber membranes (double thickness) were placed, as shown in Figure 3.1, to protect the ice sample during immersion in the circulating anti-freeze/water coolant mixture. For Ice(2), samples were prepared by first cooling the mold in the freezer, placement of crushed ice in the mold, and pouring precooled (T=0°C) tap water over the crushed ice. Very little ice melted when com- bined with the precooled water. The crushed ice was also formed from ordinary tap water, with a hardness close to 450 parts per million as calcium carbonates. Ice(3) was prepared by placing dry natural fresh snow in the precooled mold and pouring precooled distilled water over the snow. The fresh natural snow was collected and stored in the freezer and later, before use, was sieved on a No. 4 U.S. standard sieve, with nominal grain diameter of 0.187 inch. Ice(2) and Ice(3) were cloudy due to entrapped air bubbles. These two ice types are both polycrystalline, similar to that which forms in the pores of the frozen sand. The average density of all ice samples was close to 56.2 lbs/cu. ft. (0.90 gms./cu. cm) i 1.2 percent difference depending on the temperature (Pounder, 1967). The prepared ice samples were transferred to a bath in which an anti-freeze/water coolant mixture at the test temperature circulates around the protected sample. All samples were cooled at least 10 hours before testing to permit temperatures to equalize throughout the sample. Constant dis- placement rate tests were carried out on ice samples labeled as th in) exc vol tie bath 90811 6O I-l through I-32 in Appendix A. Constant load (creep) tests were conducted on ice samples labeled as CI in Appendix B. 3.3 Sand-Ice Samples: A commercially available sand produced by the Wedron Division of the Pebble Beach Corporation of Wedron, Illinois, was used in this investigation. The Wedron sand consisted of sub-angular quartz particles with a specific gravity of 2.65. The sand gradation was uniform with all material passing the No. 30 U.S. standard sieve and retained on the No. 40 sieve (size range of 0.0232 to 0.0165 in.). The coefficient of uniformity was about 1.50. The pull-out samples were, 6 in. in diameter and 6 in. high, prepared in the same split mold used for ice samples. A sand volume fraction of 64 percent was selected for samples, except those prepared for the study of sand concentration effect. This volume fraction is comparable to values normally encountered in the field and insured the development of dilatancy and interparticle friction in front of the lugs. The value of 64 percent sand by volume corresponds to a dry density of 105.8 lbs./cu. ft., void ratio of 0.5625, and ice saturation close to 97 percent. To insure this high degree of saturation, the mold was partially filled with a pre—determined amount of distilled water and sand was slowly poured into the water permitting air bubbles to escape to the surface. The sample was tamped with a steel rod (0.25 in. in diameter) to give the desired sand packing. The methods of sealing and lining the mold, freezing the sample and transferring it to the coolant bath for testing were similar to those described for the ice samples. Preparation of frozen samples with sand particles in dispersed positions, i.e. with sand concentrations lower than 64 percent, involved WEI les wer Dif dia Ire — . ~~-‘Lx‘m.’ . ~.—. .. ‘-' .- . 7-. ..— —.—.. .....- v 61 use of sand chilled to below freezing and then carefully mixed with dry natural snow (sieved through a No. 4 sieve). This sand—snow mixture was then placed into the cold mold and distilled water, precooled to 0°C, was poured over the mixture. Very little snow melted as a result of pouring ice water over the snow and sand mixture. The resulting sample contained uniformly dispersed sand particles. For each sample, a specified amount of air-dry sand was pre—determined to give the required sand concentration. After sample preparation, the excess sand was air-dried, weighed, and deducted from the pre-determined amount to give the weight of sand in the sample. Several sand concentration values, vs, were considered; 64.0 percent, 52.8 percent, 48.6 percent, 44.5 percent, 32.3 percent, 17.5 percent, and 0 percent for the snow-ice sample. Tests were also conducted on frozen sand samples of different heights (1 in., 2 in., 3 in., 4 in., 5 in., and 6 in.). These samples were prepared in the same manner, except that for samples with heights less than 6 in., styrofoam plates 6 in. in diameter and about 1 in. thick were added to the top of each sample to make a total height of 6 inches. Different diameter samples were prepared using available molds with diameters of 1.9375 in., 2.75 in., and 4 inches. These samples were prepared in the same manner as described for the 6 in. sample diameter. F"9Llr Lead wire to force transducer Mounting bracket for dis- placement transducer . Thermister lead wire [L L I w r 77:-_-- T—L —— _ - l circulating coolant ‘ —-Membrane l_--_ 1r:-rfé--» Rod tug—~84 Frozen' .‘ WVVWW A. I I . I I i ; Soil - . I ISpecimen «e—Load frame ‘I ' ‘T—f‘s I. 9 T1 I i. . I I I I \\\\ I , Reaction 1 l I l : I Beam LaiJ L1 :lIr‘ \ L95]— Membrane—ee—I Reaction 7 4' Plate Removable Eye connector for Nasher attachment to hook at bottom of coolant tank . Mounting bracket for displacement trans— ducer core Figure 3.1: Equipment for pull-out tests including a frozen sand sample, steel rod with lug, and loading frame immersed in the circulating coolant. n. 12 in. 1.5 in. L4 "1 F , ‘ri P- Q. Rod diameter, d [lllllllll : I JDIHII] (b) Lug -i I;TI§ length, 3g in. Lug height, h , Lug face angle, 450 59(‘\ 1/8 in. ‘ ____ (C) Figure 3.2: Bar configuration. (a) Plain rod. (b) Plain rod with 90 degree lug. (c) Lug with 45 degree face angle. CHAPTER IV EQUIPMENT AND TEST PROCEDURE 4.1 Equipment: Constant displacement rate and constant load (creep) pull-out tests were conducted using the loading frame shown in Figure 3.1. The frame consists of a 6 in. diameter by 1/2 in. thick sample reaction plate; upper and lower 1.5 in. by 5 in. by 12 in. aluminum beams; two 5/8 in. diameter 16 in. long steel rods, for load transfer from the upper to the lower beam; and eye connectors at the top and bottom. The frame stiffness was assumed to be high compared to that of the reinforcement rods. Attached to the upper beam was a 10,000 pound capacity load cell (Strainsert Model FL10 —25PKT) for monitoring the applied load. Displacement of the steel rod relative to the base of the frozen sample was monitored using a San- born Linearsyn differential transformer (Model 585 DT—lOOO). This transducer was supported by a bracket mounted at the top of the steel rod (Figure 3.1). The LVDT core was supported by a small rod attached to the lower reaction beam. An insulated steel rectangular coolant bath, 14 in. by 14 in. by 16 in., helped confine the coolant liquid surrounding the frozen sample. The anti-freeze/water coolant mixture circulates from a refrigeration unit to the bath as shown in Figure 4.1. Equal parts of water and ethylene glycol was close to the optimum combination for the coolant mixture. A one inch external covering of styrofoam insulation helped maintain the 64 ten par cir Sens 65 sample and bath test temperatures. A Graham electric motor, with variable speed gear box, mounted on a 10,000 pound capacity Soiltest loading frame (Figure 4.1) provided the constant displacement rate pull-out loads. Displacement rates available from the variable speed gear box ranged from about 10"5 to 10‘1 in./min. For constant load (creep) tests, a steel lever system (Figure 4.2) with arm ratio of 8:1 was attached to the Soiltest load frame. Dead weights, up to 550 lbs., were applied to give a maximum pull- out load of 4,400 pounds. A Sanborn two-channel recorder (Model 77028) with preamplifier (Model 8805A) was used to monitor loads and displacements for all tests. At maximum sensitivity, one millimeter stylus deflection on the displacement strip chart represented 0.0005 in. displacement for the transducer. This sensitivity limited the range of creep data obtainable for small dis- placements observed for ice adhesion to plain rods. For the load chart, at maximum sensitivity one millimeter of stylus deflection corresponded to 14 lbs. applied to the load cell. A Hewelett-Packard digital Logging Multimeter (Model 3467A) and thermistor was used for monitoring sample temperatures. The thermistor was embedded in the sample during pre- paration with the lead wire entering through an opening in the upper circular plate (Figure 3.1). Measurement of the rod surface roughness was made using a Physicists Research motor (Mototrace Type V, No. 680) which moves a tracer (Model LA4-10) on the surface in question at constant speed of 0.221 in/sec.; a profilometer and DC input (Type 0, Model 8, No. 538) with a dial gage for reading the maximum and minimum surface aspirity heights. At maximum sensitivity, a one micro-inch height of aspirity could be read on the gage. SUl rep in dat 66 was achieved or when excessive displacements were reached. For constant load (creep) tests, incremental step loads were added until either failure occurred, the ultimate load capacity of frame was reached (about 4,500 lbs.), or the displacement limits on the load frame was reached. Recorder strips were labeled and the data for each test was transcribed to test summary sheets. For measurement of rod surface roughness, a duplicate surface for each steel type was prepared on a flat plate, for easy tracer movement on the surface. Measurements were made by connecting the tracer to the profilometer, and the latter to the DC recorder. After warm-up, the recorder stylus was adjusted to the chart center. Paper movement was selected at 10 cm/min. and the attenuation knob was adjusted to keep the trace on the recording paper for the highest asperity on all surfaces. As the tracer moved on each surface, the maximum and minimum asperity heights (in micro-inches) were read on the profilometer gage, while a continuous record of the surface irregularities was being made on the recorder strip chart. The corresponding aspirity heights (including the maximum and minimum) were given in millimeters on the chart. For each surface, these measurements were repeated several times for a better representation of the surface roughness. A roughness factor, defined by Wright (1955), was used as a criterion for the rod surface roughness. The data and method of calculating the roughness factor are presented in Chapter V. th. te: lUs Cor was red 67 A Sanborn one-channel chart recorder with DC input (Model 322) was used to make a continuous chart record of the surface irregularities. 4.2 Test Procedure: After sample preparation, placement in the test loading frame, and cooling to the desired test temperature, several additional steps were required for completing the test. The transducers were connected to the recorder which was allowed to warm up for approximately 30 minutes prior to testing. After the warm—up period, the stylus needles were adjusted to a zero reading for load and displacement. For the constant displacement rate tests the loading ram of the Soiltest load frame was adjusted and attached to the upper eye connector in Figure 3.1, but with no applied load. The sample temperature was observed and recorded. During a constant load (creep) test, which normally took several days, the coolant refrigeration bath maintained test temperatures to within j 0.10°C. Large room temperature variations did influence the coolant ’ bath temperature. For test temperatures warmer than -10°C, the variation appeared to be within i 0.050C. In all cases, these temperatures variations did not appear to have affected the test results. The gear box controls were adjusted to give the desired displacement rate, and the ram was engaged with upper eye connector. The strip chart paper movement was selected according to the loading rate. As the test progressed, the stylus needle deflections on the recorder was ad- Justed, as needed, to keep the trace on the recording paper. All constant displacement rate tests were continued until complete failure was observed by sudden rupture in the case of plain rods. When deformed rods (with lugs) were used, the test was stopped after an ultimate load Ch 01‘) Electric motor and gear box for mechanical drive Loading ram Coolant Out ’ ‘—‘ Insulation ~‘-‘-. Cold bath Pull-out specimen ""'l l Coolant . Reservoir l l L._._.- .....J l *-7- Coolant In l' I l l l Soiltest load Recorder Refrigeration frame Unit Figure 4.1: Diagram of test system for constant displacement rate tests. I 69 Load transfer plate Lever Arm (8:1 ratio Transducer lead res Coolant out *- Pull-out sample Load frame (Figure 3.1) Coolant In Dead weights Supporting plate Hydraulic jack Figure 4.2: Diagram of test system for constant load (creep) tests. CHAPTER V EXPERIMENTAL RESULTS A summary of experimental data along with a brief discussion of their implications are given in this chapter. The material is pre- sented in two parts: constant displacement rate tests and constant load (creep) tests. 5.1 Constant Displacement Rate Tests: In this section, results are presented for a series of constant displacement (or loading) rate pull-out tests conducted to determine the influence of displacement rate, temperature, bar size, sample height, water impurities, sand concentration, lug size and shape, and bar surface roughness on the adfreeze bond strength characteristics of frozen pull-out specimens. Physical properties of ice and sand—ice specimens, including the steel rods, are listed in Table 5.1. Test results for these samples are summarized in Table 5.2. 5.1.1 Displacement (and Loading) Rate Effects: Pull-out tests were conducted on frozen sand samples with a sand volume fraction close to 64 percent (dry unit weight of 105.6 lbs./ cu. ft.). The bar displacement rates ranged from about 0.0001 in./min. to 0.1 in./min. The corresponding loading rates ranged from about 2 lbs./min. to 20,000 lbs./min. The pull-out specimens were tested at temperatures ranging from -2°C to —26°C using two bar configurations; a 70 Na in“ tin ste the IGCO perm (Fig the the lncn OCCUI and ' ObSel n d( Fate rods. 71 plain cold—rolled 5/8 in. diameter steel rod, and a 3/8 in. diamter rod with a single 1/8 in. high lug as shown in Figure 3.2 (b). For the plain rods, typical load and displacement variations with time are shown on the recorder strip chart in Figure 5.1. As the test starts, the load increased with time at an almost constant rate while the displacement showed little or no increase until an initial slip occurred. At rupture a large reduction in the load was observed and in some cases zero values were noted. The displacement before rupture, the elastic portion, was in most cases too small (about 0.0005 in.) to be clearly shown on the recorder. Due to equipment limitations, the "pre-failure" displacements were estimated on the basis of very small recorded movement. During testing the bond resistance or stiffness permitted development of a nominal (machine) displacement rate An (Figure 5.1) only after rupture had occurred. The observed behavior may be attributed partially to stiffness of the test system. In turn, the test system stiffness was dependent on the rigidity of all system components and connections. As the load increased, elastic strain energy was stored in the test system (i.e. the test frame, loading ram, loads cells, etc.). Once rupture had occurred and the loading rate decreased, the strain energy was released and the corresponding slip and increase in displacement rate were observed, as shown in Figure 5.1. Since the nominal displacement rate An does not correspond to the ”pre-failure” loading stage, the loading rate P, as defined in Figure 5.1, was used in place of 6“ for the plain rods. The time to failure for all plain rods ranged from a few seconds to abm tehi wit) depi rods str' vs.- sho» ice adhe 72 about two hours depending on the loading rate, and to some extent on temperature. At colder temperatures the time was longer. For plain rods with lugs, the time to failure ranged from one hour to about 12 hours depending mainly on the lug size. It took longer to reach failure for rods with larger lug sizes. Data for each test, as given on the recorder strip (Figure 5.1), were transcribed to a data sheet from which a load- vs.-displacement curve was plotted. Typical load—displacement curves are shown for plain rods at different loading rates in Figure 5.2. Initially, ice adhesion combined with sand friction prevents slip. After the adhesion was broken and partial slip had occurred, a small residual value for adhesion and friction controls the pullout load. At the slow rate (35 lbs./min. in Figure 5.2) the "healing" effect due to ice recrystalli- zation, was more pronounced than at the faster rate (1978.6 lbs./min.) although an increase in load was also observed after failure at the latter rate. The "healing” effect at slow rates may be attributed to the fact that more time permitted more ice refreezing as compared to the fast rates. The change in loading rates illustrate two features; the faster rates produced a higher peak load and a larger initial slope within the elastic range of the curves in Figure 5.2. The right hand scale of this figure shows the bond stress, 1, calculated by dividing the load by the rod surface area. This calculation assumes a uniform stress distribution along the rod. The bond strength (ultimate value at failure, Tu) is plotted versus the loading rate P, at different temperatures, on a log- log plot in Figure 5.3. A consistent linear relationship between Tu and P, on a logarithmic scale, appears to exist at all temperatures. Using the least-squares fitting method, the relationship suggests a power law oft 0i“ wher para chos of n temp con beth Fl gu anal 0i“ wher lhes diSp 0the prob Ol‘ 73 of the form: . . m Tu : TC (P/PC) (5.1) or P = PC(tU/Tc)n (5.2) where n = 1/m is the strain—hardening parameter in compression tests. The parameter T corresponds to the "proof” bond stress at an arbitrarily C chosen loading rate, P taken equal to 1 lb./min. in this study. Values c9 of m, n, and T listed in Table 5.3, indicate that these parameters are c’ temperature dependent. Despite the fact that the nominal displacement rate In does not correspond to the pre~failure stage, a general linear trend was observed between TU and an on a log-log scale at the same temperatures as shown in Figure 5.4. Thus, a power law may be established using the least-squares analysis, of the form: Tu = Té (én/éc) (5-3) 07‘ an = ac (TU/TC)“ (5 4) where m', n', 6,, and ré are equivalent to m, n, PC, and TC, respectively. These parameters also appear to be temperature dependent. The large data scatter made it difficult to analyze the effect of displacement (and loading) rate on the adhesive strength of ice specimens. The scatter may be attributed to the large variability in the ice material. Other researchers (Jellinek, 1957 b; Gold, 1978) have noted the same problem. For the 3/8 in. diameter rod with a single lug, the displacement (or loading) rate appears to have an effect on lug bearing capacity similar to CU C6 Fi mo W6: on C0 fu' the hit tha and POW to dis but the is} 74 to that on adfreeze bond for plain rods in frozen sand. The load-displacement curves for two displacement rates, Figure 5.5, both indicate a signifi- cantly different failure mechanism from that for plain rods shown in Figure 5.2. Initially, adhesion combined with friction and a slight mobilization of bearing action on the lug prevents slip. After adhesion was broken and partial slip had occurred, bearing action of frozen sand on the lug restrained movement of the reinforcement bar and prevented complete rupture. However, some reduction in the load may occur before full mobilization of bearing action on the lug. This "initial yield” was more noticeable at the lower rates (Figure 5.5). As the displacement increased, the load was gradually transferred to the lug until full mobilization of the ultimate lug bearing, Pu, was reached at about 5 mm displacement. This observed lug performance shows a close similarity to the bearing capacity behavior of frozen soils. The displacement and loading rates are both plotted versus the ultimate load Pu on a logarithmic scale in Figure 5.6. The data indicate that an approximate linear relationship may exist between Pu and I, or PU and P on a log-log scale. Using the least-squares fitting method, a power law of the form given in Figure 5.6 may be suggested for either re- lationship. The two regression lines in Figure 5.6 appear to be almost parallel to each other, implying that the same failure meChanism governs both the displacement rate and the loading rate. This fact may be the result of both lines representing data from tests on the same samples. Note that the displacement rate an.at which the specimens were loaded in Figure 5.6, is believed to be close to the true rate. The In value represents the OCI 5.] Ice to rod rat tur sho cl S sma p10 Fig. We] SEtI of 3 rate may atier 75 the slope of the straight line portion after the "initial yield" has occurred, while the load was still increasing on the strip chart. 5.1.2 Temperature Effect: The temperature effect on ice adhesion, sand friction, and mechanical interaction was determined for a sand volume fraction of 64 percent. Ice and sand-ice samples were tested at temperatures ranging from -2°C to -26°C, using plain and deformed rods (with a single lug). For plain rods typical load-displacement curves plotted at different temperatures in Figure 5.7 indicate a behavior similar to those at different loading rates (Figure 5.2). The bond strength Tu increased with colder tempera- tures as it did with faster loading rates. The displacement curves also show the same initial behavior characteristics of smooth bars followed by a sudden drop in the load. The ultimate (peak) load developed at very small displacements, about 0.0005 to 0.001 inches. Also note in Figure 5.7 that the ”healing" effect was more pronounced at temperatures colder than -150C. At these temperatures several cycles of failure (represented by immediate rupture) and "healing“ were observed. Using the data in Figure 5.3, the ultimate bond strength Tu can be plotted versus temperature T for different loading rates, as shown in Figure 5.8. The loading rate indicated on each curve in Figure 5.8 is the average of all loading rates for samples tested at the same machine setting with a nominal displacement rate. For example, the average value of 157.4 lbs./min. corresponds to samples tested at a machine displacement rate of 0.0029 in./min. The data scatter for some points in Figure 5.8 may be attributed to small difference in loading rate, with a common average value, pavg , indicated for each curve. de wh pl n I Re 0f Sh: file! At the fa; Par 76 To reduce data scatter, values of Tu interpolated (Figure 5.3) to the given average loading rate shown in Figure 5.8 were plotted versus temperature in Figure 5.9. The data in this figure appear to be more consistent and the curves are improved. The bond strength for the plain bars, Figure 5.9, show a linear relationship with temperature at the slow (5.6 lbs./min.) loading rate. At higher rates strength increased more rapidly for the warmer temperatures, down to -50C. At colder temperatures the increase in strength was similar to that for the slower loading rates. For the temperature range between —50C and —ZOOC one may deduce, using the least-squares fitting, the following linear relationship: ru = a'+ b'o (5.5) where e = —T, a'and b'are constants which depend on the loading (and dis- placement) rates as indicated in Figure 5.9. The temperature effect can be extended to include parameters n and n' (defined by Equations 5.2 and 5.4) for plain rods in frozen sand. Recall that the slopes of lines in Figure 5.3 were almost equal to those in Figure 5.4 at the corresponding temperatures. Therefore, if the values of n (Table 5.3) are plotted against the corresponding values of n' as shown in Figure 5.10, one may conclude that n is the same whether displace— ment rate or loading rate is used. For this reason values of n (or n') are plotted against temperature in Figure 5.11 giving a nonlinear relationship. At temperatures warmer than -ISOC the relationship appears to be approx— imated by a straight line. In general, values of n increased as temperatures decrease. The rapid increase in n as temperature goes below —150C occurs because the n parameter is cotangent of the angle at which the regression lines in Fl'QUY‘es 5.3 and 5.4 are inclined from the horizontal axis. A th no Se all no st tel all: 77 semi-logarithmic plot of the n parameter versus temperature, shown in Figure 5.12, gives approximately a linear relationship. The least- squares fitting method gives n = exp (1.224 + 0.0886 9) (5.6) (for -26°C 5 T g -2°C) where o = -T. The change in n value with temperature indicates a change in the mechanism which controls failure of plain rods in frozen sand at different temperatures. Temperature effect on ice adhesive behavior was generally similar to that observed for sand-ice material in Figure 5.7. More data scatter was noted, as compared to the frozen sand, when the ultimate ice adhesive strength was plotted against temperature as shown in Figure 5.13. Sensitivity of ice adhesion to the same minor factors, mentioned earlier, appears to be the main cause of scatter (Jellinek, 1967; Barns et al., 1971; Gold, 1978). The data trend shown in Figure 5.13, despite the noticeable scatter, indicates an almost linear increase of adhesive strength with colder temperatures. This statement may be limited to temperatures in the range of -SOC to -15°C. There was no data above ~50C and below -150C the scatter was too large to give a reliable conclusion. The line segment shown in Figure 5.13 with dashed lines indicates limitations of the results. The linear relationship (solid line) given in the figure was obtained using the least—squares fitting, where o = -T. The temperature influence on lug behavior appears to be similar to that for the displacement rate effect. Pullout sand-ice samples were tested at different temperatures, using a plain rod with a 1/8 in. height lug. Typical load-displacement curves are plotted in Figure 5.14. At low wi WEI P0 to re 90 SEI in Dle C(lll bar temperatures, below —15°C, the load reduction due to "initial yield" was less noticeable than at warmer temperatures. Only a reduced rate of load increase was observed below ~150C. The curves generally show the same initial behavior characteristics as for plain bars, followed by a drop or reduced rate of load increase. Additional lug displacement continues to mobilize frictional and dilatancy strength components of the frozen sand in front of the lug leading to increased pullout loads. The ultimate load Pu, plotted against temperature in Figure 5.15, showed a linear increase with decrease in temperature at the given displacement rate. No adjustment was required to Pu values, since displacement rates for individual data points was close to the average displacement rate, éavg’ for all points. The "initial yield" loads, designated Pjy in Figure 5.14, also appear to vary with temperature. The data in Figure 5.15 show a nonlinear relationship between Piy and T. The temperature effect on other lug shapes (Figures 3.2 b and c) was also considered for comparison with the present 9OQ-lug shape. Further discussion on this aspect will be made in a later section. 5.1.3 Bar Size and Sample Height Effects: Experimental data presented in previous sections were based on frozen specimens 6 in. in diameter by 6 in. high with a 5/8 in. diameter plain rod. The diameter of all bars with lugs was 3/8 in. Starting with the effect of rod size on bond strength of plain bars, four bar diameters were selected for pull-out tests; 3/32 in., 3/16 in., 3/8 in., and 5/8 in. The tests were carried out at two temperatures; —10°C and -20°C, for comparative purposes. Note that all tests on plain rods, regardless of bar size, sample size or temperature, showed the same load-displacement ch di ra to al al re ot th th di th Cd DO at Do on th da at 79 characteristics as summarized in Figures 5.2 and 5.7. Data from tests on different bar sizes, summarized in Figure 5.16, show a nonlinear increase in bond strength with increase in rod diameter, d. The dimensionless ration d/H, where H is the sample height, provided a convenient number for expressing the bar size effect on the bond strength. This ratio may also be related to the bar stiffness relative to the total load applied along a certain height H. Data points with question marks in Figure 5.16 are those doubtful results caused by possible leakage of coolant fluid into the sample, or other equipment problems. For rod sizes larger than 3/8 in. (Figure 5.16) the rate of strength increase has decreased. There was some increase in the 5/8 in. rod strength (d/H = 10.4 percent) over that of the 3/8 in. diameter rod (d/H = 6.25 percent). When tested at different temperatures, these two rod diameters showed similar strengths (Figure 5.17). The difference in strengths was consistently small at all temperatures and can be neglected in comparison to the experimental scatter for some data points. Plotting the data of Figure 5.16 on a semi-logarithmic scale (Figure 5.18) suggests a linear relationship between the ratio d/H and Tu at both temperatures. Note that the colder temperature, -20°C, corres- ponds to a higher rate of strength increase with increase in d/H. Based on linear regression analysis two empirical expressions were deduced for the two temperatures as given in Figure 5.18. These equations represent data within the range of 2 percent < d/H < 10 percent. The effect of varying sample height on bond strength of frozen sand, at -10°C, has been considered for two bar diameters; 3/8 in. and 5/8 in. ti 51' Th 3/ th th lh st to We cu be Ii. bu on 80 Test results are summarized in Figure 5.19 for both bar sizes. The data show that sample height appears to have a small effect on bond strength. The strength increased slightly as height was increased from 1 to 6 inches. 