Two cm SLOPES m HBROUS ORGANIC sous~ , Emma AND mums ‘ Dissertation for the Degree of Ph. D. ' momma: STATE UNIVERSITY WAYNE a same. 1975 134:2“ - . Unevztt —- --v— w" .- wl“; "flu r l This is to certify that the thesis entitled TWO CUT SLOPES IN FIBROUS ORGANIC SOILS BEHAVIOR AND ANALYSIS presented by Wayne A. Charlie has been accepted towards fulfillment of the requirements for Ph.D. Civil Engineering degree in Q‘.{B, QLMFjLKAAJhLVj;\_ Major professor Date ““0339“ ‘ \0\’\§ 0-7 639 ABSTRACT TWO CUT SLOPES IN FIBROUS ORGANIC SOILS BEHAVIOR AND ANALYSIS By Wayne A. Charlie The behavior of two cut slopes in a consolidated fibrous organic soil (papermill sludge) landfill is analysed. Information presented includes site data, physical properties of the fibrous organic soil, in-situ and laboratory shear strengths, lateral move- ments near the cut slope, and a stability analysis for the observed slope failure. A 3:4 (8 = 53.1 degrees) sl0pe l6 feet (4.88m) in height was stable. Observed lateral movements were less than l inch (2.54cm) ten days after excavation. The sl0pe was then trimmed to a l:8 (B = 82.9 degrees) slope l6 feet (4.88m) in height which failed four days later. Immediately preceeding failure lateral movements were close to 3.75 inches (9.52cm). Fresh sludge samples and field water contents were taken at the time of construction of the landfill. Undisturbed block samples of consolidated sludge and field water contents were taken at the time of slope excavation. Laboratory shear test results, using triaxial, plane strain, and unconfined compression tests, are presented. It is shown that soil mechanics theory can be used to predict the stability of slopes excavated in a sludge landfill. The significant increase Wayne A. Charlie in shear strength of the papermill sludge as a direct consequence of consolidation resulted in a stable 3:4 slope with small observed lateral movements. This behavior was in contrast to the very soft, almost fluid behavior of the fresh sludge placed in the landfill during construction. For the l:8 slope, Janbu's method for a composite failure surface gave excellent agreement between the actual factor of safety and the computed factor of safety. The field vane shear strength, corrected by Bjerrum's method for deformation rate and sludge anisotropy effects, appeared to give a good representation of the undrained field shear strength for the sludge. A finite element inethod (FEM) of analysis, using laboratory test results and a bilinear stress-strain model for sludge behavior, was in good agreement with observed field behavior for the l:8 slope. Triaxial test data show that the strength of pulp and paper- mill sludges appear to be frictional and in accordance with the principle of effective stress. Angles of internal friction (effective stress basis) ranged from about 45 degrees at low organic contents (28%) to about 70 degrees at higher organic contents (63%). The high values for 5 represent an exceedingly strong material but may be unrealistic in assessing the strength. Fibers extending across failure surfaces probably go into tension as the sample is deformed, thereby giving a pseudo value for the angle of internal friction. Large strains are required to fully mobilize available strength. For a given organic content, anisotropic consolidation increased the angle of internal friction when the direction of compression was normal to the plane in which the fibers would tend to be aligned. Unconfined Wayne A. Charlie compressive strengths were also greatest for sample compression normal to the plane in which the fibers would tend to be aligned. Lower values for the angle of internal friction and the unconfined compres— sive strength were observed when the direction of compression was in the plane of maximum fiber alignment (horizontal). It is shown that the papermill sludge has properties in many respects similar to peat and other fibrous organic soils. TWO CUT SLOPES IN FIBROUS ORGANIC SOILS BEHAVIOR AND ANALYSIS By ._< -- \ gfi- ' Wayne A: Charlie A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements of the degree of DOCTOR OF PHILOSOPHY Department of Civil Engineering l975 ACKNOWLEDGMENTS The writer wishes to express his appreciation to his major professor, Dr. 0. B. Andersland, Professor of Civil Engineering, for his encouragement, initiative, and aid throughout the writer's doctoral studies and for his guidance during the preparation of this thesis. Thanks are also due the other members of the writer's doctoral committee: Dr. T. S. Vinson, Assistant Professor of Civil Engineering; Dr. w. A. Bradley, Professor of Metallurgy, Mechanics, and Materials Science; and Dr. R. Carmichael, Assistant Professor of Geology. The writer also owes his appreciation to: Dr. Robert P. Vallee for the construction of the landfill; Mr. Tom Danis Sr. of the B. G. Danis Co., Dayton, Ohio for his help and cooperation during the excavations in the landfill; Mr. Donald Kindred for his cooperation and suggestions during the field portion of the research; Mr. Rodney w. Lentz for his time and suggestions; Mr. Leo Szafranski for his help in preparation of required apparatus for experimentation; and to his friends who helped proofread the manuscript and gave encouragement throughout the writer's doctoral studies. Special appreciation is also given to the writer's parents for their encouragement. Appreciation is also given to the Rohn family. Thanks are also extended to the U.S. Environmental Protection Agency, the National Council of the Paper Industry for Air and Stream Improvement, and the Division of Engineering Research at Michigan State University for the financial assistance which made this research possible. ii TABLE OF CONTENTS ACKNOWLEDGMENTS LIST OF TABLES . LIST OF FIGURES LIST OF SYMBOLS Chapter I. II. III. INTRODUCTION A. Need for Study . . B. Objectives of Study . C. Nature and Scope of Study LITERATURE REVIEW A. Physical Properties of Fibrous Organic Soils . l. Composition . . . . . . . . 2. Consistency Limits 3. Water Content . B. Stress- Strain Characteristics 1. Organic Fibers . 2. Kaolinite Clay. . . 3. Fibrous Organic Soils as a Composite Material 4. Similarity to Organic Soils . C. Vane Shear Strength vs. Field Shear Strength D. Movement and Stability of Cut Slopes . l. Shear Strength Theory . . 2. Rotational Movement . 3. Composite Sliding Surface 4. Failure Zone Around Slopes During Excavation : ENGINEERING PROPERTIES OF PAPERMILL SLUDGE A. Physical Properties . B. Strength Characteristics . l. Triaxial Shear Tests . a. Sample Preparation iii Page ii vi . viii xii Chapter IV. VI. 2. 3. b. Undrained Test . . c. Consolidated- Undrained Test Plane- Strain Shear Tests Field Vane Shear Tests FIELD SITE, INSTRUMENTATION, MONITORING AND EXCAVATION A. Field Site . B. Instrumentation and Monitoring . l. C. 2 3 4. 5. 6 7. E Horizontal Movement . a. Slope Indicator Casings b. Surface Measurements Vertical Movement . Piezometers . . Total Pressure Cells . Temperature Sensors Vane Shear . . Dutch Cone Tests xcavation for the Experimental Slopes FIELD AND LABORATORY TEST RESULTS A. Physical Properties of the Papermill Sludge . B. Strength Characteristics of the Papermill Sludge . l. 2 3 4 5 C. S l 2 3 4 5: Triaxial Shear Tests . a. Fresh Sludge Samples . . b. Undisturbed Sludge Samples Plane-Strain Shear Tests Unconfined Compression Tests In-Place Vane Shear Tests Dutch Cone Penetration Tests lope Behavior Lateral Movement Vertical Movement . Pore Water Pressure Temperature . . . Total Pressure Cells . ANALYSIS AND DISCUSSION OF PROJECT RESULTS A. Physical Properties of the Fibrous Organic Soil 1. 2. Consistency Limits 3. Water Contents . 4. Unit Weights . . 8. Strength Characteristics of the Fibrous Organic Soil l. Stress- Strain Behavior . . . . . 2. Strength Parameters Ash (or Organic) Content a. Total Stress Basis b. Effective Stress Basis . iv Page Chapter C. Movements and Stability of the Experimental Cut Slopes . . . . . . . . l. Slope Movements 2. Development of Failure Zones 3. Slope Failure . 4. Stability Analysis for the Failure Surface VII. SUMMARY AND CONCLUSIONS A. Engineering Properties of the Fibrous Organic Soil B. Behavior of a Cut Slope in Fibrous Organic Soil C. Practical Implications of the Investigation REFERENCES APPENDICES A. Surface Movements B. Slope Indicator Data C. Settlement Plate Data D. Piezometer Data E. Temperature Data . . F. Vane Shear and Dutch Cone Data G. Total Pressure Cell Data . H. Average Daily Temperature and Precipitation . I. Triaxial Test Data . . . . Page l33 I33 I34 I48 149 l53 153 155 l57 l59 l65 I66 I69 l9l l96 200 202 206 208 216 Table 2.1. 5.1. 5.2. 5.3. 5.4. 5.5. 6.1. A.1. B.1-21. C.1. C.2. C.3. C.4. 0.1. 0.2. 0.3. LIST OF TABLES Physical properties of the fresh papermill sludge (after Vallee, 1973) . Variation in water contents for one cubic foot block samples Physical properties of the papermill sludge, October l972. . . . Summary of 6 values for the triaxial and plane-strain tests . . . . Summary of triaxial test results . Summary of triaxial and plane-strain test results on block E . . . Material numbers and properties for the finite element analysis . Surface movements . Slope indicator data . Settlement plate elevations at the bottom sand blanket Settlement plate elevations at the middle sand blanket Settlement plate elevations at the top sand blanket Settlement plate elevations at the mid-points of the lower and upper sludge layers. . . . . Pore water pressures for the lower and upper l/4 points of the lower and upper sludge layers . . . . Pore water pressures for the center of the lower and upper sludge layers Pore water pressures for the lower and middle sand blankets . vi Page 12 68 69 72 73 86 112 167 170 192 193 194 195 197 198 199 Table E.1. F.1. F.2. F.3. G.l. H.1. 1.1-43. Temperature data for the papermill sludge landfill . Vane shear strength data, September 7, 1972 Vane shear strength data, October 6, l972 . Dutch cone penetration results, September 7, 1972 Total pressure cell data Average daily temperature and precipitation Triaxial and plane strain test data . vii Page 201 203 204 205 207 209 2T7 Figure 2.1. 2.2. 2.3. 2.4. 2.5. 3.1. 3.2. 3.3. 3.4. 4.1. 4.2. 4.3. LIST OF FIGURES Plasticity chart (Unified Soil Classification System) with data points for several fresh pulp and papermill sludges . . . . . . . . . Correction factor for converting vane shear strengths to field shear strengths (after Bjerrum, 1972) . . Equations and definitions for shear strength theory, effective stress basis . . . . . Relations between angle of internal friction (5), principal stresses, and undrained shear strength (Lambe and Whitman, l969) . . . . . . . . (a) Forces in the circular arc analysis (after Bishop, l954). (b) Notation to Janbu's (l957) analytical procedure . . . . . . . . . . . (a) Fibers in papermill sludge (Magnification X 30). (b) Undisturbed block sample of consolidated sludge Triaxial tests. (a) Mounting the cylindrical sample. (b) Anisotropic consolidation in the triaxial cell. (c) Newly prepared sample (left), failed and oven dry sample (right) . . . . . . (a) Sample preparation using a high speed rotary saw. (b) Plane-strain apparatus mounted on base of triaxial cell . Acker Vane dimensions and equation for computation of the in-situ shear strength . . . . . . Distribution of settlement plates, piezometers, and total pressure cells in the instrument groups . . Slope indicator casing locations, A through G, and 3:4 slope, plan view . . . . . . . . . Experimental slope cross-sections. (a) 3:4 slope. (b) l:8 slope . . . . . . . viii Page 10 23 29 3O 33 4O 42 48 52 54 55 57 Figure Page 4.4. Horizontal control stake locations, plan view . . . . . 60 4.5. 3:4 slope preparation. (a) Sludge removal by dragline. (b) Slope cross-section, October 13, 1974 . . . . . 65 4.6. 1:8 slope preparation. (b) Trimming the upper sludge layer. (b) Sludge removal using a dozer, October 24, 1972 . . 66 5.1. Field water contents of the sludge in the landfill, October 1972 . . . . . . . . . . . . . . . 70 5.2. Stress—strain behavior of fresh sludge in undrained shear, sample U-3-7 . . . . . . . . . . . . . . . 75 5.3. Consolidated undrained triaxial test results for sludge sample U-3. (a) Kf line. (b) Water content. (c) Undrained strength . . . . . . . . . . . . . 76 5.4. Consolidated undrained triaxial test results for sludge sample U-l. (a) Kf line. (b) Water content. (c) Undrained strength . . . . . . . . . . . . . 78 5.5. Stress-strain behavior of consolidated sludge in undrained shear, sample G-5 . . . . . . . . . . . . . 79 5.6. Consolidated undrained triaxial test results for block G, anisotropic consolidation, vertical axis. (a) Kf line. (b) Water content. (c) Undrained strength 81 5.7. Stress-strain behavior of consolidated sludge in undrained shear, sample G-lO with the major principal axis horizontal . . . . . . . . . . . . . . . . 82 5.8. Consolidated undrained triaxial test results for block G, isotropic consolidation, and horizontal axis. (a) Kf line. (b) Water content. (c) Undrained strength . . . 83 5.9. Stress-strain behavior of consolidated sludge in undrained shear, sample 6-20 with a vertical axis, 01 constant and 03 decreasing . . . . . . . . . . . . . . . 85 5.10. Stress-strain behavior of consolidated sludge in undrained plane-strain and triaxial shear, block samples E-5 and E-ll . . . . . . . . . . . . . . . . . . 88 5.l1. Consolidated undrained plane-strain and triaxial test results for Block E, anisotropic consolidation and axis vertical . . . . . . . . . . . . . . . 89 ix Figure 5.12. 5.16. 5.21. 6.1. 6.2. 6.3. 6.4. 6.5. Page Variation of unconfined compressive strength with sample orientation . . . . . . . . . . . . . 