5.1.4 Lug Size and Shape Effects: A 90 -lug with different heights was welded to each of three iden- tical plain, 3/8 in. diameter, cold-rolled steel rods. A fourth rod, with no lugs (h = 0), permitted measurements to be made on four lug sizes. Tests were conducted at -10°C and —20°C for comparative purposes. The load-displacement curves for lug heights of 0, 1/16 in., 2/16 in., and 3/16 in., plotted in Figure 5.20, all show a typical behavior except for the plain rod (with no lugs). The latter showed a significant drop in the load after bond due to adhesion and friction was broken. A standard 3/8 in. diameter deformed bar was also tested in frozen sand at ~100C. The hot-rolled steel rod (usually more brittle than the cold-rolled steel) has lugs spaced at 0.3125 in. with equivalent lug height of 1/64 inch. It was anticipated that the load would exceed the equipment capacity for a 6 in. sample height with standard deformed bar. Therefore, tests were carried out on sample heights of 2 and 3 inches. The load-displacement curves for these two samples, presented in Figure 5.21, show a different behavior from those in Figure 5.20. Generally, there was an "initial yield “ as for other lugs, caused by rupture of adhesive and frictional bond, followed by an increase in the load as bearing forces were mobilized on the lugs. After a peak load was achieved, the load decreased mono- tonically with additional displacement as shown in Figure 5.21. This behavior appears to be more dependent on the lug height and spacing than 81 on the number of lugs in each sample. For comparison, the displacement curve for a plain rod is also shown in Figure 5.21. The ultimate load Pu is plotted versus the ratio of lug area A] to the rod cross—sectional area Ar in Figure 5.22 for all lug sizes. This ratio appears to give a more consistent variation of load than does the lug height. Although the relationship shown in Figure 5.22, for both temperatures, may not be linear, they can be reasonably approximated by a straight line. The small data scatter with large loads suggests good agreement between tests. It was convenient to represent two least-squares regression lines in Figure 5.22 by the linear relationships given in the figure for each temperature. The data points indicated by question marks in Figure 5.22 were not included in the regression analysis. These data are doubtful due to possible leakage of anti-freeze coolant into the sample. The two points indicated for a standard.deformed bar were cal- . culated as if they were a single lug, using the data from Figure 5.21. The method of calculation will be explained in Chapter VI. Since these two points are nearly identical with each other, and consistent with the general trend of the other data, they were included in the regression analysis. Changing the lug shape from a 90 degree angle, Figure 3.2 b, to a 45 degree angle, Figure 3.2 c, did not appear to have a significant effect on the experimental results. Typical load-displacement curves for both types (Figure 5.23) show an almost similar behavior, although some relatively minor differences may be noted. These differences were not repeated when the two types are compared at several temperatures in Figure 5.24. For practical purposes, the ultimate loads, Pu, for both lug 82 shapes are close enough to be considered equal. The same conclusion may be drawn for the "initial yield" loads, Piy shown in Figure 5.24. Generally, an almost linear variation of ultimate loads, P“, with temperature may be noted. The linear relationship shown in Figure 5.24 can be considered applicable to both lug shapes for temperatures ranging from —2°C to -20°C. The "initial yield" loads Piy appear to change rapidly in a non-linear fashion at temperatures above -2°C. Below -2°C the loads appear to increase almost linearly with colder temperatures. An empirical least-squares equation of the form given in Figure 5.24 appears to be applicable to both lug shapes for temperatures ranging from -2°C to —20°C. 5.1.5 Bar Surface Roughness: The terms smooth and rough are often used to describe a certain surface texture. Surface texture is considered as those aspects of fine surface topography, or small-scale irregularities, that might be neglected in comparison with any measurable lug height. Smoothness and roughness are relative terms that have not yet been well classified or precisely de— fined. Besides, there are no sub-divisions (or terms) to identify the intermediate conditions between the two limits of rough and smooth surfaces. These two characteristics depend to a large extent on the degree of magnification to which the surface is exposed. At a higher magnification there are greater irregularities, no matter how smooth the surface appears to the naked eye. Several roughness criteria have been suggested in the literature by different authors. Each criterion appears to have its merits, and requires a certain measurement technique. The one favored in this st V6 6C de Ch gr ch ea ch do su st di f6: 83 study is the ”roughness factor” Q, defined by Wright (1955) as follows: Lr ‘ Lt p = -—-———— X 100 Lt (5.7) where Lr = length of the "roughness line“ in Figure 5.25, and Lt = total length of the standard chords, LC, forming the "unevenness line.” From Figure 5.25, note that as the chord length LC decreases the value of Lt increases when the "unevenness line" comes closer to the actual surface. However, Wright (1955) tried different chord lengths (8 cm, 4 cm, 1 cm, 1/2 cm, 1/4 and 1/8 cm) and compared the value of Lt for each one with that of a series of four 8 cm chords, i.e. Lt = 32 cm. He recommended a standard chord 8 cm in length. Four standard chords are desired, whenever possible, to give Lt = 32 cm as shown in Figure 5.25. In this study the profilometer and the DC recorder described in Chapter IV were used for measuring roughness of three steel surfaces; ground-finished, cold-rolled, and shot-blasted surfaces. The strip chart recorder output for each surface type is shown in Figure 5.26. For each surface represented in this figure, a single 8 cm standard chord was chosen for practical reasons, hence a value of 8 cm for Lt in Equation 5.7. Note that the chord length of 8 cm, measured on the strip chart, does not represent the actual tracer distance travelled on the steel surface. The chord length, and the "roughness line," both depend on the strip chart movement per unit of time, i.e. chart speed which was different from that of the tracer on the actual surface. The roughness factor Q is a relative number which may be used only for discriminating the three surfaces. Tests were also carried out on three bars, each with a 45°-lug but having different surface roughnesses; ground—finished 84 cold-rolled, and shot-blasted as for bars with no lugs. The load-displacement curves for the rods with no lugs (Figure 5.27) clearly indicate that the shot-blasted surface with the highest roughness factor) showed the highest ultimate load. The residual load Pr for this surface was also the highest compared to the other two surfaces. The ultimate loads are plotted versus roughness factor on a logarithmic scale in Figure 5.28. Since the data in this figure are almost linear, they were approximated by a straight line to give the power law given in Figure 5.28. Consideration of lug height as part of the roughness definition will be discussed in Chapter VI. 5.1.6 Water Impurities and Sand Concentration: The effect of water impurities on the adfreeze bOnd strength of ice and frozen sand materials was included to provide a basis for comparison. The initial objective was to evaluate the contribution of ice adhesion to the total bond strength of frozen sand to plain steel rods. Samples of crushed ice saturated with distilled water, prepared and tested at several temperatures, provided a polycrystalline structure similar to the ice which forms between sand particles. The crushed ice prepared from ordinary tap water, contained about 450 parts per million (ppm) in hardness as calcium carbonates. The experimental results for snow ice (distilled water), crushed ice (tap water), and ice layers (distilled water) are summarized in Figure 5.29. Data scatter makes comparisons difficult. Bands indicated by the lines show that water frozen in layers has a significantly lower strength as compared to crushed ice. The effect of bar size on bond strength has been neglected based on data shown in Figure 5.17. Ice structure and water impurities represent the only difference between the three ice types shown in Figure 5.29. To separate the effect of ice structure from that of water impurities, several samples of fresh snow, saturated with distilled water, were frozen and tested. Test results for Ice (3) shown in Figure 5.29 appear to give the highest bond strengths. Comparing Ice (1) with Ice (3) only on the basis of structure and ignoring minor difference in water impurities, one may conclude that the polycrystalline ice possesses a higher adfreeze bond strength than monocrystalline ice. A comparison of Ice (2) with Ice (3), neglecting differences due to ice grain size, shows that water impurities reduce the ice adfreeze bond strength. To verify this conclusion, several frozen sand samples were fully saturated with tap water during preparation and were tested. Test results are compared with those from tests on samples saturated with distilled water in Figure 5.30. The data clearly indicate the effect of water impurities on bond strength of frozen sand to plain rods. Constant displacement rate bond tests were also carried out on samples with different sand concentrations. Preparation of samples with a sand fraction less than 59% (by volume) was described in Chapter 111. Test results, plotted in Figure 5.31, showed that the range in which strength varied significantly is limited to a sand concentration of 45 percent to 64 percent sand by volume. This conclusion has important implications relative to design and construction procedures for friction piles in permafrost. It is believed that the sand concentration in most naturally and artifically frozen soils would not fall below about 40 percent soil by volume. In addition, the scatter in test results for samples with vS < 45 percent was large enough so that the bond strength ad ci Sp: 86 was not clearly defined. 5.2 Constant Stress (Creep) Tests: In this part of the study, pull-out specimens were tested by applying a constant load while continuously monitoring the displacement until either failure occurred or the equipment displacement limit was exceeded. Most samples were tested by a step loading procedure. Each load increment was maintained for a time long enough to achieve a steady— state displacement rate (secondary creep). The effects of load, temperature, lug size and position, sample diameter, and sand concentration on the pull-out loads are considered in this section. Physical properties of all ice and frozen sand samples tested under constant load are listed in Table 5.4. Test results on these samples are summarized in Table 5.5. 5.2.1 Load Effect: The data from Section 5.1 permitted a preliminary prediction of the initial load increment to be applied to each sample. Tests on plain rods did not show, in general, a clear indication of the actual creep behavior for the small displacements due to equipment limitations. The first four samples failed before any precise measurement of the creep displacement could be taken under each step loading. Transducer limita- tions t 0.0005 in. prevented more.accurate measurements for the small displacements associated with creep for the ice adhesion component of adfreeze bond. The failure displacement was often too small to be pre- cisely measured with the available recorder at its maximum sensitivity. However, some data was acquired by running additional tests on specimens with plain rods. These data were, in most cases, obtained on 87 the basis of visual judgement using a magnifying lense to enlarge the stylus movement on the strip chart. Typical creep curves for plain rods, in sand-ice specimens tested at —10°C, are shown in Figure 5.32 (a and b). For sample number CS-29, Figure 5.32 (a), an initial load increment of 250 lbs. did not appear to achieve the secondary creep stage. A second load increment, which brought the total load to 530 lbs., was then applied to the specimen. This load appeared to cause tertiary creep failure almost immediately in the sample. The duplicate sample, number 08—30 in Figure 5.32 (b), was tested under loads as indicated on the creep curves. The displacements plotted versus time in both figures, were close to the actual values measured during the load application. The creep displacement rate ac was defined as the slope of the straight line portion of each curve in Figure 5.32 ( a and b). Data points with the large scatter, in this figure on plain rods and the subsequent tests, were approximated by straight lines. The total loads are plotted versus their corresponding displacement rates on a log-log scale in Figure 5.33. The four data points appear to be consistent with each other and give a straight line relationship. Based on data summarized in Figure 5.33 it appears that the creep displacement rate of plain rods in frozen sand increases with increase in applied load according to a power law similar to that given by Equation 5.4. For rods with lugs, the loading effect was more clearly shown in contrast to that described for plain rods. The scatter in data points was far less. A creep curve for step loading, on a 3/8 in. diameter plain rod with a 900-lug, is shown in Figure 5.34 (a). Several points 88 may be featured in this figure. The creep displacements at all loading stages were large enough to be measured on the recorder with reasonable accuracy. These displacements were the result of bearing action of frozen soil on the lug. The stress history appears to have some effect in re— ducing (or almost eliminating) the primary creep, for loading stages following the first load increment. 0n the other hand, the displacement rate does not appear to be much influenced by the stress history, for the continuous loading condition. To explain this, refer to Figures 5.34 (b) and (c), both of which show creep curves for two more duplicate samples step-loaded at the same temperature (-10°C). Comparing the displacement rate of 2.53 X 10'“ in/min. for the third load increment (P = 2780 lbs.) in Figure 5.34 (a) with that of 2.5 x 10'” in./min. for the first load increment (same total load, P = 2780 lbs.) in Figure 5.34 (b), the small difference may be due to interpretations from the plot. Also, the same comparison would hold for the displacement rates corresponding to the last load (P = 3560 lbs.) in Figure 5.34 (b) and to the first load (P = 3560 lbs.) in Figure 5.34 (c), respectively. The difference of 1.7 X 10’” in./min. (about 17 percent) may, again, be considered within a possible experimental scatter. Tests on other duplicate samples, Table 5.5, confirmed the same behavior as shown for the previous three samples. However, when the sample was unloaded, the creep rate appeared to be far more influenced by the stress history than in the loading case. Sample 05-18 was step- loaded from 1220 lbs. to 2380 lbs. as shown in Figure 5.35. After that, and before total failure, the sample was unloaded back to 2100 lbs., 1540 lbs., and to the initial load increment of 1220 lbs. As shown in 89 Figure 5.35, only the 2100 lbs. unloading stage showed some creep at a constant rate of 4.25 X 10’5in./min., which was reasonably close to the 5.09 X 10'5 in./min. value for the loading stage. When the sample was unloaded from 2100 lbs. to 1220 lbs. in two steps, the final displacement remained almost constant with very negligible decrease after 22 hours. This behavior may be attributed to densification in front of the lug during the loading stages. It was also possible that the 22 hrs., of unloading from 2100 lbs. to 1220 lbs., may not have been long enough for the sample to reach complete recovery, and then to start creeping again. Had the recovery occurred, the creep rates then would have, probably, been slightly less than the corresponding rates of the loading stages. Creep curves for other duplicate samples were also plotted, with the creep rates summarized in Table 5.5. Creep data for these samples are given in Appendix B. Using the data in Table 5.5, the total load P applied at each stage can be plotted against its corresponding creep rate SC on a log-log scale, as shown in Figure 5.36. A linear trend on this plot describes the creep behavior, at least within the range of experimental data. A straight line was fitted to the data points, using the least-square analysis, and the empirical power law indicated in Figure 5.36 can be written. Note that the regression line in Figure 5.36 is ended with dashed lines as shown, due to the limited data available at both ends. 5.2.2 Temperature Effects: The temperature effect has been considered on a 5/8 in. diameter plain rod, and on a 3/8 in. diameter rod with a single lug, both in frozen sand. A clear conclusion, again, can not be drawn for the plain 9O rod samples, because of difficulty with precise measurement of very small displacements. Three different temperatures; -60C, -10°C, and -15°C, were selected for comparison. At each temperature two duplicate samples with the same plain rod (5/8 in. in diameter) were step-loaded until failure. As observed for the two samples tested at -10°C (Figures 5.32 a-and b) creep curves for step loading on samples at other temperatures showed the same behavior. Figures 5.37 (a) and (b) show a similar behavior at both temperatures with relatively small displacements (less than 0.002 in.) for all loading stages which was followed by a sudden rupture. The last segments of both curves appear to represent tertiary creep. Before failure, the colder temperature, -15°C, reduces creep displacements at all loading stages. It also reduces the total displacement at failure; for example, compare the value of 0.004 in. for P = 1040 lbs. at -15°C (Figure 5.37 b) with 0.012 in. for P = 640 lbs. at -69C (Figure 5.37 a). The total.load P, applied at each loading stage was plotted against the corresponding displacement rate SC on a log-log scale at ~6°C, -10°C, and -150C, in Figure 5.38. The data points at all temperatures show some scatter, especially at —6°C. Only two data points are plotted for -60C, to remove any possible confusion in showing the temperature effect. For the other temperatures, —lO°C and -15°C, the data are approximated by straight lines only for comparison. The general trend of these lines indicates, qualitatively, that a power law may govern the relationship between applied loads and the corresponding displacement rates. Note that other data points for -6°C may all be considered questionable, hence they were not shown in Figure 5.38. Further tests on duplicate samples did not appear worth while, because of equipment limitations for small displacements. The temperature effect on lug behavior remains to be covered. Iden- tical pull-out frozen sand specimens were tested at -2°C, -6°C, and -150C. Creep curves for step loading on these samples, Figure 5.39 (a to c), showed a behavior similar to those at -10°C (Figures 5.34 and 5.35). The data for tests at -2°C, -6OC, and -15°C are compared to those plotted for -1OQC, in Figure 5.40. The creep displacement rates decreased at colder temperatures for a given applied load. Under small loads, the displacement rates appear to be overestimated at all temperatures. However, it is believed that when the applied load is smaller than the long-term strength, the steady-state (secondary) creep rate was not achieved within the few days available. The data points in Figure 5.40 are approximated by a straight line for each temperature. The four lines are almost parallal to each other, implying that the failure mechanism, of bearing action on lugs, is the same at all temperatures. Assuming a linear relationship on a log-log scale also implies that a power law of the form defined in Figure 5.40, would govern the P versus SC relationship. Since the lines were assumed parallel to each other, the parameter m in Figure 5.40 should be inde- pendent of temperature. Only the "proof" load Pce is a function of temperature. The value of PCB corresponds to an arbitrarily chosen displacement rate 8C of.5 X 10.9 in,/min. 5.2.3 Lug Size and Position: Creep pull-out tests were conducted on frozen sand specimens with 3/8 in. diameter rods having lugs heights of 1/16 in., 2/16 in., and 3/16 in. The creep behavior for different lug heights was similar to that observed for the 2/16 in. lug height. For comparison the exper- imental data are summarized in Table 5.5 and are also plotted in Figure 5.41. Seven tests on duplicate samples with a 2/16 in. lug height and the corresponding data points gave a consistent linear trend as shown in Figure 5.41. Three samples with a 1/16 in. lug height and two samples No additional with a 3/16 in. lug height were tested using step loading. tests were conducted with the 3/16 in. lug height, since its maximum bearing load would exceed the equipment loading capacity. All data plotted as straight lines in Figure 5.41. The dashed line in this figure was estimated from three data points for a creep test on a standard 3/8 in. diameter deformed bar, with lug height of 1/64 inch. The load P in Figure 5-42 was divided by 10 for transformation to a single lug load in Figure 5.41. This procedure assumes that the applied load was equally carried by all 10 lugs for the standard deformed rod in a 3 in. sample height. Although the regression lines in Figure 5.41 are not exactly parallel to each other, it appeared that the difference in slopes may have resulted from limited experimental data, especially for the 1/64 inch and 3/16 inch lug heights. The other two lines, for 1/16 in. and , 2/16 in. lug heights, appear to closely parallel each other, implying that the bearing action mechanism of frozen soil on any lug size is the same. A power law, relating the load and creep rate, was deduced for each lug size and it has the form given in Figure 5.41, where m was made the same as that for the 2/16 in. lug height, assuming that the lines are parallel. The "proof“ load PC is dependent on lug size, and its values are given in Figure 5.41. Up to this point all lugs tested were positioned at the mid-sample 93 height, i.e. half-way between the loaded end and the free end of the sample such that z = H/2. The distance 2 equals 0 at the base plate (loaded end). The effect of possible lug interaction with the base plate on creep behavior was considered by placement of a single 2/16 in. lug at z = H/4 and z = 3H/4. The alternate lug locations were obtained by reversing the rod direction before sample preparation. Test results for these two lug positions, summarized in Table 5.5, did not show any sig- nificant difference in behavior when compared with that of the H/2 lug position shown in Figure 5.43. All data points in this figure appear to be close enough to neglect any minor differences. The above results show that lug position does not have an important influence, if the 2 distance is maintained beyond a height H/4 from the base place. Since the data are consistent with each other, for all lug positions, they were included in one regression analysis in order to deduce a single empirical equation. This equation, shown in Figure5.43, is a power law that is valid for the three lug Positions. 5.2.4 Sample Diameter and Sand Concentration: In concrete structures, a minimum cover requirement is considered necessary for development of the normal bearing action against lugs for deformed bars (Mains, 1951; Ferguson, 1966; Perry and Thompson, 1966). In pull-out tests used to evaluate the load transfer behavior a minimum over requirement for the steel bars would seem necessary. In this 'nvestigation, the cover required to develop the bearing action on the ugs is represented by a minimum sample diameter relative to the rod ize and lug height. Three additional sample diameters; 1.938irn, 2.781 in., and 4 in. be- ide the 6 in. diameter were selected for this purpose. The choice of 94 diameters was based on availability of steel molds in the laboratory. Sample preparation depended to some extent on sample diameter but was similar to the standard procedure described in Chapter III. Creep behavior for the step loading technique on the different pull-out specimens did not differ from those mentioned earlier. The pull-out load P is plotted against its corresponding creep rate ac on a log-log scale in Figure 5.44, for tests on the different sample diameters. The influence of sample diameter appears to be more significant for diameters less than 4 inches. The loads, interpolated to creep rates of 10‘” in./min. and 10-5 in./min., are plotted in Figure 5.45 against a ratio A defined as: x = (D-d)/2h (5.8) where D is sample diameter, d is rod diameter, and h is lug height. This ratio is believed to be some measurement of the frozen sand cover. The load appears to increase nonlinearly as the ratio A increases (Figure 5.45) until it reaches a value of about 13 where the load was no longer affected by sample diameter. The ”critical“ sample diameter corresponding to A = 13 is about 4 in. This conclusion indicates that test results, obtained in this investigation on 6 in. diameter samples were not being affected by sample diameter. Another factor, briefly described in Section 5.1.6 on plain rods, was sand concentration which is now considered in terms of lug behavior. All samples tested at sand fractions less than 64 percent by volume were Prepared by mixing a pre-weighed quantity of dry precooled sand with dry fresh snow to give the desired sand concentration. Two samples of snow- ice (saturated with distilled water) included the zero sand fraction for 95 creep tests. Samples with sand fraction below 50 percent showed a different behavior from that observed for samples with 64 percent sand concentration. Creep curves for step loading on these samples are presented in Figures 5.46 and 5.47, including the snow-ice samples. For the initial load increment of 520 lbs. note that the displacement for all of these specimens remained unchanged (almost zero reading on the recorder) for a period of time. This time period appears to be a function of the sand fraction; longer times for the lower sand concentrations. Thereafter, the displacement increased with time in the normal manner. Further discussion on this behavior is made in Chapter VI. The effect of sand fraction on lug bearing action was similar to that observed for adhesion and friction to plain rods (Figure 5.31) with constant displacement rate tests. Loads interpolated to two different creep rates; 10’” in./min. and 10‘5 in./min., using the load versus creep rate curves in Figure 5.48, showed that they vary significantly in the range of about 43 percent to 64 percent sand (by volume) as shown in Figure 5.49. In this range, frictional and dilatational strength components of frozen sand appear to be more effective. Below a sand fraction of 43 percent the change in strength was not significant. To evaluate the amount of lug load reduction as sand fraction vs was educed from 64 percent to 51 percent (by volume), consider loads at elected creep rates. Loads for v5 equal to 64 percent (P64 percent) are lotted against loads for Vs equal to 51 percent (P51 percent) in Figure .50. An almost linear relationship between P64 percent and P51 percent is noted for the range of creep rates selected. This result implies 96 that the amount of load reduction due to decrease in sand fraction was almost constant and independent of the creep rate ac, at least within a range of creep rates. As shown in Figure 5.50, values of P64 percent equal 1.75 times P51 percent, i.e. about 43 percent reduction in the loads occurred on reducing vs from 64 percent to 51 percent. 97 le 5.1: Physical properties of ice, frozen sand specimens, and steel rods, for constant displacement rate tests. ple Mater- Steel VS H D d h o. ial surface (%) (10.) (10») (l”°) (l”°) Ice(1)* CR“ 0 5.866 5.677 5/8 0i -- .. 0 5.750 5.875 5/8 0 .. .. 0 5.688 5.875 5/8 0 .. u 0 5.438 5.938 5/8 0 .. .. 0 5.938 5.875 5/8 0 .. .. 0 5.938 5.969 5/8 0 .. .. o 5.938 5.875 5/8 0 .. .. 0 6.125 5.938 5/8 0 .. .. 0 5.875 5.938 5/8 0 0 .. .. 0 5.969 5.938 5/8 0 1 .. .. 0 5.938 5.938 5/8 0 2 .. .. 0 6.000 6.000 5/8 0 3 .. .. 0 6.000 6.000 5/8 0 4 .. u 0 5.906 6.000 5/8 0 5 .. .. 0 5.938 6.000 5/8 0 6 .. .. 0 5.938 6.000 5/8 0 .. .. 0 5.344 6.000 5/8 0 .. .. 0 5.906 6.000 5/8 0 9 .. .. 0 5.938 6.000 5/8 0 3 .. .. 0 5.000 6.000 5/8 0 .. .. 0 6.000 6.000 5/8 0 Rem... .. 0 6.000 6.000 3/8 0 .. .. 0 6.500 6.000 3/8 0 .. u 0 6.375 6.000 3/8 0 .. .. 0 6.125 6.000 3/8 0 .. .. 0 6.000 6.000 3/8 0 .. .. o 6.000 6.000 3/8 0 Ice(3)* " 0 6.197 6.000 5/8 0 .. .. 0 6.000 6.000 5/8 0 .. .. 0 6.375 6.000 5/8 0 (Continued) .. .. 0 6.375 6.000 5/8 0 l 98 1le 5.1: (Cont'd) 1ple Mater- Steel Vs H D d h lo. ial surface (%) (in.) (in.) (in.) (in.) :2 Ice(3) CR 0 6.500 ' 6.00 5/8 0 . FS(DW)* CR 64.0 6.000 6.00 5/8 0 2 " " 64.0 6.000 6.00 5/8 0 l 1 " " 64.0 6 000 6.00 5/8 0 ’ 1 " " 64.0 6.000 6.00 5/8 0 s " " 66.3 6.871 6.00 5/8 0 s " " 64.0 6.000 6.00 5/8 0 1 " " 64.0 6.000 6.00 5/8 0 3 " " 64.0 6.000 6.00 5/8 0 a " " 64.6 5.938 6.00 5/8 0 10 " " 64.0 6.000 6.00 5/8 0 1 11 " " 64.0 6.000 6.00 5/8 0 3 12 " " 64.0 6.000 6.00 5/8 0 13 " " 64.0 6.000 6.00 5/8 0 14 H " 64.0 6.000 6.00 578 0 .5 H " 64.5 6.000 6.00 5/8 0 .6 " " 64.0 6.000 6.00 5/8 0 7 " " 64.0 6.000 6.00 5/8 0 8 " " 64.0 6.000 6.00 5/8 0 9 H " 64.0 6.000 6.00 5/8 0 0 " " 64.0 6.000 6.00 5/8 0 1 " " 64.0 6.000 6.00 5/8 0 2 H " 64.0 6.000 6.00 5/8 0 3 H " 64.0 6.000 6.00 5/8 0 I " " 64.0 6.000 6.00 5/8 0 3 n " 64.0 6 000 6.00 5/8 0 s H " 64.0 6.000 6.00 5/8 0 ' " " 64.0 6 000 6.00 5/8 0 n H 64.0 6.000 6.00 5/8 0 n " 64.0 6.000 6.00 5/8 0 1' " 64.0 6.000 6.00 3/8 0 + (Continued) 1' " 64.0 6.000 6.00 3/8 1/16 99 able 5.1: (Cont'd) ample Mater- Steel Vs H D d h .No. ial surface (%) (in.) (in ) (in.) (in.) -32 FS(DW) CR 64.0 6.00 6.00 3/8 2/16 -33 " H 64.0 6.00 6.00 3/8 3/16 , -34 " H 64.0 6.00 6.00 3/8 3/16 1 -35 H H 64.0 6.00 6.00 3/8 0 I -36 H H 64.0 6.00 6.00 3/8 1/16 -37 " H 64.0 6.00 6.00 3/8 2/16 -38 " H 64.0 6.00 6.00 3/8 3/16 -39 H H 64.0 6.00 6.00 3/16 0 -40 H H 64.0 6.00 6.00 3/32 0 -41 H H 64.0 6.00 6.00 3/16 0 -42 H H 64.0 6.00 6.00 3/32 0 -43 H H 64.0 6.00 6.00 3/8 2/16 -44 H H 64.0 6.00 6.00 3/8 2/16 -45 H H 64.0 6.00 6.00 3/8 2/16 -46 H H 64.0 6.00 6.00 3/8 2/16 -47 H H 64.0 6.00 6.00 3/8 2/16 -48 H H 64.0 6.00 6.00 3/8 2/16 -49 H H 64.0 6.00 6.00 3/8 2/16 -50 H H 64.0 5.00 6.00 3/8 0 -51 H H 64.0 4.31 6.00 3/8 0 -52 H H 64.0 6.00 6.00 3/8 0 -53 H H 64.0 3.00 6.00 3/8 0 .54 H H 64.0 2.00 6.00 3/8 0 55 H H 64.0 1.00 6.00 3/8 0 56 H H 64.0 1.00 6.00 3/8 0 57 H H 64.0 6.00 6.00 3/8 2/16 58 H H 64.0 1.00 6.00 3/8 0 59 H H 64.0 1.00 6.00 3/8 0 . 60 H H 64.0 6.00 6.00 3/8 0 51 H H 64.0 6.00 6.00 3/8 0 32 H H 64.0 6.00 6.00 3/8 2/16 (continued) 53 H H 64.0 6.00 6.00 3/8 0 100 1 )le 5.1: (Cont'd) hple Mater- Steel Vs H D d h 19. ial surface (%) (in.) (in.) (in.) (in.) 54 FS(DW) CR 64.0 6.0 6.0 3/8 0 55 " H 64.0 6.0 6.0 3/8 0 56 H H 64.0 6.0 6.0 3/8 0 1 57 " H 64.0 6.0 6.0 3/16 0 i 58 " H 64.0 6.0 6.0 3/8 2/16 59 H H 64.0 6.0 6.0 3/8 0 70 " H 64.0 6.0 6.0 3/16 0 71 " H 64.0 4.0 6.0 3/8 0 72 " H 64.0 6.0 6.0 3/8 0 73 " H 64.0 6.0 6.0 3/8 0 74 H H 64.0 6.0 6.0 5/8 0 . 75 H .. 64.0 6.0 6.0 3/8 0 I 76 H H 64.0 2.0 6.0 5/8 0 V 77 " H 64.0 5.0 6.0 3/8 0 78 H .. 64.0 5.0 6.0 5/8 0 79 " H 64.0 3.0 6.0 3/8 0 zo H " 64.0 4.0 6.0 5/8 0 u '7 H 64.0 2.0 6.0 3/8 0 2 H H 64.0 3.0 6.0 5/8 0 3 H H 64.0 2.0 6.0 5/8 0 4 H '7 64.0 2.0 6.0 5/8 0 5 H GF** 64.0 6.0 6.0 3/8 0 6 " H 64.0 6.0 6.0 3/8 0 7 H H 64.0 6.0 6.0 3/8 2/16 (45°)+ 3 H 38** 64.0 6.0 6.0 3/8 0 l H CR 64.0 6.0 6.0 3/8 2/16 (45°) 1 H SB 64.0 6.0 6.0 3/8 2/16 (45°) H CR 64.0 6.0 6.0 3/8 2/16 (45°) H H 64.0 6.0 6.0 3/8 0 H H 64.0 6.0 6.0 3/8 2/16 (450) u n 54,0 6.0 6.0 3/8 0 (Continued) 5 n 54.0 6.0 6.0 3/8 0 101 ale 5.1: (Cont'd) nple Mater- Steel Vs H D d h V0. ial surface (%) (in.) (in.) (in.) (in.) 96 FS(DW) CR 64.0 6.00 6.0 3/8 1/8 (45°) 97 " H 64.0 6.00 6.0 3/8 1/8 (45°) 98 " H 64.0 +2.00 6.0 5/8 0 99 " H 64.0 4.00 6.0 5/8 0 100 H H 64.0 3.00 6.0 5/8 0 101 H H 64.0 5.00 6.0 5/8 0 102 H H 64.0 6.00 6.0 5/8 0 103 H H 64.0 2.00 6.0 5/8 0 104 " H 64.0 0.50 6.0 5/8 0 105 H H 64.0 5.00 6.0 5/8 0 106 H H 64.0 2.00 6.0 5/8 0 107 H H 64.0 5.00 6.0 5/8 0 . 108 H H 64.0 3.00 6.0 5/8 0 1 109 H H 64.0 6.00 6.0 5/8 0 110 H H 64.0 4.00 6.0 5/8 0 111 H H 64.0 5.50 6.0 3/8 0 112 " H 64.0 5.62 6.0 3/8 0 113 H H 64.0 6.00 6.0 3/8 0 .14 " H 64.0 6.00 6.0 3/8 0 ‘15 FS(TW)* H 64.0 6.00 6.0 3/8 0 16 H H 64.0 6.00 6.0 3/8 0 17 H H 64.0 6.00 6.0 3/8 0 18 '1 H 64.0 6.00 6.0 3/8 0 19 FS(DW) H 64.0 6.00 6.0 5/8 0 20 H H 64.0 2.00 6.0 3/8 s08”r 21 H H 64.0 3.00 6.0 3/8 SDB 22 H H 64.0 6.00 6.0 3/8 1/16 23 F(SID)* H 42.0 6.00 6.0 3/8 0 :4 H H 29.6 6.00 6.0 3/8 0 ' H H 53.8 6.12 6.0 3/8 0 (Continued) 6 H H 52.7 6.00 6.0 3/8 0 102 >le 5.1: (Cont'd) iple Mater- Steel Vs H D d h [9. ial surface (%) (in.) (in.) (in.) (in.) .27 F(SID) CR 30.3 6.0 6.0 3/8 .28 " " 44.2 6.0 6.0 3/8 Ice - Ice layers (distilled water) (1) (2)- Crushed ice (tap water) saturated with distilled water Ice(3)- Snow ice saturated with distilled water DW)- Frozen sand (with distilled water) FS(TW)- Frozen sand (with tap water) F(SID)- Frozen sand (snow ice with distilled water) CR- Cold-rolled steel surface GF- Ground-finish steel surface SB- Shot-blasted steel surface Plain rods for h = 0 All 909-lugs, unless noted (450)- 45 degree lug SDB- Standard deformed bar, with h = 1/64 in. 103 19_§;§i Summary of test results for constant displacement rate tests. ple T 6n P “P Puff 5r (or P) p. ( °C) (in./min.) (lbs/min) ((15s“ ) (lbs ) (x10-3in.) -10.1 4 24x10'3 140.0 930 190 0.90 -15.1 4.50x10'3 136.8 620 105 0.76 -15.1 4 40x10'3 130.0 607 200 1.50 -15.1 4.90x10'3 105.4 455 96 1.10 - 6.1 * * * * * - 6.1 3.68x10’3 89.6 112 56 0.40 -20.0 3.90x10'3 136.4 500 175 0.001 -20.0 3.60x10‘3 115.7 216 130 0.28 -10 0 3.55x10'3 111.8 326 82 0.40 0 -10.1 3.32x10'3 91.6 336 94 0.20 1 -10.1 3.43x10'3 94.0 470 78 0.20 i 2 -26.1 9.00x10‘4 126.0 840 120 0.20 1 3 -26.7 4.00x10'3 143.2 1480 180 0.24 4 -26.4 3.50x10'4 4.9 440 ‘320 2.00 5 -26.6 8.00x10'4 22.5 990 140 0.80 6 -20.4 1.05x10'3 27.0 1040 90 1.40 7 -15.5 3.52x10'4 23.6 2830 200 5.70 3 -10.1 2.30x10'4 28.5 890 80 0.75 9 - 6.6 not recoded 22.1 1940 300 4.40 1 -10.1 2.60x10-4 26.4 1780 200 2.80 1 -20.1 6.15x10'4 23.0 1740 210 0.80 2 -10.1 5.70x10'4 21.6 540 30 0.20 1 -22.0 5.645(10’4 20.1 624 50 0.40 -20.0 5.105(10’4 17.2 560 32 0.40 ~ -15 0 5.40x10’4 20.0 670 40 0.10 -6.0 5.655(10'4 16.1 210 16 0.10 - 2.0 5.80x10’4 19.1 105 10 0.10 -10.0 4.50x10'3 183.5 1560 70 0.75 -14.8 1.92x10'3 233.3 1435 30 0.50 -16.0 4.50x10”3 280.0 880 50 0.25 (Continued) )le 5.2: (Cont'd) 104 nple T én g 16. ( °C) (in./min.) (lbs/min) 31 - 6.0 Fast rate 1290.0 32 -10.0 4.61x10’3 258.0 1 -10.0 2.40x10‘3 159.5 2 -10.2 5.001110"4 32.5 3 - 6.3 6.97x10'4 29.7 1 -14.6 3.67x10'4 30.7 5 -20.0 5.00x10'4 32.7 5 -26.7 6.38x10'4 37.5 7 -26.8 6.15x10'4 39.7 3 -27.1 1.32x10'3 208.7 9 -20.0 2.53x10"3 210.3 10 - 6.3 1.12x10'3 186.7 11 -15.1 3.86x10'3 204.6 12 -10.0 3.73x10'3 222.7 13 - 6.0 1.96x10'2 2133.3 14 -15.2 3.00x10‘2 2033.3 15 -10.0 2.13x10'2 1978.8 16 -25.6 4.00x10’2 2210.0 17 -20.0 1.32x10’2 2240.0 .8 -25.0 1.10x10'4 5.1 .9 —1o.0 1.66x10'4 4.5 :0 - 6.0 1.00x10"4 4.4 :1 —15.0 1.86x10'4 6.5 2 -20.0 1.33x10‘4 4.4 3 -10.0 3.83x10'3 268.1 4 - .0 4.00x10’3 100.0 5 - .0 3.71x10'2 1714.3 6 - .0 8.60x10’5 2.1 7 - .0 6.00x10"4 26.3 3 -20.0 3.90x10“2 2478.3 . P (0:1PU) (oruPr) 6:3 (lbs.) (lbs.) (x10 in.) 430 Not recored 1030 70 0.001 1075 135 0.16 1300 280 2.20 860 400 1.60 2090 520 2.50 2810 575 1.80 2740 600 1.90 2800 450 0.80 3800 920 1.00 3260 580 0.80 1400 200 1.80 2660 430 1.20 2450 970 2.60 1920 330 1.40 3660 530 0.60 2770 440 0.40 4420 900 0.70 3360 750 0.20 3440 1080 2.90 1630 1200 1.80 720 380 0.50 2080 580 1.50 2770 1000 1.40 2480 540 1.50 450 240 4.10 720 320 6.10 210 190 3.60 460 350 2.40 3420 770 0.01 (Continued) e 5.2 (Cont'd) 1le T é é Piy Pu 5r 0 . n. (or Pu) (or P ) - L;_ ( ) (1n./m1n.) (lbs/min) (lbs.) (lbs?) (x10 3in.) 1 -15.0 LVDT OFF 220.9 2540 660 LVDT OFF 1 -10.0 8.00x10'4 29.3 880 140 0.80 . -10.0 5.20x10'4 29.7 1560 1040 1.20 E -10.0 5.33x10'4 33.4 2040 1520 2.00 1 -10.0 5.825(10'4 32.0 2190 1830 2.00 -10.0 4.21x10’4 31.3 2320 4800 2.80 5 -20.0 6.94x10“4 138.7 1040 300 1.00 5 -20.0 5.10x10'4 32.8 1820 2660 0.01 ' -20.0 3.90x10'4 37.5 2360 3580 1.60 -20.0 4.10x10"4 35.8 3400 7020 0.60 1 -10.0 5.00x10'4 27.1 130 40 0.40 1 -10.0 4.32x10'4 5.3 80 20 1.20 1 -20.0 5.43x10‘4 15.8 530 50 0.40 a -20.0 4.50x10“4 7.4 152 80 0.20 1 -10.0 2.10x10'2 2220.0 2220 .4320 3.00 * -10.o 3.36x10'3 198.1 2080 4540 1.60 i -10.0 7.00x10'5 4.8 1120 1000 2.00 -15.0 2.80x10'4 30.6 2080 3800 1.80 -26.0 5.02x10’4 33.0 2540 6080 2.00 - 6.0 5.70x10'4 32.4 1200 2080 2.60 - 2.0 3.285710'4 17.0 440 1390 1.50 -10 0 5.63x10'4 28.4 610 120 0.40 -10 0 1.14x10'4 5.2 730 120 0.01 -1o.0 1.40x10'4 6.3 940 140 0.01 -10.0 5.63x10'4 24.3 54 130 1.00 -10.0 6.50x10'4 20.4 224 64 0.10 -10 0 1.44x10'4 9.6 48 28 2.00 -10.0 3.00x10’4 14.4 144 64 0.16 -10.0 4.435(10'4 34.7 1560 2920 0.20 -10.0 6.00x10'4 10.4 188 40 0-40 (Continued) 105 le 5.2: (Cont'd) 106 le T ' ' P' P p _0 . 6n. P . (or1Pu) (oruPr) 6:3 0. ( ) (1n./m1n.) (lbs/min) (lbs.) (lbs.) (x10 in.) 9 -10.0 6.80x10"4 13.7 96 40 0.16 0 -15.0 1.255(10’4 33.8 760 200 0.10 1 -26.0 6.31x10'4 24.1 880 400 1.00 2 -20 0 4.65x10'4 29.0 1740 4580 0.10 3 - 2.0 2.25x10‘4 17.3 260 50 0.60 4 - 6.0 9.50x10'5 18.2 520 100 0.30 5 -15.0 6.31x10'4 22.6 880 220 0.10 6 -20 0 6.47x10'4 23.9 800 320 0.40 7 -20.0 LVDT OFF 16.3 480 210 LVDT OFF 8 -20.0 2.30x10‘4 17.7 1220 4580 0.10 9 -25.4 6.50x10‘4 21.8 1060 420 0.05 0 -10.0 5.87x10'4 12.3 344 120 0.40 1 -10.0 6.10x10‘4 19.5 495 95 6.00 2 -10 0 5.50x10'4 12.0 520 160 0.80 3 -15 0 4.675110'4 25.5 1170 470 0.40 4 -20.0 * * * * * 5 - 6.0 4.50x10‘4 11.6 625 175 0.10 6 * * ‘k ‘k * 'k 7 -10 0 4.10x10‘4 11.7 780 190 2.00 3 -10.0 * * * * * 9 -10.0 4.75x10'4 13.7 540 140 1.40 1 -10 0 * * * * * 1 -10.0 4.50x10'4 9.0 270 60 0.80 2 -10.0 * * * * * 1 -10.0 3101104 6.8 290 80 0.60 : -10.0 * * * * * 1 -10 0 3.24x10'4 20.0 530 180 0-10 1 -10.0 2.80x10"4 24.4 670 140 0.10 -10.0 5.93x10'4 23.2 2090 2730 0.40 -10.0 7.50x10'4 18.5 1740 730 3.20 (Continued) e 5.2 (Cont'd) 1le T ' ' P' P o . 6n. P . (orTPu) (orupr) 6E3 _;_ ( ) (1n./m1n.) (lbs/min) (lbs.) (lbs.) (x10 in.) -10 0 5.501110“4 25.0 1560 3380 0.10 1 -10 0 5.39x10'4 30.0 2160 3400 1.00 -15.0 5.00x10‘4 23.0 2160 4360 1.50 -15 0 6.25x10'4 20.5 1250 280 0.80 -20.0 5.20x10'4 34.9 2720 4620 0.10 -20.0 5.85x10'4 18.0 1700 440 0.40 1 -26.0 6.671(10'4 22.2 1840 640 0.10 1 - 6.0 5.601110"4 27.6 1380 2040 3.00 - 2.0 5.67x10‘4 19.3 580 1520 4.50 1 -10.0 5.73x10’4 25.0 576 145 0.40 1 -10 0 6.67x10’4 36.9 1920 480 1.80 10 -10.0 5.60x10'4 31.2 1280 290 0.80 11 -10.0 6031104 44.2 3120 1220 2.00 12 -10.0 5.71x10’4 41.7 3380 1180 1.50 13 -10.0 5.70x10’4 28.1 980 . 260 2.40 1.4 -10.0 * ‘k 'k 'k * 5 -10.0 * * * * * 6 -10.0 5.86x10'4 25.0 576 120 1.60 7 -10.0 * * * * * 3 -10 0 5.80x10'4 26.5 530 130 0.01 9 -10 0 5.001110"4 35.0 1960 480 2.00 1 -10 0 5.561(10‘4 28.2 500 120 0.80 1 -10.0 6.671(10'4 20.0 560 40 0.50 2 -10 0 6.251110"4 21.2 640 80 0.10 1 -15.0 4.751110'4 25.2 1060 280 0.70 -15.0 4,00x10'4 25.8 1250 240 0.40 1 -10 0 4.201110‘4 17.3 580 30 1.00 -10 0 4.841110’4 20.3 460 40 0.40 -20.0 2.101(10‘4 24.6 1330 180 0.60 -20 0 2.801710‘4 22.0 810 170 0.10 107 (Continued) 108 able 5.2: (Cont'd) . . p. P amp16 6 . 6“. P _ (or1Pu) (oruPr) 6f3 JE1;_ _(__Q) (1n./m1n.) (lbs/min) (lbs.) (lbs.) (x10 in.) -119 -10 0 1.17x10'4 33.4 1370 240 0.90 -120 -10.0 4.601(10'3 170.0 1420 2300 7.50 -121 -10.0 4.50x10'3 235.0 2100 4025 4.40 -122 -10.0 6.70x10'4 40.0 1600 1750 1.80 -123 -10.0 8.20x10'4 22.0 375 120 0.50 -124 -10 0 6.80x10'4 31.8 525 60 0.20 .125 -10.0 7.001x10'4 20.8 225 75 0.10 126 -10 0 8.401(10‘4 44.0 710 145 0.40 127 - 9.9 1.10x10‘3 31.6 525 60 0.80 128 -10.0 8.10x104 30 0 320 40 0.50 _________________________________________________~_____________ Piy for lugs, Pu for plain rods (both correspond to the small displacement 6r) Pu for lugs, Pr for plain rods (both at large displacements) Data void (leakage of fluid or equipment defect) 1le 5.3: Temperature effect on the parameters used in Equations 5.1 to 5.4. Tc* m n Td** m' n' C) 12§;1 12511 ______ 16 0.1945 5.40 17 0.2220 4.50 48 0.1585 6.31 62 0.1852 5.40 113 0.1087 10.40 137 0.1404 9.35 145 0.1000 11.40 167 0.1016 10.60 213 0.0400 23.00 240 0.0436 22.90 270 0.0314 31.00 308 0.0314 31.00 ‘nterpolated from Figure 5.3 for PC — l lb./min. ‘4 in./min. nterpolated from Figure 5.4 for °c — 10 109 e 5.4: Physical properties of ice, frozen sand specimens, and steel rods used in constant load (creep) tests. Sample height H = 6 in. and cold—rolled steel rods were used for all specimens. le Mater- VS 0 d h z ___ 1§fl____ .L;2_1 .Lifl;1 (in.) (in.) (in ) Ice(1)* 0 6 00 3/8 1/8** 3 0+ " 0 6 00 3/8 1/8 FS(DW)* 64 00 5/8 0** NA H 64. 00 5/8 0 H H 64. .00 5/8 0 H '1 64. 00 5/8 0 H H 64. 00 3/8 2/16 H 64. 00 3/8 2/16 H 64. 00 3/8 2/16 H 64. 00 3/8 2/16 H 64. 00 3/8 1/16 H 64. 00 3/8 2/16 H 64. 00 3/8 3/16 H 64. 00 3/8 2/16 " 64. 00 3/8 1/16 64. ” 64. ” 64. " 64. " 64. ” 64. " 64. " 64. -vwWNO\U‘I-¥>Wl\>1—IO .938 3/8 2/16 .00 3/8 2/16 .938 3/8 2/16 .00 3/8 2/16 .938 3/8 2/16 .00 3/8 2/16 .781 3/8 2/16 " 64. " 64. " 64. ” 64. OOOOOOOOOOOOOOOOOOOOOOOOOOO NOSI—IOSI—HOSHmmmmmmmmmmmmmmmmmmmon O O (A) \ (I) N \ ...—J OW .CDzJ'IOOOU'IOU'IOOOOOOOOOOOOOOO Continued) Table 5.4: (Cont'd) Sample No. 68-28 CS-29 CS—30 CS—31 CS-32 CS-33 03-34 38-35 33—36 IS—37 IS-38 SS-39 6—40 S-41 S-42 S—43 S-44 S-45 Mater- ial FS(DW) Vs ( 7 64 64. 64. 64. 0 0 0 0 0 .0 0 0 6 3 6 6 8 5 .0 0 0 0 6. 6. 6 6 6 6. 6 6 6 6 6 6. l 4 6 6 4. 6 00 See Table 5.1 for abbreviations. * All 90 degree lugs, h = 0 for plain rods. Lug position from reaction base plate l—Not applicable lote: For sample cs-44, H = 3 in.) 508* 1/8 wwwmwwww 00000000 00 Z . > . O 111 Table 5.5: Summary of test results for constant load (creep) tests. tc Sample 0T P U __111;_ I__£;JL (lbs.) (in./min.) CI-l -10.0 520 2.881110"3 CI-2 -10.0 200 2.701110“7 280 62.5x10'7 360 6.25x10'7 440 20811106 520 4.34x10‘6 Cs-1 -10 0 1420 TC 05-2 -10.0 1040 TC CS-3 -10.0 750 4.41x10‘° 910 2.00x10‘5 cs-4 -10.0 520 TC CS-5 -10.0 2300 1.00x10'4 2500 1.68x10'4 2780 25811104 3020 3.75x10'4 3180 4.46x10'4 :s-6 -10.0 2800 2.50x10‘4 3080 4.361110'4 3320 6.961110'4 3560 8.30x10‘4 :s-7 -10.0 3560 1.00x10'3 3780 1.66x10'3 4000 2.00x10'3 S-8 -10.0 4000 2.861110'3 5-9 -10.0 1400 4 67x10'4 1560 7.00x10'4 1800 1 0411103 2080 1.66x10-3 (Continued) 112 Table 5.5: (cont'd) Sample T P 39 No. ( °C ) (lbs.) (in./min.) cs-10 -10.0 1580 8.33x10'5 1860 9.38x10'5 2140 13311104 2300 1.31x10'4 03-11 -10.0 2000 1.61x10“5 2480 4.05x10’5 3040 6.71x1o'5 3600 9.07x10'5 4160 2.04x10'4 cs-12 -10.0 4000 LVDT OFF cs-13 -10.0 850 8.00x10‘5 1200 2.12x10“4 1560 5.89x10'4 2600 7.181110'3 05-14 -10.0 4500 9.75x10‘3 cs-15 -10 0 3000 2.50x10'2 Cs-16 -15 0 1550 1 881410"5 2000 2 75x10“5 2500 5.391110"5 3000 1 06x10"4 3500 2 45x10‘4 4000 7 00x10"4 -5 :5-17 —10.0 2500 8 00x10 4 3500 1.00x10‘ 2500* u 1 41x10‘5 -5 s-18 -10.1 1220 1.82x10 5 1540 1.77x10' 1820 3.64x10“5 (Continued) 113 Table 5.5: (cont'd) Sample T P éc No. ( OC 1 (lbs.) (in./min.) CS-18 -10.1 2100 5.09x10'5 2380 6.94x10'5 2100 u 4.25x10'5 1540 U Negative value 1200 u 0 cs-19 -10.0 1500 9.271110‘4 cs-20 -10 0 1500 4.58110"5 2000 1.11x10'4 2500 3.85x10'4 3000 9.30x10'4 CS—21 -10.0 1000 3.20x10‘5 1740 2.92x10‘4 CS-22 -10.0 1500 4.13x10'5 2000 6.25x10‘5 2500 zoom"4 3000 5.221110“4 3500 1.28x10'3 :s-23 -10.0 1500 2.83x10'4 s-24 — 6.0 1020 1.97x10‘5 1500 4.57x10'5 1980 1.21x10’4 2500 5.40x10'4 3000 2.88x10'3 5—25 -10 0 1500 1.69x10‘4 1980 1.00x10'3 -6 1-26 -10.0 1020 3.89x10 1500 3.75x10‘5 (Continued) _-__— ___‘_—‘ l ‘ 114 Table 5.5: (Cont'd) Sample T i P 6C No. , ( °C ) (155.) (in./min.) CS-26 -10.0 1940 3.751110"5 2500 1.94x10'4 05-27 -10.0 1020 4.551110"6 1500 1.13x10'5 2020 1.20x10‘4 2500 4.641110”4 3000 TC CS-28 -10.0 1020 7.57x10“7 1500 2.961110"6 1980 64311106 2500 2.30x10‘5 3000 2.02x10"4 cs-29 -10.0 250 0 530 4.50x10’6 Cs-30 -10.0 250 57111107 410 2.051110“6 570 4.93x10”6 730 TC :s-31 -10.0 160 =0 240 =0 360 =0 480 =0 600 =0 720 20 840 =0 960 =0 1080 TC (Continued) 115 Table 5.5: (Cont'd) Sample T P 6C No. ( OC ) (lbs.) (in./min.) 05-32 -15.1 240 PC 400 =0 600 =0 760 =0 900 =0 1080 =0 1280 TC cs-33 -15 1 400 1.101110"7 560 24417107 720 23251107 880 8.33x10'7 1040 4.96x10'° CS-34 - 6.1 160 4.36x10—7 280 4.101(10‘7 400 1.251110”6 520 50051107 640 TC cs-35 - 6.0 280 7.581110“7 400 5.80x10’7 520 1.00x10'6 640 8.30x10”7 720 1.00x10'6 800 9.60x10'7 920 2.20x10"6 1040 TC CS-36 -10.0 520 1.66x10’5 1080 2.26x10T4 1560 1.22x10'3 (Continued) 116 able 5.5: (Cont'd) ample T P éc N0. ( °C ) (lbs.) (in./min.) s-37 -10.1 520 7.05x10"5 1080 1.68x10‘3 S-38 -10.0 520 8 5011106 1080 2.441110”5 1520 2 68x10"4 1980 TC s-39 -10 0 520 9.521110"6 1080 2.121110"4 1560 1.25x10"3 s-40 -10.0 520 5 38x10"6 720 7 00x10‘6 1080 7.37x10'5 1240 7 30x10"5 1560 2 8511104 5-41 -10.0 520 21.0110"4 600 5.00x10'4 680 12911103 5-42 -10.0 520 2.70x10'6 720 4.98110”6 1080 28011105 1240 3.57x10"5 1560 8.29x10'5 1840 2.50x10'4 2120 1.281110”3 -43 -10.0 1080 1.27x10’5 1440 2.831110'5 1840 5.00x10’5 2200 1.051110“4 (Continued) 117 able 5.5: (Cont'd) ample T P 5c No. ( °C ) (lbs.) (in./min.) 5-43 -10 0 2560 2.35x10'4 2840 5.62x10'4 5-44 -10.0 1080 5.60x10'6 1560 9.00x10'6 1980 3601110"5 2560 TC 5-45 - 2.0 520 1.10x10‘5 800 2.70x10‘5 1160 1.28110"4 1560 1.04x10'3 Primary creep Tertiary creep Unloading .mcwewowam wow1ucmm see we? c? mcoc _wmpm sperm Low mvcouwc pcwEwUQFQmwv new UmOF pngu awcpm _mowaae .H.m mcsmed o .CWE .p .8549 .5. . a wee; _mzuwmmm cmom agepmww :5 .33 32.5.51 118 Anwocm_:mv m .wczpqzc pm pcwEmUQFQmwo L Qw_m uooHT u 01x‘9 119 for the bond of frozen sand (vS = 64% D 250 . A. - _Pr/P =1978.6lbs./min. _ ‘ (S-15) _ E“ _200 - -‘-—_222.7 118.7an \. (s- 12) - (D "\- 1 — I \ (Linear scale between _150 '5 , 35 0 lbs /min numbered points) °- /1 (5-109) ‘5 1-EI ‘ - 3: . 1 F l S _ 1 Plain rod, 3 = 5/8 in. 1100 E - Frozen sand (v5 = 64%) 13 *l D=6in.,H=6in. ‘ ) -' T = —10‘t I \ l P \ \ A 1 o \ I 1 ES!“ \ A - 50 \ _\ \. __\ 1 \ I O-O E! O A—A ' ‘d I I I I I a I I ' ‘ A ‘ TL 0 0 Si 1 2 3 4 5 6 Displacement, 6, X 10'2 in. 5.2: Typical load-displacement curves at different loading rates ) to a plain steel rod. 120 .moczpmcwaewp pcwcwmmwv pm no; _wwum :waQ prmEmwu .2? m\m ON 0..» ow ooH m 3 $3 n mi 38 53¢ 68 £9.83 econ 93 co 3?. @532 08 Swarm. “Wm 93m: .CWE\.m8_ .a .aoam meeeaos coom 003 com oce ocm 9.: cm 3 om S m m e m H - — q < a u u u . u — _ - . _ q u u u — - - . u c u u 1 b.1111 Ama:_m> E use at 184 m.m a_8ae mamv .11 121.1 1.1 .mUom- I Evoenst ..\.1\1\ . E . .111 1 1 - .Av AV . I“ \ \ \ \ \I \I- I\.\III_ bl \ \ ... 1 \G \1\ 1 0 \II \111 A0001 1 \|\\ \\ \ I. \ \ I 1d \1 4 1 \ \‘I‘ 11 \1 11 11 1111141111002- nuI. 11111111 .111111111 \\ \Ill III-«ml‘ I III-IIIIII Bio mHl 181111“ - 111. - .... )d‘ see. . 1 11111111 .mww1111 .x 11 .1111111111 1- 18d ‘nl ‘uifiue44s puoa aiew111n 121 do; FEB (.3336 .5 w}. m 8. $st 0 m: 2.3 53¢ 68 53:83 econ of co 8.? 8.525023% Efeoc do 5th Jim 23ml 1 ewes-.5 .ce .mpmm Ewe-.8235 _mchz we. we N19. m c v m mug w o v m .513 u u . _u q q u q u n u —u u a a u c - - OH \I \ll‘O‘ I ON .0 .o .. 383:; .E -111 \\U N1 2... m. _e .562 m m 288 83 111.. 6 11-111 . m 11101-1. Av . S m... 11111 . m \ III a o \ \ 1 . m \I \. pom: “ow W. U C U 3 II\ \I I. 3 o L. n e I \ I 1. .EA . .V ‘ 1‘ \I o 4 4 COH W o 1 - -1 1 41.81411 \ I‘ I.“ \l \ \ .IIIB. .- 1111 111.111.111.111 . . SN 1 \ %\ I % 0.0mHl ’I n‘ . .‘III I LII “11.1111 '1‘ Doom- d 11E I )1 ... III... B. l -I 0|- II ,0- d4 IflDdl I . LOO? 122 F (5-44) ELIJ-—————--———-C1 / 1% = 3.36 x 10'3 /El 1'n./m1’n. E] - E] Pu (S-57) <——— _____ —O--—-—O /,O 5.33 x 10'” in./min. / OI _ / I I/ _ Eli] }3 , T = -100c 65/ h = 1/8 in. C} / d — 3/8 in. 1 x (9’ v = 64% 1 s 7 q\ 1” 1 ‘®~®@’ 1 l ,. l 1 / (Linear sca1e between numbered points) I I I l E 1 I 1 I 4: I O E' 0.01 0.02 0.10 0.20 0.30 C) Disp1acement, 5 , in. ure 5.5: Typica1 1oad-disp1acement curves at different disp1acement rates for a p1a1n rod with a sing1e 1ug.in frozen sand (v5 = 64%). "- 1h, 123 .uoofl1 pm A&¢o u m>v ucmm :mNog% cw xpwumamu map mpmapr: wsp co mmpmx acwnmor tam pcwemum—amwv $0 pummem ©.m mgzmwm TOH Nuofl m1c.m :1OH mloH m1oH v-fi a 1 —.-- u. d —.~—-d - - —-.-_ d .uuQu-q a u .:?E\.:? .m .mpmm pcmEmomramvo 1 1 . a m> O 1 o m> nu p H . H m u .203- u H .1.... 1 755.5 386 u 3 O 1\ . .111 u z 111 111 1 A m \@V oowm n a 11" 11. 1 maN.o . . I G \ A 1. D 1 n ® \\ 111 . Sméfip ocofi n n_ u _l \ I 1 \ \ H n - 1 quo n m>v ucwm chogm 1 1 A.:w m\H 1 I ..:w w\m 1 UV m=_ m :22; e02 grep; - n .ewa\.mn_ .2 .mpem meweeoe u 1 ' NcH moH 10H nd ‘p901 6n1 919w111n oSqL G 124 (Linear sca1e between numbered points) I l I l l l l l -1 210 P1ain rod, d = 5/8 in. ._ Pavg = 24.4 1bs./min. :5an = 4.5 x 10‘L+ int/min - 170 Frozen sand (vS = 64%) .. 140 I I3 01 Bond Stress; T, psi " 7O .1 - 35 0 Disp1acement, 6, X 10'2 in. ' o n . t 1 5.7: T ica] 1oad-disp1acement curyes at differen 0 gure tggperatures for a p1ain rod in frozen sand (vS = 64%), 0 [ P1ain Rod _ d = 5/8 in. [,0 v5 = 64% I I P avg. (1bs./min) Temperature, T, 0C e 5.8: Temperature effect on the bond strength of frozen sand (vS = 64%) to a p1ain stee1 rod, at severa] 1oading rates. 126 ;. (VaTues of Tu adjusted to P avg' using data from ‘ Figure 5. 3)u Best Fit Lines - = + Tu a be avg a b (Tbs./min.) (psi) (psi/0C) _ / /1:1 - A 5«6 0 12.0 —- /// // .1 .1 28.0 0 12.6 - o //A E] 157.4 55 11.0 / I/_ 0 2136.0 116 9,75 -/////.. Jun-I’ll! IIIIJIII Temperature, T} 0C 5.9: ReTationship between temperature and bond strength of frozen sand (v = 64%) to a 5/8 in. pTain rod, at severaT Toading rates. 4O 32 24 a 5.10: 127 / / P1ain Rod ’/ d = 5/8 in. // _ [[0 /’. —26 - vS — 6.A /, éf ,/ . . GII/ #1 WG) / -20 — E / E ‘(D :S 45 E- 0) / I— .o/ -15 _ -10 .— 1’ {’1’ —6 _. ‘D -2 - / 2’ I J I I I 1 I l I 8 16 24 3? 40 n' Comparison of strain hardening parameters, n based on constant Toading rate and n' based on constant dis- pTacement rate, for 5/8 in. diameter pTain rod in frozen sand (vS = 64%). 128 PTain rod, d = 5/8 in. / 0 Frozen sand, vs = 64% / / O n / 1. n' / a / / / / / / _ / / o / . ,xa / / - / O // / _g,/0 ”. ‘ 1 1I1|11l1111I1111I11111 0 -5 -10 ~15 -20 -26 Temperature, T, 0C 2 5.11: Temperature effect on the n parameter as defined by Equations 5.1 and 5.3. 129 [ PTain rod, d- 5/8 in. Frozen sand (vS = 64%) ’9 Best Fit Line 0 ’ n = exp(1.224 + 0.0886 e)\:’// o = -T / / ./ / / I / / / _ / ii _ o ,’ ./ _ ,f/ O // . (Data from Figure 5.11) - / O [6 " / o/ ’l 14' I I I I I I I I I I 1 L; l I 441 I I I j -5 -10 -15 —20 —25 Temperature, T, 0C 5.12: ReTationship between temperature and the n parameter for a p1ain rod in frozen sand (v5 = 64%). 130 Pavg = 24.5 1bs./min. 6avg = 3.65 X 10-3 - Ice (Frozen in Tayers) _ / / / _ Best Fit Line /’ ’q = 4.67 6 ~18 / _ (9 BT/ _ O O? (3 ‘ O? ,4/8 —" ’- I I I I I I I I I I I I I I I 4 0 -5 -10 -15 -20 Temperature, T, 0C re 5.13: Temperature effect on ice adhesion to a 5/8 in, diameter pTain rod. 131 vS = 64% d = 3/8 in, -26°C h = 1/8 in. 6 = 4.5 x 10‘” avg in./min. -150C O~-—-——---——O-- — (5-46? A. _ ,’ -1n°c ' E]-""""B_-—B'— :_ ,/ (5-57) I] ' -606 ii [AT/E1 —20<: I ' 0-0---_-----.0---_ _ y’fl/x’ i- 37 ,0’ I . _.0’ II Ov'o"O .I I (Linear scaTe between numbered points) ’I I 'I I I I J I I I I I I J l J I I I I I I—1 r—I N 0 E; C2 C? 0.10 0.20 0.30 DispTacement, 6, in. e 5.14: TypicaT Toad-dispTacement curves at different temperatures for a pTain rod with Tug in frozen sand (vS 132 [ El / _ / _ aavg = 4.5 x 10‘“ in./min. / d = 3/8 in. // — h = 11/8 in. / _ v5 = 64% V) —D. E; _ 0:3 2 E] - m P vs T '>5 u E] _ Q'— m“ 'U _ (U 3 E1 Piy Vi;,I:3L’C3 //0 E3 E1 I/IC) / " //’ / _ /o E] / / / / o /’ _ / / — / G ' // Temperature, T, 0C L4 1 J I I I I I I 1 I I I I 4 I I I I I I I I I J -5 -10 -15 —2O -25 yier” Toads,_in frozen sand (vs — 64% . ‘ure 5.15: Temperature effect on Tug bearing, uTtimate and ”initiaT 133 Rod Diameter, d, in. 3/32 6/32 12/32 I I | 20/32 | _' PTain rods in frozen sand D = 6" Favg = 24.2 Tbs./min. + d 6avg = 5.3 X 10‘L+ in./min. H — H _I P — T = 200C” 13 /’ _. ’1’ [I 1’ 1... / 1” " -100C _. // ”' ”',,, ——’ C) ‘3/ E // [3 o I—’ z’ o - // ” (3 9 /’ (D 1” _ E] z’ / ,z' / / -/ O o? // I J I J J I I I I J O 2 4 6 8 10 Ratio, d/H, % re 5 16' Effect of rod size (diameter) on the bond strenath of frozen sand (v = 64%) to piain stee] rods. 5 134 Pavg = 25.0 Tbs./min, — éavg = 5.0 X 10“+ in./min. - G d = 5/8 in. 0 d = 3/8 in. O // . o/ 0 1| _ O O o I [IIIIIIIIJIIIJIJIIIIIIIII O -5 -10 ~15 -2O -25 Temperature,0C 3 5.17: Comparison of bond strength for two pTain rod diameters in frozen sand (vS = 64%) at severaT temperatures, 135 .mUOL :wm_q Op Axvo n m>v ccmm cmNoew mo spmcweum econ new ewpmg :\u asp cwmzpmn awsmcowumme ”mfl.m mgzmvd & .I\U .oeumm 8 S S a. a. N m m a m. N H _ . _ . _ . _ _ _ _ _ o o \11 o X o1 \ \ \1 I om mm m. m. 9 I .1? a 133 9: om + 3 u 3 ma 1 02 W S .1. Id Doom- 1 e D . m 1.1 DOS- 1 e O .u 1 8m n1 . SSS .72 x S 1 36m. . m . w .cwe\.mn_ m.em u m>6a oov 136 F T= 40°C - Favg = 24.5 1bs./min. ... _L', - . éavg 5 X 10 in./min. (3 d 3/8 in. - CD d 5/8 in. Least-Squares Line (3 ' O 8 o o C) c) i; o . ‘ j I I J I I l I I l I I 0 1 2 3 4 5 6 e 5.19: SampTe Height, H, in. Effect of sampTe height on bond strenoth for pTain steeT rods in frozen sand (vS = 64%). 137 1.6 [ 8 — A A ‘ z T = -100(: O ._ ///// fiavg = 25 Tbs./min. éavg = 5.0 X 10'“ in./min. _ ZK//// H = 6 in. 2 _ .—-——'CP——‘- ‘ A /EJ"’ (3—57) / EIZ h = 2/16 in. 1 _ ZS—ik A// ‘V‘-—-—“’-— - - --‘V-—--- ; '75 (5-122) 1 A; {v / h = 1116 in. . ‘V E] 1 W/ - I (Linear scaTe between numbered points) _. I‘ I I \ I \ 1. ~ . ’ \ (S—JO) f EEID-C) {)_ PTain bar h = 0 I I l I I I I I l I I I I I I I I I o_ . ..10 0.20 0.0 Disp1acement, 6, in, 9 5.20: Load-dispTacement curves for a 3/8 in. steeT rod with four Tug sizes in frozen sand (v5 = 64%) at —100C. 138 0 E pm - j \ T = ”100C / a 1?an = 2201bs./m1‘n. 5 /El \ (3an = 4.5 x10'31'n./m1'n. . d = 3/8 in. E] \ h - / ' / E] — 1 64 1n. 9 ' \ . / \ D E’\ 5 ' I] \x . 000‘s a\_ G I \. E] -191 ) _ O Q \ ( ) I \ El H= 31h , ten 1ugs /O \ \m . , o\ \B /O O\\ \E] ) I— 0/ @\\ \E / \ ./ Q ‘0\ Elcf) (5-170) \\ ) ’ H= 2 in. C2\‘\ / Seven 1ugs \\ v \ ; O . - (S-30) (L1near scale between numbered p01nts) H = 6 in. No Iugs ’ J l L I I I I I I I I I I I I I I l I I I I I I I H v—I N 0 8 O. O. 0.10 0.20 0.30 0.40 - C:- O Disp1acement, 5, in. re 5.21: Load—disp1acement curves for a standard deformed No. 3 bar in frozen sand (vS = 64%) at -100C. 8.4 7.2 4.8 rure 5.22: 139 = 25 1bs./min. = 5.0 X 10‘“ in./min, = 3/8 in. Residuai ioads for piain rods Caicuiated for a standard deformed No. 3 bar 40% / T : Pu = 0.65 (1 + 3,3'j;// ,’ I}? Least-Squares /}3 ,’ Line [I ‘z /' E]? I’ / / / /<— T = -10 F P C) I 1/54 9’ I / l l ,’ h=1/16 in. 2/16 3/16 m. I I I l I l J l J I 1 2 3 Ratio n = A1/Ar Effect of 1ug size (height) on the uitimate 1ug capacity in frozen sand (vS = 64%) 140 6 __ _ 900—1ug 450-1ug_ 5 .— T = —]00(‘. . $an = 4.5 x1o'~ in./min. = 64% 4 _ /A—A_ ‘ / 3 _ f / , - / // C) A // 2 _ / o l / I / B A/ ,0 ' \ I, l ‘0“ ,Q/ o 900-1.ch 1 :- 0-00’ A 450-Lug I (Linear scaie between numbered points) 0 A . . . I A I I . I A I . . . . I ES ES 23 » 0 C3 - - 0.10 0.20 0,30 Dispiacement, 6, in. re 5.23: Typical 1oad——disp1acement0curves for piain rods with two iug types; 450 -1ug and 90 —1ug, in frozen sand (vs= 64%), U) o ' 141 = 25 ibs./min. / = 5.0 x10” in./min, / 6 vS = 64% / - « h - 1/8 in. / _' d = 3/8 in. C a I 450—1ug I O, [a goo—iug (o = -T) - ' +Pu= 1.05 (1+o_1ge) for 200C< T< ~20C El 8 - B a — E/ /= o. 65 (1 + o 0966) _ for 263 C< T< -2°C )3 (Least— Squares Line) ‘ G.) / —/ [O 7 Temperature, T, 0C I...I....I.J#I..JII.1.II. -25 —5 -10 -15 -20 gure 5.24: Reiationship between temperature and 1ug bearing capacity in frozen sand (vS — 64%). .Ammmfi .pcmwcz memm::: Tlllee Snuff l’i _mmom mm 143 : a . h I. . Acwevmm .as Axmsvmm if mwvfi mmm HNNH owm NmH meF m cpwz .ugmcu amgpm mcp :o vmugoowg mm mmommgsm _wwpm mo mmazp mwgcp Esawxma wommgzm _wmpm vwgm Louomm mmwccmsog mzp mw wCWF =mmwcgm30L= mo spasm; muLOLU ugmucmpm mo cpmcwfi FmpOH uxogo ugmucmpm a mo cpmcwb .mmwpgwaoga mecp mo Lem mpzapzo Fmoeaz» ”mm.m wezabd u-p L _J_J_J Q .mcwpgwpcmo mcp Eogm veg: 1mme «pgmco awgpm qugoum; any so vo>meao mm mpcmww; mcwccoamoggoo wzp mgm Axmsvmm w Agesvmm .prmEonwoLa msp co uw>xwmno mm mmwpwxwamw we mpsmvm; vcm E:EPCTE wgm Amevam a Aswevam ea uapman-po;m "mm um__oe-e_ou “mu bewd-u:=oew new I o.mH m.HH m.m¢ m.mm mm o.wH o.oH o.mm m.mm mo 0.9 o.m m.o m.¢ *mw EE EE .CF: .:_2 ugtccao 144 3.0 [— _ T = -100C : / ' 2 5 Pavg 24 lbs. min . — . = “L; . . 6avg 5.0 X 10 1n./min. _ d = 3/8 in. v5 = 64A 2.0 __ C) Ground-Finish steel, p = 90% m C Cold-Rolled Steel, 0 = 625% D. E A: Shot-Blasted, p = 1A8 % i 5 'U D _l (Linear scale between numbered points) 0.5, \ \(s-86) l \ l/ (\A pr \ ego-GIG —————— e—-——o——l ———— 0 . l J I J I l l l J o .1 1 2 3 4. 5 6 7 8 9 Displacement, a, X 10’2 in. Ire 5.27: Load-displacement curves for three types of steel finish, in frozen sand (vS = 64%) at ~100C. 145 4i _ Plain rods, d = 3/8 in. T = -100C 2 - I5: 24 lbs./min. C) Best-Fit Line PU = 0.019 00.606 : C) . <3 - ' ' l - .0 '8 ' 'E z 2 L? 0.: 0.0 'o E +—> L (D l I I} I l I l l l l I l I J J 50 80 102 200 400 600 800 103 2000 Roughness Factor, p, % ure 5.28: Effect of Surface roughness on the bond strength of frozen sand (vS = 64%) to plain steel rods. l0 146 / 100 lbs./min. // /‘\\\\\\\\ fl '0. m < to II \ (1) Ice layers (distilled water) (2 Crushed ice (tap water) ( l ) 3) Snow-ice (distilled water) 1 I I I I I I I j 1 I I O -5 -10 ~15 -20 —25 Temperature, T, 0C ire 5.29: Bond strength dependence on ice sample preparation method. 147 280 '_ _ _ Pavg = 25 lbs./min. C) 6 = 4.43 x 10‘“ in /min av O O 240 — 9 O / / 200 _ /// _ / 0 l/ 160 — G // /’ - (I a“ 120 _ 0 / / I /' - / ' / O 9.0 - O / C) ./’ ’0 ' / O Distilled water 40 .. O 0 Tap water 0 J I I I I I 4 I I I I I I J I I I I I I I l I I O —5 -15 -20 -25 —30 Temperature, T, 0C gure 5.30: Bond strength dependence on water impurities for a 3/9 in. diameter plain rod in frozen sand (vS = 64%) at several temperatures. 140 120 100 148 . . / Plain Rod, d = 3/8 in. 9) T = -100c lo 13 — ' / avg - 24.5 lbs./m1n. / . . . / Gavg - 5.45 X 10 u in./min. 6? Peak Strength, TU //t) ___ ————— — — — — — i O / 09 Range for ice Q? C) 0? X/ Residual Strength, Tr¢ §,/’/ __________ X_———>(————x —— x I l I I I l I I I I J I I I I I I I I I I I I I I 10 20 30 _40 50 60 70 Percent Sand by Volume Tigure 5.31: Effect of sand fraction on bond strength for plain rods, peak and residual at -1G°C. c w um r§qw n >V .CWE Nofl x .p .aEwH I Avmscficoov .mmumu .0: 2%.? team 53$ 5 we; FEE m 9:23 98% :0 325 mm Amv .uocfin >Lsu megu ”mm.m aczmwa , qr mm qfl mm CH m m a m o . . _ . _ _ _ _ _ . — _ — _ q — q C O . AJ 4 a "llll + 01 1101‘ 0 III ll III LII N .m 2%: cmm u a m. S mw 9 a m w 3 m w 0o m 3 qu H > w ‘ VA 000.? n H .mfl cmm n a + M _ Cw w\m u v I m m. aom :wm_a . mmlw; 0H Cm-mu .c: acaEmm ADV ”Aeazcwucoav Nm.m menace .:_E Ncfl x .p .mavp mm wfl NE CH m m . — u _ - — . — - .:?E\.cc B-CH x am.o .mn_ omm+ . .CwE\.:w ouOH x mO.N H 0% Ha .mDF OHV H & .mn_ cum n a New n m> cgz- ”H .:w q\m u U .wom :Tm_m SWIM; .n3_ :3\ 9 ‘1uawaaeLdsgg danj _ X ‘3 g-UL 'UL 100 80 E 151 Plain Pod, d = 5/8 in. . T = -1nOC 60 ' v = 6M~ so _ S / _ (3 40 - / ' C) 3n _ 20 ’/O 10 . J L . I I I j I J I I I I I 4X10’7 6 8 10'6 2 3 A 6 8 10'5 igure 5.33: freep Displacement Pate. 5C. in,/min, Loading effect on the creep rate of a plain steel rod in frozen sand (vS = 647) at —100C, ,. , ~ . ._ . 1, ., i... . 