90 Experimental landfill, immediately before slope excavation. (a) Vane shear strength. (b) Dutch cone resistance . . . . . . . . . . . . . . 92 Tension cracks. (a) Photo. (b) Crack locations on October 25, 1972 . . . . . . . . . . . . . . 94 (a) Initial slope failure, October 29, 1972. (b) Slope condition on November 21, 1972 . . . . . . . . . 95 Cross-section of 1:8 slope, before and after failure . . 97 Lateral movement. (a) Slope indicator casing A. (b) Slope indicator casing B. (c) Slope indicator casing C. (d) Slope indicator casing D. (e) Slope indicator casing A and D. (f) Slope indicator casing E and F. (g ) Slope indicator casing G . . . . . 98 Settlement in the top, (:) - (:) , and bottom, (;)- <:), sludge layers. (a) Instrument groups 4, 6, and (b) Instrument groups 3, 5, and 7 . . 106 Pore pressure versus time curves. (a) Instrument group 4. (b) Instrument group 5 . . . . . . . . . . . . 108 Temperature versus time. (a) Thermistors 1, 3, 5, 7, and 9. (b) Thermistors 4, 6, 8, and O . . . . . . . . lll Horizontal and vertical total stresses, bottom sludge layer . . . . . . . . . . . . . . . . . 112 Weight loss versus temperature for a papermill sludge sample from block C . . . . . . . . . . . . . 116 Relationships between ash content and consistency limits . 117 Plasticity chart (Unified Soil Classification System) with data points for several fresh pulp and papermill sludges . . . . . . . . . . . . . . 119 Relationships between water content and undrained shear strength . . . . . . . . . . . . . . . . 121 Specific gravity-ash content relationship for the West Carrollton sludge . . . . . . . . . . . . . 122 Figure Page 6.6. Undrained stress-strain behavior of a normally consolidated papermill sludge with 01 constant and 03 decreasing . . . . . . . . . . . . . 125 6.7. Influence of organic content on the angle of internal friction, effective stress basis . . . . . . . . 130 6.8. Composite action of a clay-water matrix with organic fibers. (a) Stress-strain curves. (b) Failure envelope . . . . . . . . . . . . . . . . 132 6.9. Casing movements at elevation 94.6 ft. during and after excavation for the experimental slope . . . . . . . 135 6.10. Time-rate of lateral movement. (a) Slope indicator casing A. (b) Slope indicator casing B. (c) Slope indicator casing C. (d) Slope indicator casing D. (e) Slope indicator casing E and F. (f) Slope indicator casing G . . . . . . . . . . . . . . . . 136 6.11. (a) Excavated slope showing the section to be analyzed. (b) Finite element idealization of slope cross-section. (c) Typical finite element configuration of the slope showing the excavation sequence . . . . . . . . . 143 6.12. Development of failure zones for the l: 8 slope, s u/p= 3. 45 and K= 0.4. . . . . . . . . . . . . 147 6.13. Stability calculations using Janbu's (1954, 1957) method, total stress basis . . . . . . . . . . . . . 151 A.1. Slope failure areas, plan view . . . . . . . . . . 168 xi LIST OF SYMBOLS y intercept, effective stress basis pore pressure parameter slice width cohesion total stress strength parameter coefficient of consolidation cohesion, effective stress basis void ratio Young's modulus normal force on slice sides factor of safety Henry's coefficient of solubility thickness of sludge layer or sample thickness of sludge layer or sample at the end of primary consolidation plasticity index coefficient of permeability total stress earth pressure coefficient line through 6f versus qf coefficient of earth pressure at rest length liquid limit normal force xii .0! .0l .0 ‘0 'UI U1 ‘0 'U center of failure circle consolidation pressure initial pressure; present overburden pressure 1 E (51 + 53) 5 at failure force applied surface load 12 (51 ' 53) 6 at failure line load radius shearing resistance shear force initial degree of saturation time temperature shear force pore water pressure initial air pressure pressure necessary for full saturation water content total weight distance shear force on slice sides depth to a point in a soil layer inclination angle of force xiii a = slope of pf versus qf y = unit weight y = unit weight of water A = increment e = strain a = normal stress 0 = effective normal stress 01.02.03 = pr1nc1pal stresses normal stress on failure surface at failure = shear stress on failure surface at failure Tff u = correction factor 6 = friction angle based on effective stresses ¢u = total stress strength parameter The Greek Alphabet a Alpha 8 Beta y Gamma 6 Delta 6 Epsilon g Xi n Eta O Theta A Lambda u MU xiv >< Nu Pi Rho Sigma Tau Phi Chi Psi Omega CHAPTER I INTRODUCTION A. Need for Study In order to protect the nation's lakes and streams, the pulp and paper industry removes a large percentage of the suspended and dissolved matter from their effluent streams. In the United States, an estimated 6kg) of waste solids, having a volume close to 200,000,000 cubic yards (1501(1061m3),are removed annually (Gillespie, 2,500,000 dry tons (2,300 x 10 Mazzola, and Gellman, 1970). As many times happens, one solution pre- sents another problem. Today, disposal of these large volumes of pulp and papermill sludges in an economical and ecologically safe manner is a major problem for the paper industry. More than 1,100 acres (4,450,000 m2) of land are in use as depositories for these man-made waste materials. These deposits, which may have water contents in excess of 300 percent (percent of dry weight), are very unstable and are subject to large settlements when any load is placed on the surface. Mechanically dewatered papermill sludges can be described as a fibrous organic soil which have the physical appearance of clay interwoven with cellulose fibers. Their composition depends on the type of manufacturing process and the conservation steps at the mill, for both pulp and papermill wastes. In general, the solids include clay (used in Paper as a coating and filler), fibers, and fine pulp which escape the pulp or paper making process. Fiber losses during 1 production, generally averaging three percent or less, are significant because of the large quantities of fibers produced per day (Nemerow, 1971). Land disposal of papermill sludge appears to be the most feasi- ble approach currently available. Bacon (1967) has suggested the possibility of using sludge as an economical method for land recla- mation, especially in marginal lands, coal mining areas, and abandoned gravel pits. A survey conducted by Gillespie (1969) indicated that landfills are in wide use for the disposal of papermill waste solids throughout the United States. However, landfills are not necessarily an inexpensive or trouble-free means of disposal. Many land disposal sites have experienced difficulties with the waste. Many of these difficulties are due to a lack of understanding of both the engi- neering properties and field behavior of these materials. Guidelines for the efficient and safe disposal of pulp and papermill solid wastes are incomplete (Mazzola, 1969). Landfill construction that is most suitable for efficient operations, for extending both the capacity and life of disposal sites, and designed for future uses requires an understanding of many variables. These include volume change and settlement, slope stability and bearing capacity, and changes in water content through drainage. Possible adverse environmental effects must be guarded against. It is desirable that a completed landfill be stable and have the potential for a number of future uses, including recreation, agriculture or as a foundation for light construction. The size and slope of sludge embankments will be determined by the embankment stability. However, little information is available on field shear strengths and stability of cut slopes in these sludge deposits. Core sampling investigation of a few existing sludge deposits found that many of the pulp and papermill solid waste landfills were very un- stable, of low shear strength (0.12 to 0.37 kg/sq cm), and contained high water contents (Mazzola, 1969). Previous studies (Vallee and Andersland, 1974) showed that large volume changes do occur under a small surcharge (surface loading). Results also showed that a sig- nificant increase in shear strength occurred as a result of consoli- dation. These results are the same as those expected for compressible soils such as clays, loose silts, and most organic soils (Terzaghi and Peck, 1967). B. Objectives of Study The general objective of this study was to contribute basic information on the stability of pulp and papermill solid wastes. This information was obtained through field observations, laboratory tests, and analysis of the data. This information is needed for developing guidelines and recommendations on the design, operation, and regulation of landfills containing pulp and papermill solid wastes. The specific objective of this study was to determine whether methods and theory used to estimate the stability of cut slopes in soft clay soils could also be used for excavations in consolidated sludges. A field stability study, involving two cut slopes in an experimental sludge landfill project, provided data which has been compared to predictions based on soil mechanics theory and experimental laboratory data. The following is a summary of specific items of research and implications relative to the stability of the landfill which are discussed in this thesis: 1. Surcharge loads in combination with drainage blankets make possible a large reduction in water content of fresh papermill sludge in a landfill. This consolidation improves the shear strength of the sludge. The magnitude of this increased shear strength was demonstrated by both field and laboratory tests. 2. Undrained shear strength data obtained by the vane borer is compared with shear strength data from laboratory triaxial and plane- strain tests. Laboratory tests were conducted on both fresh sludge samples and undisturbed block samples obtained from the landfill. Suitability of the shear strength for the stability calculations is discussed. 3. An excavation was made to produce a 3:4 slope (8 = 53.1 degrees). Two weeks later this stable slope was trimmed to a 1:8 slope (B = 82.9 degrees). Observed lateral and vertical movements within the sludge landfill, resulting from the excavation, are sum- marized and discussed. 4. Failure zones develop where the maximum shear stress approaches the shear strength. Although the overall factor of safety may be above unity for a given slope, local or small areas in the slope may be stressed beyond their shear strength. Development of these failure zones during the excavation of the 1:8 slope are studied using the finite element method of analysis and laboratory stress-strain data. 5. Slope failure occurred shortly after excavation of the 1:8 slope. By definition, the factor of safety against slope failure should be equal to unity. Using soil mechanics theory and both laboratory and field shear strength data, the slope stability was analyzed so as to compare the field behavior with predicted behavior. 6. Pore water pressures and total pressures were recorded at various points in the landfill before and during slope excavation, after slope failure, and during the following winter and spring. Implications relative to the slope behavior are discussed. Specific items relative to the consolidation behavior and the leachate analysis and lysimeter study are covered elsewhere (Andersland, et al., 1973). C. Nature and Scope of Study Theories on soil strength and slope stability (Terzaghi and Peck, 1967; Lambe and Whitman, 1969; Janbu, 1954 & 1957) provided the theoretical basis for the research work. Test equipment and test techniques used were similar to those described in soil mechanics literature. Many similarities between papermill sludges and organic clay, peat or muck become evident when the experimental data is reviewed. The research program was a continuation of an earlier project which involved construction of the experimental landfill and monitoring of instrumentation during consolidation. Laboratory work for the determi- nation of certain physical properties and one-dimensional consolidation characteristics of the fill material have been reported by Vallee (1973). The stability study portion of the project was initiated in early September, 1972, to observe the behavior of cut slopes in consolidated sludge and to provide data needed to verify in situ vane and laboratory shear strengths used in stability calculations. The field work involved in situ vane shear strength tests, installation of slope indicator casings and additional piezometers, removal of the dike on the North side, excavation for the experimental slope in two increments, taking undisturbed block samples and field water contents at several levels in the exposed cut, and monitoring of field instru- mentation as needed to provide a continuous record of the slope per- formance. Laboratory work included tests to determine the current physical properties of the sludge and the shear strength parameters and stress-strain properties based on both triaxial and plane strain type test methods. The ash content (organic content), taken on a number of samples, provided a check on sludge uniformity and helped show which samples were more representative of the sludge. Failure zones which developed in those regions where the maximum shear stress values exceeded the undrained shear strength of the sludge were studied using a finite element method computer program (Dunlop, ££_El;: 1968). Development of failure zones in the 1:8 slope were simulated as the excavation proceeded to greater depths and compared to actual field behavior. CHAPTER II LITERATURE REVIEW Information on the design, operation and engineering charac- teristics of papermill sludge landfills is very limited. Sanitary landfill design and operation (Stoll, 1971) is