1.1 W ”vasecpcoav m-mo oz a_aamu fimv cocr- pm “see u >v ecwm :aNocc e? pgawm; o=_ .CW qua a got; to; .:w axm :wm_a m mo unecmor Qoym Low wm>Lso qmmcc ”qm.m wczmwd ca mm mm mm em cm m1 aw a a o _ u — a — q — 1 — u — q — u _ u — - — D .:?g acfi x up each . cm s _ .. . ... I .mnfi comm - mmfl CTE\.CT :-cfi x ae.fl .ma_ ocmm . 0mm 2 w I - mam New n m> - .:?E\.:% :-cfl x mk.m aocfl- n F 1 Gem .WDF CNCM .C—. m\x_fl H I b ,1 .Cr A. a, H :,cc x ma.q u w . «\o a - mme ..mn_ owfim “ a UDF ago 5pc; com cua_a 5 . c dSL daaug u; g_01 X ‘39 quamaoeL .G 153 mfl mumu .oz mFQEmm Anv zeg mcfi x .p .wETH #1 NH CH m m a c C 1 q 1 d 1 — 1 - u u 1 u u 1 .n ooJ.\ .\ \ .CFE\.:w :-oH x m.~ - ma_ emkmi :wE\:w:-cH x om.a .mn_ owom - m L .:ws\.cw xem “ > :-c_ x mm.e .mn_ ommm cocfi- u H 1 .cw m\fi u c - . _ _ .cw mxm n t . Cwa\cw :-cm x m.w n 0% .mn_ comm n a 53_ mco gpvz we; Cwm_a 9H ww we “Avm22wuc01V am.m wczowd 'u; 3-01 X ‘39 ‘1uawaoeldsgg danJ CQ-7 ' Plain rod with one lug . d = 3/8 in, _ P = 4000 lbs. _ h = 1/8 in, SC: 2_0 X 10-3 T = -100F in/min. vS = 64% 3780 lbs, 1.F6 Y 1P'3 in.’min. “ 3560 lbs. 1.0 x 10‘3 in./min. [—I '\) CA) -I> UT 33 Time, t, X 102 min. Figure 5.34 (Continued): (Cl Sam!)16 “0‘ “3’7. F3 .mnr emmfi + .fluqm u m>v vcmm chogw c? czF mco Ewe: no; :meQ m onwuworcz >3 cwzo__ow onwvmoF prm Low ww>gsu owmcg . .cwe.:v m-cfi x aw.m .mn_ cmafl+ .CWE\.CT m-cfl x ac.m .mn_ ccflmi mlcfi x m.m .mnF ommmi .cTE\.cw m-cH x mm.q u on .cwE\.cw mica x mm.H .mn_ o¢mH QOCHI u H wfi 'Ul z-UI X ‘39 ‘1uawaoeldsgg . l m , cocr- pm “Nam u >V ucmm :wNogm :? a:_ mac saw: no; :mea m we wpmg pcwawumFQWTu awwgu co pum1mw uCTvGOA “em.m wasawa .EEXE .uw _mumm pawEmumEmE mod No. L: m m 1 m TS a m a N 175 m o ..q N PS — _ —.-—-ul|-1_ —quus__ ‘ - ___-__—d _ H . . - N . 1 UV . . I . Na 6 . . . . . q M... H O O . I a. l\ \.\\mNm.:m mloH now - m D. \\\\ Ar _ . SETHF - m m x as: $338-3me - W .5 w; u L .m . .. CH no 5 m2. u u m. m:_ wco spwz no; :meQ 1 cm ‘w 157 ”.1 CS—Rl'. Plain Rod 10 h d = 5/8 in. ,5 _ T = -60C '6 .'_ 6 X 10'7 ? P(lbs.) (in,’minél Cl x 1 160 4.35 90 2 280 4.10 '2 3 Ann 1.?5 <14 0% 4 520 5.0 U (D E 5 640 °° .9 C D. 0) CI.) 5. LA _ A i 0 2 4 6 8 Time, t, X 102 min, re 5,37: Creep curves for a plain rod in frozen sand (v = 65%). Step loading procedure, (a) Sample No, FS-34, 3t -60F, (Continued)‘ LA) 0 gure 158 r‘q_3q 1 Plain 90d d = 5’8 in, 'T=—1WC V = 64% s “F'P = 1040 lbs. ac = 4.95 x 10'6 . / . in. min. 880 lbs. 8.33 X 10'7 in,/min. l 4— — _ _ _ .(_ _. — i 720 lbs. 2.8? X 10‘7 in,’min_ 560 lbs. 2.44 X 10‘7 in/min. 400 lbs. 1.1 X 10‘7 in,’min. I I I I I I I I I J I I J 7 fl 6 8 10 1? Time. t. x 10? min, 5.87 (Continued): (b) Sample ”0. CS—33. —IFOC, ream u m>v tcmm :wNCL1 c? no; :meQ m mo ope; amwcu co powwwm eczpmgwasme 5.7.5 .5 .umv .35., #55833? 396 c w m wncfi a m w _ . _ _ _ _ _ _ _ _ (\l pom- n H 4 159 LOCHI u H “Rum 9:6? ca 9553415 walls Pal [day ‘1 _Lsd 160 . .. m Aeazc1pcoev com- pm .ma-uc .oz a_aamm Amy been u >V tcmm :wNocw cw ozroco wco cpwz to; :TGFQ m ocvtmop ampm Low mw>Lso waLL “om.m mgsuvd _cwe “cm x .p .wEwH mi ah ; vu _ e .. .- 2.55 cw mgr: x m r c .mpr cwm .cva\.:w m.c .CWE\.CT :-cfi x aa., .. , .‘J mnrcm m a 1.0 .a “m S d .:%E\.:v m-c m. . 3 m c m a NINE w. LO t Aeqm u m>v tcmm :mNOLu 0y . a . m.c L. ”Sal”; Egmncv .u o:_ mco Lye: we; gemFQ Iaom- pa .ea-ac .o: w_aema ADV “Avazcwpcoav om.m masama .cwa ac, x I“ .aEPF N mm mm mm a“ cm mm 0H m a c . I . . . . . . _ . _ . _ . a. . . --I c 9 . .:_E\.cW . .:wg\.cw mIcH x no.H .:TE\.:w s mIcfi x Rm.q .mDF Cmcfi JIcH x <.m .cwea.:w .mo_ ccmfi I . .,. :Icfl x Hm.~ mn— CCmmIY .mn_ caofi J I m.o mm . 4 .LOQIHH C.H m .QFE\.:P Asvm n >V beam chcgd I ,._ _...n w I. .. m C” > aa a a. fl :1 m\r I g a? m\m I UV mar ooom u a o:_ mco 59?; co; :TmFQ 9 'quamaoeLdstu danJ I) .Qomfi- pm .mHIMU .oz a_asmm ADV ”Avasccpcouv mm.m aazmwa .cws OH x .p .aETH N 162 mHImu cw mm Nm aN 1N CN «M NH a w c _ . _ . _ . _ . _ _ . _ . _ . — _ q I :wE\.cw m-cH x ma.fl % :FE\.:F .cTE\.:v .mn_ coma ”a OH x mm.w mIcH x mN.N I mIWDFIOOmN mn_ OOON .cTE\.cw . :IcH x mo.H .mn_ ooom I OCTE\OC_I I :Icfi x m<.N .ma_ oomm I poms u H “saw u m>v Ucmm :wNogd A.:w m\fi I 5 ..CT a1” ” UV .cwE\.:v :Icm x N u ow c:_ mco spTz non Cwmfim .mn_ ooov u a 1N. a< cm. 9 “auawaoeLdsIa daaag Z) ‘ 'UL .mwxsmewQE¢p Lzom pm flawm I m>v ucmm chocw c? cap ,:I m\H m spwz no; .:N «\m mepm :Tmpa m Low mwpmg ungwUmFQme awmcu “cq.m mgzuwd .:w&\.:I .Um .mymm pcmswumFQmwc wagc NICE m m 1 N , CH a m 1 N :Icfi a m Q N I CH 1.. . _ _ _ _ _ __ _. _ . _ _ _ _.______ _ 163 ... 8.11 I I m : ONIM H I __ 2; I Ia 8.; m: I 8a S AN¢o u m>v ucmm :mNogd sdII ‘d 'p90i paltdav 164 .LQLHI um flaqc I m>v uccm cmNogm cw mo:_ co spez to; (cw «\m _mwpm CImFQ a do Lc?>m;wn ammco wsp cc mgowm; 0:? mo pumwwm .cIa\.:I .ow .mpmo ucwawum_QmIc wagu ”Hq.m wczowd 1c NIcH mICN :IoH mIcH mIonv - - . —--- - u 1 —-- —- q _ ___—__. - - —_- . ... om a S} Q \I\ _ p \ \ \q . ON m EN 0 \ \O\\ I N. w: Sh D \\\ Ill I \ Sim 8%: :5: 38V . . I 3.5 $> G I a w mar: no I.:p I n my mm A .V; n, A .3; a \. II \I i \I H .1 DI n\m\ I u n a a. I. I. ma AVII II II I m a» E l Im- U o I \ 2:55 585 I 3 #11 .\\I\\.\ III CDIVIDR‘UCNJCJ U; H L ... s . m . . . .QQLI pm $2 I : ucmm :ch-C 5 in m .cz Emucfim m agrono— Qmpm LE mwizo 3w: ”N115 9:6.qu .CIE «CH x .p .wEFH E S S. m a a N c a . . _ . _ _ _ _ . _ _ _ . c EaxEm-S x 9m IIIII .n: E: I I IIII‘INR ... I.Iu I11 I I I I ac m m .c.:=\.c.p w mIoH x o.w mm .mn— coma .m a, - - I we. IL. or; I H 3 .555 we: -. .S ,I. w PS x 36 Ium fl Wc: .a - 1 I w .mf cm? I a $st I 3 ES cmNoi I1 .5 $1. I I. If «to. I U I NH 93 to; _quLOI-Et m. .cz ULmtcmpm IL. 33¢ I .u L S. m .00 OH- pa AN am I >v ecam CINOLI CI .mcorppmoa Cato I a m: . w\H a guy: we; _mmpm . . p Im.v u — c? .c_ w\m cIm_q a Low m>Lzo mum; Aawmcuv pcwemomFQmvaumOA ”m¢.m wczmwu .:vE\.cw .uw .wpmm pcmsmuaFvao amwgu NICE m .q N mICH m < N :ICH c . c Q N ”WIC— _____.__ _ ________ _ ______ ___ _ H. I N. .2? o I 1 N _ I I I: ZCII H N I do ,o A¢\ V I m P nu _ I ”m AN\IV cw c.m I N a. I e. :1: 2.551 I N E m H A.:IE\.:I mooo.o I awv I N .0 \I “I . . I q II.\ mow.oA w\UmVN m I Amavxva H . cucfi- I I I o wcwk mmgmzom-pmmmg A\qm I m>v Ucmm :mNogm I CH ms. .2. CHH o _3_; :3. :2 ....I ___..f. sde ‘d ‘PPOT paIdev ,cocfi- pm Ayam I m>v ocmw chCLI cw u:— .cw q1H m Luv: to; _wwpm Is? q\m CmeQ m we mpmg cwmgu co prmgmwt wFQEmm we pumwwm u¢<.m wgzovu .cIE\.cI “ow .mpmm pcmewom_QmIc omega m-cfixm a mIcF m o w m N r-cfi a m m-cfixm — _ _ — — _v _ _ _ _ — u _ _ l—‘ u — _ a — — _ .cr . I I . am H 3 AV oooH- I I - .cI wN.N I a mu AVIAN- ”w .:w oo.¢ I Q mg .:I oo.m .. I. ANwm I m>v ccmm :wNogd o:_ .cv a\fi m sprz to; .2? m\m :meQ 100v paI SGIN ‘d ”p201 168 .s' S ,g’ I: 35 3i S 8 (- T N <" m D l I I I II . H II-— ——-— 9 _ ///,/’//’ 6 = 10* in./min, 0 (Data from Figure 5.44) Cl -/ G) (3...... / C)’////”fl-—éc = 10'5 in./min. 1 ‘ / / o / / / -/ // D = Sample Diameter ‘ / // Plain rod with a lug / / d = 3/8 in. - / / h = 1/8 in. = _ o n // I I I I J I J I T I IOIC I I 0 fl P 1? 15 20 ?A A = (D-d)/2h Pull-out load dependence on soil cover for a plain steel iqure 5 45: _ . 3’8 in, rod with a 1/8 in, luo In frozen sand (VS _ - 6AWI M 325538 No.3 I > 5:2 wmImu .oz @353 E uooT pm ucmm :39; 5 m3 .5 w: a 5:3 9:8 583 3.585 33 Low 8?:6 395 65m 8.sz .55 N2 x J .5: CN 0.. E E. S E. m m N N c _ u u q q _ n - a — _ - h - 0 _ VIIIIflIHI—Ill I C T I II- I I. I III?! I 7 555551; ma JV I I I I I II I NH. N - l. I- I. I. 1 CS: C.- .. .. .. n 7 . .mIm: x 3 N m NN. M mflZ 33 I a m J G ELI-5 x $.N I mm. m. mw 5: 83 w l I a w a . U I EN MI 9 I 3 - 8. .m... I (II II I II. I. I NR. goS- I H 3%.; I m3 32mm 53.: 2: .5 a; I 5.5 E: .5 a; 55 Q: can: so; 170 m. :I I II qq I > LIT; o«-mg oz ¢_Qamu ,nv “flvmzc?gcocv ¢¢.m mgzcwu .5?5 NC_ x .p .mewk om mm cm H OH I m _D_ _ PF . W _L A. ‘ ‘I'Y I'll .:w£\:w wIcH x mm.o .mnF cwm .CEIE 3.2 x S.“ .fl: ES II ¢I Cwa\c? mIcH x mw.fl I .mQF cmmfl Locru n H . m Axe wv I >V wccm :mNogu c=_ .5? aIH I III; be; .c? m\« :vmpq OMImc qm 9 ‘1uawaOELdsga deadg 3 6 171 .& m.~m I m> saw: NMImu .cz mpgamu ”UV “htmzcvpcogv c¢.m mgzowu Icwa Ncfi x .p .IETI VN mm ca qfl IF q_ 0H CH a u q N - — — - u _ a — - Cwsxcw mICH x we.“ .mn_ cwm uooHI I I PNm.Nm I m>v ncmm :wNogm 03. pscww: 6; 9H . .. . I. m 52.3 to,» Ir; arm EEK CTECT mICF x mm H .I 0% \IIL; mn_ cqcP I l ‘39 ‘1uawaaeLds;a danU 5C. x 10‘2 in, Creep Diso1acement. Figure 5,47: 48 J> D 32 24 172 CI-] Snow-ice. T = —]00F P1ain rod with one 1ug (d = R/P in, h = 1’8 in.) P = 520 lbs. 5C: 2.88X]0_3‘ in./m1n. 40 80 170 160 200 240 Time, t. min, Creep curve for a p1a1n 3’9 in stee] rod with a 1/8 in, 1ug in snow-ice (vS = 0) at -10°C. .mcofimbcmuccu $32; .35 pcmxwwit use cocHI “E Ucmm 53.: c? 53F .2? m\H.I SIT; wee; _wmpw .E w\m FEE Low mwpmm 29:85ng $0.5 “Sim 9:5: _c.E\..E .uc .Bmm #55833? $95 moOme. mICH :ICH mICn cICH BICfi — - .—___——— — -—-_—-_ A —_—__—~— —\—_-___-_ _ H D - N. D I D 1 q. L . B J m I H \\\M\\\\ \.\\\U AmoTzofiv I -_ m a la \NCC H > D wo¢.m< H m> Q ‘0 m, I .\.\.\\\.I..\\ Yam. up I > 1T (omimm I m> a I. .. I m ... m q K 3 I > x em um I > ‘ I . . , w I em, 2 I > G $3. I m> 0 Im to .,I.Il . . l#CH ocp um 92% :wNOLu “gcwm; 03_ .ew m\H e epvz U01 .CI m\« megm :Im_a sdm ‘d ‘pP’O‘l PSHddV 174 41 Plain stee1 3’8 in, rod with a 1/8 in. 1uq — T=~1nc .33.— ‘i _ (Data from Figure 5.48) 0. _U“ .— I'D .3 . 1| 8' w 2 __ (5 'c _ -4 . . 6 — 10 in./min. “U _ . .9 Ti __ D. < l _. __ Snow—ice 0 l l l l J I l I l 1 I I l l I O 8 16 24 32 40 48 56 64 Percent Sand by Vo1ume. vS Figure 5.49: Load capacity dependence on sand concentration durina creep for piain stee1 3/8 in, rods with a 1/8 in. 1u0 in frozen sands at -10°C 175 - (D / I/ ' Piain 3/8 in. rod with a /,’/ 1/8 in. “.19. / 3 F Frozen sand (3 T = 100C //// _ (D 8. /// s: i 0 Q“ 2 _ P64% ... 1'75 P519: '55 Vaiid for ac _<_ 4.0 X10-”in./min. u L o >U') g: F- //// (Data from Figure 5,48) 1% _ o 3 / / 1 t / F / / ~ / I/ i 0 L l l 4 I l L l J_ n l l I 0 1 2 3 Load, P(vS = 51%), Kips Figure 5.50: Comparison of iug ioads at different sand concentration for frozen sand at ~100C. CHAPTER VI ANALYSIS AND DISCUSSION 1 Load Transfer Mechanisms: Shearing resistance at the rod—frozen sand interface develops as a sult of ice adhesion (or cohesion) and soil grain friction. When a igle lug is added mechanical interaction caused by lug bearing against a frozen soil adds to load transfer between the rod and frozen soil. ice ice adhesion and particle friction appear to have a similar load ansfer behavior, it was convenient to consider them in the same section. 3 bearing will be discussed in a later section. [.1 Ice Adhesion and Sand Friction: These two adfreeze bond components provide shear resistance to l displacements relative to the frozen soil. Each components contribu— In to the total resistance has been considered separately throughout 5 study. Ice pullout specimens (prepared in different ways) were ted, using a 5/8 in. diameter plain cold-rolled steel rod. It was erved that ice adhesion was sensitive to many variables including perature, loading rate, ice structure, water impurities, stress and erature history, and other factors. Control of all these variables difficult due to the complexity of the load transfer phenomenon. JItS of these tests, summarized in Figure 5.29, show the upper and er limits of ice adhesion for various conditions. Only a brief arpretation of these results will be given here, since adhesive 176 177 properties of ice deal with complex physico-chemical phenomena which are outside the scope of this investigation. Starting with the temperature effect, the results show a general linear variation of ice adhesion with temperature (Figure 5.13) despite the large scatter. This is in agreement with work reported by other authors, as shown in Figures 2.1 and 2.2. Values of ice adhesion to plain wooden piles obtained by Tsytovich and Sumgin (1959), appear to vary almost linearly with temperature in the range of —7°C to -20°C (Figure 6.1). Although no displacement or loading rate was mentioned, these values are compared with Ice (1) in Figure 5.29. Ice (1) appears to be most similar to that reported by Tsytovich and Sumgin. Further comparisons with previous studies, unfortunately, are not as promising due to the diversity in test conditions, ice types, and contact surfaces. The increase in ice adhesion at colder temperatures has been attributed to a reduction in thickness of the liquid-like layerat the ice inter- face (Jellinek, 1957 b; Barnes et al., 1971). Returning to Figure 5.29, the effect of water impurities on adhesive strength may be noted by comparing Ice (2) and Ice (3). Tap water often ontains 1 p.p.m. or more flourine, in addition to about 450 p.p.m. in ardness as calcium carbonates. Jones and Glen (1969) observed a reduction f about 35% in ice shear strength at -70°C due to increase in flourine ontent from 0 to 0.05 p.p.m. and the reduction was about 60% when lourine content increased to 0.5 p.p.m. The two authors attributed he results to different types of physico-chemical defects and dislo- ations in ice crystals caused by the hydrogen fluoride (HF) molecule hich enters the ice lattice. 178 The effect of water salinity on strength of ice and frozen soils have been investigated by many authors. Velli and Karpunina (1973) rec— commend that the adfreeze strength of frozen saline ground to concrete piles be taken with a factor of 0.75 of that of fresh water, based on several in-situ tests. In fact the reduction in adfreeze strength due to using tap water in Figure 5.30 was about 45 percent, which is far more than 25 percent. More recently, OgataIet al.(1982) observed that a 3 percent increase in water salinity of alluvial sand over distilled water caused about 70 percent reduction in its unconfined compression strength at ~200C. They also observed that the rate of strength de- crease with increase in salinity was largest for a low salt concentra- tion,in the range of 1 percent. This was attributed to the increase in unfrozen water content due to the salt concentration. Creep defor- mation in the sand was also observed to be largely influenced by the increase in salt concentration. Similarly, Sego et al. (1982) showed that an increase in salinity of frozen sand caused a non-linear decrease in its proof strength, the exponent n from a power law, and a similar decrease in Young's Modulus, at -7OC. Temperature history is believed to have some effect on ice adhesion. Its effect, when combined with the other factors, appears to be far less significant on the sand-ice behavior. More consistent data were obtained from pullout tests on frozen sand than those on ice. All specimens were frozen at about -24°C prior to testing. Ponomarjov (1982) experimentally showed that soil samples at first expand on freezing (due to phase change of water). The expansion continued to a maximum value at about ~80C (if the samples are fully saturated). __— ' ""‘" "““‘°"""’ '-* ’~—' —‘ 179 With a decrease of temperature below —8°C, thermal contraction reduces the sample back to its original size at about -55°C. Ponomarjov attributed this reverse deformation to the presence of gases and the possibility of deformation of ice crystals when the gases change in volume due to changes in temperature. Theoretical predictions made by Ponomarjov (1982) compared well with his experimental data. Considering these possible changes in the pullout specimens, a 5/8 in. diameter circular hole (in the ice at -24°C) would expand* by 6.5 X 10-5 in. if the temperature were increased to -2°C. A steel rod of the same diameter, frozen in the ice, would contract by 1.5 X 10"5 in. The net effect would be a small gap of 8 X 10"5 between the ice and rod. If these assumptions are correct and the gap does exist due to tempera- ture history, then the adfreeze bond would be weakened and the reinforcing effect due to surface ”tension“ would be less. This weakening may also +occur during the test due to differences in Poisson's ratio of steel and ice. As the rod is pulled a slight reduction in its diameter will differ from that in the ice. The effect of temperature history and that due to differences in Poisson's ratio may not be as severe as they would first appear. The net result may be a cancellation of effects. The load—displacement curves for plain rods in ice and frozen sand (Figure 5.2) are very similar. This behavior indicates a very small displacement leading to rupture at ultimate load followed by a small slip (Figure 5.1). Experimental work reported by Parameswaran (1978 b) on model piles in frozen Ottawa sand showed a similar *See Michel (1978) for the coefficient of thermal expansion of ice. 180 load-displacement behavior. The Wedron sand appears to have properties similar to the Ottawa sand except for possibly grain shape. As shown in Figure 6.2, the ultimate adfreeze bond strength occurs at small dis- placements, followed by immediate rupture. The displacements in Figure 6.2 are normalized with respect to the rod (pile) diameter. The 25 percent difference in strength was probably due to a difference in soil types, rod surface roughness, and test conditions. The creep behavior observed for plain rods in Figure 5.32 (a) and (b) was similarly reported in the literature. Vyalov,et al. (1973) stated that one of the model piles in ice (at -O.4°C) remained under a pulling stress of 4.26 psi for 1200 hours without any noticeable displacement, but then it suddenly pulled out. The effect of rod diameter on frozen sand bond strength, Figure 5.18, does not agree with the findings reported by Frederking (1979) ; for wooden piles in ice (Figure 2.9). On the other hand, the results showing effect of ice thickness on bond strength in Figure 2.9, agree with a similar trend observed on frozen sand in Figure 5.19. The theoretical work of Mohaghegh and Coon (1973) also supports an increase in adhesive strength with increasing ice thickness for the case of thick circular plates. ‘Although the effect of rod diameter does not agree with Frederking's findings, it would agree reasonably well with the general trend if one considers the combined effect of d and H in terms of the ratio d/H. Combining Figures 5.18 and 5.19 on one plot, for T = —10°C, gives the relationship between Tu and d/H shown in Figure 6.3. A ratio of d/H in the range of 6 percent to 10 percent appears to be an optimum 181 one in yielding the maximum bond strength. The dashed line represents both lines in Figure 2.9 plotted versus log (d/H) in Figure 6.3. Regardless of the numerical values, the general trend of decreasing bond strength with increasing d/H, in the range shown, is the same in both the present study and Frederking's study. The temperature effect on bond strength of frozen sand appears to agree reasonably well with field tests conducted by Crory (1963) on 8 in. diameter steel pipe piles in frozen sand slurries (Figure 6.4). Data from Figure 5.3, interpolated to a loading rate of 7 lbs./ min., is equivalent to the 10 kips/day indicated on the ultimate strength curve of Figure 2.11. In fact, Crory's dashed line in Figure 6.4 gives 50 percent higher values than those of the ultimate strength curve of Figure 2.11. This is explained by Crory's (1963) statement that a well-graded sand slurry, vibrated in place, has an I adfreeze strength about 50 percent higher than its silt counterpart at the same temperature. Differences between Crory's values and those given in this study may be due to scale effect, test conditions, and dry densities (sand concentrations). Small differences in dry densities makes a significant difference in the adfreeze strength, as shown in Figure 5.31. For sand concen- trations greater than 50 percent (82.7 lbs. per cu. ft. dry density) the frictional component of adfreeze strength becomes more significant. The long-term adfreeze strength Tlt proposed by Vyalov (1959) in Equation 2.11 for 6 in. diameter timber piles in frozen silty sandy loam is also plotted in Figure 6.4 for comparison. At warm temperatures (above -3OC) the agreement between the three studies appears to be at its best. .——.___’ . L...- .9" “‘2 _.' ' ‘ *')- ‘- 7 -— 7 7? Aq- 1. ,I_, 182 At this point, it is convenient to distinguish between the two components, ice adhesion and sand friction, by plotting a typical load-displacement curve for a test on ice and one for a frozen sand. Figure 6.5 clearly shows the difference in ultimate and residual loads. Crushed ice was chosen to simulate the polycrystalline ice believed to exist in the frozen soil. Although the initial (at rupture) displace- ment, or, for frozen sand in Figure 6.5 is slightly larger than that for ice, the difference is only part of the experimental scatter. Both materials, ice and frozen sand, showed essentially the same average initial displacement, about 0.002 in., considering the difficulty with precise displacementmeasurements on the recorder. Also, the initial displacement for all plain rods in iceIand frozen sand specimens ap- peared to be independent of temperature and loading rate. A slight decrease in the displacement was observed at loading rates higher than 200 lbs./min., especially in ice specimens. The initial displacement includes elastic bond displacement, rod extension, deflection of the reaction beam shown in Figure 3.1, and deformation of the frozen specimen. The latter was estimated to be about 8.0 X 10‘6 in. for a maximum load of 3000 lbs. applied to plain rods in frozen Wedron sand. Data from previous work (Bragg, 1980) was used in the calculations. The corresponding rod extension was esti- mated to be 3.26 X 10'“ in. using Hook's law and a steel elastic modulus of 30 X 106 psi. The reaction beam deflection (as a simply supported beam) was estimated to be 3.0 X 10"5 inch. The total deflection due to the system stiffness (about 3.5 X 10'” in.) appears to be negligible in comparison to the average 0.002 in. initial displacement. This .. _.___-_,_. -4. 183 displacement increased with increasing rod surface roughness as shown in Figure 5.27. The increase was probably due to interaction between sand particles and steel surface roughness, and which requires larger displacements for mobilization. The greater adfreeze bond strength for frozen sand, compared to ice, develops because the presence of rigid sand particles adjacent to the steel requires that a large volume of the ice matrix be involved in the failure process. Another comparison between ice adhesion and sand friction can be made using data for frozen sand in Figure 5.17 and data for crushed Ice (2) in Figure 5.29. The best-fit lines for data from both figures are reproduced in Figure 6.6 with residual loads for ice and frozen sand (from Table 5.2) plotted against tempera- ture. At ultimate loads the frictional component ruf contributes about 50 percent to 60 percent of the total adfreeze strength for the frozen sand. The frictional component becomes more significant for residual loads, Trs. The frictional contribution Trf to residual loads ranges from 78 percent to 84 percent. Note that these percentages are some— what high due to the presence of water impurities in the crushed Ice (2), which was formed from ordinary tap water. The choice of crushed ice, for comparison in Figure 6.6, was made instead of the snow-ice because the latter had the highest data scatter as shown in Figure 5.29. Also, the crushed ice strength values in Figure 5.29 are intermediate between the two extreme types, Ice (1) and Ice (3). The error, of under-estimating the adhesive strength for polycrystalline ice (in sand pores), is believed to be compensated by ignoring the contact area between sand grains and steel 184 rod. However, Lambe and Whitman (1969) reported that measurements of the contact area between sand particles (about 0.06 mm in. diameter) showed that typically it is approximately 0.03 of the total area. For quartz, with a hardness of about 1100 kg/mmz, the stress on an asperity (in contact with the steel rod) must exceed 1,500,000 psi to produce plastic deformation. The frictional component is, therefore, only slightly affected by neglecting the contact area of sand grains in the calculation. The adhesion and friction components also vary with the displacement rate at a given temperature along with surface (or pile) type as shown in Figure 2.13. In this figure, Parameswaran (1981) showed that the frictional contribution varied from about 84 to 93 percent of the total adfreeze strength of frozen sand to steel piles. This over-estimated percentage (at ultimate loads) was made when Parameswaran under—estimated the percentage of ice contribution. He simply multiplied the ultimate values of ice adfreeze strength (solid lines in Figure 2.9) by the porosity of frozen sand (0.2377) in order to obtain the dashed lines in Figure 2.12. In doing so, he had attempted to simulate the polycrystalline ice which exists in the sand pores. The ice represented in Figure 2.9 may not be polycrystalline ice since it was prepared by freezing the distilled water which had been poured around the pile to the required height, .1.2 Lug Bearing: The addition of a single lug, by welding, to a plain 3/8 in. iameter rod permits bearing action of frozen sand on the lug to ontribute to the total pull-out load. To illustrate the relative 185 contribution of each component, load-displacement curves for ice and frozen sand, both with a plain rod, and a third curve for frozen sand with a plain rod and single lug, are plotted in Figure 6.7. Two stages considered for comparison include the "initial yield" (failure) and the ultimate load (large displacement) conditions. The lug contribution has now been added to the ice adhesion and sand friction discussed earlier. The displacement curves for specimens with lugs show initial behavior characteristics similar to those observed with plain rods. After the initial rupture, mobilization of lug bearing prevents the load from dropping to the residual value. When the "initial yield" loads, P , for rods with lugs are compared W with the ultimate loads. Pu’ for plain rods at different temperatures (Figure 6.8) the lug contribution ranged from about 25 percent at -26°C to about 75 percent at -2°C. Considering the ultimate condition at large displacements where the total load was transferred almost entirely to the lug (Figure 6.7) the adhesion and friction become negligible. Comparing the ultimate lug loads Pu with the residual loads Pr for frozen sand from Figure 6.6, the lug contribution (P1 in Figure 6.9) ranges from 90 percent at -26°C to 100 percent of the total load at 0°C. Similar conclusions can be drawn on comparing lug contribution with the residual load for different lug sizes (Figure 6.10). In Figure 6.10 lug contribu- tion increased from an average of 85 percent of the total load for h = 1/64 in. to 95 percent for h = 3/16 in. at temperatures of -10°C and -20°c. It is of interest to compare the pull-out loads for plain rods and lugs with the uniaxial compressive strength “U for frozen sand. To —7— -- -1 -.-“--- _ ... _- _.. _ . 186 do so, strength data from Bragg (1980) are compared with the ultimate lug pull-out capacity Pu’ the "initial yield" loads Pi , and the ultimate y bond strength Tu in Table 6.1. Values for the uniaxial compressive strength correspond to an average strain rate é of 3 X 10'6 per avg. sec. in Bragg‘s (1980) Figure 5.9. This strain rate corresponds to a nominal machine displacement rate In of 5.0 X 10'” in./min., calculated by multiplying é times £0 (= 2.82 in.), where to was the length of avg. uniaxial test samples in Bragg's (1980) study. Note that comparisons based on equal displacement rates in both types of test (bond and uniaxial comparison tests) do not mean equal strain rates. Differences in sample size, test conditions such as applied confining pressures, and other factors onld not yield equal strains in both tests. Equal displacement rates were chosen only to make the comparisons under similar conditions. There is some similarity in both tests because frozen soil experiences compression under the lug and also in the uniaxial compression test. Comparisons are made for lug movement at the same rate as the loading ram in the compression test (neglecting any differences due to machine stiffness). The data in Table 6.1 are plotted in figure 6.11. Although the relationships are not linear, they are approximated by straight lines which pass through the origin, except for the ru-vs-c relationship. By analogy to Equation 2.17 the ratio of bond strength, including lug bearing, to the frozen sand cohesion (C.= oU/Z) ranges from 0.190 for plain rods to 0.390 for lugs. Values of‘k suggested by Weaver and Morgenstern (1981 b) in Equation 2.17 ranged from 0.6 for plain piles to 1.0 for corrugated iles, with c-values evaluated on a long-term basis. W0 standard efinition for "corrugated” piles was mentioned by Weaver and Morgenstern 187 (1981 b). For comparison purposes the cohesion (c = ou/Z) was defined on the basis of a horizontal Mohr-Coulomb envelope (a = 0). Should this envelope be inclined to the horizontal at an angle ¢, values of c would be slightly reduced, thus increasing the values of K for this study. A comparison also can be made between the lug bearing capacity q1 (lug contribution P], in Figures 6.9 and 6.10, divided by the lug area A1) and the uniaxial compressive strength cu. Such a comparison, shown in Figure 6.12, was based on equal displacement rates for both tests. As shown in Figure 6.12 the relationship is not linear but can be approximated by a straight line. This relatidnship indicates that the ultimate lug bearing capacity is about seven times the uniaxial com- pressive strength of frozen sand. 6.1.2.1 Lug Behavior in Frozen Sands: Lug behavior in frozen sand may be considered analogous to a deep plate (or footing) in frozen ground. Experimental work reported by Ladanyi and Paquin (1978) using a standard penetrometer (1.4 in. dia- meter) in a frozen quartz sand (e0 = 1.034, Vs: 49.15 percent, Cu = 2.27) provides comparative data for use with the lugs. The penetrometer placed at a depth of 18 in. can be classified as a deep footing. Data sum- marized in Figure 2.15 have been transformed into punch stress versus creep rate on a log-log scale in Figure 6.13 and compared with data from Figure 5.40 for a 1/8 in. height lug (equivalent punch diameter equals d + 2h = 0.625 in.). Both tests were conducted at -6°C. Both relationships are almost linear, especially for the penetrometer. The two lines are almost parallel indicating that a similar mechanism =.-—-fi-' “4“?” ' _‘cc '- A 188 appears to control the creep rates in both cases. ‘The main reason for a difference in creep rates (or strength) is believed due to the difference in void.rat105 (or sand fractions) 0f the two sands. The importance of sand fraction on lug bearing loads has been shown in Figure 5.49. A reduction in the sand fraction from 64 percent to 49 percent at -100C resulted in a load reduction close to 49 percent for creep rates of 10‘“ in./min. or 10"5 in./min. A larger reduction would be anticipated at warmer temperatures such as ~60C. Additional factors responsible for the difference in applied stress shown in Figure 6.13 involve the punch diameter, 0.625 in. for the lug versus 1.4 in. for the penetrometer. The significance of this difference in diameters is shown in Figure 5.41 and from Vyalov et al. (1973). When the P-values (in pounds) from Figure 5.41 were normalized with respect to the lug area A] to give q1 = P/A1 ( as punch pressure in psi) the solid-lines in Figure 6.14 were obtained to help explain the difference between curves in Figure 6.13. These lines clearly show that creep rate increases with an increase in lug size for the same stress level. This result is also supported by the experiments conducted by Vyalov,et al. (1973) on punches of three different sizes loaded in ice at -2.3°C. For comparison the results of those experiments are included in Figure 6.14. Their data indicates that as the punch diameter was increased from 1.26 in. to 12.6 in. (10 times larger) the punch pressure decreased about 50 percent to 70 percent. For the present study, increase in lug height from 1/16 in. (0.50 'n. equivalent punch diameter) to 3/16 in. (0.75 in. punch diameter) aused a reduction in pressure of about 17 percent to 20 percent, 189 depending on the stress level. The difference in punch sizes indicated in Figure 6.13 may, therefore, have contributed about 25 percent to the total reduction in strength shown. Note that the comparisons made in Figure 6.13 are valid for the range of creep rates indicated, which do not necessarily coincide with the same range of strain rates at which the uniaxial compression tests on both sands were conducted. Ladanyi and Paquin (1978) indicated that when trying to relate the behavior of a deep footing (punch) with that of a representative soil sample under triaxial test conditions, the problem most difficult to solve is usually that of selecting the strain rate in the test that would be representative of the average strain rate of the soil during pene- tration. Since the strain rate around a footing decreases continuously with distance, various interpretations are possible. The one considered by Ladanyi and Paquin (1978), relates the penetration rate of a circular footing with the time to failure of a soil eIement located below the base in the line of penetration, by a semi—empirical expression, the same as proposed by Ladanyi (1976). Based on that expression the two authors estimated that a range of penetration rates, from about 2 X 10-6 to 1.1 X 10“3 in./min., for their punch size of 1.4 in. diameter (Figure 6.13), would be equivalent to a strain rate of about 1.8 X 10"8 to 8.3 X 10’6 per second. In fact, both ranges are lower than the lowest applicable creep or strain rates in their experiments. The difference in depths of punch embeddment in Figure 6.13, do not iPpear to be a significant factor. As noted in Section 2.5, when a punch ;ettles more than about 5 percent of its diameter, the soil enters into , viscoplastic region and the effect of burial depth becomes negligible. 190 Under such conditions, no effect of burial depth was observed for depth to diameter ratiolJVB between 3.3 and 5.0 in ice (Sego, 1980) and between 5 and 15 in frozen sand of Ladanyi and Paquin (1978). The decrease in creep rate, noted in Figure 2.16, with the increase of burial depth is, probably, due to the fact that the settlement did not exceed 1 percent of the footing diameter. Since the lug penetration, or displacement, 6, exceeded the equiv- alent footing diameter (more than 200 percent) the burial depth did not appear to have any effect on the lug creep rate. This may be observed from Figure 5.43, where the lug position 2 was changed from 1.5 in. (D'/B= 4.5/0.635 = 7.2) to 4.5 in. (D'/B= 2.4). The equivalent depth of embeddment D' was measured from the sample top surface (at z = 6 in.). It is believed that some reinforcing effect by the steel rod to which the lug is welded, may be involved in eliminating the effect of burial depth on the lug creep rate. The steel rod would prevent any side tilting of the lug, which might occur at shallow depths. Lug position was also studied relative to possible interaction between the lug and the base plate. Data summarized in Figure 5.43 also imply that with the lug position as close as 1.25 in. (1.50 less 0.25 in: of total creep displace— ment) to the base plate, the creep rate was not affected. Due to equipment limitations, the distance 2 was not made smaller than 1.25 in. This minimum distance, which showed no interference between the lug and reaction base plate, corresponds to aIJUHBratio CI 7.6 (= 4.75/0.525) and to a z/B ratio of 2 (= 1.25/0.625). 191 6.1.2.2 Lugs versus Standard Deformed Bars: The measured peak loads for a standard deformed bar (d = 3/8 in., h = 1/64 in., lug spacing = 0.3125 in.) shown in Figure 5.21 were trans- formed into single lug loads as indicated in Figure 5.22. For example, the peak load for the 3 in. sample height (about 4000 lbs. in Figure 5.21) was divided by the number of lugs (10) after subtracting the residual load of 60 lbs. (= 120 X 3 in./6 in.) for the corresponding plain rod, i.e. P = (4000 - 60)/10 = 396 pounds. The latter was then added to the 120 lbs. residual load, giving a total of 516 lbs. load for a 6 in. sample height with a single lug. Similar calculations were applied to the 2 in. sample height in Figure 5.21 in order to obtain the two data points indicated in Figure 5.22. Although these points agree well with experimental data points for other lug heights, there is a dif- ference in the load-displacement behavior for the standard deformed bar (compare Figure 5.20 with 5.21). The decrease in load after about 0.04 in. displacement (Figure 5.21) appears to be due to : (1) the lug inter- action effect, and (2) the small ratio of lug height (0.015 in.) to the maximum particle size (0.023). Little or no interaction between the reaction base plate and the nearest lug was anticipated because of adequate clearance between the deformed rod and removable washer in the support plate. Besides, if the lug spacing to lug height ratio were to be considered it would be large enough (0.3125/0.125 = 21) to prevent any interaction between the lugs. The interaction should, therefore, be explained in terms of the ratio of lug spacing to equivalent punch width, which is in this ase less than one (0.3125/0.405). Such lug interference is illustrated 'n Figure 6.15. As shown in this figure, when the soil stress under the ‘vngr-.\- sitim' '4 I» .1 - . 192 ‘ top lug (No. 1) is go, the stress under the second lug would be 1.27qo using Boussinesq's stress distribution. Soil stresses under successive lugs can be evaluated in a similar manner as shown in Figure 6.15. It has been estimated that a maximum stress of 1.37 qO occurrs under the sixth lug, where its value remains constant for subsequent lugs. If the above assumption is reasonable, failure would initiate in the soil under the bottom lug and move upwards, due to lug interaction. As the lug penetrates into the soil, it leaves a gap equal to the dis- placement, thus weakening the support for the next lug. When the ultimate load is reached, the gap would have reached its limiting size, the soil support would decrease and hence the load for any further displacement (beyond 0.04 in.) as shown in Figure 5.21. In addition to lug interaction effect, when the lug height is smaller than the particle size the frictional and dilatational components may not be fully mo- bilized in front of the lug. A creep test on the 3/8 in. diameter 1 standard deformed rod (Figure 5.42) indicated a reasonable agreement I with tests on other lug heights as shown in Figure 5.41. In general, - standard deformed rods tolerate smaller displacements at failure than i single lugs (compare 0.04 in. in Figure 5.21 with 0.30 in. in Figure 5.20). 6.1.2.3"L0ng+Term Lug Bearing Capacity: The data shown in Figure 2.4 suggest that frozen soil strength decreases exponentially with time to failure. The relationship described by Equation 2.1 indicates that the long—term strength (when tf goes to infinity) is zero. Vyalov (1963) pointed out that after some long period of time the additional strength reduction is so insignificant Jh—._" v _‘ A... 193 that it can be neglected in engineering calculations. The same con- clusion applies Us the lug behavior in frozen sand. A plot of load versus time to failure was prepared, for all creep tests on single lugs at -10°C, and is shown in Figure 6.16. In this figure, the time to failure tf was defined as the time required to achieve a certain displacement since complete tertiary creep failure was observed only on the last load increment. Excessive displacements (such as 0.25 in. or 1.0 in. as shown in Figure 6.16) may be considered as the basis for defining failure. Values of tf corresponding to a certain load increment were obtained by extra- polation. The displacements 0.25 in. (or 1.0 in.) were divided by the creep rate corresponding to that load increment, after subtracting the ”pseudo" instantaneous elastic displacement 61 andvalues of t.1C are listed in Table 6.2 for different load increments on a 3/8 in. rod with a 1/8 in. lug height in frozen sand at -100C. The data summarized in Figure 6.16 indicate that the long-term load capacity was about 32 percent of the instantaneous capacity for 0.25 in. allowable displacement, and about 38 percent for a 1.0 in. maximum allowable displacement. Thus, assuming about 4500 lbs instantaneous strength for both cases, any load less than about 1800 lbs. in Figure 5.40 would not reach a secondary creep rate stage within the experimental times used. Creep rates for loads below the long-term strength would continue in the primary stage and attenuate until the rate approached zero at infinite time. Creep rates for initial loads below 1800 lbs. in Figure 5.40 would be over-estimated if they were considered as secondary creep rates, even though they were measured at the end of that step loading. Also, at the small initial loads the adhesion and friction —>——_ - ‘3- 1"-“ 1‘. a x. .- T‘V' . _l ,- ‘ 1 A‘v :- 194 contribution along the rod was significant (Figure 6.8), thus giving some errors in creep measurements, especially at colder temperatures (below -IOOC). However, at large displacements the lug contribution becomes far more significant (Figure 6.7) and neglecting the residual loads would not cause significant errors. 6.1.2.4 'Sample Size and Sand Concentration: The effect of sample diameter on the creep behavior of lugs in frozen sand has been considered in Figures 5.44 and 5.45. Note that sample diameters greater than about 4 in. would not affect the pull-out capacity for the bar and lug sizes used in this study. The reduction in strength at diameters smaller than 4 in. may be attributed to (1) the contrib’ ution of sample deformation to the total creep, and (2) the increased effect of stress concentration under the lug area. For sample diameters greater than 2 in., it was estimated that sample deformations under a 4000 lbs. load would be negligible in comparison to soil creep under the lug. Therefore, stress concentration under the lug area is believed to be the main factor in reducing the load for sample diameters less than 4 inches. For these smaller diameters, visual inspections of samples after failure indicated that rupture had occurred on planes inclined at about 600 from the horizontal, thus suggesting that the soil samples may have failed due to stress concen- tration. The latter also produces high tensile stresses in the tangential e—direction with possible failure in tension. The effect of sand concentration on lug bearing, summarized in Figures 5.48 and 5.49, may be compared with similar effects on the uniaxial compressive strength summarized in Figure 2.5 for Ottawa sand. 195 The average grain size of Ottawa sand used by Groughnour (1967) was 0.0306 in., slightly larger than that of the Wedron sand used here (about 0.0138 in.). Besides, the Ottawa sand grains were well—rounded compared to the sub-angular shaped Wedron sand grains. Other properties are believed to be almost the same for both sands. To make possible a closer comparison, one curve has been chosen from Figure 2.5; that corresponding to -12.03°C and a strain rate of 1.33 X 10-” per min. ‘This rate appears to correspond to a nominal (machine) displacement rate of about 3 X 10-“ in./min., based on a sample length of 2.26 in. used by' Goughnour (1967). Load values were interpolated from Figure 5.48, for 6c of 3 X 10'” in./min. and different sand concentrations. These loads were increased by about 13.5 percent to allow for the decrease in temperature from -10°C to -12.03°C. Using Figure 6.9 the ultimate loads in Figure 5.24 were reduced by 240 lbs. to account for the residual shear loads along the rod. A residual load of 90 lbs. at —12°C for the ice sample (vS = 0) was considered in the calculations. The adjusted loads were divided by the lug area to obtain the lug bearing pressure q]. Values of q] are plotted versus sand concentration vS in Figure 6.17. The unconfined compressive strengths cu, show bi- linear relationships with Vs' Although the lug bearing may not vary linearly with sand concentration (Figure 5.49) it was approximated by two straight lines whose intersection point gives a critical sand con- centration close to 43 percent sand by volume. This point, which is quite close to the 42 percent observed by' Goughnour (1967), appears to indicate a change in the failure mechanism for frozen sands. This sand concentration corresponds to a porosity of 0.580 which is close to 196 0.476 for the loosest possible packing of uniform spheres (in cubical array) listed by Harr (1962). Therefore, at the critical volume concentration, sand grains just begin to make contact as the soil behavior becomes dependent on the closeness of adjacent sand particles. Goughnour (1967) reported that samples of frozen Ottawa sand with more than 42 percent sand by volume showed a more rapid initial volume decrease (under compression tests) followed by a volume increase which progressed at an increasing rate, and was similar to the volume increase of dense unfrozen sand (Bishop and Henkel, 1962). Goughnour suggests that three mechanisms may serve to strengthen samples made with sand and ice versus those of pure ice. The first is associated with sand volume concentration in the sample and is probably caused by virtually all ice plastic deformation. This mechanism may explain the behavior represented by the first line segments in Figure 6.17. The second mechanism is associated with grain to grain contact and is the result of friction at these contacts. The third mechanism is associated with volume increase of dense samples and has a counter- part in unfrozen sand. The sample volume increase is impeded by the ice matrix. Thus the ice matrix effectively exerts a confining pressure on the sand particles. The effect of this ice exerted pressure is to increase the effective stress on the sand skeleton, thus increasing its resistance to deformation similar to unfrozen soil. This "equivalent“ confining pressure continues to increase until dilatancy levels off at a critical void ratio or the limiting ice cohesion is overcome. 197 6.1.2.5 Lug Bearing in Ice: The lug behavior observed under the initial load increment in Figures 5.46 and 5.47, for samples with a sand fraction below 50 percent, appears to support Goughnour's (1967) first mechanism. He suggested that virtually all of the plastic deformation is accomodated by the ice matrix. This appears possible only when the sand friction and dilatancy do not significantly contribute to the total resistance. As shown in Figure 6.17 these components begin to develop at a sand fraction close to 42 percent. There may be some reinforcing effect by the sand grains which would impede the deformation mechanism of pure ice. Below the critical sand concentration (about 42 percent), the lug behavior ap- pears to be mainly influenced by the ice deformational characteristics. In this case, seven deformation mechanisms have been identified by Gold (1963) in observing surface features of ice during deformation. These include slip bands, grain boundary migration, kink bends, dis- tortion of grain boundaries, crack formation, cavities, and recrystallization. Since ice creeps under very small stresses (Vyalov, 1963) the behavior observed in Figure 5.47 cannot be attributed to these seven mechanisms. The initial delay in the creep of snow-ice under pressure appears to be caused by bond (shear resistance) along the rod. This bond was mobilized at much smaller displacements as compared to lug bearing. .The delay time observed in Figures 5.46 and 5.47 for the 520 lbs. initial load increment can be considered as the time to failure of the bond resistance under that load. Since the creep displacement at bond failure would have been too small to measure 198 with the available equipment, no precise correlation can be made between the sand fraction and time to failure (or the initial delay time). From a careful consideration of the snow-ice behavior shown in Figure 5.48 one may conclude that a residual bond resistance of about 200 lbs. along the bar may have caused higher loads in some of the snow- ice samples as compared to the sand-ice samples. Otherwise, there is no reason why the data points would not be consistent with the dashed line extrapolated from the data point of test number CI-I (Figure 5.47). This data point appears to be a coincidental point in which the residual bond resistance may have been the least. For snow-ice and sand—ice (sand fraction below 50 percent) samples prepared by pre-Cooling the mold and the rod below 0°C a thin layer of ice was observed around the rod soon after adding pre-cooled distilled water. For those samples the bond resistance along the rod may be due mainly to ice adhesion. That is probably why the initial delay time was not much affected by the sand fraction. Since the snow-ice was expected to have the lowest lug bearing compared to the sand-ice, the bond contribution in the latter may also be less significant than in the snow-ice. No correction for the residual bond (due to ice adhesion) was made in Figure 5.48, since it should be negligible in sand~ice and no accurate measurements for its value in snow-ice was possible due to equipment limitations. 6.2 Creep versus Constant Displacement Rate Tests: Comparison of strength data from constant strain rate tests and data from creep tests was made by several authors (Goughnour, 1967; Hawkes and Mellor, 1972; Bragg, 1980). In this study, the adfreeze bond ___.— — 9‘2-"&.g —n._r ~I.;-~~l~ "' .3 — 199 strength for plain rods in frozen sand from constant displacement rate tests has been compared with the strength from creep tests as shown in Figure 6.18. There appears to be a reasonable agreement between the results from both tests. Assuming that the observed displacement rates (6n and 6C) are representative, there appears to be a transition from creep data (slow rates) to constant displacement rate (high rates). The change in slopes of the lines in Figure 6.18, at about 10'“ in./min., indicates a change in the strength mechanism upon transition from slow creep rates to the fast displacement rate for both temperatures. For lugs, the displacement rates for both test types were approx- imately in the same range (Figures 5.6 and 5.36). The lug capacity from creep tests is plotted against lug capacity from constant displacement rate tests, at different temperatures, lug sizes, and creep rates, as shown in Figure 6.19. The data in Figure 6.19 indicate that creep tests produce lug capacities which are slightly higher than those obtained from constant displacement rate tests. It is believed that this higher strength was a result of some densification and stiffening of the frozen sand in front of the lug during creep. The difference is, however, small and might be neglected for practical purposes. 6.3 Correlation of Experimental Results: The empirical equations deduced in Chapter V are combined in this section in order to give a composite equation which relates the lug capacity to the test variables. A similar equation has also been derived for the adfreeze bond strength of plain rods. 200 6.3.1 Plain Rods: The ultimate bond strength Tu of frozen sand (64 percent sand by volume) with a plain steel rod (5/8 in. diameter) was observed to depend on the nominal displacement rate én (machine speed) as shown in Figure 5.4 (and Equation 5.3). Bond dependence on the loading rate P was illustrated in Figure 5.3 and expressed by Equation 5.1, where TC and m (= l/n) are the temperature dependent parameters shown in Figures 5.11 and 5.12, respectively. Since measurements of loading rates were more reliable than the displacement rates, it seemed reasonable to use loading rates for further correlations. Substituting 10.5 a for Tc in Equation 5.1 (Figure 5.9) and with PC = 1 lb./min. gives the following relationship: 10.5 6 Im (6.1) Tu (psi) exp - (1.224 + 0.0886 6) as shown in Figure 5.12, and where m = 1/n e = -T. Since Equation 6.1 was derived for a 5/8 in. diameter rod (d), 6 in. sample height (H), rod roughness p of 625 percent, and sand fraction vS of 64 percent, these parameters may also be included in this equation. To do so, consider the combined effect of the ratio d/H using the data in Figure 5.18. The two regression lines are combined by plotting Tu/G versus d/H on a log-log scale. This eliminates the temperature effect and gives the empirical relationship shown in Figure 6.20. This procedure implies that at a given ratio d/H the bond strength Tu is a linear function of temperature a. This assumption appears to be true for all loading rates P below 6.0 lbs./min. as shown in Figure 5.9. Assuming that the optimum ratio of d/H is 10 percent (Figure 6.3) and neglecting the effect for d/H z 10 percent, the value of Tu in Equation 201 5.1 can be multiplied by (d/10H)S, where s = 0.692 if d/H g 10 percent and s = 0.0 if d/H z 10 percent. The roughness factor Q can be included by multiplying Equation 6.1 by (p/625)0'35“, using the relationship in Figure 5.28. The sand fraction vS was included in Equation 6.1 by replotting the data in Figure 5.31 on a log-log scale. An experimental power law of the form shown in Figure 6.21 can be deduced, applicable for v a 45 5 percent. Combining all test variables into one equation leads to TI (psi) = 10.5(P°)"‘ (II/625W3‘5‘*’42 percent in Figure 5.49, is dependent on the creep rate. The latter condition complicates the solution. It means that for every value of creep rate a certain empirical equation must be used to account for the sand concentration effect. Although several procedures can be made to avoid this compli- cation, plotting the load P versus sand fraction vS on a log-log scale appears to be the simplest procedure. Choosing an arbitrary creep rate, say 0.0005 in./min., the load 204 P can be interpolated from Figure 5.48, and plotted against the cor- responding vS values on a log-log scale as shown in Figure 6.25. The linear relation suggests a power law of the form: q (psi) = 15790 (vs/54)2.6su (valid for vS a 45 percent sand by volume) (6.7) The overall effect of different factors may be considered by combining Equations 6.5, 6.6, and 6.7 to give the following composite empirical equation: q (PSI) = 0.2288 (1 + a)0-6 (éc)o.203 (A1/Ar)-0.191 V52.654 (6.8) The range of experimental data limits Equation 6.8 to the following conditions: 20C 3 e s 20°C 10-5 in./min. : éc g 10-2 in./min. 0 g Al/Ar g 3 v5345 percent sand by volume The remaining question involves a relationship between the applied lug bearing pressure q and time to failure tf. Most creep curves for sand- ice specimens did not reach tertiary creep within a relatively short time period, say less than 24 hours, except at large loads (more than 4000 lbs.). In constant displacement rate tests, the time to failure varied from a few hours up to about 36 hours. Besides, the failure was clearly defined by two peaks (see Figure 5.20). In creep tests, it appears reasonable to use a certain limiting creep displacement 6f as a basis for creep failure criterion in the frozen sand. This has the advantage of limiting the total displacement to acceptable values 205 in the design. From the displacement behavior for a constant stress creep test (first load increment in Figure 5.34) it follows that: 5f = 5i + tf If (6-9) where 61 is the pseudoeinstantaneous displacement. A small part of this displacement is elastic, which may be neglected, and the major part is plastic (irreversible). Equation 2.6 shows that the plastic strain (second term) is related to the applied stress by a power law. By analogy, a similar power law may be deduced by plotting the measured displacements 61 versus the applied lug load P (Figure 6.26). Dividing the empirical equation shown in this figure by the lug area gives: 8i = 8.3 X 10‘8 ql"+29 (6.10) By rearrangement of variables in Equation 6.8 and some calculations, the creep displacement rate 0C is given by: 'C = —2.95 0.941 —13.07 4.93 6 8980 (1 + e) (Al/Ar) vS q (6.11) Substituting for a, and 6C from Equations 6.10 and 6.11, respectively, into Equation 6.9, and rearrangement of terms gives the time to failure tf: 5f - (8.3 X 10'8) ql'h‘29 tf = 8980 (1 + e)-2.95 (A1/Ar)0.941 VS-13-07 qho93 (6.12) To compare Equation 6.12 with some of the experimental data, the "failure" or limiting displacement 5f should be defined. Values of 0.25 in. and 1.0 in. were earlier selected as convenient limiting dis— placements, a The time to failure tf was observed for these limiting f0 displacements and the corresponding applied load was noted. For step 206 loading creep curves, an extrapolation procedure was used to estimate some values of tf. The data are summarized in Table 6.3 and plotted in Figure 6.16. This figure shows that lug bearing pressure decreased with time until it reached a finite value q1t after a fairly long time. Neglecting 6,, Equation 6.12 predicts that the lug bearing capacity will go to zero as tf approaches infinity. Figure 6.16 suggests that the long-term lug bearing capacity, q1t, does exist since infinity is far beyond the usual service life. Note that when the applied lug pressure is lower than qlt’ the secondary creep rate becomes practically zero. For these reasons, it appears reasonable to replace q in Equation 6.12 by (q-q1t). In this case the lug bearing capacity q would tend to a finite value q1t as tf tends to infinity. The data in Figure 6.16 may now be compared with Equation 6.12. Only data points corresponding to 1.0 in. limiting displacement are re- plotted in Figure 6.27 on a log-log scale. Experimentally derived data and failure times predicted by Equation 6.12 (dashed lines) are in reasonable agreement. 6.4 Theoretical Predictions: This experimental study has been primarily concerned with pull-out loads for a steel bar embedded in a small frozen sand sample. A model pile or anchor section is preferred when they save money and when questionable assumptions are required for analytical methods. There are some limitations imposed on straight-forward application of the results from model tests to full-scale structures. Rocha (1957) suggests that the following conditions must be fulfilled; the geometry, stresses, strainssdisplacements, time required, Poisson's ratio, modulus of 207 elasticity and other properties of the model should be proportioned to those of the field structure. The main purpose here is to adopt some of the analytical methods, using the basic creep parameters of frozen Wedron sand (Bragg, 1980) and the available theories, in order to predict the pull-out capacity of plain and deformed rods. The failure mechanisms of plain rods are different from those of lugs. The two cases are, therefore, treated separately. A theoretical attempt has also been made to relate both cases to the roughness criterion defined in Equation 5.7. 