oriented towards municipal wastes and provides little information on stability and strength characteristics of papermill wastes. Strength data for these sludges are essentially nonexistent except for laboratory work (Andersland and Laza, 1971). Literature related to pulp and papermill sludge is available in the areas of composition, methods for solids removal, improved dewatering techniques and conservation steps required to reduce fiber loss in production. A. Physical Properties of Fiberous Organic Soils Composition Gillespie, Gellman and Janes (1970) defined ”high ash sludges" as those which have a fixed solids content of 60 percent or greater. Andersland, §£_21; (1972) found that the organic content of the fresh papermill sludge from the West Carrollton, Ohio, landfill varied from 40.6 to 67.8 percent. The physical properties of these sludges show a wide variation due to the type of paper being produced and the internal methods being used to recover the fibers. Mazzola (1969) examined sludge deposits from eight different mills for physical properties including water content, ash content, Atterberg limits, vane shear strength, and a study to evaluate decomposition. Decom- position of the organic fiber in the sludge, if found to be signifi- cant, could lead to larger settlements, loss of shear strength, and possible gas production due to biological action. MacFarlane (1969) states that the gas content in peat deposits is of considerable theoretical and practical importance. Laboratory and field measure- ments of pore pressures, permeability, and rate of consolidation, etc. are affected by the presence of gas. Samples from a sludge deposit taken at depths of 2 and 12 feet (0.61 and 3.66m) and representing ages of l and 12 years were examined using photomicrographs (Mazzola, 1969). No visual indication of degradation was observed. This lack of decomposition was attributed to four factors: 1. the inhibition to degradation of microbial substances bound to clay, 2. the absence of available nitrogen in papermill waste effluent, 3. the lignin content of the fiber, and 4. the hydrophilic nature of cellulose. Both aerobic and anaerobic biological organisms responsible for the breakdown of organics require a minimal source of nitrogen for the synthesis of new cell tissue (Eckenfelder and O'Connor, 1961). Decom- position of cellulose becomes essentially inactive when the available nitrogen becomes less than 1.2 percent (Imshenetsky, 1968). Mazzola (1969) estimated the available nitrogen for the sludges examined at 0.0002 to 0.0005 percent. In recent years, to reduce the dissolved 800 of the wastewater, an accelerated aerobic biological treatment which requires the addition of nitrogen to increase biological activity, is used before the solids are settled out as sludges (Nemerow, 1971; Koch and Lugar, 1958; Eckenfelder and O'Connor, 1961). Therefore, the possibility exists that some newer deposits may have larger amounts of nitrogen than reported by Mazzola (l969). Consistency Limits The consistency limits (Atterberg limits), largely through the work of A. Atterberg and A. Casagrande (1948), have become very useful characteristics for classifying soils. The consistency limits indicate the range of water contents (in percent of dry weight) for which a disturbed soil or sludge may be considered as a fluid, plastic, or solid. The liquid limit (Lw) is the water content at which the soil will flow and close a groove of standard width when jarred in a specified manner (ASTM D 423). The fibrous nature of the sludge samples interferes with making the required groove cross section. The plastic limit (Pw) is the water content at which the soil begins to crumble when rolled into threads of a specified size (ASTM D 424). Casagrande (1966) suggested that peat ranges from low plasticity for thoroughly weathered deposits to non-plastic for highly fibrous deposits. Organic soils fall below the "A" line on the plasticity chart as shown in Figure 2.1. Casagrande suggested that, with an 10 .mmmuapm Fpmscmqmn ecu apaa smog» Pmcm>mm com mpcmoa name new: Asmumxm cowpmuwewmmm_o Pwom vowewcsv “Lego pruwummpaun.P.m «snow; 3 a a uueHH easeua ooc oom Omm owm oqm ooN ooa ONH om cc 0 1 u q M! q a u 1 q u u u q C l n 0% _I chma .mvcmuwmmmu II I I 4 umummv upon ‘ mo mmaku maowumew ‘ b .. ow .70.. I .(\ B a» s o 1 L I. \\\II/ V) m. \ . .oxx . 8H m .\ a( I \ osu m. \ \ 4 X \ roe . \ . o2 d1 a \ \ I \ ll‘ . CON Sums .mumg cam “Canaan—mpg umuwmv onuooaaafino 4 :maH .mnmA can camHmumvg woummv aouaaamm D .. w Q a Q a o coda Haaauo m can as zmmum P oqm 11 increase in fibrosity, the points on the chart move down and to the left. Mazzola (1969) concluded that the plastic and liquid limits of papermill sludges were dependent on the ash content, which is indicative of the clay content of the sludge. An increase in fiber content reduces the influence of the clay, hence plasticity would be expected to be reduced. These findings are in agreement with those reported by Vallee and Andersland (1974) for fresh papermill sludge and by Bauer (1966) and MacFarlane (1969) for peat, muck, and similar highly organic soils. 0n Casagrande's (1948) plasticity index (Lw - Pw) vs. liquid limit chart, the fresh sludge samples tested by Andersland and Laza (1971) fall below the "A" line as shown in Figure 2.1. Mazzola (1969) found that the field water contents (w), for the field sludge samples tested, were greater than there respective liquid limits. The liquidity index (w—Pw)/(Lw-Pw) for field sludge samples tested ranged from one to over 1000, with most of the deposits in essentially a fluid state. The consolidation potential for deposits with a high index is large since a high index indicates an uncon- solidated material, which, when loaded, will experience a large degree of consolidation. A high index also indicates that if the deposit is disturbed there will be a decrease in the shear strength, since remolding transforms the soil into a thick viscous slurry (Terzaghi and Peck, 1967). Consistency limits reported for the fresh papermill sludge by Vallee (1973) are summarized in Table 2.1. 12 TABLE 2.1 PHYSICAL PROPERTIES OF THE FRESH PAPERMILL SLUDGE (AFTER VALLEE, 1973). Sludge sample Consistency limitsl Ashz Solid33 Specified No. Elevation L P content content gravity in layer, ft. w w % Z by wt. L-O 5 325.4 141.6 35.7 28.5 2.01 L-l* 2.5 257.3 102.7 42.2 27.2 2.05 L-2* 7.5 247.7 105.6 43.3 28.2 2.07 0-1+ 2.5 184.5 86.0 59.4 34.4 2.24 U-2+ 4 218.5 101.6 46.5 31.9 2.07 U-3+ 5 297.5 133.0 36.5 26.9 1.91 0-4+ 7.5 287.4 122.1 34.2 29.0 1.87 U-s+ 10 302.8 138.6 32.2 28.4 1.92 + *Average of three samples. Average of 3 tests per sample location. 1L --liquid limit. P —-plastic limit. ASTM test methods D 423-66 and w w 0 424-59. 2ASTM test method D 586-63. 3Solids content of fresh sludge. Water content by dry weight given by the equation 100 WA = 100 [ % solids by wt. - l 1' 4ASTM test method D 854-48. Laboratory test sample locations. Sand :'-'-;'.:’::':. " WWW "I. " x U-S Upper sludge layer 1 U-4 x U-3 x U-2 X U-l Sand ' ,-o.- "::-:1’:..-. °: -~-::-- :. .. ' \ X L—2 Lower sludge laye X L-O )‘L—l Sand n.«w.nxpuucaHBAHanwanfiEfl%§ Nature 801 13 Water Content The water found in pulp and papermill sludges exists in three different phases (Gehm, 1959): (1) free water, (2) adsorbed water and (3) absorbed water. The free water is not bonded to the sludge and is readily removed, while the adsorbed water molecules are firmly bound by the hydroxyl groups of cellulose and can only be removed with difficulty. The absorbed water in cellulose fibers is not removed by normal mechanical methods. Mazzola (1969) found that the water content for a single sludge deposit varied in both the horizontal and vertical direction. An inverse linear relationship was found to exist between water content and the amount of ash per sample. This appeared to explain the variation of water content observed in the horizontal direction. Water contents ranged from 46 to 740 percent with no samples taken from below the ground water table. Mazzola (1969) noted that the water content of the sludge deposits changes very little with time. Peat and muck deposits have also been reported (MacFarlane, 1969) to give similar results. 8. Stress-Strain Characteristics The stress-strain behavior of fiberous organic soil or paper- mill sludge depends on the composite behavior of the material com- ponents. Papermill sludge consists primarily of pulp fiber debris and kaolinite clay. Organic Fibers The fiber debris includes portions of the elongated cell walls of the wood structural elements. Undamaged, the fibers are tapered, 14 thick- or thin-walled tubes, closed at both ends. Their dimensions and overall structural properties vary within every plant species (spring or summer wood) and between different species. The average length ranges from about 1 mm (beech, straw) to 3 or 4 mm (spruce, pine) or even centimeters (cotton, hemp). The width varies from 10 to 40 microns. Mechanical treatment can alter the dimensions and shapes of the fibers considerably. In paper, thin-walled, long and flexible fibers are collapsed to ribons, where thick-walled, short and rigid fibers retain much of there tubular shape. Cellulose fibers swell in water, mainly in thickness, and shrink when being dried (Corte, 1966). Swelling of the cellulose fibers can result in a 200 to 300 percent weight increase, a one percent length increase, 15 to 20 percent diameter increase and up to a 35 percent volume increase (Mazzola, 1972). Jayne (1959) reports Young's Moduli for softwood fibers to 6 ). be 2.5 to 3.6 x 105 kg/sq cm (3.6 to 5.2 x 10 psi Kallnes and Bernier (1962) reports Young's Moduli for spruce fibers to be 2.8 to 6 3.5 x 105 kg/sq cm (4.1 to 5.1 x 10 psi). Tensile strengths have been reported from 10 to 50 grams per fiber, which is a stress of 4 to 10 x 103 kg/sq cm (5.8 to 14.5 x 104 psi). Values are very dependent on the method of clamping, rate of straining or loading, relative humidity and plant species (Jayne, 1959; Leopold and McIntosh, 1961; and Harter, gt_gl;, 1963). Robertson, gt_g1;_(1961) have reported on the bending and shearing resistance of fibers. There is little known of the bonds between fibers in paper. Corte (1966) reports experiments on a wet fiber mat deposited on a 15 laboratory sheet-making machine that was treated with alcohol to extract the water without disturbing the geometrical structure of the mat. The alcohol was displaced in a similar way with carbon tetrachloride. The resulting sheet had virtually no mechanical strength. These experiments show that the coherence and strength of a sheet of paper are caused primarily by hydrogen bonds between the hydroxyl groups of cellulose on the surfaces of adjacent fibers, and not by the mechanical entanglement of the fibers. At and above about 20 percent solids content, according to experiments by Lyne and Gallay (1954), hydrogen bonds are formed. At high water contents (over 10 percent) the hydroxyl groups of water compete with those of cellulose and by mechanical stirring, the fibers can usually be completely separated (Brecht, 1962). Studies for the purpose of evaluating the effect of fiber on sludge behavior, by examining both the relative amount of fiber and the length of the fiber present, have been conducted. The amount and length of fiber was found to have a strong influence on the effectiveness of removal of water by mechanical pressing methods (NCASI Tech. Bull. No. 174 and 136). Andersland and Laza (1971) reported that, for fresh papermill sludge samples, the organic content had a direct influence on the angle of internal friction. Kaolinite Clay The primary clay mineral added to the fiber suspension for paper making is kaolinite (5 to 10 percent, sometimes up to 25 percent by weight). It is added partly for economic reasons because it is l6 cheaper than pulp, and partly because it improves the appearance of the paper, and because it makes the sheets lie flat and improves the printability of the paper (Corte, 1966). In recycling, the fibers are the economic portion recovered and the clay is the waste product along with some lost fibers. In paper production, some clay and fibers are lost during production. Paper sludge, therefore, is composed primarily of the lost or unwanted fibers and clay. Kaolinite is an important and common two-layer mineral (layer of gibbsite on top of a layer of silicate). Olson (1974) has reported on more than 200 triaxial compression tests conducted on commercially available kaolinite. For this clay the liquid limit ranged from 40 to 50 percent, the plastic limit 27 to 31 percent, and the specific gravity was equal to 2.65. Olson observed that the angle of internal friction, 5, ranged from 25 to 30 degrees. Gibbs, fl; (1960) reported an angle of internal friction of 25 degrees. Lamb and Whitman (1969) report that the plastic limit of kaolinite ranges from 27 to 37 percent and the liquid limit ranges from 38 to 59 percent depending on the exchangeable ion. Fibrous Organic Soils as a Composite Material Papermill sludge consists primarily of fiber debris and kaolinite clay. This composite material should have mechanical properties depend- ent on the elastic behavior of the fibers imbedded in the plastic clay and the bond between these fibers and the clay matrix. The shear strength parameters for kaolinite clay with zero organic content has been reported by Gibbs, et al. (1960) and Olson (1974). Laza (1971) 17 has reported on the shear strength parameters of papermill sludge with varying amounts of organic fibers and clay. However, little is known about the wet strength of the fibers, their stress-strain properties, both average and range of fiber length and shape, and the type of bonding between the fiber and the clay matrix. There is also little data on properties of random oriented discontinuous fiber reinforced composites. It is known that the size and shape of the fibers plays a very important role in determining their properties. Fibers with smaller diameters can, in general, take higher stresses than fibers with larger diameters (Sears, 1962). Paper fiber, when viewed under a microscope, shows a balloon swelling (bamboo-like) structure. Such fibers are generally lower in strength, but because of the bamboo grip, a substantial matrix reinforcement may be attain- able through friction, even in the absence of good adhesion. As generally accepted, the load is transfered from the matrix to the reinforcement through shear. The shear results from displace- ments of the reinforcing fibers by means of shear tractions at the fiber-matrix interface according to the stresses on the composite (Wohrer and Economy, 1966). The presence of the fibers should rein- force the sample and help retard the propagation of cracks. The relatively low modulus of the clay matrix should allow for the effective transfer of stress to the higher modulus fibers, provided the length of the fibers is sufficient. 