6.4.1 'Bond for Plain Steel Rods: The stress and displacement analysis for frozen soil surrounding a plain rod (Figure 2.12) reviewed in Chapter II may now be adopted for comparison with the present experimental data. Equation 2.13 suggests that creep parameters from simple shear tests can be used to predict the bond vs. displacement rate relationship for a plain rod in frozen soil. Since some data (Bragg, 1980) from unconfined compression tests on frozen Wedron sand are available, the shear strain rate Ic from Equation 2.15 may be used, with the proof stress TC replaced by Ocue’ in Equation 2.13 to give: 399”2 ( / )“/(n-1) (6.13) c Ta Ocue For given values of a, n, e , and Ocue the relationship between C Ta and 0 can be established for a given temperature. Consider, for example, the experimental lines in Figure 6.18 for the -10°C, and a 5/8 in. diameter plain rod (radius a = 5/16 in.). Using the available data (Bragg, 1980) on frozen Wedron sand, with n = 11.765, éc = 6.0 X 10‘5 208 min.’1, and “cue = 1875 psi at —100C, Equation 6.13 was plotted on a log- log scale in Figure 6.28. The theoretical solution provided by Equation 6.13 significantly over-predicts the bond strength in comparison with the experimental lines in Figure 6.28. This large difference between the predicted and experimental strength values may be partly attributed to the difficulty with precise measurement of small rod displacements due to equipment limitations. Also, the difference between the predicted and experimental values appears to depend on the proper choice of o and éc for use in Equation 6.13. For example, using 0 = 7067 psi cue and éc = 60 min.'1, as given by Bragg (1980), in Equation 6.13 would CUB reduce the predicted bond strength by about 13.5 percent. Equation 6.13 was derived (Johnston and Ladanyi, 1972) for piles in permafrost ground with boundary conditions slightly different from those applicable to the pull-out specimen. For example, the effect of soil stresses at the base plate on the strains around the rod were ignored. Derivation of Equation 6.13 clearly implies that the n-value for bond and compression tests is the same, thus assuming the same failure mechanism for both tests. Experimental data (Table 6.4) showed that the n-value from creep bond tests is about 31 percent of that from compression tests, and its value from bond tests with constant displace- ment rates is about 88 percent of that from compression tests, as shown in Figure 6.29. Therefore, the failure mechanism on the rod-soil interface is not the same as that on a shearing surface within the frozen soil. Jellinek (1957 b) observed that at temperatures warmer than -14°C (Figure 2.1) the adhesive strength of ice was smaller than its cohesive strength. At temperatures colder than -14°C he observed that all the breaks were cohesive, i.e. within the ice crystal, thus indicating 209 that the adhesive strength of ice to stainless steel at these temperatures was higher than its cohesive strength. In sand-ice materials, sand friction becomes a contributing factor to the total bond strength. The introduction of sand friction would make it difficult to assume whether or not the adhesive and cohesive mechanisms in sand-ice are the same, without further experimental work. It may be of interest to compare Weaver and Morgenstern's (1981 b) Equation 2.16 with some of the creep data on plain rods shown in Figure 6.30. Information on the time t, elapsed after load application, and the corresponding creep displacement 6C for use in Equation 2.16 were obtained from the creep curves in Figure 5.32(a and b). Weaver and Morgenstern (1981 b) assumed constant values for the creep parameters b, c, k, and m on the basis of available data on frozen Ottawa sand. As shown in Figure 6.30, the predicted (dashed) line considerably under-estimatesthe strength for frozen Wedron sand. This might be attributed to differences in particle surface features of Wedron and Ottawa sands. Also, calculations show that a slight change in the value of c, according to Equation 2.16, would significantly affect the results. No primary creep data on frozen Wedron sand are available, to show whether or not the c-value remains constant with temperature as assumed by Weaver and Morgenstern (1981 b). 6.4.2 Load Prediction_Based on Cavity Expansion Theory: Lug bearing forces can be predicted on the basis of cavity expansion theory. The solution proposed by Ladanyi and Johnston (1974) for frozen soils (Equation 2.18) was based on an analogy for an expanding spherical cavity in a linear elastic-plastic infinite medium (Hill,1950). 210 The theory uses experimentally determined creep parameters for frozen soils, thus modifying the model to be used for a non-linear viscoelastic- plastic medium. With this procedure it appears that creep settlement and bearing capacity of frozen soils under deep circular footings may be predicted. A comparison between the experimental data (Figure 5.40) for the lug behavior and Equation 2.18 can now be made. The lug area may be considered as the difference between two concentric circular footings. The inner circle corresponds to the rod cross-sectional area. The outer one corresponds to a footing with diameter d + 2h (or B), where h is the lug height. For given values of et, Ocua’ n, p0, and n the relationship between q and 6C can be established for a certain temperature. To apply Equation 2.18 unconfined compression test data from previous work (Bragg, 1980) on frozen Wedron sand was used. Bragg (1980) observed that the failure strain 5f was almost constant throughout the tests. At strain rates below 10'5 sec‘l, its value was about 0.045 independent of temperature. At higher rates the value of cf at all temperatures decreased slightly with strain rate indicating a more brittle behavior. For comparison, a constant cf value equal to 0.045 was assumed for use in Equation_2.19 at all temperatures. Values of Ocue’ c, n are temp- erature-dependent according to Bragg (1980). Using the condition of n = 1 if 6C a 0.1 B, the value of n was assumed to be 1.0, since the lug settlement 6 in all creep tests was larger than 0.1 B. The value of p0 was set equal to zero in all calculations, since no confining pressure was applied to the pull-out specimens. Results from these comparisons are summarized in Figure 6.31. The 211 predicted loads, P in this figure, were obtained by multiplying g, calculated from Equation 2.18 for each case, by the lug area. Note that the friction angle a was assumed to be constant, and equal to 300 for all temperatures and strain rates. This assumption seems reasonable since Ladanyi (1981) reported that the friction angle for most frozen soils is almost equal to that of the corresponding unfrozen soil. The predicted loads (dashed lines) in Figure 6.31, generally, over-estimate the loads at creep rates below about 10‘“ in./min. and appear to under- estimate the loads at higher rates. The reason appears to be a difference between n-values from compression tests and those from bond tests. If values of n from bond tests, were used in Equation 2.19 the predicted loads would be significantly improved. Since the experimental lines in Figure 6.31 are parallel to each other, they clearly indicate that the failure mechanism for a deep lug (or footing) in frozen sand is the same for all temperatures from —2°C to -15°C. A single value of n (4.93) can be assumed for these lines. Other reasons for a difference between the predicted and experi- mental lines in Figure 6.31 may include a difference between the actual lug shape and the assumed circular footing in the theory, or the presence of the rod which may prevent the formation of a complete semi- spherical plastic "cavity" zone under the lug. Assuming a perfectly plastic (incompressible) material within the cavity may not be entirely compatible with the observed behavior. Uniaxial creep compression tests on frozen sand reported by Bragg (1980) showed that the volumetric strain increased with the creep strain. It was not clear whether reducing the dilatancy by application of confining pressure would have any effect on the volumetric strain. Visual inspections after thawing of all pull-out specimens lead to the conclusion that continuous crushing of sand particles had occurred as the lug continued to penetrate through the soil. Crushing of sand grains was clearly shown by the observation of a thin layer of powdered quartz radially pushed into the frozen soil all along the deformed zone behind the lug (Figure 6.32). It appeared that prior to crushing of grains complete melting of frozen water must have occurred under the high pressure (estimated at 25,000 psi for sample 08-14). The condition in front of the lug may correspond to stage II in Figure 2.7. Pressure melting may have occurred locally around the lug as the lug continued to penetrate into the soil. A sudden failure was not characteristic of the sample behavior, hence global pressure melting did not occur. The cavity expansion theory assumes a maximum limit for the footing displacement 6C of 0.1 to 0.2 B. The experimental lines were based mostly on the step loading procedure. Under the initial load increments creep rates often did not reach the steady-state, as shown earlier in Figure 5.40, thus under-estimating the strength. Under the same loads the total displacements did not exceed 0.2 8 (Figures 5.39 a to c). At higher loads (over 2500 lbs.) the displacements far exceed 0.2 B without reaching tertiary creep (or failure), thus violating the assumption of a maximum 6 of 0.2 B in the theory. 6.4.3 "Roughness CriteriOn for Steel Rods: The pull-out capacity of plain rods increased with increasing rod surface roughness as shown in Figure 5.28. If the roughness factor defined in Equation 5.7 is modified, lugs can be considered a part of the rod surface roughness, as a large-scale asperity. In this case, 213 the question arises as to how much roughness a single lug will add to the plain rod. To help explain the procedure used to define a single lug "roughness" the actual heights of asperities SP (in micro-inches) observed on the profilometer for different steel surfaces have been listed in Figure 5.26. Also listed are the corresponding heights SR as measured on the strip chart recorder (in millimeters). The latter record was used as a basis for measuring the roughness factor of plain rods. To consider the lug as a large-scale asperity 0n the rod surface, a correlation was made between values of SP, minimum and maximum in Figure 5.26, with the corresponding values of SR as shown in Figure 6.33. The relationship in this figure was linearly extrapolated to include the actual lug height h, which is equivalent to SP in micro—inches on the profilometer and to SR in millimeters on the recorder. For example, if h = 1/8 in., the equivalent roughness SP = 125000 micro-inches on the profilometer and SR = 52090 mm on the recorder based on the relationship in Figure 6.33. This procedure is also illustrated in Figure 6.34. The information in this figure was calculated for a cold-rolled steel rod with a single lug (h = 1/8 in.) frozen into a 6 in. high sample. Assuming that the tracer stylus could be moved 6 in. along the rod, the equivalent length Lt in Figure 5.25 would be 2720 mm (Figure 6.34) on the recorder strip chart. This length was calculated in proportion to the standard chord Lc of 80 mm used earlier for plain rods. A chord length of 80 mm on the strip chart was observed to correspond to 0.1767 in. on the actual surface. The observation was based on a tracer speed of 0.221 in./sec. on the surface roughness, and a corresponding strip 214 chart recorder speed of 10 cm/second. The total "roughness line" length Lr in Figures 5.25 and 5.26 equals (2 X 5209 + 272 X 58/8) or 12,390 cm for the cold-rolled steel rod in Figure 6.34. The roughness factor 0, based on Equation 5.7, equals {(12390 — 272) X TOO/272} or 4455 percent. In the same manner, the roughness factor for rods with surface irregularities, including lugs, can be estimated. The effect of lug height on the ultimate loads shown in Figure 5.22, can be transformed in terms of roughness effect. Values of roughness factor p which correspond to different lug heights are listed in Table 6.5, with their ultimate loads. The data, plotted on a log-log scale in Figure 6.35, show a reasonable agreement with the data summarized in Figure 5.28. At small values of p, below 100 percent, the ultimate load appears to be less influenced by surface roughness. This behavior was attributed to the fact that bond strength of frozen soil does not totally depend on mechanical interaction between the soil grains and rod surface roughness. Even on a perfectly smooth surface, 0 = 0 percent, there will be some ice adhesion which may give a finite value for the ultimate load. For this reason, the best fit line was extrapolated as shown by the dashed curve in Figure 6.35. 6.5 'Applications: Design of frozen soil structures, which involve reinforcement, piles, or anchors, requires that suitable criteria be available for selection of allowable adfreeze bond stresses and displacements. Bond strength and creep rates are dependent on the frozen soil material properties, temperature, and surface properties (type and roughness) of the reinforcement member, pile, or anchor. To allow for complex geometry 215 within the structure and that stresses and strains may vary with time and temperature, a non-linear viso-plastic finite element analysis appears to be the most effective method. In this section, a simplified analysis is explored for a reinforced frozen soil beam, under pure bending moment. The analysis is based on certain assumptions which require further verification by means of beam tests. Also, a preliminary analysis considers some of the experimental pull-out test results for application to piles and anchors in permafrost. 6.5.1 Frozen Soil Reinforcement: There is general agreement that the behavior of frozen soil in tension is quite different from that in compression at strain rates higher than - 10‘5 sec.’1 (Vyalov, 1962; Hawkes and Mellor, 1972; Haynes et al., 1975; Haynes and Karalius, 1977; Bragg; 1980; Eckardt, 1981). For frozen Wedron sand, it was observed that the ratio of compressive to tensile strength, oc/ot, was about 5. Therefore, a frozen soil beam may fail because of a weakness in tensile strength. Also, it was noted in Figure 2.18 that beam deflections can be greatly reduced with reinforcement. For a simple beam subjected to pipeline load as shown in Figure 1.1 (c), or the laboratory beam model in Figure 2.18, the analysis can be simplified by neglecting tensile resistence of the frozen soil. Consider, for example, the beam in Figure 2.18 which failed under a total load increment P of 433.1 lbs., when reinforced with a 3/16 in. diameter plain rod (800, 1983). The corresponding external bending moment was calculated to be 5630 inch—pounds. It is of interest to compare this bending moment with that estimated from an analytical procedure. A cross-section for this beam is shown in Figure 6.36 (a). Using 216 Bernoulli's theorem (a plane section remains plane after bending) a linear strain distribution was assumed throughout the beam depth as shown in Figure 6.36 (b). Assuming the equillibrium condition shown in Figure 6.36 (c) and neglecting the soil resistance in tension, the position of the neutral axis 21 can be determined using Equation 2.22. Now calculate the resultant force FC in the compression zone using Equation 2.24 and available data on frozen Wedron sand (Bragg, 1980). For a temperature of -10°C these data include the proof stress Ocue = 1875 psi at éc = 6 X 10'5 per minute, and n = 11.765. The radius of curvature R can be replaced by zl/ec, where e is the compression strain c at the outer fiber. Substituting these parameters into Equation 2.24, the compressive force FC can be expressed in terms of 21 and ac ( with b = 2.75 in.) as follows: FC = 10858 21 eCO-OBS (6.14) The resisting force in the tension zone is controlled by the steel tensile strength or by the bond resistance. In reinfcrced concrete, where creep is almost negligible in comparison to frozen soil creep, it is nor- mally designed such that bond slip does not occur and failure is governed by the steel tensile strength (Hughes, 1976). In frozen soil, where there is no generally accepted design philosophy, bond creep is significant and it cannot be neglected. Interaction between the adfreeze bond and tension of steel rods depends on different factors including time, temperature, and rod surface roughness. While the bond resistance varies significantly with these factors, the tensile resistance remains almost constant for a given rod cross-section. Based on the available experimental data, the following calculations show that adfreeze bond resistance for the 3/16 1 MW ~ 217 in. diameter plain rod (Figure 6.36 a) controls and that it was small in comparison to tensile resistance in the rod. The bond resisting force Fb (Figure 6.36 c) is given by: ' m Fb n L d TC (of/tf 6C) (6.15) where L ‘ 20 in. is the bond development length (Figure 2.18), d 3/16 in. is the rod diameter, of = 0.06 in. is the bond displacement of the rod at failure (Figure 5.32 b), and tf = 5040 min. is the time to failure for the beam test (Soc, 1983). The creep parameter Tc, 6C, and m, obtained from Figure 5.33 include values of 26.5 psi, 10"6 per min., and 0.37, re- spectively. Substituting these values into Equation 6.15, gives Fb = 333 pounds. Comparing this value with that due to the rod tensile resistance of 1100 lbs. (based on 40000 psi yield stress) suggests that bond failure would be more probable than tensile failure. Equillibrium requires that Fb = Fc’ and hence: 10858 21 eC0°°85 = 333 (6.16) According to Equation 6.16, the value of 21 = 0.082in. for ac = 10'5, and 21 = 0.04 in.for cc = 0.045 (failure strain based on Bragg‘s (1980) data). In both cases the value for 21 is small compared to the depth d' of 2.5 in. in Figure 6.36 (a). Therefore, any value for ac in the range of 10-5 to 0.045 would not result in any significant error. With an average value of 0.06 in. for 21, and (d' - 21) = 2.44 in. (Figure 6.36 b), the internal resisting moment would be 812.5 in.-lbs (= 2.44 in. X 333 lbs.). It is clear that the adfreeze bond would be inadequate to counter act the applied bending moment of 5630 inch-pounds. For this particular beam, a significant soil contribution must exist in the tension 218 zone. It was anticipated that introduction of the frozen soil tensile re- sistance Ts would shift the neutral axis upward, as shown in Figure 6.36 (d), thus further complicating the analysis. For beams reinforced with deformed rods, which appear to tolerate larger displacements than plain rods (Figure 5.20), the strain 5 at the reinforcement level (Figure 6.36 r b) would be large enough to cause failure of frozen soil in tension before bond failure occurs. In this case, neglecting any soil tensile forces may introduce less error than the case of using plain rods. More ex- perimental data on the beam behavior is needed before proceeding with the analysis. 6.5.2 Pile or Anchor Capacity: Pile installation in permafrost often involves dry augered holes with a mixture of soil and water used to fill the annulus around the pile (Figures 1.2 b and c). Piles and anchors develop their load supporting capacity when the soil-water slurry is solidly frozen in place ( Anders- land et al., 1978). Pile capacity is primarily dependent on the long-term adfreeze bond strength of the frozen slurry, the pile type and surface roughness. There appears to be a general agreement that pile design in ice-rich soils should be based on limiting creep deformations, and in ice-poor soils design should be based on allowable adfreeze strengths (Weaver and Morgenstern, 1981 b). End-bearing at the pile tip is nor- mally neglected, particularly in ice-rich soils. Steel rods embedded in frozen sand specimens can be viewed as a section of a model pile. It appears reasonable to consider the experimental data herein in terms of potential field behavior of piles in permafrost. 219 Consider the following example involving a steel pipe pile (1 ft. diameter and 25 ft. length) to be used as a vertical support in a warm permafrost with an average temperature of -2°C. A sand slurry backfill, carefully controlled as to density, is placed around the pile as shown in Figure 1.2 (b). The permissible pile displacement is limited to 1 in., and the maximum active layer thickness is predicted to be 5 ft. during a 20 year service life for the structure. The allowable axial load is required for the pile (cold-rolled steel surface). The pile capacity is to be based on limiting creep deformation to 1 inch. For the 20 year service life and pile deformation the creep rate will be 8.5 X 10"8 in./min. This rate corresponds to the slow rate range in Figure 6.18. Since very limited creep data are available in this range, it will be assumed that the constant displacement rate power law (Equation 5.3) is applicable. Using the data in Table 5.3, Equation 5.3 bcomes Tu = 12 a (10000 an)°°222. Since no loading rate P was given, Equation 6.2 could be written in terms of the displacement rate an as follows: Iu (psi) = 12 (10000 an)0'222(p/625)0°325 (vs/64)2'2”6 (d/IOH)S 0 (6.17) Substituting d/H = 5.0 percent (1/20), s = 0.692, vS = 60 percent, 0 = 625 percent (cold-rolled steel), in = 8.5 x 10'8 in./min., and e = 20C into Equation 6.17, the adfreeze strength Tu = 5.436 psi gives an allowable axial pile load of 49183 pounds. Note that the effective em- beddment depth H was taken as 20 ft by neglecting the top 5 ft (the active layer). Also, any downdrag loads, were ignored in the example. Corrugations (lugs) have been used on pipe piles (Figure 1.2 c) to increase load capacity on the trans-Alaska gas pipeline project (Thomas 220 and Luscher, 1980). The lugs were spaced at 1 ft, with a lug height h = 3/4 inch. If similar lugs are used on the 25 ft. piles, there would be 21 lugs in the effective 20 ft. embeddment. Load-displacement curves reported by Thomas and Luscher (1980) for corrugated piles showed a behavior similar to that observed for the lugs (Figure 5.14) with no "initial failure" and no drop in load at the ultimate condition (Figure 5.21). This behavior appears to indicate no lug interaction, described in Figure 6.15 for the standard deformed rods. Using Equation 6.8, with IS = 60 percent, A1/Ar = 0.2656, 6° = 8.5 x 10"8 in./min., and a = 2°C, gives q = 7105 psi for a single lug on a corrugated pile, and the pile load becomes 213,445 lbs. per single lug. The total allowable axial load for 21 lugs through the 20 ft. depth bearing layer would be 4,482,339 pounds. This load compared with the 49183 lbs. for plain piles is about 91 times higher. Such a load, however, would exceed the ultimate com- pressive strength bbout 550000 lbs) for a pile cross-section with a 3/8 in. wall thickness. The lug height can be reduced and the spacing can be increased and still obtain a load capacity equal to that of the steel pipe. Note that the confining lateral earth pressure was neglected in the analysis. Had the confining pressure been considered, higher loads (for plain and corrugated piles) would be obtained. Anchors are also used in permafrost for resisting uplift forces in various types of structures. The adfreeze strength of grouted rod anchors, or pile anchors, may be estimated from pull-out tests on plain rods in the same manner described for the pipe piles, using Equation 6.2. Screw anchors of the type shown in Figure 1.2 (d) can be simulated by the lug behavior observed in this study. The bearing capacity of a single helix (screw) anchor can be estimated using Equation 6.8. 221 The foregoing examples indicate that the scale effect (due to data transformation from a small—scale laboratory model to a large-scale field structure) can be eliminated by applying the dimensionless ratios d/H and Al/Ar‘ However, when considering the load-displacement curves, the pull-out load can be normalized with respect to the rod surface area, to give a nominal bond stress, and the corresponding displacement can be normalized with respect to the rod radius to give the average shear strain, assuming a uniform stress and strain distribution along the rod length. Further model studies and dimensional analysis are required in order to make possible a multiple regression analysis for further applications. 222 Table 6.1: Comparison of frozen sand cohesion with the bond and lug bearing capacity. T 00 c=ou/2 q1 Pu/nH dt Pjy/fiHdT tuft ( °c ) (2531 (psi) .1921 (psi) (psi) (£11 - 2 1100 550 7200 200 113 27 - 6 1700 850 10692 297 174 78 -10 2100 1050 15012 417 230 127 -15 2500 1250 19872 552 297 191 * Data from Bragg (1980), values of Cu correspond to éavg = 3.0x1076 sec."1 (Bragg's Figure 5.9). i d = 3/8 in., H = 6.0 in. if For a 3/8 in. diameter plain rod. (Other data from Table 5.2 for Savg = 5.0x10-4 in./min. and Pavg = 25 lbs./min.) 223 frozen sand at ~100C. Table 6.2: Sample h No. in.) 08-9 1/16 CS-13 1/16 CS-15 1/16 CS-5 2/16 CS-6 2/16 CS-7 2/16 CS—8 2/16 CS-lO 2/16 A l (sg.in.) 0.08590 0.08590 0.08590 0.19635 0.19635 0.19635 0.19635 0.19635 ql 129;). 16298 18161 20954 24214 9895 13970 18161 30268 34924 11714 12732 14158 15381 16196 14158 15686 16909 18131 18131 19251 20372 20372 8047 9473 6Cx10- (in./min.) 5 46. 70. 104. 166. 21. 58. 718. 2500. 10. 16. 25. 37. 44. 25. 43. 69. 83. OKONO OOOV mmoooooo 003030 100.0 166. 200. 286. (Continued) Effect of lug size on creep rate and lug bearing in 224 Table 6.2: (Cont'd) S l - - amp e .h A, q1 6Cx10 5 No. (in.) (sq.1n.) (psi) (in./min.) CS-10 2/16 0.19635 10899 13.30 11714 13.10 CS—14 2/16 0.19635 22918 975.00 CS-18 2/16 0.19635 6213 1.82 7843 1.77 9269 3.64 10695 5.09 12121 6.94 CS-11 3/16 0.33134 6036 1.61 7485 4.05 9175 6.71 10865 9.07 12555 20.40 05-17 3/16 0.33134 7545 8.00 10563 10.00 225 Table 6.3: Values of ”psuedo” instantaneous displacement 61 and time to failure tf at different creep loads for a 1/8 in. lug in frozen sand, (6f is the assumed failure displacement). Sample P 61 tf(min.) for: No. ribs.) (m) 6f= 1.0 in. 6f= 0.25 in. cs-5 2300 0.081 9188 1688 2500 0.088 5431 967 2780 0.097 3270 605 3020 0.100 2400 400 3180 0.106 2004 322 05-6 2780 0.080 3680 680 3080 0.084 2100 380 3320 0.088 1310 233 3560 0.092 1094 190 05-7 3560 0.084 916 166 3780 0.090 548 96 4000 0.093 454 77 08-8 4000 0.081 320 59 CS—lO 1580 0.028 11669 2665 1860 0.032 10314 2319 2140 0.034 7263 1624 2300 0.035 7366 1641 CS—14 4500 0.120 95 13 CS-18 1220 0.022 53736 12527 1540 0.029 54859 12486 1820 0.036 26483 5879 2100 0.038 18978 4243 2380 0.039 13876 3069 226 Table 6.4: Comparison of the n parameter from unconfined compressirn tests with that from bond tests. T n n n' n” 18:; C b b — 2 3.30 5.40 4.50 -- — 6 8.70 6.70 5.40 —- -10 11.67 10.40 9.35 2.70 -15 12.19 11.40 10.60 4.80 “b "b ”6 From compression tests (Bragg, 1980) From bond tests, Figure 5.3 From bond tests, Figure 5.4 From creep bond tests, Figure 5.38 Table 6.5: Variation of ultimate load with rod surface roughness, including lugs. Type of Lug** h p Pu steel shape .11fl;1 (_%_)_ (lbs.) CR* 45° 1/64 1085+ 1050 CR 90° 1/16 2540 1740 CR 90° 2/16 4455 2920 CR 90° 3/16 6370 4800 CF 45° 2/16 3920 2730 CR 45° 2/16 4455 3380 SB 45° 2/16 5319 3400 * CR: Cold—rolled steel surface GF: Ground-finish steel surface SB: Shot—blasted steel surface * * For description of lug shapes, see Figure 3.2 i Data for a 3/8 in. standard deformed bar reduced to a single 1/64 in. lug. The 6 in. rod length was assumed to have the same roughness as that of the cold-rolled steel surface. 228 300 S C) avg = 3.65 X 10‘3 in./min. 280— V Stehle (1970) / (H-section, 3 in., 6 in., and 12 in.) : 240 _ Tsytovich and Sumgin (1959) (Ice to plain '§_ - ////// wooden piles, long- ; term basis) 'T 200 _ I; 4.) CD 8 L a 160 - /o .“>’ . / g / g 120 — / § / / / / ” 80 ‘0.“‘Frederking (1979) /’ / (Ice to 3 in. dia. wooden // piles) 40 V (Ice(1), Figure 5.29, 5/8 in. ./ plain steel rod) // 0 ~./. . l I I I I I a . I I I igure 6.1: Temperature, T,°C Temperature effect on ice adhesion to different materials. 140 '5 D. l:\ I? U) OJ L 4.: U) 60 'U C O CO 40 20 7igure 6.2: 80 I! S 229 . = 2.53 X 10'3 in./min. = -6.2°C ample (S-10) (Plain steel rod, 5/8 in., H = 6 in.) A [I /l [I / I I l /I ’ I (Painted steel pile, d = 3 in., l l H = 7.5 in., Ottawa sand) I \ I \ ' \ I - o—o——o——- llf\\ V \ ________________ I l J l l J l 1 I I 1 2 3 4 5 6 No rmalized Displacement, 26/d, Percent Typical bond stress versus displacement curves for plain steel piles (rods) in frozen sands. AmPMeprmE “cmcwwmwu mo mmFTQ cpv ucwm :mNoem new wow to; :\e cape; 65p sews spacmepm vcog mo cowumwem> Hm.o wezmwd eeeecma .I\e .oepam moH m m a N NoH w o v m CH m w e N H —-_u—-_ q —d-—_-__ - —..u~.- a - O \. \ c III/ \ I ow .eee\.ee mIoH x ec.m I e .uoeII/./ . m. up mowIzocm :e mo_ea cocoozv xx - ”W o / 0 al.. mw Amnmfiv mewxsmwmgd IIIIIIY/ Amfi m mczmwd Eocm mpmov w 62 // I ow mw UI Amfi.m beamed n1 Eoem mumev . . / c .m .eee\.ee .IoH x mH.m I e I . I ONH . .ucmm :wNocm Cw mvoc _wwpm III. oooHI I H E 08H Bond Strength, psi gure 6.4: . — graded sand slurry) p_I 03 O |_.I N O to L0 .... Pavg. = 7 lbs./min. C) ---— Crory (1963) (8 in. steel piles in well- (Data interpolated from Figure 5.3, d = 5/8 in.) C) ” // /” / ,.a"’ Vyalov (1959) _ / // (Equation 2.11, for / 6 in. timber piles "I, 0/ in frozen silty sandy [/1 . . I I I I I 1 . I . . I 10aIm)I I —5 -10 -15 -20 —25 Temperature, 00 Comparison of bond strength for different pile types in frozen sandy soils. 1200 1000 800 [ T = -10°C Pavg. = 25.5 lbs./min. - (Plain steel rod, d = 5/8 in.) -+-Frozen sand (vS = 64 percent) Crushed ice 600 T 400 (Linear scale between numbered points) 200 \ #1—21 _Residual loads, Pr .L_.___>ae-.-e-—.—-.-’—.--.--.-.- . 0 0.01 .0.04 0.06 0.08 0.10 Displacement, 6, in. a 6.5: Comparison of load-displacement curves for a plain steel rod in ice and frozen sand. UVIIU Jul cllytll, pbl 320 [ 280" 240 — 160 — 120 . 80 — I‘J (A) L.) ‘——---- Tu vs. T for frozen sand T vs. T for Ice / / .___ _ Tr vs T for frozen sand _ 1’ ————— Tr vs. T for Ice 2"], Pavg. = 24.6 lbs./min. = 'LI' ' °avg. 5 X 10 in./min. L *— Sand Friction. Tuf Ice adhesion "’,.e [I ”f/.' 4 ’//,//’/// ’ ”,,.—" Sand Frictgon, rf , ’ .ec’T”’ Ice Adhesion~\\ / _‘ ' 1- r'.‘T j" 771': I_1' . . I . . 1 Temperature, T, 00 Comparison of ice adhesion and sand friction for a 3/8 in. plain steel rod embedded in ice and frozen sand. 234 I Gavg. = 6.4 X 10.1+ in./min. Pavg. = 28.5 lbs./min. _ T = —10°c d = 3/8 in. (Linear scale between numbered points) Lug bearing Plain rod with lug in frozen sand (S-57) _ h = 1/8 in. I i i‘L—Plain rod in frozen sand (S—30), h = O A “/ Plain rod in ice (I-22), h = 0 Sand Friction \ x. Ice Adhesio A \ ~o— —.— ——"——_—)(I_ H ‘ "TQI 'I'.:-'Q_ T'LL— —l-—I- +—."' T"?".‘ L. l 8 ‘ 0.1 .02 ' 0,10 0.20 0.30 Displacement, 6, in. 'e 6.7: Comparison of lug bearing, sand friction, and ice ad- hesion effects on the load-displacement curves for steel rods. 235 4.2!- ' : “14' ' °avg. 5.0 X 10 in./min. 3.6 __ Pavg. = 24.6 lbs./min. 3.0 — I” m h / ,2— Plain rod with lug if“ d=3/8 in.,h=1/8 in. g? (Figure 5 24, for Lug Contribution, / .3 Piy vs T) v’ if m 1.8 - ' 3 D_ . - Plain rod U“) E d=3/8 1.11., h=0 _J 1'2 (Figure 5.17, for - ,r Pu vs. T) ./ - / Adhesion and 6 n / friction OL(.1.1....II...I.JI.I.JI-II 0 -5 -10 -15 -20 -25 Temperature, T, 0C gure 6.8: Lug contribution for the initial bond rupture condition at different temperatures. 