31995 (1966) points out that, for an elastic fiber of length (L) and radius (r) embedded in a plastic matrix, there will be a tangential stress (I) exerted on the fiber 18 by the slipping matrix. The stress (ox) in the fiber at a point distance x from one end is and the elastic strain in the fiber is O X e = -- (2.2) X E The fiber stress increases approximately linearly from the ends. Wohrer and Economy (1966) and Kelly and Tyson (1964) state that the "rule of mixing" can be applied to calculate the potential strengthening attainable with random discontinuous fibers, as expressed by, the following equation: _ LC+ * oC - k of Vf (1 - 2E) om Vm (2.3) in which. * cc, of, cm = break stress of composite, fiber, and matrix, Vf, Vm = volume fraction of fiber, and matrix, Lc’ L critical fiber length, fiber length k 0.2 for random fiber orientation The critical fiber length (LC) is defined as the maximum length at which the fiber will pull out of the matrix and not break. 19 The critical length (Lc)’ the average length (L), and the average breaking stress (of) of the fibers, along with the deviations from the averages, are unknown for papermill sludges. If these were known, it would be theoretically possible to calculate the strength of the composite (0c) by considering the properties of both the fiber and the clay matrix using the "rule of mixing" equation. Further research is needed to explain the mechanism and effect of fiber reinforcement in papermill sludge and other fibrous organic soils. Similarity to Organic Soils Considerable work has been reported in the literature on consolidation properties of highly organic soils such as peat. Limited work has been reported regarding the shear strength since these soil types are generally avoided in engineering practice. Organic terrain has only come under serious scientific study within the last few years. The National Research Council of Canada, through its Associate Committee on Geotechnical Research (NRCC—ACGR), first gave serious consideration to the problem of organic terrain in 1947. MacFarlane's (1969) handbook on muskeg (peat) contains a review of the state of the art of organic terrain and the outcome of discussions at the annual meetings of the NRCC-ACGR. Little research has been done on the correlation of different types of peat with the physical and strength properties. Peat is composed of organic material. When submerged beneath the groundwater table, peat is not entirely inert and undergoes a very slow anaerobic decomposition which produces methane gas. When the water table is 20 lowered, oxidation of peat occurs releasing carbon dioxide. No widely recognized method is presently available to measure the gas content of peat (MacFarlane, 1969). Low shear strengths and large settlements of organic soils, when loaded, are partly due to a low degree of consolidation found in the field (MacFarlane, 1969). This may be due to the low effective vertical pressure and the long drainage paths. The low effective vertical pressure is due to (1) the low specific gravity of the organics,(2) the lack of a surcharge, and (3) a high water table. Hanrahan (1954) pointed out that one of the difficulties in tests on peat is the anisotropic nature of the material. Obtaining repre- sentative undisturbed samples is very difficult. Hanrahan (1954) ran triaxial tests on undisturbed peat samples which were first consolidated and then allowed to swell. These tests were difficult to carry out due to the large and non uniform volume change associated with the peat. The friction angle 4 for the overconsolidated samples was only about 5 degrees leading Hanrahan (1954) to conclude that the strength of overconsolidated peat was exclusively cohesive in character. Adams (1961 and 1965), using consolidated-undrained triaxial tests on peat, observed friction angles as large as 50 degrees. In each test the pore pressure buildup was rapid and at failure essentially equal to the cell pressure. Cohesion values were found to be negligible. The value of K0 was determined to be 0.3 from anisotropic consolidation with no lateral strain. Other investigations (Hanrahan, gt_gl;, 1967) on remolded samples of an organic peat have shown similar results. The values for E varied from 0.7 to 1.0 psi and the friction angle 6 ranged 21 from approximately 35 to 44 degrees. The pore pressure coefficient B was found to be unity for the soft saturated peat. MacFarlane (1969) discusses the use of surcharges on peat and muck to increase shear strength and to reduce the long-term settlement. Preconsolidation has become widely accepted in Canada and has specific application where the depth of peat is in excess of 6 to 8 feet (1.83 to 2.44 meters). With surcharges on peat considerable settlements can be expected and the stability of the peat must be ascertained. Kovalenko (1969) reported a field test in which a surcharge (2 meter sand layer) was placed over a peat deposit to accelerate the consoli- dation. As the consolidation progressed the shear strength of the peat increased from about 0.1 to about 0.3 kg/sq cm. The organic content of the peat was not reported. MacFarlane (1969) and others have suggested an approximate method (max error of 18 percent in extreme cases) for determining the specific gravity of peat. It assumes that the ash is composed of clay materials with a specific gravity of 2.7 and that the organic material has a specific gravity of 1.5. The average specific gravity of the peat solids is then given by the equation G = (1 - AC) 1.5 + 2.7 (Ac) (2.4) where AC is the ash content. Andersland and Laza (1971) used consolidated-undrained triaxial tests with pore pressure measurements on an integrated pulp and paper- nfill sludge and a secondary fiber mill sludge. Cohesion values (E) 22 ranged from zero to 0.3 kg/sq cm. The angle of internal friction (6) ranged from about 45 degrees at low organic contents (28%) to about 64 degrees at a higher organic content (50%). Large strains were required to fully mobilize the available shear strength. Triaxial test data show that the strength of pulp and paper mill sludges to be essentially frictional and in accordance with the principal of effective stress. It was shown that both shear strength and permeability were influenced by the solids content of the sludge and the amount of organic matter. The pore pressure coefficient 8 was found to be unity for saturated sludge. C. Vane Shear Strength vs. Field Shear Strength In 1948 Cadling (Bjerrum, 1972) developed the vane test for in-situ measurements of the undrained shear strength. Most of the uncertainties due to disturbance of samples used for the laboratory determination of shear strength were thereby removed. Originally, shear strengths measured with the vane were assumed to be equal to the field undrained strength. However, an analysis of actual failures by Casagrande (1960) and Bjerrum (1972) shows that the undrained strength measured by an in-situ vane test is, in general, greater than the field strength. Bjerrum (1972) observed that the discrepancy between the vane and the field shear strength for 14 embankment failures was larger the more plastic the clay. He therefore developed a corre- lation between the ratio of the vane shear strength to the actual shear strength at failure and the plasticity indices of the clays (Figure 2.2). Hence 23 (S) =(S) '“ u field u vane 1.2 L. .3 1c) \\\ U (U be N\\\ 0§ “- 0.8 \\ 4.1 \ s. 0.6 O L.) O. - 0 20 4o 60 80 100 120 1p % Plasticity Index Figure 2.2.--Correction factor for converting vane shear strengths to field shear strengths (after Bjerrum, 1972). 24 (Su)field = (Su)vane.L1 (2'5) where u equals the correction factor from Figure 2.2. Three of the fourteen embankment failures cited by Bjerrum (1972) to define the correction factor where embankments of organic clays. 0. Movement and Stability of Cut Slopes Dewatered high ash pulp and papermill sludges disposed of in landfills may have a solids content as high as 40 percent by weight (equivalent to 150 percent water content by dry weight). When pulp fibers are present in significant amounts (greater than 15 percent by weight) the sludge appears fibrous and will hold its shape in the dewatered condition. In the absence of fiber, the sludge is putty- 1ike, and fluid at solids contents as high as 35 percent. The ash materials in these sludges are comprised mostly of kaolinite clay with small amounts of lime, titanium oxide and iron. The semi-liquid to liquid state of these dewatered sludges means that lateral confine ment is needed during construction of a cell type of landfill. The use of drainage blankets together with a small earth surcharge permits drainage of water from the sludge resulting in a significant decrease in volume and an increase in the strength of the sludge. The weight of overlying sludge helps consolidate material at lower levels. Information on shear strength is given in Section V-B. The vertical movement or settlement of the experimental landfill surface was produced entirely by the decrease in water content asso- ciated with consolidation. Photomicrographs of fibers from papermill 25 waste deposits that have been in place for up to 12 years have shown that virtually no decomposition of the fiber had occurred (Gillespie, Mazzola, and Gellman, 1970). The presence of lignin (Umbreit, 1962) and clay (Lynch, 1956) and the absence of sufficient available nitrogen (Imshenetsky, 1968) are known to inhibit the biological breakdown of cellulose. All three of these conditions probably exist in a papermill sludge landfill. Prediction of the amount and rate of settlement observed in an experimental sludge landfill has been presented else- where (Vallee and Andersland, 1974). Lateral movement may occur when an excavation is to be made in the sludge landfill or when the foundation for a structure is to be placed on the consolidated papermill sludge. Factors affecting the behavior of excavated slopes include slope height, slope angle, unit weights, pore pressures, initial stress conditions (prior to exca- vation), stress—strain and strength characteristics of the sludge, creep characteristics of the sludge, drainage conditions, time, and perhaps more. Information on initial stresses, based on the total pressure cell data taken towards the end of the consolidation period and data on other factors, are given later in this thesis. During excavation the stresses on the slope surface are reduced to zero. This reduction in stresses will induce strains and displacements in the exposed sludge slope. Numerical techniques for predicting slope deformations require information on the stress-strain behavior of the consolidated sludge. Experimental data are given later in this thesis on sludge samples tested under conditions closely simulating field conditions. 26 Soil or sludge located beneath a sloping surface has a tendency to move downward and outward under the influence of gravity. Material beneath foundations moves downward and outward as loads approach the bearing capacity of the material. When this tendency is counteracted by the shearing resistance of the soil or sludge, the slope or foundation is stable. Otherwise a failure occurs. For a slope this failure may take the form of a flow, a rotational movement along a circular slip surface, or a movement along a composite slip surface. Slides in soil or sludge may be caused by external disturbances such as excavation near the base of the slope or additional loading on or behind the slope from more fill or the placement of some other load. Failure in soils may also be caused by a temporary increase in pore water pressure or by a progressive deterioration of the strength of the material. In principle an analysis of the distribution of displacements or stresses throughout a slope could be used to decide the question of its behavior. At present, however, there is generally insufficient knowledge of the in situ stresses and stress-deformation-time proper- ties of soils to make this approach practicable. As a result it is general practice to use limit equilibrium methods to assess the stability of soil slopes (Lambe and Whitman, 1969). In all methods of limit equilibrium analysis, a condition of incipient failure is postulated along a continuous slip surface of known or assumed shape. A quantitative estimate of the factor of safety of the slope with respect to shear strength is then obtained by examining the equi- librium of the soil mass above this rupture surface. The problem is usually assumed to be one of plane strain. The two methods of analysis .1- 27 summarized include rotational movement along a circular slip surface and movement along a composite (non-circular) slip surface. A summary of a recent approach for investigating the development of failure zones around slopes during excavation completes this chapter. Methods for evaluating the stability of slopes are summarized in the following sections. Shear Strength Theory Information on bearing capacity and slope stability of papermill sludges in landfills is not available. One must draw on methods availa- ble in the field of soil mechanics which require data on the shear strength of the sludge material in question. Shear failure starts at a point in a mass of soil when, on some surface passing through the mass, a critical combination of shear stress and normal stress is reached. Experience has shown that the Mohr-Coulomb theory of failure has been very successful for defining failure in soil materials (Terzaghi and Peck, 1967). This theory, represented in the form Tff = C + off tan 6 (2.6) states that the shear stress Tff on a failure surface at failure is a function of the normal stress off on that plane at failure and the material properties cohesion c and angle of internal friction 6. In this form the soil skeleton must carry all the normal stress, that is the soil must be free draining. For cohesive soils or papermill sludges that are not free draining, the pore fluid will carry part of the normal stress. This 28 portion cannot contribute to the frictional resistance and shear strength. Hence for these materials the stress carried by the pore fluid must be subtracted from the total normal stress and the shear strength will be based only on that portion of the normal stress carried by the soil skeleton. This is done by measuring the pore water pressure during triaxial testing and presenting the results in terms of effective stresses. Equation 2.6 now becomes Tff = E + (off - u) tan 6 (2.7) where u is the pore water pressure, 6 is the cohesion intercept based on effective stresses, and 6 is the angle of internal friction based on effective stresses. Equation 2.7 represents a straight line with intercept on the shear stress axis equal to E and slope angle equal to 6 as shown in Figure 2.3. The shear strength, so defined, is the maximum shear stress that may be sustained on any plane in a given soil or sludge material. When information on the pore pressure u is not available or when total stresses are to be used in a stability analysis, the undrained shear strength Tff, defined as tan 6 (2.8) Tff = Cu 1 Off u may be used. The total stress strength parameters cu and 6u denote the apparent cohesion and the angle of shearing resistance, respectively. When 6u equals zero, cu equals l/2(o1 - 03)f where 01 and 03 are the major and minor total principal stresses at failure. Relations between angle of internal friction (5), principal effective stresses, and shear strength at failure are shown in Figure 2.4. 29 Tff- c + offtan 6 A» shear stress . 6 - 6 ’\‘\,9/ a — -— — _ \09 q = a + tan 0 «16 / f f '0 e / m @069 / 1b 6 1 N / .-c // “-3 I/I': " ' .18 10““ normal 4- _ stress F3 0'1 1" x _ _ + ._ = 0'1 “3 Pr 2 0”1 " “3 2 E _ tang: tan-07 2— or X: a _ ._ X _ 0' + 0* tan 0 l 3 + x _ _ tan 6 = E or x = C x — _ _ tan 6 “1 “3 2 _ _ sin 6 = a = C 3:1 +33 tan 0: tan$ Z + x but tang = sin$ . tan a = sin6 'c' ‘a‘ 0| ll Figure 2.3.--Equations and definitions for shear strength theory, effective stress basis. 30 T + 5 a 9 33 «19>? u ¢0 m u 959 8 - - .5 9 ‘0] g 03 =J -7 ~ID- O3 01 normal 0 E _ 33 stress 2 3 _ ‘1 2 0 ¢ 63 1f: tan [45 '1' E Undrained shear strength a = %{51 ’ 63)f '8 .. f 23 [tan2 (45° + %) - 1] Figure 2.4.--Relations between angle of internal friction (6), principal stresses, and undrained shear strength (Lambe and Whitman, 1969 . .- D- s g o 31 Experience has shown that the E and 6 values determined by consolidated-undrained triaxial tests on soils with pore pressure measurements (Bishop and Henkel, 1962) correlated well with field behavior. For these tests a soil sample, usually 1 l/2-in. in diameter by 3 in. high, is subjected to an all-around pressure 0 and allowed 3 to consolidate under drained conditions. The vertical stress 01 is next increased under undrained conditions until the sample fails. Failure is taken to be the maximum deviator stress (01 - c or for 3) some soils is taken at an arbitrary strain of 10 percent or 20 percent. During the loading period measurements are taken of pore water pressure, axial deformation, and axial load. Results from each test are repre- sented by an effective stress circle at failure. If several triaxial tests are performed with different consolidation pressures and the measured stresses corresponding to failure plotted, the points repre- senting failure are given by the envelope of stress circles. This envelope is known as the rupture line and, although it may not be perfectly straight, it can be represented by a straight line with sufficient accuracy so that the resulting material properties ade- quately reflect field behavior for soils. In normal laboratory evalu- ation three to five tests are made and the rupture line is drawn tangent to the observed failure circles. Since this method of evaluation depends on visual determination of the tangent points, it is desirable to adopt a method that uses the points of maximum shear stress at failure. Lambe and Whitman (1969) represented these points as _ 51 + 53 - c31 ' C33 01 ' 03 9f ---35-- and 9f - --3;———--——7;——— (2.9) 32 These points are unambiguous and precisely determined, allowing curve fitting methods to determine the line of best fit. This method gives the Kf failure line and results in a y intercept 5 and a slope angle 6. The geometric transformations given in Figure 2.3 permit compu- tation of the desired values of E and 6. Detailed information on triaxial tests used in this study are given in Chapter III. Rotational Movement The circular arc analysis which is sufficiently accurate for most purposes is that given by Bishop (1954) and generally termed the Bishop simplified method (Figure 2.5a). This method is derived by equating the moments about point 0 of the weight of soil within ABCD with the moment of the shear forces acting on the slip surface. For convenience the soil within ABCD is divided into a number of slices, one of which is shown in Figure 2.4a. The normal effective force (P - ut) on the base of the slice considered, denoted by P, is found by resolving forces vertically. Thence, assuming that (Xn - Xn+]) = O, the following expression for the factor of safety F is obtained: 1 - _ 1 F =-———————-- 2[{C b + W - u b tan }-—-] 2.10 ZW sin a ( ) ¢ ma ( ) where ma = cos a (l + %-tan a o tan 6) (2.11) Symbols are defined in Figure 2.5a. The factor of safety F is defined as the ratio of the available shear strength of the soil to that required 33 =orlgin 'Y Slip surface ’ (of any shape) A.“ u = pore water pressure (a) (b) Legend b = slice width W = total weight of slice c = cohesion x = distance E = normal force on slice sides X = shear force on slice sides 1 = length of slip surface 2 = depth to a point 0 = center of failure circle a = inclination of base P = force normal to base Yw = unit weight of water R = radius of failure circle 0 = normal stress 5 = shearing resistance r = shear strength u = pore water pressure Figure 2.5.--(a) Forces in the circular arc analysis (after Bish0p, 1954) (b) Notation to Janbu's (l957) analytical procedure. 34 to maintain equilibrium. As the term F appears on both sides of equation 2.10 the solution has to be obtained by a process of suc- cessive approximation. Convergence is very rapid and the method can be carried out easily by hand or by computer (Bailey and Christian, 1969). Values of ma can be read off a chart for any assumed value of F. In general the error resulting from use of the Bishop simplified method is 7 percent or less and is usually under 2 percent (Whitman and Bailey, 1967). For the total stress (6u = 0) analysis the shear strength mobilized equals cu/F. Since this shear strength is independent of the normal stress on the slip surface, a simplification results. Equating moments, as before, yields the expression for the factor of safety F. If the method of slices is used this expression has the form: Zcut F = -———1———- (2.12) 2W Sin 0 This expression is exact, and is easily adaptable to irregular s10pe profiles and non-uniform shear strength conditions. Composite Sliding Surface A rather accurate method foranalyzing noncircular slip surfaces is given by Janbu (1954, 1957). In order to render the problem stati- cally determinate Janbu assumed that the reaction forces dN (Figure 2.5b) acted at the center of the base dt of the slice and that the position of the resulting earth pressures E and E + dE at the interface 35 between adjacent slices are known. Using the notation of Figure 2.5b, the equations of equilibrium for each slice are: Vertical: dW + dP + dT = dS sin a + dN cos a (2.13) Horizontal: dE - d0 = - dS cos a + dN sin a (2.14) Moment about M: de + E dyt - dEht + d0 2 = 0 (2.15) For a stability analysis in terms of effective stresses, introduction of the appropriate expression for shear strength leads to the following working formula for finite differences: 2 Tf cos.2 a - Ax F = (2.16) 0 - Eb + 2(p + t) tan a - Ax where E + (p + t - u) tan 6 Tf = _ 1 , (2.17) 1 + (tan a . tan 6)-F AW AP AT p :—+—=’YZ +q, and t=—o Ax Ax Ax By assuming a reasonable position for the line of thrust, accurate values for the internal forces, E and T, are obtained by means of successive approximation procedures. Initial values of E and T can be calculated for the condition t = 0. When Tf is introduced into the moment equation for slip circle analyses, one obtains the formula 36 derived by Bishop (1954). Total stress (6u = 0) analysis for non- circular slip surfaces is provided by using the average undrained shear strength on the base of the slice in equation 2.17. Failure Zone Around Slopes During Excavation Failure zones develop in excavated slopes when the maximum shear stress values approach the shear strength of the papermill sludge or when tensile stresses exceed the very low tensile strength of the sludge. When idealized elastic properties are assumed for soil slopes, local overstress will occur when the factor of safety (by the slip circle method) lies below a value of about 1.8 (Bishop, 1954). Plans for the experimental papermill sludge landfill included slope failure (factor of safety close to unity), hence local overstress, such as tension cracks, was anticipated. It appeared desirable to determine in what portions of the experimental slope failure first occurred and how it progressed. In order to predict stresses within the slope, it was necessary to employ analytical procedures other than the equilibrium methods. The finite element method of analysis, as used by Dunlop, gt_gl; (1968) in their analyses of slopes in soil, appeared suitable for investigating the development of failure zones in the sludge slope. The basic concepts of the finite element method are summarized in the following paragraphs and its application to the experimental papermill sludge slope is given in Chapter VI. The finite element method may be thought of as an application of the displacement or stiffness method of structural analysis. The basic concept of the method is that a continuum with infinite degrees 37 of freedom can be approximated as an assemblage of elements inter- connected at a finite number of nodal points having £1 finite number of unknowns. The elements may be triangles, groups of triangles, or rectangles for two-dimensional plane strain analyses. Within each element, displacements are assumed to vary in such a way that compati- bility within the element and along its boundaries is maintained. Displacement continuity between adjacent elements is satisfied at common nodal points. For triangular elements with three nodal points this may be accomplished by specifying displacements which vary linearly in two mutually perpendicular directions within the element. For elements with more nodal points, higher order displacement vari- ations are employed. The finite element analysis of an elastic continuum consists of five basic steps: 1. Idealization of the continuum so that the finite element assemblage simulates the continuum, 2. Determination of the stiffness properties of each element to obtain a total stiffness matrix, 3. Prescribe boundary conditions, 4. Analysis by standard structural methods to determine the nodal point displacements, and 5. Determination of the element stresses from the nodal point displacements, since forces acting at the nodes are uniquely defined by there displacements (Zienkiewicz, 1971). Because each element in the assemblage may have a different modulus value from its neighbors, the method is well-suited to soil 38 problems involving heterogeneity. Approximate analyses of nonlinear earth structures are possible by incremental loading or iterative procedures. The finite element method is also capable of handling virtually any boundary conditions specified in terms of forces, stresses (resolved into nodal forces) and displacements. Mixed bounda- ry value problems may be handled as easily as problems involving only force or displacement boundary conditions. Dunlop, §t_gl;_(l968) performed a detailed finite element analysis of excavated soil slopes. In their analysis the basic finite element consisted of a quadrilateral composed of four constant strain triangles. The study provided computations of displacements, strains, and stress distributions, and it enabled the location of failure zones. The effect of such factors as in situ stresses, anisotropy, variation of strength within the soil deposit, pore pressure distri- butions, and sequential construction were studied. Various consti- tutive laws, such as linear, bilinear, and multilinear (piecewise linear) were compared. Requirements for boundary conditions for plane-strain, element sizes and element shapes, and a finite element computer program for excavated slopes are given by Dunlop, §t_gl;_ (1968). CHAPTER III ENGINEERING PROPERTIES OF PAPERMILL SLUDGE The physical properties and streSs-deformation behavior of the papermill sludge are needed for making slope stability predictions, based on theory, for comparison with observed field behavior of the experimental cut slopes. Methods and equipment for measurement of these engineering characteristics are described below. Reference is made to standard test procedures where possible. A. Physical Properties Physical properties of papermill sludge characterize, to some extent, the quality of the sludge relative to engineering purposes. The fibers in the sludge are shown in Figure 3.1a. Information on measurement of water content, unit weight, specific gravity of the solids, ash (or organic) content, and consistency limits are included later in this thesis and have been reported by Vallee and Andersland (1974). The water content and unit weight are used in describing changes in the sludge as a result of consolidation. Specific gravity was required for computations involving solids-water-air relationships. Ash contents from block samples provided more information on sludge uniformity. Consistency limits were reported for the fresh papermill sludge by Vallee and Andersland (1974) and are summarized in Table 2.1. 