6.6 [ Pavg. = 24.6 lbs./min. : -LI’ ' °avg. 5.0 X 10 in./min. . -————-- Frozen sand with lugs 4 6 _ —-—- Frozen sand] Plain rod ' -——— Ice only G. = 3/8 in. 3'6 7 h = 1/8 in. Ultimate and Residual Loads, Pu and Pr’ kips Lug contribution, 2.6 . P1 - Ultimate loads, Pu (Figure 5.24) 1.6 ‘ / 0.6)- . u -—””’ ./I/ Residual loads, Pr _,,””' 0.3— _/ . Sand Friction -—""”’ Ice Adhesion __ ’/ __ ____-———— ""'—' 0 —————-.--r‘—'."'."."'II...I....I.r...| 0 -5 -10 -15 —20 —25 Temperature, T, 00 igure 6.9: ultimate conditions. Comparison of ice adhesion, sand friction, and lug contri- bution for steel rods at different temperatures and Ultimate and Residual Loads, Pu and Pr’ lbs. 7200 6000 4800 3600 2400 1200 Lug Height, h, in. 1/64 1/16 2/16 3/16 I I I I . = _u n a I °avg. 5.0 X 10 in./min. 1F//' Pavg = 24 6 lbs /min = 3/8 in. ///// d / / ' Least- -Squares Lines //, for Pu in Figure 5. 2 ~200C/ // o _ -100Cr/’ Lug Contribution /’ / _ ’/ Residual Loads, P 44 3:3; I A II. Al/Ar Ratio 6.10: Lu contribution to the ultimate pull—out capacity of a plgin rod, with a single lug With different lug heights, in frozen sand. 238 1.0 ” [ d = 3/8 in., h = 3/8 in., H = 6 in. 3% _ savg. = 5.0 X 10'“ in./min. g: ‘8 Pavg = 24.6 lbs./mi'n. I != \ 3 D- _ U .6 C f5 4 —El—— (Pu/find) = 0.390 c / U I .— ii” .4 ___—()—-- (Piy/an) = 0.227 c 3; I Tu = 0.190 C/ / :3 Cohesion, c, Ksi re 6.11; Comparison of frozen sand cohesion (at different tempera— tures) with the bond and lug bearing capacity. [ Pavg. = 24.6 lbs./min. éavg. = 5.0 X 10‘” in./min. 15‘ A (D _ C h = 3/16 in. 3" = 1/16 in. 3' = 2/16 in. Lug Bearing Capacity, q], Ksi 10_ q] = 6.87 Cu ___—v / / - / C) / 5 ’ l l I I -2°c -60c -100c -150c / - / 47 (Data for h = 2/16 in. listed in Table 6.1) 7 O / . I . I l l 1 I I I J I 0 0.5 1.0 1.5 2.0 2.5 3.0 Uniaxial Compressive Strength, cu, Ksi 'igure 6.12: Relationship between lug bearing capacity and uniaxial compressive strength for frozen Wedron sand. .pom: um ucmm Npngc :wNogw c? prmeogpwcwa memEmwu .CV ¢.H a mo wasp spwz ccmm cognmz :wNogm Cw Low>mzwa m:_ we cemwgmaeoo ”mH.o wgsmwd .CTE\.:w .om .wpmm ucmeomFQm?o amwgu mica w w v N :ioH w w v N muoH w m - a . 1 —.-.<. a - ANH.N magma; goat name .000. u e ,.e? wfi u .o .pemogma me u m> ..CW e.H 1 my Amnmfiv cwzcma new wzcmumg no . nfl/uh. \0 .N \iiiinv nu on.m wgsmwu Eogw mpmc .oowu n P ..c? m n .o - .pcwogwa aw n m> ..cwemmo.o n mvmwi - a 4\\\\\ -m \4\ -w A.:m w\H u s . ace .ea m\m n e Law; .;N + e " mav ; s paiiddv Lsd ‘b ‘ssauq 241 .Acuczav mm2wpoom Lw_:ugwo use mm:_ Low Ammemv mem :o mocmucmqmu mpm; qmeo .:wE\.cW .0m .mumm pcwewuwFQmwo gmwgu N miofi w w v N :-oN N m e N m-oN N 0-0N w w e N N-oN N o .i —- I v u I - I d —Q I u a u I I ‘ [Jll I —- I I I I I \q 1 \ ~ \Q \\ Ex. ‘\\ \\ \\ . \mV \‘ ._ so MN- pa a3 5 65:: .5 QNN u 6\ 4‘ \ \\ G\ \E “ ANNNNV ._m be .>o_az> .ca om.© u .+\ mu,\\ .u \ .5? mN.N u m .w\ .:w mN.o u m . .CN ®N\m u g . H¢.m wgsmwu Eogm mama H .:F mNo.o u m A.=w N\m " a .;N +e “ my i .:N mN\N u ; uooHu gm Ucmm :wNOLw Cw was; mo. mo. H.o N.o m.o ueN.o aezmawa gs» ‘b ‘ssang (uound JO) fini pailddv Boussinesq's stress distribution (q/qO = 0.27 for z/r = 1.57 and x/r = 1.0) I 1 qo l \ z = 0.3125 in. ' 2 _l__; 1. 27 q0 ).\1\\‘ Frozen ']\‘ =1/64 in. Soil Steel bar ‘\\1. ' (d = 3/8 int;\‘*( 1.343 q0 3 "‘“ (= q0 + 0.27 x 1.27 qo) gmk Load (Not to a scale) re 6.15: Pressure bulb overlap for consecutive lugs on a 3/8 in. diameter deformed bar. 243 L8 002- pm a; .Axeo u m>v .ncmm :mNogw c? map .2? m\H m spvz we; .cW w\m m .mpcmEmUNFQmwu amwgu wwwmwumam on m>prFmL emo— mo mocovcwamv wave "0H.m wgsmwm om ma om ON NH OH w o e N o . _ la. . iIAIL /__ . _ . _ . _ . _ . _ q o .cva OH x .pcmEmUMFvaw umemvuwam m come 0% .Nu .meH m n J .H nu nu ll' (loll. N nu “Fm .mvmo_ ExmpumcoN m w , A.:w m\H u s new ..Cw w\m u U .uooH- um vcmm cmNogw Low N.o wpnmh EOLN mpmov sdtx ‘d ‘PPOl Pallddv 244 15.2 . [ T = -120C . : 'Li' ' aavg. 3.0 X 10 in./min. 12.4 q1 vs vs 6.8 - 4.0 _ 0.8 Compressive Strength Cu and Lug Bearing q], Ksi C) 4:. (Data from Figure 5.48 adjusted for temperature difference and residual loads) Goughnour (1967), cu vs. vS (é = 1.33 X 10"+ min.'1, data from Figure 2.5) J n l igure 6.17: 10 20 3O 40 50 60 Sand Volume Fraction, Vs’ percent Sand Volume fraction effect on the unconfined compressive strength of frozen Ottawa sand and the lug bearing capa- city of frozen Wedron sand. .389. 3m.» 2958233 3328 use 3mg ammgu LE £32 ucmeumEmg US 5.50:3 a mm .23 :mwofi 5 no; :23 a .8; 5333 28m ”26 $sz .55.”: . m .5 cm mwpmm “cmEmomEmE U. o NIOH mioH :iOH miOH mioH BIOH ..1.I_— _ — —-I-I- - I —¢-II- I I —IIII¢u u I _III-III I OH \\ \MIUOS- \. \\ \\ QBJH LNS 8 \\ \ o O 5 \ \I‘ U 4 \ \ iii D. 2 \\\ I S 1. d. 002. . m 003. u H H .147 - l H n. Awmd $sz 3mg $851111. L m3 d S Sim 933“: mpmme cw #2328 I! - $3“ n J; vzmm choi - o u ; ..CN N\m u u .uoc :Nm_a ..T=-100C.,h=1/8 in.,c'Si's variable (Data from Figures 5.6 and 5.36) _ [3‘ T = ~100C, 5 = 0.0005 in./min., h is variable 6 (Data from Figures 5.22 and 5.41) . EJ ‘h = 1/8 in., 5 = 0.0005 in./min., T is Variable (Data from Figures 5.24 and 5.40) 5— /}3 .. ' n .5? /’ >4 4 - 1/ U,“ El 4.) § ' {C-P Q mmmn——+. /+ _ 6 § 3 “ Point // U a E‘ / L x’ ‘4— " UG- 2— G/ // I! 13 / 1‘ / .9/ 0 J J l 1 i L l J I l 0 1 2 3 4 5 6 P6 from Constant 5 Tests, Kips :igure 6.19: Lug capacity comparisons, creep tests versus constant displacement rate tests, for different test conditions. 247 ru/e, psi/0C 20 O { Gavg. = 5.0 X 10'1+ in./min. C) ' Pavg. = 24.2 lbs./min. O ,’ [3‘ 8’ E! Z \ \ \\ 10 .. \ _ C) (Data from - Figure 5.19) 8 - E] C) E] 6 - / 8 4 - /, C) / 3 _ Best-Fit Line Tu/e = 16.8 (d/10 H)0'692 (Data from Figure 5.18) 2 - 1 . l I l J 1 l n I l . 1 1 1 2 3 4 6 8 10 20 3o Ratio d/H, percent Figure 6.20: Modified relationship between bond strength and the ratio d/H for plain steel rods in frozen sand, (v5 = 64%). £0.50me 9:8 US 5.50ch m we uooT pm ncmm :38; E 30; 38% FEB 08 55:33 ucom "MN.m mgzmwd 248 \w “smegma .m> .cowpode mE:_o> scam E 8 om S om ON 2 — _ _ a _ . _ . _ . OH 1 ON m. 0 m... I w- P :m.m 8%: E8; 8.2: - S m. o 8 0 I 0 lllllll ii iI in.| ii In iu.ii i..i ii nu.i.i..- 1 cm W. l. S 00 . ow m. . 38382 n E _. w 3N N l 03 m4 UI oooH- pm vcwm :mNOLd n OON .m. o n z . .cw m\m u U “to; :Twra g 08 Ksi u, Bond Strength, T Figure 249 F Plain rods , h = O L C) d = 5/8 in. _ . d = 3/8 1.11.] (Data from Figure 5.17) . Pavg. = 25 lbs./min. C) - I”-” / . (5”’ 1| / . Equation 6.2 1”, " fl .. 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I d $5 58.25% 2:... 2:25: U x wHN 20533 6353.5 .1 II II I OH w. 8nd 953.; so: 32: 8:: 5:05:83 l L ON Frozen sand Steel rod ———-—L—a» «\k‘ Initiai position Void Fina] position '9’ 2:57 A 1.. .. . .1 ‘. / Zone of crushed sand Figure 6.32: Zone of crushed sand observed around the lug, at the end of creep tests. 260 .mmuwmgzm mepm pcwgwkmeu Low mpgmww; Auwgwamm mo mmavme “gage qwgpm vcw LapwEoywmogg :wmzpma newpm—mggoo .Cw: .am .mewao_weoea :0 pgmwmz Nowewam< om om ow om ON OH _ . _ _ _ _ _ _ _ . P AmN.m mgamwm Eogw mumov mummgzm cmpmmFQupozm mumwgsm umFFog-vFou mumdgzm _mmum cmVwauuczogw O r—l C) N om H. V a S 3 d O L. J J p L. a 1. J rA G H S a U0 .L. G 5 U! 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I. o \\\x -08 m 25% S ” <2: 3a \o 1 82 m. mew; “wa-pwmm a .1 m O\ ‘p - OOON nd Am.w m_nmk Eoge mommy mu 33 SE 0 .s .E Sm u u £8; FEE O m oooe \\\nu uoofi- pm Apcmugma am u >V team :mNogm 263 .vog mepm :wmra m Luv: vaLomcwwL Emma ucmm cowpwucoo _mspoq Aev cowpwucou coasmm< ADV :wNOL$ m Low EswgamPszcw w o mcowpvncoo "om.m mgsmwm newuummummogo Emwm Amv TTismN.N u a ...t4 cowpsnwtpmwo somepm ADV ow HN AHN n .UV ,Lm. albrlll UCOHI :m.N n _U PM Ucwm cmNOLm .r»..... woe mepm :Nm_a .ce ©H\m CHAPTER VII SUMMARY AND CONCLUSIONS The results and conclusions based on this investigation are sum- marized in the following sections: test methods; load transfer mecha- nisms; applications-- reinforcement, piles, anchors; and recommendations for future work. 7.1 Test Methods: Measurement of adfreeze bond between frozen sand and steel bars has involved use of constant displacement rate and constant load (creep) pull-out tests. Test temperatures included the range of -2 CC to -26 OC and were closely controlled (:_0.05 0C) by immersion of protected samples (membrane enclosed) in a circulating and refrigerated coolant liquid. A specially constructed load frame supported the frozen sample while one end of the steel bar was attached to an eye connector and hook at the bottom of the coolant tank. An external loading system permitted pull- out of the bar at a constant displacement rate or bar creep movement relative to the frozen soil for a constant pull-out load. The following conclusions refer to sample preparation methods and test procedures: 1. Small rod displacements prior to bond failure and slip req- uires a high sensitivity for measurement equipment. Transducer sensiti- vity of at least :10'5 in. is desirable to show elastic movement prior to rupture in constant displacement rate tests and creep movement in constant load tests. 264 265 2. Loads selected for creep pull—out tests are limited by the high immediate bond failure stress and a lower long—term bond strength. Smaller loads do not develop steady—state creep rates needed for predic- tion of bar pull—out capacity. Vyalov's (1963) equation may be used for prediction of the long-term bond strength corresponding to a specified rod displacement. 3. The step loading procedure provided creep rate data for several pull—out loads on each sample. The initial time interval and load must satisfy long-term strength requirements to insure development of steady- state creep. 4. The ultimate load capacity of plain rods was dependent on rod and sample size as represented by the ratio of rod diameter to sample height, d/H. An optimum d/H ratio, on the order of 6 to 10%, appeared to give the largest adfreeze bond strengths for plain rods in frozen sand. 5. For 3/8—in. diameter rods with 1/8-in. high lugs, frozen soil diameters of 4 in. or more were required to avoid any influence of sample diameter on lug bearing capacity. Lug height h, rod diameter d, and sample diameter D may be used to define a ratio A = (D-d)/2h for which values should be at least 13 in order to avoid any influence of sample diameter on lug bearing and pull—out loads. 7.2 Load Transfer Mechanisms: Adfreeze bond between frozen sand and embedded structural members (reinforcement, piles, or anchors) include: (1) ice adhesion, (2) fric— tion with sand particles, and (3) mechanical interaction of frozen soil with surface roughness of the structural member. These bond components involve different load transfer mechanisms. Ice adhesion is the result 266 of increased attraction between water molecules and the surface of the structural member at freezing temperatures. Surface type (steel, wood, paint, etc.) and contaminants (salts, minerals, etc.) in the ice signi— ficantly influence adhesion forces at the interface and cohesive forces in the ice. Friction with soil particles is dependent on the friction angle between the soil particles and structural member, and is propor- tional to the normal stress that is pushing the particles against the member. Surface roughness of the structural member introduces particle dilatancy and reorientation effects adjacent to the surface. An increase in surface roughness by the introduction of lugs on the surface permits bearing forces to interact with frozen soil. The result was a significant increase in load transfer as surface movement mobilized mechanical inter- action forces. The following conclusions refer to load transfer mechanisms: 1. Ice adhesion was mobilized at very small displacements with rupture typically at less than 0.002 inches. The presence of sand part— icles increased the ice matrix volume involved in rupture and thereby increased the adfreeze bond. An increase in surface roughness by use of lugs added significantly to the adfreeze bond with no observed change in displacements required for initial rupture. 2. Friction between sand particles and the structural member was negligible as shown by the small residual loads. Unconfined frozen sand samples contribute little normal stress on sand particles adjacent to the structural member. 3. An increase in surface roughness, by the addition of a single lug, gave load—displacement curves showing the initial rupture of ice adhesion followed by mobilization of bearing forces on frozen soil. Residual ice 267 adhesion and friction for larger displacements were negligible in contrast to the larger bearing forces. 4. Use of multiple lugs, a deformed steel bar as used for concrete reinforcement, showed an increase in the ultimate pull-out load in a direct ratio to the number of lugs after residual adhesion and friction loads were subtracted. A modified load—displacement curve suggested a possible relationship between ultimate load, lug size and spacing, and maximum particle size. 5. Sand density (or sand volume fraction) significantly influenced the adfreeze bond strength for a given creep rate, bar and lug size. For ice—rich samples (sand volume fraction < 42 %) the pull—out load depends primarily on plastic deformation of the ice matrix. For ice-poor samples (sand volume fraction > 42 %) the adfreeze bond and pull—out load incr- eased abruptly with mobilization of sand dilatancy and particle reorient- ation effects along with soil bearing forces on the lugs. 6. Colder temperatures (range of —2 0C to —20 0C) and larger displacement rates both increased the adfreeze bond components. Expe- rimental relationships were developed which account for temperature, bar displacement (or creep) rate, and other test variables. 7. A roughness factor defined by Wright (1955), provided excellent correlation with increased bond or pull-out loads for plain rods. An increase in surface roughness, the addition of lugs, extended this corr- elation suggesting possible future design applications. 7.3 Applications-- Reinforcement, Piles, Anchors: Structural members (reinforcement, piles, anchors) are embedded in frozen soil to take tensile forces or to transfer and distribute compre- 268 ssive loads in such a way that stability of the structure is maintained. In all cases load transfer between the frozen soil and the structural member involves the adfreeze bond and possible slip at their common inter- face. Installation in frozen ground commonly involves dry augered holes with a mixture of sand and water used to fill the annulus around the pile or anchor. Load supporting capacity develops when the sand—water slurry is solidly frozen in place. Load capacity is dependent on the long-term adfreeze bond strength of the frozen sand in the zone adjacent to the structural member. Several conclusions can be made relative to design considerations for placement of these structural members: 1. The dry density (or sand volume fraction) of the sand-water slurry should be as high as possible to insure a high adfreeze bond str- ength. Vibration of the slurry during placement to insure a relatively high dry density appears to be a desirable requirement in construction specifications. 2. The use of multiple lugs on the structural member will signi— ficantly increase the long—term pull-out load. The lugs increase both the initial ice adhesion and friction and are responsible for develop- ment of bearing forces on the lugs at larger displacements 3. Lug spacing should be such that forces which develop in front of the lugs do not overlap with pressure zones from adjacent lugs. A preliminary analysis based on Boussinesq's equations suggests that a lug Spacing should be at least twice the lug width (d+2h). The design should also allow for formation of a void space behind the lug with length equal to the allowable pile or anchor displacement. 4. Constant load (creep) pull-out tests using pile and soil materials 269 of the same type as proposed for a project will help an engineer to account for the many variables which affect adfreeze bond strength. Field tests are needed to correlate test results on model pile sections with full size piles. 7.4 Recommendations for future work: Additional research is needed on several aspects related to the bond and slip of steel bars in frozen sand. Several specific problems are outlined below: 1. The influence of confining pressure on bond components should be investigated. The available predictions are mostly based on the ass- umption of soil THCOWPPESSlblIlto’ or volume constancy. The effect of confining pressure on the volumetric strain of frozen sand (which char- acterizes the dilatational behavior of soil in front of the lug) does not appear to have received the attention it warrants. 2. Use of standard deformed bars for reinforcement appears to provide a significant capacity at fairly small displacements. Further tests are needed on these bars in order to provide design information on the most appropriate lug spacing and lug size. 3. In order to precisely evaluate the bond stress along steel bars, it will be necessary to monitor the stress distribution along the bars during pull-out tests. Redistribution of stresses with time, during creep tests, is also anticipated. Measurement of stresses and strains along the bar can be achieved by using a split rod which accommodates a number of strain gages. 4. Laboratory investigation of the performance of reinforced beams would provide valuable information on the time dependent interaction bet- 270 ween the reinforcement and the frozen sand beam. Properly instrumented beams would help define the strain distribution in the beam. Such infor- mation would be a significant contribution to developing design proced- ures for field applications of reinforced frozen earth structural elements. 4. Further model studies and dimensional analysis are required in order to make possible a multiple regression analysis for further appli- cations. BIBLIOGRAPHY BIBLIOGRAPHY Reference Code: ASCE: American Society of Civil Engineers CGJ: Canadian Geotechnical Journal HRB: Highway Research Board ICP: International Conference on Permafrost ISGF: International Symposim on Ground Freezing JACI: Journal of the American Concrete Institute JSMFD: Journal of the Soil Mechanics and Foundations Division NAS: National Academy of Sciences, Washington, D.C. NRC: National Research Council RR: Research Report SR: Special Report USA CRREL: U.S. Army Cold Regions Research and Engineering Laboratory USA SIPRE: U.S.AArmy Snow, Ice and Permafrost Research Establishment 271 BIBLIOGRAPHY Alkire, 8.0.; and Andersland, 0.8. (1972) ”The Effect of Confining Pressure on the Mechanical Properties of Sand-Ice Materials," Journal of Glaciology, Vol. 12, No. 66, pp.469-481 Andersland, 0.8. (1963), Discussion-Session 6—Physicomechanical Properties of Frozen Soil, Proc. 1st ICP, Lafayette, Ind., NAS-NRC Publ. 1287, pp. 338-339. Andersland, 0.8.; and Akili, W. (1967) "Stress Effects on Creep Rates of Frozen Clay Soil,” Geotechnique, London, Vol. 17, No. 1, pp. 27-39 Andersland, 0.8.; and AlNouri, I. (1970) ”Time-Dependent Strength Behavior or Frozen Soil,“ JSMFD, ASCE, Vol. 96, No. 5M4, pp. 1249-1265. Andersland, 0.8.; and Douglas, A.G. (1970) ”Soil Deformation Rates and Activation Energies," Geotechnique, London, Vol. 20, No. 1, pp. 1-16. 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Weaver, J.S.; and Morgenstern, N.R. (1981 b) "Pile Design in Permafrost,” CGJ, Vol. 18, No. 3. PP. 357-370. Wright, P.J.F. (1955) "A Method of Measuring the Surface Texture of Ag- gregate," Magazine of Concrete Research, Vol. 7, No. 21, pp. 151-160. APPENDICES 281 APPENDIX - Data: A. Constant Displacement Rate Tests. B. Constant Stress (Creep) Tests. \ 282 Table A—1: Ice Samples I—l to I—21 (Ice 1) Ice (1) samples were formed from distilled water in four layers (6 in. sample height). Average density equals 56.1 lb./cu.ft. A 5/8 in. diam- eter plain steel rod was used with samples I—l to I—21. Sample I—l: Sample I-3: T = —1o.1°c T = —15.1°c H = 5.866 1n H = 5.688 in. D - 5 677 1n D = 5.875 in. L = 5 685 In L = 5.719 in. P = 140 lbs./min. 13 = 130.0 lbs./min. 5n= 4.24x10—3 in./min. 6n= 4.40x10_3 in./min. t (sec.) P (lbs.) 5 (XIO—Bin.) t (sec.) P (lbs.) 6 (xlO_3in.) 225 430 0.24 60 52 0.04 295 630 0.25 120 187 0.07 340 760 0.50 180 330 0.11 360 820 0.60 255 557 0.77 400 930 0.90 280 607 1.50 400 360 10.00 286 370 5.91 406 310 11.00 292 310 7.75 412 290 12.00 300 270 8.85 418 270 12.75 315 250 10.16 436 250 14.00 375 230 14.75 460 \ 240 15.50 435 218 19.31 475 230 16.50 495 210 23.72 670 200 30.00 615 200 32.32 895 190 46.50 Sample I—2: Sample I—4: T = -15.o°c T = —15.1°c H = 5.750 in. H = 5.438 in. D = 5.875 in. D — 5 938 in. L = 5.625 in. L = 5.375 in. 1>= 136.4 1bS,/min. i>= 105.4 lbs./min. . _ . -3 . . 6n: 4.50x10 3 in./min. 6n= 4.90x10 1n./m1n. _ -3. t (sec.) P (lbs.) 5 (x10 31...) t (sec.) P (lbs.) 5 (x10 1n.) 2 40 0.010 220 390 0.37 20 85 0.025 259 455 1.10 65 150 0.080 259 220 9.20 110 200 0.135 265 170 11.26 170 360 0.210 280 150 13.32 230 510 0.282 295 135 15.10 272 620 0.760 310 126 16.46 272 220 7.640 370 110 21.72 278 185 9.110 430 100 26.65 290 165 10.580 505 96 32-53 305 152 11'900 Note: At t=0, P=O and 6=O, unless 350 130 15.440 —— noted. 395 120 19.120 575 105 32.350 283 Table A—1: (Cont'd) Sample I-S: (Leakage, data discarded) Sample I—6: Sample I—8: T = —6.1°C 1 = -2o.o°c H = 5.938 in. H = 6.125 in. D = 5.969 in. D = 5.938 in. L = 5.969 in. L = 6.125 in. P = 89.6 lbs./min. P = 115.7 lbs./min. 6n= 3.68xlo"3 in./min. én= 3.60x10_3 in./min. t(sec.) P(lbs.) a (x10'31n.) c (sec.) P (lbs.) 6 (x10'31n.) 6O 90 0.037 100 200 0.04 75 112 0.404 112 216 0.28 81 95 1.03 118 196 1.08 87 82 1.765 124 172 2.01 93 77 2.500 130 160 2.60 135 67 5.300 160 144 4.80 195 63 9.120 220 140 8.80 255 60 12.870 380 135 18.00 315 58 16.690 435 56 23.900 Sample I—9: 0 T = —10.0 c §EEE£E_£:ZL H = 5.875 in. T = -20.0°c D = 5.938 in. H = 5.938 in. L = 5.834 in. D = 5:900 in' P = 111.8 lbs./min. L = 5.812 in. . _3 ' , 5n= 3.55x10 in./min. P = 136.4 lbs./m1n. 3 8n= 3.905.1073 in./min. t (sec.) P (lbs.) 6 (x10 in.) —3. 75 112 0.01 t (sec.) P(lbs.) 6 (X10 in.) 120 216 0.20 220 500 0.001 175 326 0-40 220 278 5.000 175 100 6-00 235 253 6.786 240 90 10.60 250 240 8.214 330 84 16.80 280 222 11.785 450 82 23.00 325 207 15.000 385 195 19.285 Eeeele_1:192 590 175 32.142 T = _10.10C H = 5.969 in. D = 5.938 in. L = 5.938 in. (Continued) 284 Table A-1: (Cont'd) Sample I-lO: (Cont'd) Sample 1-13: P = 91.64 le./min. T = -26.7OC 6n= 3.32;;10'3 in./min. H = 6-0 in- D = 6.0 in. t (sec.) P (lbs.) 6 (X10_3;'Ln.) L = 6.0 in. 90 134 0.01 P = 143.2 lbs./min. 165 240 0.12 6n= 4.02.10'3 in./min. 220 336 0.20 220 120 5.60 t (sec.) P (lbs.) 8 (xlO-3in.) 250 112 8.80 ’ 310 100 13.60 90 170 0-01 415 94 19 40 430 1040 0.08 ' 620 1480 0.24 620 190 40.00 S l I—ll: -5EEL51——7;—- 640 220 42.14 T = —10.1 c 645 220 42.54 H = 5.938 in. 730 195 43.10 D = 5.938 in. 840 200 45.00 L = 5.938 in. 940 180 65.00 p = 94.0 lbsé/min. Sample I-l4: 6n= 3.43x10 1n./m1n. T = —26.4OC —3. H = 5.906 in. £;£§EELL P (lbs.) 6 (X10 in.) D = 6.000 in. 250 ‘ 370 0.01 L = 5.910 in. 270 424 0.08 - _ . 300 470 0.20 P — 4.9 lbsg/min. 300 145 6.00 6n= 3.5x10 in./min. 320 105 10.00 _3 350 90 12.00 t (min.) P (lbs.) 5 (x10 in.) 380 85 14.88 0.0 0 0.0 455 78 18' 84.8 2140 3.6 84.8 320 38.6 Sample I—12: 90.0 440 42.0 T = —26.1°c 90.5 330 43.0 H = 6.0 in. 96.0 420 44.0 D = 6.0 in. 96.5 325 45.4 L = 6.0 in. 101.7 400 46.2 ' . 102.2 320 47.4 P = 126 lbs./m1n. 106.5 390 48.2 6n= 0.9x10_3 in./min. 107.7 320 49.0 3 111.4 375 49.8 t (sec.) P (lbs.) 6 (x10 in.) 113.0 320 50.4 116.0 355 51.0 110 165 0-08 118.4 320 51.8 400 840 0.20 400 140 5.60 580 120 8.20 285 Table A—1: (Cont'd) Sample I—15: —26.6°c 5.938 in. 6.0 in. 5.938 in. 22.5 lbs./min. T H D: L P t (min.) 18 32 44 44 70 8.0x10'4 340 680 990 160 140 Sample I-16: in./min. P (lbs.) 8 (XIO—Bin.) 0.40 0.45 0.80 12.80 33.60 t (sec.) P (lbs.) Sample I—l7: (Cont'd) 6 (x10_3in.) 1 = —20.4°c H = 5.938 in. D = 6.0 in. L = 5 938 in. P = 27 lbs./min. 6n= 1.053.10—3 t (min.) P (lbs.) 6 (x10‘31n.) 10.0 320 0.8 25.0 680 1.2 38.5 1040 1.4 38.5 100 20.0 48.0 90 30.0 Sample I—17: T = -15.5°c H = 6.344 in. D = 6.0 in. L = 6.344 in. P = 23.60 lbs./min. 6n= 3.52:.10‘4 in./min. —3. t (min.) P (lbs.) 6 (X10 1n.) 10.0 180 1.40 17.5 320 1.60 31.5 665 1.62 44.7 1010 1.68 57.8 1350 1.90 71.0 1710 2.22 84.2 2060 2.62 (Continued) 97.7 2380 3.34 102.2 2480 3.48 119.8 1830 5.70 119.8 200 18.00 125.2 300 18.80 127.3 200 20.80 131.5 250 21.60 134.5 200 23.20 Sample I—18: T = —10.1°c H = 5.906 in. D = 6.0 in. L = 5.906 in. P = 28.5 lbs./min. 6n: 2.3x10‘4 t (min.) P (lbs.) 6 (x10_3in.) 7.5 360 0.40 24.5 750 0.42 31.2 890 0.75 31.2 80 8.80 40.3 80 10.80 Sample I—19: T = -6.6°c H = 5.938 in. D = 6.0 in. L = 5.969 in. P = 22.1 lbs./min. 3n: ** t (min.) P (lbs.) 6 (x10'3in.) 43. 62. 80. 82 84. 85. 85. ** O O .0 O 5 5 0 1030 1470 1890 1920 1940 1890 300 OOJ-‘WNl—IOO DDOOON-L‘N p—a Not recorded due to lack of recording paper. Table A—1: (Cont'd) Sample I-ZO: T = —10.1°c H = 5.0 in. D = 6.0 in. L = 5.0 in. P = 26.4 lbs./min. 0n= 2.6x10-4 in./min. t (min.) P (lbs.) 6 (x10'3in.) 60.0 1300 0.4 76.5 1720 1.2 79.0 1760 1.6 81.0 1780 2.8 83.0 60 19.0 100.0 245 20.6 108.0 200 26.0 Sample I—21: T = —20.1°c H = 6.0 in. D = 6.0 in. L = 6.06 in. P = 23.0\1bs./min. Sn: 6.15x10'4 in./min. t (min.) P (lbs.) 6 (x10'3in.) 43.0 810 0.4 75. 1740 0.8 75. 100 17. 84. 200 17. 5 5 8 0 8 95.8 450 18.6 96.0 220 22.4 100.0 260 23.2 104.0 220 25.0 112.0 210 28.6 287 Table A-2: Ice Samples I—22 to I—27 (Ice 2) Ice (2) samples were formed from crushed ice (tap water) and saturated with distilled water. Average density equals 56.1 lb./cu.ft. A 3/8 in. diameter plain steel rod was used with samples I—22 to I-27. Sample I—22: Sample I-25: T = -10.OOC T = _15'000 H = 6.0 in. H = 6.125 in. D = 6.0 In. D = 6.00 in. L = 6.0 in. L = 6.125 in. P = 21.6 lbs./min. P = 20 lbs./min. 6n= 5.7x10—4 in./min. 6n: 5,4x10_4 in./min. . -3. — t (mln.) P (lbs.) 6 (x10 1n.) t (min.) P (lbs.) 6 (x10 3:6.) 25 540 0-2 33.5 670 0.1 25 0 11-6 33.5 64 14.0 29 40 12.4 50.0 48 23.0 34 30 15.2 70.0 40 34.0 60 30 30.0 104.0 40 52.0 183 30 99.0 Sample I—26: Sample I—23: T = —6.OOC T = -22.0°c H = 6.0 in. H = 6.5 in. D = 6.0 in. D = 6.0 in. L = 6.0 in. L = 6'5 in- P = 16.1 lbs./min. P = 20.1 lbszl/min. (.311: 3.65X10—4 in./min. 5n= 5.64x10 in./min. _3 t (min.) P (lbs.) 5 (x10—3in.) t (min.) P (lbs.) 5 (x10 in.) 13 210 0_1 31 624 0.4 13 48 3.5 31 16 13.6 14 32 5.5 34 72 14.0 16 16 8.0 74 50 36.8 M Sample I—24: T = —2.OOC T = —20.OOC H = 6.0 in. H = 6 375 in. D = 6-0 }n' D = 6.00 in. L = 6'0 1n' L = 6.375 in. f = 19.1 lbs./min. P = 17.2 lbs./min. 0n= 5,8){10—4 in./min. . _ , -3. 6n= 5.1x10 4 in./m1n. 3 t (min.) P (lbs.) 6 (x10 in.) t (min.) P (lbs.) 6 (x10 in-) 5 5 ,105 0.1 32.5 560 0.4 5.5 20 4.0 7 0 10 6.0 32.5 16 12.4 30 0 10 19.3 35.0 50 13.0 44.0 32 18.4 Note: At t=0, P=O and 6:0, unless 76.0 32 34°6 _’_—— noted. 288 Table A—3: Ice Samples I—28 to I—32 (Ice 3) Ice (3) samples were formed from snow—ice saturated with distilled water. Average density equals 56.1 lb./cu.ft. A 5/8 in. diameter steel rod was used with samples I-28 to I—32. Sample I-28: T = -10.0°c H = 6.197 in. D = 6.00 in. L = 6.197 in. P = 183 5 lbs./min. 8n= 4.5x10-3 in./min. 6 (min.) P (lbs.) 6 (x10—Sin.) 1.0 150 0.01 2.0 300 0.02 3.0 460 0.03 4.0 640 0.04 5.0 840 0.05 6.0 1060 0.06 7.0 1300 0.25 8.0 1500 0.40 8.5 1560 0.75 8.5 100 15.00 10.0 70 15.00 10.2 70 18.00 11.0 ‘ 70 21.00 13.0 70 28.75 15.0 70 36.25 17.0 70 45.60 Sample I—29: T = -14.6°c H = 6.0 in. D = 6.0 in. L = 6.0 in. P = 233.3 lbs./min. 6n= 1.922(10_3 in./min. 1 (min.) P (lbs.) 6 (x10-3in.) 6.15 1435 0.5 6.15 0 20.0 7.25 140 20.5 7.50 105 24.0 8.25 100 27.0 9.00 100 31.0 12.00 70 37.0 15.00 40 43.0 18.00 30 48.8 Note: At t=0, P=0 and 6=O, unleSS noted. Sample I-30: T = —16.0 C H = 6 375 1n D = 6 00 1n L = 6 375 in P = 280 lbs./min. 0n= 4.58x10—3 in./min. t (min.) P (lbs.) 6 (x10-Bin.) 2.75 880 0.25 2.75 70 13.00 3.00 70 13.20 4.00 70 18.50 5.00 60 24.75 8.00 60 41.60 11.00 50 56.60 14.00 50 70.35 §§TPle_1:211 T = —6.0°c H = 6.375 in. D = 6.00 in. L = 6.375 in. P = 1290 lbs./min. 0n= ** t (sec.) P (lbs.) 6 (x10—Bin.) 20 430 ** Rupture at fast rate §29212_1:§§1 = —10.0°c — 6.5 in. = 6.0 in. = 6.5 in. P = 258 lbs./min. 6n: 4.615x10'3 in./min. t (min.) P (lbs.) 6 (x10—316.) HUSH—3 | 4.00 1030 1.0 4.00 0 24.0 4.75 105 25.0 5.50 70 29.0 7.00 70 37.2 11.00 70 60-0 24.00 70 120.0 289 Table A-4: Frozen sand samples. Sample S—l: Sample S—3: T = ~10.0°c T = -6.3°c D = 6.0 in.* D = 6.0 in. H = 6.0 in.* H = 6.0 in. L = 6.0 in.* L = 6.0 in. vs= 64.0 2 * vS= 64.0 x d = 5/8 in.** d = 5/8 in. h = 0 (plain rod) h = 0 P = 195.5 lbs./min. P = 29.7 lbs./min. 6n= 2.0x10'3 in./min. 6n= 6.967x10'4'in./min. t (min.) P (lbs.) 6 (x10-3in.) t (min.) P (lbs.) 6 (x10—316.) 3.34*** 640 0.16 20.5 640 0.8 4.58 890 0.22 29.0 860 1.6 5.50 1075 0.27 31.0 830 3.0 5.50 236 8.27 34.0 700 6.2 5.67 190 9.10 39.0 570 10.6 5.84 175 9.50 39.0 500 14.8 6.34 160 10.70 65.0 400 26.0 7.34 145 13.10 8.34 135 15.50 Sample S-4: 0 * Average values, unless noted. ; = 610 in? ** Coidgrolled steel, unless H = 6.0 in. no e . _ . *** at t=0, P=O and 6=0, unless Vs: ZA?01;' noted. d 5/8 in Sample S—2: h 0 T = —10.2°c P = 30.7 lbs./min. D = 6.0 in. 6n: 3 67X10—4 in./min. H = 6.0 in L = 6-0 in- t (min.) P (lbs.) 6 (x10—Bin.) vs: 64.0 2 57 1790 0.8 d = 5/8 in- 65 2060 1.5 h = 0 68 2090 2.5 ' = - 69 200 50.6 P 32.5 lbsg/min. 78 560 51.0 6n= 5.0x10 in./min. 80 590 51.6 _3 84 550 54.4 t (min.) P (lbs.) 6 (X10 in.) 87 530 56.0 21 700 0.8 99 520 60.0 29 980 1.0 38 1240 1.4 40 1300 2.2 41 1280 3.0 41 240 18.2 46 280 19.6 56 280 24.6 290 Table A-4: (Cont'd) Sample S—5: Sample S—6: (C0nt'd) o T = ‘20-1 C t (min.) P (lbs.) 6 (x10—3in.) H = 5.871 in. D = 6.00 in. 91.0 800 34.5 L = 5.781 in. 91.3 500 38.5 Vs: 66.3 Z 97.0 680 39.3 99.5 570 41.7 d = 5/8 in. 104.0 610 43.3 h = 0 107.0 600 44.7 P = 32.7 lb . ' . 