39 (b) Figure 3.1.-~(a) Fibers in papermill sludge (Magnification x 30) (b) Undisturbed block sample of consolidated sludge. 41 8. Strength Characteristics Undisturbed block samples were obtained from the landfill when the north dike was removed for the stability study. Each block was cut from the exposed slope as shown in Figure 3.10. The sides and top were wrapped in saran wrap and aluminum foil. Elevations were taken to properly describe the block location. Next a wooden box with the bottom removed was placed over the wrapped sludge. The block bottom was cut loose and the entire block turned over. After addi- tional trimming, saran wrap and aluminum foil were folded over the bottom of the block. Warm paraffin was poured into the open spaces around the block and the box bottom was attached. These block samples of sludge were easily transported to the laboratory with a minimum of disturbance. Sludge blocks were protected against possible moisture loss during storage by placing each unopened box in a sealed plastic bag. Temperature during storage did not exceed about 24°C. Fresh sludge samples, reported by Vallee (1973) during con- struction of the landfill, are identified and described in Table 2.1. Triaxial Shear Tests The triaxial test requires that the cylindrical specimen (Figure 3.2a) be sealed in a water-tight membrane and be enclosed in a cell (Figure 3.2b) in which the specimen can be subjected to a fluid pressure. A load applied axially, through a ram acting on the top sample cap, was used to control the deviator stress. Under these conditions the axial stress was the major principal stress, 0], and the intermediate and minor principal stresses (02 and 03, respectively) '11 Jim: armada 43m. :96 was wofimm .33 038mm" wouamonm 3302 A8 .200 H3533 0%. 5 33833230 Emonumdfiw 3; 03856 33.3310 05 wcflasog 73 633130328 .N .m 0.20th 3 A5 A3 42 43 were both equal to the cell pressure. Connections to the ends of the sample permitted either drainage of water and air from the voids in the sludge, or alternatively, the measurement of the pore pressure under conditions of no drainage. Generally the application of the all-around pressure and of the deviator stress form two separate stages of the test. Therefore triaxial tests are classified according to the conditions of drainage developed during each stage and any special conditions imposed on the sample to simulate field conditions. Sample preparation, undrained tests, and consolidated-undrained tests are described below. All triaxial tests were run at room temperature, close to 23°C. Sample Preparation.--Two types of samples were prepared: remolded (laboratory consolidated) and undisturbed (field consolidated). For the fresh sludge obtained during construction of the landfill, sample preparation involved placement into a cylindrical mold 7.l3 cm high by 3.56 cm in diameter. Care was taken to work the sludge into the mold so as to minimize layering and the formation of any cavities. Fibers were not oriented in any preferred direction. With the mold filled, the ends were carefully trimmed until they were perpendicular to the sample axis. Next the mold was disassembled by pulling the sides directly away from the specimen. The sample was then weighed, placed in an air tight container, and stored in a high humidity compartment until just prior to mounting in the triaxial cell. Different organic content test specimens were obtained by the appro- priate selection of sludge from the available field samples. 44 Undisturbed test specimens were obtained from block samples C and G. Specimen preparation involved cutting, by means of a hand saw, a 4 in. by 4 in. by 6 in. (l0 cm by l0 cm by l5 cm) chunk from the block of sludge. For additional strength during handling, each end of the sample was wrapped with tape and encased in wax. This sample of sludge was then placed in a motorized soil lathe. Since wire trimming devices were not suitable, a hobby tool with a high speed rotating 3/4 in. (l.9 cm) diameter circular saw was used for trimming the sludge into cylindrical specimens 2 in. (5.08 cm) in diameter by 4 in. (l0.16 cm) high (Figure 3.2c). The low sensitivity of the consolidated sludge helped minimize sample disturbance. Speci- mens were prepared with the cylindrical axis vertical, horizontal, or at 45 degrees to the horizontal as needed for the test program. After trimming, sample dimensions and weight were recorded. Sample speci- mens were stored in a sealed plastic bag and placed in a high humidity compartment until just prior to testing. Undrained Test.--The undrained strength of the sludge was determined by tests in which no overall water content change was permitted to occur during application of the deviator stress. When a saturated sludge is subjected to a change in magnitude of an all- around total pressure without change in water content, the undrained strength in a given direction remains unaltered. Thus the sludge for these conditions behaves, in respect to changes in total stress, as a material with zero angle of shearing resistance, i.e., ¢u = 0 and cu = l/2(o1 - 03). This result is a consequence of the fact that a change in all-around pressure causes a precisely equal change in 45 pore pressure, provided the sludge is fully saturated; and the effective stresses therefore remain unaltered. For partly saturated sludges there will be some increase in effective stresses as air in the voids is compressed and passes into solution. When stresses are large enough to cause full saturation the sludge again behaves as a material with zero angle of shearing resistance. Bishop and Henkel (l962) have shown that the increase in pore pressure Aua necessary to lead to 5 full saturation is given by the expression (1 - 50) Au = u -———————— (3.l) as ao S H 0 where ua0 is the initial air pressure (abs.), S0 is the initial degree of saturation, and H is Henry's coefficient of solubility (approxi- mately 0.02 at 20°C). A back pressure of 20 psi (0.703 kg/cmz) was used for fresh sludge samples and 40 psi (l.406 kg/cmz) was used for undisturbed sludge samples to ensure full saturation. No back pressure or lateral pressure was used for the unconfined compression tests. The effect of sludge anisotropy on undrained strength was determined by testing samples with their axis oriented at zero, 45 degrees, and 90 degrees to the horizontal. More details for the undrained test are given by Bishop and Henkel (l962). Consolidated-Undrained Test.--Consolidation and application of the deviator stress form two separate stages of the test. For isotropic consolidation of the fresh sludge, samples were allowed to consolidate under a cell pressure of known magnitude, the three principal stresses 46 thus being equal. Side drains consisting of filter paper strips (Bishop and Henkel, l962) were used to accelerate consolidation. Then the sample was sheared under undrained conditions by increasing the deviator stress. A back pressure of 40 psi (l.406 kg/cmz) was used for the undrained stage of the test to ensure full saturation of the undisturbed samples. The test result, in terms of total stresses, was expressed as the value of the undrained strength, cu, plotted against consolidation pressure, p. As before, cu = l/2(o1 - o3)f, since ou = 0 with respect to changes in total stress during undrained shear. When pore pressures were measured during the undrained stage of the test, the results were expressed in terms of effective stress. This permitted evaluation of the strength parameters 5 and 5 as out- lined in Chapter II. Side drains helped equalize pore pressures within the undrained specimen more rapidly when the deviator stress was increased. The stress conditions under which consolidation occurs in most practical problems does not approximate equal all-around pressure. The consolidation of natural strata under their own weight occurs under conditions of no lateral yield, for which the stress ratio (33/51 is equal to the coefficient of earth pressure at rest, K0. Therefore, anisotropic consolidation with K0 = 0.3 was used on most of the undis- turbed sludge samples. The K0 value selected was based on total pres- sure cell and piezometer data for the landfill. For selected specimens this test procedure was further modified by holding o1 constant and permitting 03 to decrease. This modified test procedure was intended to more closely reproduce field conditions existing during excavation. 47 For example, excavation for the experimental sludge landfill slope involved primarily a decrease in lateral stresses while the vertical stresses remained constant. Both the method of consolidation and any special loading conditions are given with the experimental data reported in Chapter V. Details on test procedures may be found in the Measure- ment of Soil Properties in the Triaxial Test by Bishop and Henkel (l962). Certain abbreviations describing most of the above test conditions which have come into general usage include: —TU -- consolidated undrained triaxial test with isotropic consolidation and pore pressure measurements, CED -- consolidated undrained triaxial test with anisotropic consolidation and pore pressure measurements. Plane-Strain Shear Tests Since the distance normal to the slope section was about 5 times the thickness of the sludge plus sand blankets, it was reasonable to assume that plane-strain was approximated in the cut slopes (Dunlop, gt_al;, l968). Hence it was decided to include plane-strain shear tests which would more closely simulate the slope unloading during excavation. The plane-strain device used in the test program is shown in Figure 3.3a. This device is a replica of the plane-strain device used by Duncan (l965) in his testing of clays. The essential feature of the device is a pair of end plates which force the sample to undergo plane-strain deformation during consolidation and testing. It is small enough to fit inside a six inch diameter triaxial pressure cell. The device utilizes polished lucite and a layer of silicone grease to reduce friction. 48 . 5.33. .~.\,.«..... f‘... {03:15. \ s (b) Figure 3.3.--(a) Plane-stra ial cell. iax high speed rotary saw. tus mounted on base of tr ion u51ng a 1n appara (b) Sample preparat 49 For the plane-strain test program, undisturbed test specimens were obtained from block sample E. Specimen preparation involved cutting, by means of a hand saw, a 4 in. by 4 in. by 6 in. chunk from the block of sludge. The sample of sludge was then trimmed using a specially constructed metal mitre box (Figure 3.3b). All samples were trimmed with their axis vertical. A hobby tool with a high speed rotating 3/4 in. diameter circular saw cut the pulp fibers giving a smooth trimmed sample. Since Duncan's plane-strain device required that the samples be rectangular, use of the mitre box gave samples with dimensions of 2.80 in. wide, 2.80 in. high and l.00 in. thick. The cross sectional area before and after consolidation was 3.08 sq. in., very close to the average area for the triaxial samples of approxi- mately 3.14 sq. in. After trimming, the sample dimensions and weight were recorded and the sample was placed immediately on the base of the cell; a membrane was placed around the sample, and the plane-strain device was assembled around the sample and the cell placed in position. The low sensitivity of the consolidated sludge helped minimize sample disturbance. To insure one-dimensional consolidation in the plane-strain device, side plates connected to rubber diaphragms were pushed into place against the sides of the sample by increasing the pressure in the diaphragms above thecell pressure. This assured that the cross- section of the sample during consolidation maintained the shape and area of the cap and base. The stress conditions were anisotropic, with Ko equal to 0.33. 50 When consolidation was complete, the side plates were moved away from the sample, by reducing the pressure on the diaphragms, leaving the sample standing free on two sides. A load applied axially through the triaxial pressure cell ram, acting on the t0p sample cap, was used to control the deviator stress. Connections to the ends of the sample permitted either drainage of water and air from the voids in the sludge, or alternatively, the measurement of the pore pressure under conditions of no drainage. The shearing part of the plane-strain test was run undrained in the same manner as the triaxial shear tests described in the previous section. Field Vane Shear Test Because of the extreme difficulty of obtaining representative undisturbed samples of peat and other organic soils, the vane shear test has frequently been used to evaluate in situ shear strength. In-place measurements of the undrained sludge shear strength provided the undrained strength data for comparing the predicted slope stability with the actual stability. Increase in undrained strength due to consolidation was observed by comparing test data taken shortly after construction of the landfill with data taken at later intervals of time prior to the stability study (Vallee and Andersland, 1974). The vane shear test was performed by inserting a four bladed vane (two inch diameter Acker Vane) thru the hollow core auger stem and pushed the final 6 inches to test depth. The vane was then slowly rotated until the sludge failed along a cylindrical surface with conical surfaces at the top and bottom. The maximum torque was a function of 51 the sludge shear-strength. Using the maximum torque reading and vane dimensions (Figure 3.4), the shear strength Tf was calculated as follows: 3T Tf = (3.2) 2 ZHR (2% + 3L) where 1f equals the shear strength, T equals the torque reading, R equals the radius of the vane, and L and 2 equals the vane dimensions shown in Figure 3.4. 52 l I Note: Rod resistance has ' been ignored since holes I were augured to within | 6 inches of test depth. a = 45 degrees R = 1 inch L = 3.49 inches T = Torque L —-'Rruu 2 a h T = (2 WRLTf)R + 2T1J'K.1’217h2 csc adh 2 2 0 T = 2nR tf(L +-§-2) Solving for shear strength, Tf Solving for Tf in lbs/sq ft, 3T T = . T = f 2WR1(2 2 + 3L) f 5-17 T where T is in inch-lbs. Figure 3.4.-~Acker Vane dimensions and equation for computation of the in-situ shear strength. CHAPTER IV FIELD SITE, INSTRUMENTATION, MONITORING AND EXCAVATION A. Field Site The experimental sludge landfill was constructed in an old gravel pit located close to West Carrollton, Ohio, and within sludge hauling distance of the papermill. Construction of the landfill was part of an earlier project and details of construction have been reported by Vallee and Andersland (l974). The experimental papermill sludge landfill consisted of two sludge layers, each initially l0 feet (3.05 m) thick, with horizontal sand blankets at the top, bottom, and between the upper and lower sludge layers. An earth dike provided lateral confinement for the soft sludge during and after construction. The surface load consisted of 3 feet (0.915 m) of earth fill material. Instrumentation included piezometers and settlement plates duplicated at a number of locations in the landfill (Figures 4.l and 4.2). To obtain information on slope stability, the experimental papermill sludge landfill was altered by removal of the North dike and excavation of a 3:4 slope followed two weeks later by a l:8 slope. The BJi.Danis Company, Inc., Dayton, Ohio, provided equipment and operators. Coordination of excavation operations was handled by the author working with Mr. Tom Danis, Sr. The Bowser-Morner Testing Laboratories, Inc., Dayton, Ohio, installed both the slope indicator 53 54 .maaocm pcmszeumcw 0:0 c? m~_mu mczmmmca Pepe“ new .mgmpmeonwa .mmum_a acmewrupmm 0o cowpanwgumwo--._.¢ mgzmwd SMHCONEOCTG .Hmofiuoc/uov mdoo 0~5mm00m H.300 O maouoEouwwm IT mmumfim unwewfiuom H 3% :8 Es... . . . 4. \W . .. 4!... H C (E... H H _ N +. ~.+ M+H M+H@ 0wvsamm+ «4+ «4+ 0+ 0+ + >+ 0m5m>+ \l UH H He w+ w+ \IUQMm t: is :,....-.: H : E::: m . A LPr _ 0wum30u5mb w um m¢.oo~ .H0 N. ...w m 30m v Mug 4/ \ among?“ 959% unmesuamcm H. ~—‘ '2": \---i' —— 55 North E existing gravel pit wall _ 2 middle sand I blanket 7 r—bottom of SIOpe é | 3.4 slope u ' N'FC .. ., . . . o . .0 I B + ‘ I u . O 100 20' o l‘, ' 8 + ‘ + 6 I 2 . - 5' 1 - . jEl. _ . 15 (.1; T .- —- -l—————— “l +- + (i. I .. 5 1 o ' .G - [2'! l 3* *‘7 I .3 E ' J. ' 'U - .9 .. I l 2 I ..p G) 3 AC? . \ / I '- '~H ,9, \\ / 0n ‘1:— -.- —;,-:-’--" .13 '0 ~ " "Z‘ "" - r: E 3 limit of surcharge dike \ I I I l I I \ Legend: 4' Instrument groups 1 through 8 . Slope indicator casings A through (3 Scale: 1-in. = 30-ft Assumed elevation datum T0p of gas line marker : 100. 00 ft Figure 4.2.--Slope indicator casing locations, A through 6. and 3:4 lePE. plan view. 56 casings and additional piezometers, and carried out the vane shear and Dutch cone tests prior to the excavation. A plan view of the field site after excavation of the 3:4 slope (B = 53.1 degrees) is shown in Figure 4.2 and the experimental slope cross-sections are shown in Figure 4.3. B. Instrumentation and Monitoring Instrumentation placed during construction of the experimental landfill continued to serve the monitoring needs during the stability phase of the project. Additional instrumentation placed September 7— ll, 1972, included seven slope indicator casings, six more piezometers, and horizontal control stakes. These were located so as to provide information on the slope behavior. All instruments were monitored before, during excavation of the experimental slope, and as needed during the remainder of the second year of the project. The following sections describe instrumentation for horizontal and vertical movement, piezometers, total pressure cells and temperature sensors. Horizontal Movement Removal of the north dike and excavation of the experimental slope reduced lateral stresses and pore pressures on the exposed sludge surface to zero. Unloading the slope permits lateral deformations to occur which may be stress related and/or creep dependent. The magnitude of movement may vary with depth and with the location of any failure zones. Slope indicator casings and surface measurements provided information on these horizontal movements. slope indicator casmgs Instrument 4 —\5 ft / group (a) I 10-13‘72 / earth surcharge °: pig's. sand sludge sand sludge . J? sand / natural soil ‘ o N '. slope indicator . Instrument casin 5 group 4 g 5-ft\ / (b) 1 |"—‘"‘ 10'24'72 earth surcharge ' ”1'2. . r3311 sand sludge z." -..)“ sand sludge _: ,7.;-.... ..'o- $3.5? '37: p.32 . o...“ v:,'~& '.Sand natural soil Figure 4.3.—~Experimental slope cross-sections. (a) 3:4 slope. (b) l:8 slope. 58 Slope Indicator Casings.--Flexible vertical casings were in- stalled through the earth surcharge, sand drainage blankets, and both sludge layers, to about one foot into the natural soil below the experi- mental landfill at locations A through G, shown on Figure 4.2. In- stallation involved drilling a 6 inch hole using a hollow core auger, placement of the 3.l9 in. 00 aluminum casing (0.093 in. wall), and pumping a bentonite clay-water mixture into the opening outside the casing. Lateral movement in the sludge was transferred by the clay to the flexible casing. A precision Slope Inclinometer (Slope Indicator Company Series 2008) was lowered down the casing with the orientation of the instrument governed by the direction of the Slope Indicator's fixed pair of wheels. These fixed wheels track in one of the four grooves in the casing. During installation, the grooves in the casings were oriented so two grooves were parallel (East-West) and the two other grooves were normal (North-South) to the experimental slope. Reference readings were taken after the slope indicator casings were installed and before excavation for the slope was initiated. Incli- nation readings taken at 2 foot intervals of depth were subsequently converted to lateral displacements. Sensitivity of the inclinometer permits displacement measurements in thin shear zones of less than l/l6 inch. Consecutive readings at the same orientations and depths, taken at periodic intervals of time, were used to determine the amount and rate of ground movement. Surface Measurements.--Wood control stakes, 2-in. by 2-in. by l l/2-ft. long, were placed in the earth surcharge and dike opposite 59 to the slope as shown in Figure 4.4. Movements of the sludge embankment toward the slope were noted by an increase in measured distance from the three reference stakes placed in the dike. Consecutive readings taken at periodic intervals of time were used to determine rate of surface movement. Damage to the stakes from external sources was minimal. Vertical Movement Vertical movement results from consolidation of the sludge and downward movement at and near the face of the experimental slope during and following excavation. This movement was monitored using settlement plates placed during construction of the experimental landfill. Settlement plate locations are given by instrument group (Figure 4.2) and plate number (Figure 4.l). Each settlement plate consisted of a 2-ft. by 2-ft. by l/8-in. thick aluminum plate with a 3/8-in. diameter steel rod of known length attached to the center. A l l/2-in. 0.D. aluminum tube placed around the steel rod eliminated any adhesion between the sludge and the rod. The lower plate was located at the center of the group with each higher plate offset by l l/2-ft. Ele- vations taken with a surveyor's level (or transit) on the top of each steel rod were referenced to a bench mark outside the fill area. Duplicate plate locations also served as insurance in case of accidental loss and the additional data served as a check on adjacent groups. Piezometers Piezometers measure the static pressure or head (elevation to which water will rise in an open standpipe) of the fluid in the pore 60 North q; existing gravel pit wall "' p7 l [— bottom of slope / 3=4 slow I \dzke . . a) on I s ' XI CN-3 Cl .7+ I) '2 2 I- 0 e + H 3-4 ~ 0 H H I :33 ‘1 H I 5’. 0 a) 0.x .\ g c: g I m .033: \ 5 :1 .... / o \ tho \“"' ——"""V ..E. as: —+ .510) \ l q L \"|Ill\ \. + Instrument groups 1 through 8 0 Horizontal control stakes Scale: l-in. 1' 30-ft. Assumed elevation datum TOp of gas line marker : 100. 00 ft. Figure 4.4.--Horizontal control stake locations, plan view. 61 space between the solid sludge particles. Stress reduction to zero at the exposed experimental slope will reduce pore water pressures. Measurement of these pore pressure changes involved installation of six additional units as part of instrument group 4, near the experi- mental slope. Piezometer locations are given by instrument group (Figure 4.2) and piezometer number (Figure 4.l). The pneumatic type piezometer (Slope Indicator Company Model 5l40l) used on the project did not require in-place calibration and was not subject to changes in sensitivity. The sensitivity of the unit approaches 0.5 in. of water. The sensitivity to pore pressure changes was high because the water displacement during reading of the piezometers was small (0.03 cu inches), thus requiring practically no flow of water. The standard Norton Casagrande type filter with large pore size and low air entry pressure was used because the sludge has a high degree of saturation. All piezometers were separated from direct contact with the sludge by about 3-in. of sand so as to minimize any influence sludge decomposition might have on the piezometer operation. The transducer converts water pressure into pneumatic pressure which is relayed to the surface reading station by means of twin nylon tubing. Pore pressure readings were taken with the Model 5l42l (Slope Indicator Company) portable pore pressure indicator from terminal boxes which were housed in two wooden boxes located on the landfill. Total Pressure Cells Total pressure cells helped in determining the state of stress in the sludge mass. Cell description and installation have been 62 reported by Andersland, et al. (l972). Locations of the two vertical cells and one horizontal cell, part of instrument group 7, are given on Figure 4.l. Temperature Sensors Temperature sensors, small YSI precision thermistors (Part #44033), provided temperature data at 2 ft. depth intervals for a given location in the experimental landfill. Thermistors and the method of installation have been reported by Andersland, §£_Ql; (l972). Thermistor elevations are given in Figure 4.l. Vane Shear Vane shear tests were carried out at one foot depth intervals in the sludge. The vane used was a four-bladed 2 inch 0.0. Acker Vane. Details on computation of the vane shear strength have been given in Chapter III. The vane shear test was used to determine the in situ field undrained shearing strength of the sludge deposit just prior to excavation for the slope stability study. The tests consisted of boring with a hollow stem auger to within 6 inches of the test depth, then inserting the vane through the hollow stem auger and forcing the vane vertically the last 6 inches to the test depth. This method was followed to keep disturbance to a minimum and reduce the vane's rod resistance to a value near zero. The vane's extension rod was then slowly rotated clockwise until the maximum torque was obtained. The vane was then rotated 25 times clockwise to remold the sludge adjacent to the vane. After which the remolded shear strength was determined 63 by slowly rotating the vane until the maximum torque was obtained. The shear strength (undisturbed and remolded) was computed from Equation 3.2. This procedure was repeated for each test at one foot intervals of depth. Dutch Cone Tests The Dutch Cone Penetrometer tests were carried out at one foot depth intervals. The Dutch Cone used had a 60 degree cone of base area equal to 10 sq cm. The Dutch Cone test consisted of boring with a hollow stem auger to within 6 inches of the test depth, then in- serting the Dutch Cone through the hollow stem auger and slowly forcing the cone vertically the last 6 inches to the test depth. The resistance of the cone at the test depth was recorded. This procedure was repeated at one foot intervals of depth for each test. C. Excavation for the Experimental Slope Preparation of the experimental slope involved removal of the North dike and sludge excavation so as to give the slopes shown on Figure 4.3. Preliminary information on the sludge stability was obtained by excavating a vertical trench about 40 ft. long and 8 ft. deep, down to the middle sand drainage layer, using the dragline bucket on September 2l, l972. The trench face was about 20 ft. forward from slope indicator casings B and C. The following day surface cracks had appeared about 2 ft. back from the exposed sludge face. The trench excavation was continued to a depth close to l5 ft. The next day (Sept. 23, l972) the trench remained open but with new surface cracks about 4 ft. back from the exposed face. Sand falling from the middle 64 drainage blanket removed support for the upper sludge layer to about 1 l/2 ft. back from the cut face. Dike removal was started on Sep- tember 24, l972. Heavy rain during the night softened the dike surface and adjacent area to an extent which prevented effective equipment operation. More rain delayed work until September 29, l972. Dike material and sludge was removed, weather permitting, until completion of the 3:4 slope on October l3, l972. Excavation work and the com- pleted slope are shown in Figure 4.5. Excavation for the 1:8 slope was initiated at noon on October 24, l972. The dozer removed sludge seven feet back from the toe of the 3:4 slope giving a vertical face to the lower sludge layer. Next the back- hoe removed sludge (Figure 4.6a) so as to give the 1:8 slope. Sludge was removed from in front of the slope using the dozer (Figure 4.6b). Work was completed by noon on October 25, l972. 