3 /mln Sample S—7: 6n 5.0x10 1n./m1n. T = -26.8OC . —3. H = 6.0 in t (mln.) P (lbs.) 6 (x10 in.) D = 6.0 in 28.0 680 0.20 L = 6.0 in. 47.0 1360 0.30 vs= 64.0 2 65.0 2080 0.35 82.0 2730 0.55 g ; 3/8 in 85.0 2810 1.00 . 85.6 2810 1.80 P = 39.7 lbs.£min. 85.6 0 42.90 ' — . . 114.0 860 43.50 Gn— 6.154x10 1n./min. ii; 5 2:8 23:33 t (min.) P (lbs.) 6 (x10 316.) 124.0 560 50.00 20.50 720 0.40 127.0 ~ 470 52.40 36.75 1400 0.70 132.0 500 53.40 53.00 2080 0.76 135.0 575 54.20 70.50 2800 0.80 140.0 575 56.6QI 70.5 90 31.50 90.50 810 31.70 Sample S—6: 91.00 440 36.00 0 95.50 560 37.20 T = '26'? C 96.50 430 39.20 H = 6.01m. 100.50 510 40.40 D = 6-0 }n- 102.50 440 42.00 L = 6.0 1n- 106.00 480 43.20 Vs= 64-0 2 109.00 450 44.80 d = 5/8 in. 112.50 470 46.20 h = 0 116.00 450 47.60 P = 37.5 lbsL/min. Sample S—8: 6n: 6.38x10‘ in./min. T = —27.1°c -3. H = 6.0 in. t (min.) P (lbs.) (S (X10 1n-) D = 6.0 in. 20.0 680 0.6 L = 6.0 in- 37.5 1360 0.8 Vs= 64-0 Z 55.0 2040 0.9 d = 5/8 in 73.0 2740 1.9 h = 0 73.0 110 33.7 . , (Continued) P = 20.8.2 lbs./m1n. (Continued) 291 Table A—4: (Cont'd) Sample S—8: (Cont'd) Sample S—lO: (COnt'd) ' -3 . . — 0n= 1.32x10 1n./m1n. t (min.) P (lbs.) (3 (x10 3in.) . —3. 6.0 1180 0.2 t m1 . P lb . 1 . 4;) 48“) Leg; 7.5 1400 1.8 7.00 960 0.01 8.0 220 11.4 15.50 3150 0.40 10.5 200 14.1 18.25 3800 1.00 13.0 200 17.0 18.50 10 50.00 25.00 1240 50.00 Sample s-11; 25.50 1320 50.40 _ 0 25.75 920 54.00 g : g13.1 C 26.50 950 55.40 D ‘ 6'0 :H' 1. . ‘ . I1. 3 00 920 60 00 L = 6.0 in. Sample S—9: VS: 64'0 Z T = -20.00C d = 5/8 1n., h = 0 H = 5.938 in. P = 204 6 lbs./min. E : 2:88 :2: 5n= 3.86x10_3 in./min. Vs= 64-6 z t (min.) P (165.) 6 (X10—3in.) d f 5/8 in° 7.50 1440 0.8 h — 0 13.00 2660 1.2 P = 210.3 lbs./min. 13 00 220 29-0 . . _3 . 14.75 610 29.8 (Sn: 2.53X10 in./m1n. 15.25 450 33.6 — 19.00 430 46.2 t (min.) P (lbs.) 6 (X10 3in.) 11.00 2160 0.8 §EBB£E_§:£ZL 15 50 3260 1.2 T = —10.0°c 15.50 240 35.6 H = 6_0 in. 18 50 960 36.4 D = 6.0 in_ 18.75 680 40.4 L = 6.0 in_ 28.00 580 67.2 vs= 64_0 % Sample S—lO: d = 5/8 in. --—-‘-7;-- h = 0 T = _603 C ‘ / . H = 6.0 in. P = 222.7 lb:. min. D = 6-0 in- 6n= 3.73x10_ in./min. L = 6.0 in. _3 VS= 64.0 Z t (min.) P (lbs.) 6 (x10 in.) d = 5/8 in. 6,5 1490 0.4 h = 0 11.0 2450 2.6 ' = . 11.0 590 20.0 P 186.7 16:./mln. 11,5 480 21.6 6n= 1.12x10 in./min. 14,5 470 32.8 (Continued) 292 Table A—4: (Cont'd) Sample S—13: Sample S-15: (Cont'd) " ' O“ ' T*—_“_—‘_‘—_' T = -6.0 C P = 1978.6 lbs./min. H = 6.0 in. ' — D = 6.0 in. 6n= 2.13x10 2 in./min. L = 6.0 in. , _ VS: 64.0 2 t (616.) P (lbs.) 6 (x10 316.) = . 1 4 2770 0.4 g = 3/8 1n' 1 4 430 30.7 , 1.5 780 31.6 P = 2133.3 lbs./min. 1 6 550 33.6 5n= 1.964x10_2 in./min. i g :28 23'? t (min.) P (lbs.) 6 (x10'3in.) Sample S—16: 0.90 1920 1.4 _ _ o 0.90 490 23.5 g = 623.:nC 1.00 440 24.5 D = 6.0 in. 1.05 360 30.0 L = 6.0 in. 2.40 330 52.0 V = 64 0 7' S O 0 Sample S—14: d = 5/8 in o h = T = -15.2 C . H = 5.969 in. P = 2210 lbs./min. D = 6'00 in. 6n= 4.0x10_2 in./min. L = 6.00. in. vs= 64-2 Z t (min.) P (lbs.) 6 (x10—316.) d = 5/8 in- 1.60 3680 0.4 h = 0 2.00 4420 0.7 P = 2033.3 lbs./min. 2-00 800 16-4 ° _2 2.40 1390 16.4 5n= 3.0x10 in./min. 2.55 1630 17.8 _3_ 2.60 1280 23.8 t (min.) P (lbs.) (X10 ln-) 3.80 900 72.0 1.6 3280 0.1 1.8 3660 0.6 Sample S—17: 1.8 480 40.0 T = —20.0°c 2.0 850 40.8 H = 6.0 in. 2.0 600 45.0 D = 6.0 in. 3.0 530 75.0 L = 6.0 in. Vs: 64.0 % Sample S—15: . --——'--7;- d = 5/8 in. T = -10.0 C h = 0 H = 6.0 in. ° . D = 6.0 in. F = 2240 lbfé/mln' L = 6.0 in. 6n= 1.32x10 in./min. VS: 64‘0 A (Continued) d = 5/8 in. h (Continued) Tabl e A-4: (Cont'd) 293 gample S—17: (Cont'd) —_..-. -«._... .— r > ..—.. Sample S-19: (Cont'd) t (min.) P (lbs.) 0 (x10-316.) 360 1630 1.80 375 1580 3.60 440 1200 14.40 Sample S—20: T = -6.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. VS= 64.0 % d = 5/8 in. h = 0 P = 4.4 le./min. 6n= 1.0x10-4 in./min. t (min.) P (lbs.) 6 (x10-3in.) 145 640 0.1 165 720 0.5 210 640 4.8 280 500 13.6 375 380 23.2 Sample S-21: T = -15.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. Vs: 64 .0 c:1) d = 5/8 in h = 0 P = 6.5 lbs./min. 6n= 1.86.110"4 t (min.) P (lbs.) 6 (x10'3in.) 165 1020 0.25 260 1860 0.50 320 2080 1.50 330 2000 5.50 332 720 15.50 335 540 21.80 370 620 23.80 470 580 31.50 t (min.) P (lbs.) (x10-316.) 1.50 3360 0.2 1.50 160 14.0 1.85 1020 14.8 1.90 860 17.5 3.00 750 30.0 Sample S-18: T = -25.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. Vs: 64.0 Z d = 5/8 in. h = 0 P = 5.06 lbs./min. 6n= 1.1..10‘4 in./min. t (min.) P (lbs.) 6 (x10-3in.) 340 1600 0.3 495 2400 0.9 600 \2980 0.9 680 3440 2.9 680 1080 43.0 838 2460 43.0 860 2520 45.0 865 1100 48.6 995 1080 60.0 Sample S-19: T = —10.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. vs= 64.0 x d = 5/8 in. h = O P = 4.53 lbs./min. 6n= 1.661410.4 in./min. _3. t (min.) P (lbs.) 6 (x10 in.) 172 830 0.20 285 1350 0.45 355 1630 1.30 (Continued) Table A—4: Sample S—2 —20.0O {II II II (Co 2: C 6.0 in. D = 6.0 in. L = 6.0 in. 64.0 Z <.‘ U) ll ’11- 3‘ II II II 66= 1.34x1 6 (min.) P (163.) 6 (x10—316.) 410. 630. 647 647 650. 710. OOP—‘OOO 5/8 in. 0 0-4 2550 2770 2650 1200 1000 1000 3: Sample S—2 T = —10.00 H: C 6.0 in. D = 6.0 in. L = 6.0 in. vS 64.0 2 d h 5/8 in. 0 nt'd) 4.4 lbs./min. in./min. 0. 1. 4. 21. 24. 29. P = 268.1 lbs./min. 6n= 3.83x1 t (min.) P (165.) 6 (x10—316.) 0-3 2400 2480 240 660 660 560 540 4: 8.80 9.25 9,25 11.00 11.30 11.75 16.00 Sample S—2 T = -2.0°c H = 6.0 in. D = 6.0 in. = 6.0 in. L vS= 64.0 Z d = 5/8 in. (Continued) in./min. O. 1. 30. 31. 33. 35. 51. 4 4 2 0 6 4 1 5 O O O 0 0 Sample S—24: ( h P t (min.) .50 00\IO\U1-L\-L\LON 25 00 50 25 .25 25 75 O Cont'd) 100 lbs./min. 6n= 4.0x10'3 in./min. P (lbs.) 300 0.1 390 0.8 450 2.4 450 4.1 410 7.5 330 12.3 280 16.7 240 22.7 Sample S—25: 6n —2.0°c 6.0 in. 6.0 in. 6.0 in. 64.0 Z 5/8 in. 1714.3 lbs./min. 3.71x1 0-2 in./min. 6 (x10—3in.) t (min.) P (lbs.) 6 (x10—316.) O. O. 0. 0. 0. 0. 25 35 42 45 55 90 520 640 720 640 370 320 Sample S—26: T H D L Vs P 6n d h = ll 1! II II -2.0°c 6.0 in. 6.0 in. 6.0 in. 64.0 2 5/8 in. 0 0.5 2.9 6.1 10.3 15.0 28.0 2.1 lbs./min. 8.6x10 -5 (Continued) in./min. Table A-4: (Cont'd) Sample S—26: t (min.) P (lbs.) 35 65 100 150 250 150 190 210 190 190 Sample S—27: T: L'" I n: -2.0°c 6.0 in. = 6.0 in. _ 6.0 in. = 64.0 2 5/8 in. 0 26.3 lbs./min. 295 (Cont'd) 6 (x10-3in.) .... oxoowv—‘o O‘DO‘DN 6.0X10—4 in./min. t (min.) P (lbs.) 8 (x10'316.) O). :1 H Sample S—29: T = -15.0°c H =6.0 in. D = 6.0 in. L = 6.0 in. V3= 64.0 % d = 5/8 in. h = 0 P = 220.9 lbs./min. ** t (min.) P (lbs.) 6 (x10—3in.) 13.5 17.5 21.0 32.0 50.0 Samp 420 \ 460 448 380 350 le S—28: T: :1: ll -20.o°c 6.0 in. 6.0 in. 6.0 in. 64.0 Z = 5/8 in. 0 2478.3 lbs./min. 3.9x10"2 in./min. (min.) P (lbs.) 3420 320 1060 840 770 6 (x10-3in.) 0.01 39.00 41.00 46.00 74.50 11.5 2540 ** 11.5 400 13.0 760 15.0 660 20.0 660 ** Not recorded, channel was OFF. Sample S—30: T = -10.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. vs= 64.0 Z d = 3/8 in. h = 0 P = 29.3 1bs./min. 6n= 8.0x10_4 in./min. t (min.) P (163.) 6 (x10—3in.) 30. 30. 31. 33. 39. 94. T H D L Vs: ll OOOOU‘IO 880 0.8 240 7.4 200 8.8 160 11.2 140 16.0 140 60.0 §3921£_§:§11 —10.0°c 6.0 in. 6.0 in. 6.0 in. 64.0 % (Continued) Table A—4: (Cont'd) Sample S—31: (Cont'd) Sample S—33: (Cont'd) d = 3/8 in- t (min.) P (lbs.) 6 (x10-3in.) h = 1/16 in.* . 68.5 2190 2.0 P = 29.7 lbs./min. 72,0 1870 6.0 6n= 5.23310"4 in./min. 76'0 1840 9'2 87.0 1830 15.6 . -3 t m1 . P lb . ' . ( n ) ( S ) 6 (X10 1n ) Sample S-34: 52.5 1560 1.2 o 53.0 1320 5.2 T i E10.0 C 54.0 1040 10.4 g : 6'3 :2' 66. 1 . _ ' 0 040 16 6 L = 6.0 in * A 9OO—lug, unless noted. VS: 64'0 ° d = 3/8 in. Sample S—32: h = 3/16 in. T = —10.0°c P = 31.3 lbs./min. H = 6.0 in. ' _ -4 . . D = 6.0 in. 6n— 4.212x10 in./m1n. :3: 24301;. t (min.) P (163.) 6 (x10—316.) . 74 2320 2.8 g : :4: PD' 85 2330 8.6 . “ 1n' 127 2800 26.0 P = 33.4 lbs./min. 177 3480 45.0 ' - 357 4800 132.0 6n= 5.34X10 4 in./min. 360 4440 136-0 -3. 450 4800 160.0 t ( min.) P (lbs.) 6 (x10 in.) 640 4800 240.0 61 2040 2.0 62 1800 5.6 M 64 1580 9.2 o T = —20.0 C 72 1490 14.8 H = 6.0 in. 78 1520 18.0 D = 6.0 in. L = 6.0 in. §2E212_§:§§: vs: 64.0 8 O T = -10 0 c d = 3/3 in, H = 6.0 in. 1’] = 0 D 6.0 in. . L = 6.0 in. P = 138.7 leA/mln. Vs= 64-0 Z 6n= 6.944x10_ in./min. d = 3/8 in. —3, h = 3/16 in. t (min.) P (lbs.) 6 (x10 in.) P = 32 16 . in. 7.5 1040 1.0 ~ 3 :2 8.0 420 9.0 6n= 5.82x10 in./min. 26.0 300 21,5 (Continued) Table A-4: (Cont'd) Sample S—36: T H D L Vs: II II {TD-1 I! ll . PU. ll 6n= t (min.) P (lbs ) 6 (x10-316.) —20.00 C 6.0 in. 6.0 in. 6.0 in. 64.0 2 3/8 in. 1/16 1 32.8 lbs./min. 5.1x10 4 n. in./min. T: H: D— L 07‘ "U‘ D‘D— " H II n: t (min.) P (lbs.) 6 (x10‘3in.) —20.0O Sample S-38: C 6.0 in. 6.0 in. 6.0 in. — 64.0 Z 3/8 in. 3.16 in. 35.8 lbs./min. 4.1x10 —4 in./min. 95 103 145 185 225 265 305 345 385 425 465 505 590 3400 3360 3900 4441 4921 5382 5722 6000 6280 6480 6620 6740 7020* 0. 6. 18. 36. 46 70 87 104 118. 135. 152. 167. 200. OOO‘DUDOU‘IU‘INV-‘bba 55.5 1820 0.01 59.0 1650 4.60 65.0 1610 8.70 105.0 2000 26.00 145.0 3380 45.00 185.0 2440 65.00 205.0 2500 76.00 240.0 2600 94.40 275.0 2680 113.40 310.0 2660 130.40 Sample S-36: T = -20.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. V3= 64.0 % d = 3/8 in. h = 1/8 in. P = 37.5 lbs./min. 6n= 3.9x10'4 in./min. _3- t (min.) P (lbs.) 6 (x10 in.) 63 2360 1.6 69 2330 5.7 110 2840 22.4 150 3340 37.4 170 3580 45.0 * This load caused rod yielding Sample S—39: T = —10.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. vs= 64.0 2 d = 3/8 in. h = 0 p P = 27.1 lbs./min. 6n= 5.0x10—4 in./min. t (min.) P (lbs.) 6 (x10—316.) 4.5 130 0.8 6.0 64 1.6 9.0 45 3.2 17.0 40 7.2 Table A—4: (Cont'd) Sample S-40: T = —10.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. Vs= 64.0 Z d = 3/32 in. h = 0 P = 5.3 lbs./min. 6n= 4.32x10"4 in./min t (min.) P (163.) 6 (x10—316.) 'P: Sample S-42: 7.4 lbs./min. (Cont'd) 6n= 4.5}(10-4 in./min. 8 56 15 80 17 45 42 20 1 Sample S-4l: —20.0°c 6.0 in. = 6.0 in. 0') ON .5_\ . O N II II ‘D‘Du -- k04>®®0 OUIOO-D 6 (x10'3in.) Table A—4: (Cont'd) Sample S—67: (Cont'd) Sample S—69: (Cont'd) P = 16.3 lbs./min. —3 . t (min.) P (lbs.) 5 (x10 in.) 6n= ** ————--- --————- ————————————— 50.0 510 9.2 . —3. 52.0 480 11 2 t (m1n.) P (lbs. 6 10 . ' ———*————‘ ) -$§--3£L2' 55.0 450 13.2 29.5 480 *6 64.0 420 19.0 30.0 270 46.0 210 Sample S—70: _________________________________ -—----7;- ** Not recorded T = “10-0 C H = 6.0 in. Sample S—68: D = 6.0 in. T — —20.0°c L f 2&0019' H = 6.0 in. Vs‘ ° ° D = 6.0 in. d = 3/8 in. L = 6.0 in. h = 0 VS: 64'0 A P = 12.3 lbs./min. d — 3/8 in ' _ -4 . . h _ 1/8 in 5n— 5.867x10 1n./m1n. P = 17.7 lbs./min. t (min.) P (lbs.) 6 (x10-3in.) 6n= 2.3x10‘4 in./min. 28 344 0.4 _3 29 120 6.4 t (min.) P (lbs.) 6 (x10 in.) 30 120 7.2 50 1220 0.1 45 120 16'0 150 2660 18.0 S S- l: 250 3140 34.0 ~3§3l5——7§—- 400 3840 60.0 T = —10.0 c 600 4580 112.0 H = 4.0 in. 620 4580 120.0 D = 6.0 in. L = 4.0 in. Sample S—69: Vs: 64.0 X T = —25.4°c d = 3/8 in. H = 6.0 in. h = 0 D = 6'0 in- P = 19.5 lbs./min. L = 6.0 in. . -4 , Vs: 64.0 % 6n= 6.1x10 in./m1n. d = 3/8 in. t (min.) P (lbs.) 6 (x10—Bin.) h = 0 . 25.5 495 6.0 P = 21.86 lb80/min. 26.0 145 7.6 9n= 6.5x10’4 in./min. 28.0 130 10-0 —3. 41.0 95 18.0 1'. (min.) P (lbs.) (X10 ln') 47.0 95 21.6 48.5 1060 0.05 49.0 640 6.60 (Continued) Table A—4: (Cont'd) Sample S—72: T H D L Vs d h P 66 t (min.) P (lbs.) 5 (x10—Bin.) II -10.00 C 6.0 in. 6.0 in. 6.0 in. 64.0 Z 3/8 in. 0 12 lbs./min. 5.5x10 —4 in./min. 35.5 520 0.8 35.5 120 17.6 40.0 160 19.6 60.0 160 30.6 Sample S—73:** T = -15.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. VS= 64.0 Z d = 3/8 in. h = 0 P = 25.5 1bs./min. 5n= 4.67x10_4 in./min. t (min.) P (lbs.) 6 (x10—3in.) 46 1170 0.4 52 1000 0.4 54 1000 0.6 70 1540 1.6 70 280 21.6 79 500 23.6 81 470 25.2 93 470 30.8 ** Sample loaded, unloaded, and reloaded before rupture. Sample S—74: T H D L —20.00 C 6.0 in. 6.0 in. 6.0 in (Continued) Sample S—74: 64.0 Z 5/8 in. 0 VS: D‘D... P 6 n: t (min.) P (lbs.) 6 (x10—3in.) 25.8 le./min. ** (Cont') 118 133 143 153 193 230 280 370 3040 3180 3240 3240 2880 2200 1640 1240 *‘k ** Not recorded, equipment failure Sample S—75: H II II <1 (0 II D.- II H "U ll 6n= t (min.) 44 55 55 60 69 T: H: D: L V5 d h ll —6.0°c 6.0 in. = 6.0 in. = 6.0 in. 64.0 X 3/8 in. O 11.64 1bs./min. 4.5x10_4 P (lbs.) 510 625 160 175 175 §29212_§:Z§; —10.0°c (Continued) in./min. 6 (x10- ' 0.1 3.2 14.4 17.2 21.2 Table A-4: (cont'd) Sample S—76: (Cont'd) P = 14.7 lbs./min. 6n= ** t (min.) P (lbs.) 6 (x10-Bin.) 50 1736 ** 76 1090 84 1090 124 900 ..__...__________________.____~_ ** not recorded, equipment failure Sample S—77: T = —10.0°c H = 5.0 in. D = 6.0 in. L = 5.0 in. 64.0 2 = 3/8 in. 0 = 11.7 lbs./min. 4.1x10—4 in./min. 5 (x10—3in.) 2.0 17.2 19.0 28.0 t (min.) P (lbs.) 67 780 67 220 68 190 90 190 Sample S—78: Leakage, Data void Sample S—79: T = —10.0°c H = 3.0 in. D = 6.0 in. L 3.0 in. vS 64.0 Z d 3/8 in. h — O P = 13.7 1bs./min. 6n= 4.75x1o‘4 (Continued) in./min. Sample S-79: t (min.) P (lbs.) 6 (x10—Bin.) 39.5 540 1.4 40.0 130 14.4 41.0 140 15.4 57.0 140 23.0 (Cont'd) Sample S—80: Leakage, data void. Sample S—81: T -10.0°c H D L II ll 11 II ON .0. S < 03 11 5‘0.- " 1| Ob) \ 00 H :1 9.0 lbs./min. 4.53410“4 07! 17d. ll :1 ll in./min. t (min.) P (lbs.) 6 (x10—3in.) 30 270 0.8 30 90 8.8 32 60 11.4 44 60 16.8 §EE212_§:§ZL —10.0°c 3.0 in. 6.0 in. 3.0 in. 64.0 Z = 5/8 in. - 0 H: D: L: < (D II = 8.2 lbs./min. én= ** t (min.) P (lbs.) 6 (x10—316.) 53 430 ** 80 430 ** Not recorded, equipment failure. Table A—4: (Cont'd) Sample S—83: Sample S—85: (Cont'd) T = —10.0°c -3 H = 2.0 in. 1: (min.) P (lbs.) 6 (X10 in.) D — 6.0 in. 26.5 530 0.1 L = 2-0 1n- 26.5 220 4.8 VS= 64.0 A 30.0 180 7.6 h = 0 . Sample S-86: P = 6.8 lbs./min. o , _4 T = ‘10.0 C 5n= 3.1X10 in./min. H = 6.0 in. _3 D = 6.0 in. t (min.) P (lbs.) 6 (x10 in.) L = 6.0 in. 42.5 290 0.6 VS: 64'0 Z 43.0 80 9.6 d = 3/8 in. 80.0 80 21.0 h = 0 (Ground-Finish) Sample S—84: P = 23.3 1b:./min. T = —10.OOC 5n= 4.0X10 in./min. H = . ' . - D = §.8 :2. t (min.) P (lbs.) 6 (x10 3in.) L = 2.0 in. 0.0 100 0.01 VS= 64.0 Z 24.5 670 0.1 _ . 24.5 170 6.8 g ; 8/8 1“' 30.0 140 12.0 . 35.0 140 14.0 P = 4.45 le./min. 43.0 140 17.0 én= ** 113.0 140 45.0 — S l S-87: t (min.) P (lbs.) 6 (x10 3in.) -EEEL£L——7;‘" T = -10.0 C 55 240 ** H = 6.0 in. , . D = 6.0 in. 4* Not recorded, equ1pment failure L = 6.0 in. = 64.0 Z Sample S-85: vs 0 d = 3/8 in. T = ‘10.? C h = 1/8 in. H = 6.0 1n. (450—lug, Ground—Finish) D = 6.0 in. . L = 6.0 in. P = 23.1 lbs./min. vs= 64.0 2 5n: 5,93x10‘4 in./min. d = 3/8 in. t (min.) P (1bS.) 6 (x10—3in.) h = 0 (Ground—Finish) , 35 810 0.4 P = 20 lbs./min. 160 2090 30.2 6n= 3.24x10'4 in./min. 260 2530 78.6 360 2730 129.6 Co ti d ( n nue ) 405 2730 154.6 Table A-4: (Cont'd) SamPle S—88: Sample S-90: (Cont'd) o T = —10.0 c vs= 64.0 2 H = 6.0 in. _ . D = 6.0 in d : 3/8 Pn‘ L = 6.0 1n h — 1/8 in. VS: 64.0 Z . (45°-lug, Shot‘BlaSted) d = 3/8 in. ?= 30 lbs./211n. h = 0 (Shot-Blasted) 6n= 5.39x10' in./min. P = 18.5 1 . ' . — , ES /mln t (min.) P (163.) 6 (x10 3in.) 6n= 7.5x10 4 in./min. 72 2160 1.0 . -3, 75 1960 6.0 t (min.) P (lbs.) 6 (x10 in.) 85 1960 11.2 94 1740 3.2 185 2920 52.8 94 1600 9.6 370 3400 146.0 95 1140 19.2 520 3400 225.0 97 1070 24.2 100 990 28.3 Sample S-91: 160 730 69.3 0 T = -15.0 C 175 730 80.8 H = 6.0 in. D = 6.0 in. Sample S—89. L = 6.0 in. T = —10,o°c vs: 64.0 2 g = 2'8~:n‘ d = 3/8 in. O = n. - ' = 1 . 45 -l L = 6.0 in. F /8 1n ( ug) Vs: 64.0 Z P = 23 1bs./min. = 3/8 in. 6n= 5.0x10—4 in./min. d h = 1/8 in. (45°—1ug) - t (min.) P (lbs.) 6 (X10—3in.) P = 25 lbs./min. ' -4 . . 85 2160 1.5 6n = 5.5x10 1n./m1n. 95 2160 8.0 -3. 195 2920 36.0 t (min.) P (lbs.) 6 (x10 in.) 350 3840 84.0 15.6 1440 0.1 560 4360 182.0 16.0 1560 9.0 680 4360 242.0 66.0 2300 26.5 166.0 3160 70.0 Sample S—92: 271.0 3380 121.0 T = —15.OOC 350.0 3380 165.0 H = 6.0 in 523.0 3380 260.0 D 6.0 in L - 6.0 in. sample 3'90: VS: 6400 z T = ‘10.OOC d = 3/8 in H = 6.0 in. h = 0 D = 6.0 in. , . L = 6.0 in. P = 20.5 13s./m1n. (Continued) ( Contlnue ) Table A—4: Sample S—92: 6n= 6.25x10 t (min.) P (lbs.) (Cont'd) (Cont'd) -4 in./min. 6 (x10-3in.) 61 1250 0.8 61 95 20.0 70 320 20.4 71 320 21.6 73 300 23.2 85 280 31.2 100 280 39.7 120 280 52.2 Sample S—93: T = —20.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. VS= 64.0 % d = 3/8 in. o h = 1/8 in. (45 —lug) i = 34.9 lbs./min. 6n= 5.2x10‘4 in./min. t (min.) P (lbs.) 6 (x10—3in.) 75 2720 0.1 80 2600 5.0 90 2600 9.6 190 3800 42.0 340 4480 116.0 420 4600 160.0 450 4640 175.0 Sample S—94 T = —20.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. vs= 64.0 % d = 3/8 in. h = o f = 18 lbs. 6n= 5.85x10 (Continued) /min. in./min. Sample s—94: 80 1440 0. 95 1700 0. 95 300 25. 103 480 25. 104.5 520 26. 108.0 520 29 110.0 460 32 126.0 440 41 136.0 440 48. Sample S—95: (Cont'd) T = -26.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. Vs: 64.0 2 d = 3/8 in. h = 0 f = 22.2 lbs./min. 6n= 6.67x10'4 in./min. t (min.) P (lbs.) 6 (x10—3in.) OOWO‘OOOO‘bN t (min.) P (lbs.) 6 (x10—3in.) 83 1840 0.1 83 240 28.0 103 800 29.0 103 680 32.0 105 600 34.0 115 640 39.0 145 640 59.0 Sample S—96: T = -6.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. Vs: 64.0 Z d = 3/8 in. h = 1/8 in. é = 27.6 lbs 6n= 5.6x10_4 (Continued) (45°—lug) ./min. in./min. Table A-4: (Cont'd) Sample S-96: (Cont'd) t (min.) P (lbs.) 6 (X10—3in.) 50 65 75 175 275 375 iI'aI-i II II n- Ov w- r a < H U t (min.) 30 80 160 200 320 1380 .0 1280 0 1280 0 1760 4 1960 0 2040 0 Sample S—97: -2.0°c 6.0 in. = 6.0 in. 6.0 in. 64.0% = 3/8 in. 0 1/8 in. (45 —lug) 19.34 lbs./min. 5.67x10_4 -3. P (lbs.) 6 (x10 1n.) ‘ 580 4.5 1040 23.0 1440 61.5 1520 81.5 1520 149.5 Sample S—98: —10.00c 2.0 in. 6.0 in. 2.0 in. T: H D L: vs d h P 6n= II II II II t (min.) P (lbs.) 6 (x10—3in.) 23.5 23.5 25.0 40.0 64.0 Z 5/8 in. O 25 lbs./min. 5.73x10—4 576 170 145 145 H l "U‘ 'J‘Q. < [D II H II II 6n= t (min.) P (lbs.) 6 (x10—Bin.) 52 52 58 62 80 T: H: D: L: vs= d: 5/8 in. 0 36.9 le./min. Sample S—99: — 10.000 ‘ 4.0 in. = 6.0 in. = 4.0 in. 64.0 X 6.67x10'4 1 h = 0 II P 6n= t (min.) P (lbs.) 6 (x10—3in.) 41 41 42 54 62 T = H = D = L = VS— d = h = 31.22 lbs./min. 5.6x10'4 920 320 500 480 480 Sample S—100: —10.0°c 1280 5.0 in. 6.0 in. 5.0 in. 64.0 Z 5/8 in. 0 (Continued) 460 300 290 290 §39212_§:1911 —10.0°c in./min. Table A-4: (Cont'd) Sample S—101: (Cont'd) P = 41 lbs./min. 6n= 6.03x10'4 in./min. Sample S—103: (Cont'd) 6n= 5.7}(10—1+ in./min. t (min.) P (lbs.) 6 (x10—3in.) t (min.) P (lbs.) 6 (X10—3in.) 35.5 980 2.4 76.0 3120 2.0 35.5 440 8.8 36.0 290 10.8 77.0 2920 4.0 40.0 260 13.4 77.5 1980 15.0 60 0 260 24 8 78.0 1620 20.5 ' - 79.0 1340 24.0 82.0 1250 27.5 §EEElE_§:lQi; 116.0 1220 48.0 Leakage, data void Sample S-102: Sample S—105: T = —10.0°c T = -10.0°c H = 6.0 in.- H = 5.0 in. D = 6.0 in D = 6.0 in L = 6.0 in L = 5.0 in vS= 64.0 2 vS= 64.0 Z d — 5/8 in d = 5/8 in h h = 0 P = 41.73 lbs./min. P = 35.6 lbs./min. 6h: 7.17.;10'4 in./min. 6n= 6.25x10_4 in./min. — -3. t (min.) P (lbs.) 6 (x10 3in.) t (min.) P (lbs.) 6 (x10 1n.) 81.0 3380 1.5 81 2880 2 83.0 2980 5.0 82 2520 6 83.5 1700 23.5 83 1320 21 85.0 1300 29.5 88 1080 27 88.0 1180 32.5 96 1080 32 130.0 1180 56.5 Sample S-103: T = C H = 2.0 in. D = 6.0 in. L = 2.0 in. Vs: 64.0 Z d = 5/8 in. h = 0 P = 28.1 lbs./min. (Continued) —1o.0O EEaTfl£;§:lgé: T H D _ L v: S "U'D‘Da 6n= (Contiued) —10.00 C 2.0 in. 6.0 in. 2.0 in. 64.0 Z 5/8 in. 0 25 lbs./min. 5.86x1 0—4 in./min- 312 Table A-4: (Cont'd) Sample S-106: (Cont'd) t (min.) P (lbs.) 6 (x10-Bin.) Sample S-109: (Cont'd) 23 576 1.6 L = 6.0 in. 23 210 7.2 vs= 64.0 2 24 120 8.0 d = 5/8 in. 39 12 . 0 16 8 h = 0 Sample s-107: P = 35 lbs./min. T = -10.0°c 6n= 5.0x10’4 in./min. h = 5.0 in. _3 D = 6.0 in. t (min.) P (lbs.) 6 (x10 in.) t ; 240012’ 56 1960 2.0 S ' ° 56 320 19.0 d = 5/8 in. 65 640 23.0 h = 0 67 480 26.0 P = 38.9 lbs./min. 1:; :28 §g°g n= 6.2x10-4 in./min. 030 Sample S-llO: . —3. t (min.) P (lbs.) 6 (x10 in.) T = -1O.OOC 52.5 2040 3.0 H = 4.0 in. 52.5 460 20.0 D = 6.0 in. 57.0 . 500 23.0 L = 4.0 in. 74.0 500 33.5 vs= 64.0 % d = 5/8 in. Sample S-i08: h = 0 T = '10'0 C P = 28.2 lbs./min. H = 3.0 in. , _4 D = 6.0 in. 6n= 5.56X10 in./min. L = 3.0 in. -3 vs: 64.0 % t (min.) P (lbs.) 5 (x10 in.) d = 5/8 in. 17 500 0.8 h = O 17 170 4.0 ’ . 20 140 8.0 P = 26.5 le./m1n. 30 130 14.0 6n= 5.8x10—4 in./min. 60 120 31°C 66 120 34.0 t (min.) P (lbs.) 6 (x10-3in.) Sample S-111: 20 530 0.01 o 20 160 5.60 T = -10.0 C 21 130 6.40 H = 5.5 in. 41 130 18.00 D = 6.0 in. L = 5.5 in. Sample S—109; Vs: 64.0 % T = -10.0°c d = 3/8 in. H = 6.0 in. h = 0 D = 6'0 in. . (Continued) (Continued) Table A—4: (Cont'd) Sample S-111: (Vont'd) P = 20 lbs./min. 6n= 6.67x10_4 in./min. t (min.) P (lbs.) 28 560 28 320 40 40 52 40 Sample S-112: T = —10.0°c H = 5.625 in. D = 6.000 in. L = 5.626 in. vs= 64.0 2 d = 3/8 in. h = 0 P = 21.2 lbs./min. = 6.25x10‘4 in./min. 6 D t (min.) \P (lbs.) 30 640 30 240 31 100 42 80 47 80 Sample S—113: T = -15.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. vs= 64.0 2 d = 3/8 in. h = 0 P = 25.2 lbs./min. 6 (X10-3in.) 0.5 8.5 16.5 24.5 6 (x10—3in.) 0.1 9.5 12.0 19.0 22.0 6n= 4.75x10_4 in./min. t (min.) P (le-) 42 1060 42 280 58 280 6 (x10—3in.) 0.7 14.0 21.6 313 Sample S—114: L—‘UCCH llll <1 U} l 0" 4.x. 0 N5 3/8 in. — 0 5‘04 P = 25.8 lbs./min. 6n= 4.0x10-4 in./min. t (min.) P (lbs.) 6 (x10—3in.) 27 690 0.40 35 430* 0.16 38 430 0.18 63 1250** 0.24 63 280 14.20 64 220 14.40 68 250 15.80 78 240 19.80 _.__.___.__._______.______._____ * Decreasedeue to unloading ** Reloading Sample S—115: T = ~10.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. vs= 64.0 2 d = 3/8 in. h = 0 P = 17.3 lbs./min. 6n= 4.2X10_4 in./min. t (min.) P (lbs.) 6 (x10—3in.) 33.5 580 1.0 33.5 160 7.4 34.0 80 9.8 74.0 30 26.6 108.0 30 33.8 314 Table A—4: (Cont'd) Sample S-116: Sample S-ll8: (cont'd) T = -10.0°c h = 0 H = 6.0 in. ° . D = 6.0 in. P = 22 lbs.ém1n. L = 6.0 in. 6n= 2.8x10 in./min. Vs: 64.0 Z _3 d = 3/8 in. t (min.) P (lbs.) 6 (x10 in.) h = 0 37 810 0.1 ' _ - 37 330 4.4 P 20.3 lbfg/mln. 40 200 8.8 6n= 4.84x10 in./min. 52 170 14.0 75 170 20.4 t (min.) P (lbs.) 6 (x10-Bin.) Sample S-ll9: 22.5 460 0.4 o 22.5 170 4.4 T = -10.0 C 23.0 100 7.0 H = 6.0 in. 33.0 40 16.6 D = 6.0 in. 61.0 40 25.4 L = 6.0 in. 4 Vs: 64.0 Z S' 1 S-1 . amp e 017, d = 5/8 in. T = -20.0 C h = 0 H = 6'0 Pn' P = 33.4 le./min. D = 6.0 in. . _4 L = 6.0 in. 6n= 1.17X10 in./min. Vs= 64'0 Z t (min.) P (lbs.) 6 (x10—3in.) d = 3/8 in. 41 1370 0.9 h = 0 41 50 7.2 P = 24.6 le./min. 50 280 7.5 ° —4 , 56 240 8.2 6n= 2.1x10 in./m1n. 68 240 9.6 -3. t (min.) P (lbs.) 6 (x10 1n.) Samlpe S-120: 54 1330 0.6 _ o T - -10.0 C 54 280 12.8 H = 2.0 in. 59 250 16.0 D = 6.0 in. 87 210 23.0 L = 2.0 in. 113 180 27.2 VS= 64.0 Z 160 180 36.9 d = 3/8 in.** Sample S-118: h = 0.015 1n.** T = -20.0°c P = 170 lbsé/min. H = 6'0 in. 6n= 4.6x10- in./min- D = 6.0 in. L = 6-0 in. ** Standard deformed bar Vs: 64-0 Z (Continued) d = 3/8 in. (Continued) Table A-4: (Cont'd) Sample S—120: (Cont'd) t (min.) P (lbs.) 6 (x10—3in.) 2 560 0.9 4 1060 2.5 5 1260 4.0 6 1420 7.5 8 1630 13.0 10 1870 19.0 12 2030 25.0 14 2190 32.5 16 2270 40.0 17 2300 43.8 20 2300 56.5 24 2200 75.0 29 2080 100.0 53 1800 130.0 40 1610 155.6 45 1540 180.0 60 1310 250.0 81 1050 325.0 Sample S-121: T = —10.0°c H = 3.0 in. D = 6.0 in. L = 3.0 in. Vs: 64.0 Z d = 3/8 in.** h = 0.015 in.** P = 235 lbs./min. 6n= 4.5X10_ in./min. t (min.) P (lbs.) 6 (x10—3in.) 4 1102 0.5 8 2100 4.4 10 2678 8.8 12 3220 13.5 14 3378 18.5 16 3762 25.0 18 3890 31.0 21 4025 46.3 24 3940 60.5 28 3590 89.4 32 3100 117.0 36 2720 143.5 40 2470 174.0 (Continued) Sample S—121: (Cont'd) t (min.) P (lbs.) 6 (x10—3in.) 46 2300 207.0 52 2120 242.0 60 1980 282.0 68 1840 327.0 ** Standard deformed bar Sample S—122: T = —1o.0°c H = 6.0 in. D = 6.0 in. L = 6.0 in. vS= 64.0 2 d = 3/8 in. h = 1/8 in. P = 40 lbs./min. 5n= 6.7x10_4 in./min. t (min.) P (lbs.) 6 (x10—3in.) 20.0 770 0.3 40.0 1600 1.8 41.0 1570 2.5 43.0 1300 7.5 46.0 1080 15.0 50.0 1120 17.5 55.0 1150 20.0 60.0 1208 23.0 70.0 1310 29.5 90.0 1450 41.2 120.0 1560 61.2 160.0 1698 88.0 170.0 1750 116.5 190.0 1750 166.5 285.0 1750 230.0 Sample S—123: P = 22 lbs./min. 6n= 8.2x10'4 (Continued) in./min. Table A—4: (C ont'd) Sample S—123: (Cont'd) t (min.) P (lbs.) 6 (X10—3in.) 15.0 15.0 113 17.5 105 21.0 96 5 5 330 29. 32. Sample S-124: T = —10.0°c H=D=L=6 d = 3/8 in. h = 0 v = 29.6 Z P = 31.8 lbs. 6n= 6.8x10"4 S t (min.) P (lbs.) 6 (x10—3in.) 16.5 525 16.5 60 20.0 ‘60 30.0 60 46.0 60 .0 in. /min. in./min. Sample S-125: T = -1o.o°c H = L = 6.125 D = 6.0 in. d = 3/8 in. h = O v = 53.8 Z P = 20.8 lbs. 7.05.10“4 t (min.) P (lbs.) 6 (x10—3in.) 10.5 22 11.0 10 21.0 8 28.0 7 34.0 7 in. /min. in./min. 5 0 5 5 5 0.5 4.5 6.2 10.0 17.0 21.0 0.20 8.25 10.75 19.62 30.63 0.1 2.5 10.5 15.1 19.6 Samp T H d h VS 6 = II II II II II 6n= 8.4x10'4 in./min. 16.2 16.2 18.0 24.0 29.0 Samp EH <1D‘Qa S lad! 1'1— O)‘ t (min.) P (lbs.) 6 (x10—3in.) 16.6 17.0 18.0 21.0 Samp le S-126: —1o.0°c D = L = 6.0 in. 3/8 in. 0 52.7 % 44 lbs./min. 710 112 145 145 245 le S—127: —10.0°c D = L = 6.0 in. 3/8 in. 0 = 30.3 Z 31.6 lbs./min. 1.1x10'3 525 135 60 60 ~___3513t12§; in./min. 0.4 9.2 10.0 15.5 19.2 0.8 7.5 8.6 11.9 t (min.) P (lbs.) 6 (x10—3in.) Vs: 44 . 2 % P = 30 lbs./min. 6n= 8.1}(10-4 in./min. t (min.) P (lbs.) 6 (x10—3in.) 10.6 320 11.0 120 13.0 75 16.0 40 19.0 40 317 Table B—1: Ice samples CI—l and 01-2 (Ice 3) Sample CI—l: Sample CI—2: (Cont'd) T = —10.0°c -3 H = 5.87 in. ELilP§il .E_QEEEQ_ §E£§19~_12;2 D = 6.00 in. 280 550 1.25 L = 5.87 in. 600 1.00 d = 3/8 in.(Cold-rolled) 690 1.00 h = 1/8 in.(9OO-lug) 360 0 1.00 P (lbs.) t (min.) 60(x10'3in.) :88 3';§ 520 20 0.20 300 1.00 40 0.75 500 1.00 60 1.75 710 1.00 138 ::88 440 0 1.00 120 18 50 300 1'00 140 83.50 400 1‘12 160 141.00 :88 1'33 180 213.50 750 2'00 200 286.00 1000 2‘50 220 361.00 1100 3'00 240 443.50 1200 3'00 1300 3.00 Sample CI-Z: T ;_ 1P717517 1380 3.50 H i 60'... 520 0 3'50 D = 6.0 in. 100 4.00 L = 6 0 in 200 4.50 - . . 300 5.00 d = 3/8 in. 400 6 00 h = 1/8 in. 500 7:25 P (lbs.) t (min.) 6C t (m1H-) 5C W 1250 28.75 520 100 1.25 1080 0 33.12 300 5.00 50 47.00 400 7.60 100 55.00 600 10 80 200 66.88 800 15-1 (Continued) (Continued) 334 Table B—2: (Cont'd) Sample CS-39: (Cont'd) Sample CS-40: (Cont'd) P (lbs.) t (min.) 6C(x1o'3in.) P (lbs.) t (min.) 6C(X10_3in.) 520 1000 18.9 520 600 21.5 1250 23.2 800 24.0 1500 27.6 1000 27.1 1800 31.8 1250 29.0 2100 37.0 1500 31.5 2400 40.8 1800 32.8 2700 44.5 1965 34.0 3015 47.5 720 0 35‘2 1080 0 51.0 50 36.5 50 67,0 100 37.8 100 81.2 200 40.2 200 106.0 300 41.5 300 129.1 450 44.0 450 151.0 600 46-5 600 192.2 800 49.0 800 234.8 1000 51.5 1000 276.0 1200 54-0 1200 316.0 1425 57-7 1400 361.0 1080 O 57.8 1560 0 362.0 50 62-8 . 50 424.5 100 65.3 100 487.0 200 7l~5 150 537.0 300 76-6 200 612.0 450 82-8 280 712.0 600 89-1 260 837.0 800 96-5 1000 104.0 1200 111.5 Sample CS—40: 1410 119,0 0 T = -10-0 C 1240 0 120.3 H = L = 6.125 in. 50 124 0 D = 6.0 in. 100 127.8 d = 3/8 in. 200 134.8 h = 1/8 in. 300 142.8 vs= 52.8 2 450 152.8 ' c _3 600 164.0 P (lbs.) t (min.) 6 (x10 in.) 745 175.3 520 50 6.0 1560 0 175.5 100 9.0 50 190.5 200 12.8 100 205.5 300 15.2 200 234.5 450 17.8 300 263.0 , 450 318.0 (Continued) 600 393,0 700 454.2 820 585.5 335 Table B—2: (Continued) Sample CS—41: Sample CS—42: T = -1o.0°c T = -10.0°c H = D = L = 6.0 in. H = L = 6.0 in. d = 3/8 in. D = 1.938 in. h = 1/8 in. d = 3/8 in. vs= 17.5 2 h = 1/8 in. v = 64.0 T P (lbs.) t (min.) 6C(x10"3in.) S P (lbs.) t (min.) 6°(x10'3in.) 280 100 0.12 200 0.25 520 100 1.0 300 0.50 200 1.0 600 0.50 300 1.0 935 0.20 500 1.5 360 0 0.20 615 3.0 100 0.25 720 0 3.0 200 0.50 200 3.3 400 0.50 500 3.5 500 0.75 800 4.0 740 1.00 920 5.0 1222 6:33 1080 0 5.0 50 8.2 520 0 0.50 100 12.0 100 1.50 200 18.0 ‘ 200 2.62 300 21.5 300 4.50 400 25.5 400 7.75 500 28.5 500 11.00 615 31,5 938 :3'32 1240 0 31.7 840 61:00 100 37-0 200 40.9 600 0 61.00 300 44.0 100 111.00 400 47.7 200 161.00 550 53.4 300 211.00 700 58.4 400 261.00 850 59.6 500 311.00 1035 65.9 600 367'00 1560 0 65.9 750 448.00 100 75.9 680 0 448.00 200 83.4 100 555.00 300 91.5 200 655.00 450 104.0 300 780.00 600 117 1 400 918.00 750 128.4 500 1038.00 940 144.6 1840 0 144 6 50 158.4 (Continued) 336 Table B—2: (Cont'd) Sample CS-42: (Cont'd) Sample CS—43: (Cont'd) P (lbs.) t (min.) 6C(x10—3in.) P (lbs.) t (min.) 6C(x10'3in.) 1840 100 170.9 1840 100 87.0 200 192.1 200 95.8 300 217.0 300 103.2 400 233.4 450 112.0 500 267.0 600 122.0 665 317.0 800 133.0 2.20 0 317.0 iggg 123-3 50 364.5 ' 100 426.4 2200 0 155.0 150 492.0 50 160.0 210 604.5 100 168.8 210 rupture 200 175.0 300 187.5 M :38 3‘23? T = -10.00C 780 237.5 H = = . ' . D = 1: 0 :n0 in 2560 0 237.8 _ ' , ' 50 253.0 d " 3/8 ln. 1 h = 1/8 in 00 271.0 V = 64 0 7- 200 293.0 s - 3 300 317.0 . —3. 400 340.0 P (lbs.) t (min.) 6C(x10 in.) 500 363.0 1080 50 6.8 600 385.0 100 13.0 670 403.0 200 21.0 2840 0 405.0 300 27-0 50 433.0 450 31-8 100 485.0 600 35-8 200 509.0 800 40-8 300 563.0 1000 44-5 400 613.0 1150 46-4 500 663.0 50 52.0 100 54.5 _ . 300 63.2 T = 10.0 C 450 68.5 H = L = 3.0 in. 600 72.0 D = 6.0 in. 680 75.0 d = 3/8 in.** h = 0.015 in.** 1840 0 76.0 V = 64 0 7 50 83.2 S ' ° (Continued) (Continued) ** Standard deformed bar 337 Table B—2: (Cont'd) Sample CS—44: (Cont'd) Sample CS-45: (Cont'd) P (lbs.) t (min.) 5C(x10 3in.) P (lbs.) t (min.) 6C(x10‘3in.) 1080 20 2.5 520 40 9.3 40 5.0 100 16.0 80 7.8 200 21.9 130 9.8 300 26.5 200 10.8 450 31.5 260 13.0 600 35.0 350 14.9 800 40.0 450 16.8 1000 43.5 600 18.0 1205 45.8 :38 :3'2 800 0 46.5 1130 21.8 50 52.5 100 55.8 1560 0 21.8 200 61.2 40 24.2 300 66.2 100 26.1 450 72.7 150 28.0 800 88.3 250 30.0 1000 95.8 400 34.8 1130 99.3 600 35'5 1160 0 100.0 800 38.0 50 115.3 \ 1000 40.2 100 123 8 1200 42.0 2 ' 1365 43.5 00 141°C 300 156.0 1980 0 43.5 450 174.3 100 48.7 600 192.0 200 53.0 800 216.0 350 58.8 1000 241.0 500 64.2 1200 266.0 700 74.2 1400 292.3 950 88.0 1535 313.0 1270 124.2 50 403.0 2560 0 124.2 100 465.0 5 144.0 200 572.0 5 rupture 300 671.0 360 743.0 400 778.0 Sample CS-45: 455 896.0 T = —2.0°c H = D = L = 6.0 in. d = 3/8 in. h = 1/8 in. vs= 64.0 2 (Continued) ***** .4 STATE 1293 M1|1|11|11|1 H!1in11111111111111153 1') 3 O 3 0 8 2 0 7 51