65 Figure 4. 5. 3:4 slope preparation. (a) Sludge removal by dragline. (b) Slope cross- section, October 13, 1972. Figure 4. 6. 1:8 slope preparation. (a) Trimming the upper sludge layer. (b) Sludge removal using a dozer, October 25, 1972. CHAPTER V FIELD AND LABORATORY EXPERIMENTAL RESULTS The experimental results for this project are presented under three headings: physical properties of the papermill sludge, stress- deformation behavior of the sludge, and slope behavior. Each section may include laboratory test data and/or field observations. A. Physical Properties of the Papermill Sludge Physical properties of the papermill sludge, tabulated in Tables 5.1 and 5.2, include field water contents, ash contents, and unit weights. Water contents were taken at selected elevations im- mediately after excavation of the 3:4 slope (October 12, l972) and 1:8 slope (October 30, 1972). A plot of this data in Figure 5.1 shows a decrease in water content with a greater depth. The scatter of points on Figure 5.1 is apparently due to the non-homogenous nature of the sludge. Small variations in ash (or organic) content appear to significantly alter the water content based on oven dry (105°C) weights. Water contents from 1 ft. cube block samples B, C, F, and G tabulated in Table 5.1, show the range in variability. Ash contents and unit weights given in Table 5.2 refer to block samples B, C, F, and G on which extensive laboratory tests were conducted. Unit weights were determined from weight and volume measurements of carefully trimmed sludge samples. Greater consolidation of the lower sludge layer significantly increased the unit weight. 67 68 TABLE 5.l. VARIATION IN WATER CONTENTS FOR ONE CUBIC FOOT BLOCK SAMPLES Block B Block C Block F Block G 213 % 162 % 149 % 159.1 % 206 157 162 157. 7 218 163 165 153. 7 222 169 154 157. 2 212 169 150 158. 6 209 170 164 158. 6 193 169 157. 2 212 178 157. O 218 160. O 211 158. 6 204 212 206 214 202 200 Avg. 209. 5% 167.1% 157. 3% 157. 8% Block Elev. 88. 8 ft 87. 5 ft 80. 9 ft 80. 7 ft 69 TABLE 5.2. PHYSICAL PROPERTIES OF THE PAPERMILL SLUDGE, OCTOBER 1972 Sludge sample Water Ashi Sludge sample Water No. Elevation content content No. Elevation content (ft) fldgy wt) (%1 (ft) (‘70 dry wt) Block A 91. 8 196 91. 7 199 202 91.6 177 212 91.4 182* Block13 88.8 214 38.6 91.2 200 209 90.6 193 200 90.5 187 B10ck<3 87.5 183 49.1 g 90.4 188* 165 '6‘. 89. 9 194 173 g 89.4 189 Blocle 85.5 191* g 89.4 201* 187* g 89.1 144 Block E 81. 9 161* 8 88.7 149 164* g 88.4 161 162* E 88.4 172* B10Ck]? 80.9 154* 39.3 E 88.0 177 156* 87.7 173 156* 87.4 164* Block<3 80.7 157* 39.0 85.4 207 159* 84.4 175 161* 84.4 211* 83.4 204 92. 8 199 83. 4 175* .ggg 92°3 200' 81.4 163* 8 0 "3 ° 81. 4 158* 92.2 187 Field water contents correspond to 3:4 slope, October 12, 1972, except * which correspond to 1:8 SIOpe, October 30, 1972. Unit weight: block B y 72. 6 lb per cu ft. block C y = 74. 0 lb per cu ft. block F v 76. 5 lb per cu ft. 1ASTM test method D586-63. 7O surcharge 957831161..- Water content, '70 dry wt. - °' 140 160 180 200 220 240 " I I I I I I I T I t‘ '- o ‘99 o o O O 000 O _. _. C) upper © 0 layer 0 G) ... JD 0 0 O G O O ... ._ o (5) 8 o a: _ éi'é’ria'3’ 5_ g 00 G 4‘; 85f - d E o o m — F- O 0 G) _ lower — GD L- sludge _ 0 0 layer 09600 BOP 1" -—I b r- - :s'aixic'i'} — . I . ... natural Average water contents: soil upper sludge layer 186% '_ F lower sludge layer 167% 75L 1 l J I l I l 1 l Figure 5.l.--Field water contents of the sludge in the landfill, October 1972. 71 B. Strength Characteristics of the Papermill Sludge The shear strength of the papermill sludge has been measured using triaxial and plane strain tests in the laboratory and the vane shear test in the field. Results from the triaxial tests are presented for fresh sludge samples obtained during construction of the landfill and undisturbed block samples taken after field consolidation. Only normally consolidated sludges are considered under strength character- istics. Triaxial Shear Tests Fresh Sludge Samples.--Samples taken during construction of the landfill have been identified and described in Table 2.l (after Andersland, gt_§l,, l972). Portions of fresh sludge samples U-l, U-Z, and U-3 were molded into triaxial test specimens. A summary of these test results are given in Table 5.4 Laboratory data are given in Appendix I, Tables I-l through I—l2. A back pressure of 0.703 kg/ sq cm was used on all the fresh sludge samples to ensure full saturation and to de-air the space between the membrane and the sample. With this back pressure, the pore-pressure parameter 8 was equal to one. Typical stress-strain behavior of the fresh sludge in undrained shear is given in Figure 5.2. The obliquity 61/53, deviator stress (0 - o3), pore pressure change Au, and pore pressure parameter A are 1 all plotted against axial strain. The obliquity becomes very large at larger axial strains because of the very small effective minor principal stress 53. The A pore pressure parameter increases to about 0.75 at failure, which appears to be typical for the fresh sludge. Triaxial strength data for sludge sample U-3 is summarized in Figure 5.3. The 5f - if plot has been used to obtain an angle of internal friction 72 TABLE 5.3.--Summary of 5 Values for the Triaxial and Plane-Strain Tests. 5115'“ harm?“ ”.1231... ....1...) u - 1‘3l 40.6 W 61.5 Fresh sludge u - 28 53.5 cm 66.2 Fresh sludge u - 3a 63.5 E'I‘U 70.5 Fresh sludge Block 6 61.0 CAU 76.5 Field sample Block G 6l.O 010*) 45.5 Field sample H - 2c 28.6 010 45.7 Fresh sludge 34.7 01‘0” 51.4 Fresh sludge 43.6 CTU' 58.5 Fresh sludge 50 l CTU' 64.2 Fresh sludge Block E 59.3 CAU' 74.9 Field sample Block E 59.3 CAUPS. 74.9 Field sample aSample information given by Andersland et al. (l972). bSample axis horizontal. cData after Andersland and Laza (l97l). CTU - Consolidated undrained triaxial test with isotropic consolidation and pore pressure measurements. CAU - Consolidated undrained triaxial test with anisotropic consolidation and pore pressure measurements. 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Am- T 0 1 L 1 1 L L 4 1 1 1 1 L 1 L 1 1 1 1_ O 2 4 6 8 10 12 l4 16 18 20 2 e N E U \ I—I no 4: 3 4 1.— Initial dry density = 18. 32 lb/ft gm Initial water content : 289. 6% . Final water content = 127. 0% 5 " O 1 1 1 1 1 1 1 1 m 1 1 1 1 1 1 1 1 1 1 L O 2 4 6 8 IO 12 14 16 18 20 1. 5 F' Au, kg/cm2 0 0.5—- O 1 1 1 1 1 m1 1 1 1 1 1 1 1 1 1 1 L 14 0 2 4 6 8 10 12 14 16 18 20 1.0~ H 8 g 0.5 l~¢—1 < 0 1 1 1 1 1 L 1 1 1 1 1 L 1 1 1 1 1 1 1 1 0 Z 4 6 8 10 12 l4 16 18 20 axial strain, ‘70 Figure 5.2.--Stress-strain behavior of fresh sludge in undrained shear, sample U-3-7. 76 3F N E a = 43.30 F. ..V. 2' 0 Q '0 m >7 . lb 47g, ‘ _ (a) ' N 1 . 4) = 70.5° lb 2 = 0.0 II 16* O 0 g 140 .— a 0) '8 +3 85 §§ 120 - m 38$ 2 3 "T 100 — L“ oU-3-5 AL I I. L O 1 2 3 4 Consolidation pressure p, kg/cm2 8- 2- ‘ g N 1.. 17. g ?o 0'? 4,\\ DD 8’" 1- ‘“ Q 4 5 '2 U s) (C) D O I -l I L O l 2 3 4 Consolidation pressure p, kg/cmZ Figure 5.3.--C0nsolidated undrained triaxial test results for sludge sample U-3. (a) Kf-line. (b) Water content. (c) Undrained strength. 77 equal to 70.5 degrees. Next is shown the change in water content for several levels of all-around consolidation pressure. Part c of Figure 5.3 shows the increase in undrained strength versus consoli- dation pressure. Similar results are shown for sludge sample U-l in Figure 5.4. The smaller angle of internal friction, 6l.5 degrees, appears related to the lower organic content of sample U-l, 40.6 per- cent versus 63.5 percent for sample U-3. Undisturbed Sludge Samples.--Triaxial test specimens were cut from undisturbed block samples C and G which were obtained during excavation of the slope for the stability study. A summary of the triaxial test results is given in Table 5.4. Laboratory data are given in Appendix 1, Tables I-l3 through I-35. Except for the un- confined compression tests, a back pressure of 1.4] kg/sq cm was used on all undisturbed sludge samples to ensure full saturation of the sludge and to de-air the space between the membrane and the sample. With this back pressure, the pore-pressure parameter 8 was equal to one. Special test conditions include anistropic consolidation and applying the major principle stress (01) at different sample orien- tations. Unless otherwise noted, the samples were trimmed so that their cylindrical axis was the same as in the field with the major principle stress vertical. The stress-strain behavior of sample G-5, shown in Figure 5.5, corresponds to anisotropic consolidation. The coefficient of earth pressure at rest, K0, equal to 0.3, was selected on the basis of field total pressure cell and piezometer data. Figure 5.5 includes the obliquity ratio, deviator stress, change in pore pressure, and the A pore pressure parameter all plotted against axial 78 “13 fl 3 = 41.3° on 2— ,44 o lbm (a) ' N 1_ E: 61.50 IST E?: 0.0 II 14... IC" 0 O ,_, 120.. C- .8 g . U E :- 3 t 100- gr: 49° ‘9 . .S 3 I14 801- 4; 1 1 1 1 O l 2 3 4 Consolidation pressure p, kg/cmZ ..CI 4.) an $3 <1) the w E 'U U o\ .5 w «I'M 14 4 "o :3 S U 0 I I l I O l 2 3 4 Consolidation pressure p, kg/cmZ Figure 5.4.--Consolidated undrained triaxial test results for sludge sample U-l. (a) Kf—line. (b) Water content. (c) Undrained strength. 1/“3 obliquity, 0 (0'1- 03), kg/cni "J I .311, kg cm A facto r 79 Sample No. G- 5 120 r- . . Consolidation pressure p = 1.17 kg/sq cm " K 2 O. 3 90 1- O G E l “1 60 I- - - 3O ._ 1— L. O< .L m l lmL l l l L J J l L 4 l l 1 l 1 I 2 4 6 ‘1 IO 12 14 16 18 20 2 4 l +_ Initial dry density : 27. ()5 ll) /ft5 < Initial water content 153. 7”}- Final water content 130. O '3'. O. O. 0. no O. 2 0 ____L__.__1,.,.__L__J___.L J 1 1 l L 1 1 m 1 1 m 1 1 1 #1 (l g l f- 8 JO 1’ 14 111 lb’ 20 :Ixieil st 1':11'1 . I) Figure 5.5.-~Stress—strain behavior of consolidated sludge in undrained shear, sample G-5. 80 strain. The break in the obliquity curve corresponds to failure at about l9 percent axial strain. The deviator stress starts at a value greater than zero because of anisotropic consolidation. The A pore pressure parameter has decreased, in comparison to results for the fresh sludge, with the value at failure a little below 0.4. A summary of data from similar tests at other consolidation pressures is shown in Figure 5.6. The angle of internal friction obtained from the 5f - a, plot is very large, close to 76.5 degrees. This suggests that some relationship exists between the angle of internal friction and the anisotropic nature of the sludge for this group of specimens. At - greater consolidation pressures, the water content decreases while the undrained strength increases. These relationships are shown in Figure 5.6. The stress-strain behavior for sample G-l0, shown in Figure 5.7, corresponds to all-around consolidation with the major principle stress (0]) applied horizontally. This was accomplished by trimming the sample so that its cylindrical axis was at a 90 degree orientation to that in the field. Lower obliquity ratios are noted and the A pore pressure parameter has increased in comparison to sample G-5 shown in Figure 5.5. The summary of data for specimens G-lO and G-ll is given in Figure 5.8. The angle of internal friction is much lower, about 45.5 degrees, and the undrained strengths are lower as compared to data given in Figure 5.6 for the sample trimmed with the cylindrical axis vertical. The stress change prior to slope failure involved a decrease in lateral pressure as the sludge was excavated. To reproduce this 81 N = 44. 20 E < 2- no ,4 (‘0 lb ' N 1.— I67 ll 1.1.4 IO" 0 1 1 1 1 O 1 2 3 4 F +3 - 1 3 2 pf ‘ 2 , kg/cm b .5 160- (l . K = . 3 , G-9o 0 0 3 g; [a Field water contents >~ “ H 140.. .g-n 36° i L:- 120- 1 l 1 l O 0.5 1 1.5 2 Consolidation pressure p, kg/cm2 0 .12 16 c: 1.6 - <0 the "’ E 1.2 - "o o o\ .5,§’ 8 _ ' 2 . O. O? E 9:30 4 0 (C) D o - 0 J 1 I l O 0.5 1 1.5 2 2 Consolidation pressure p, kg/cm Figure 5.6.--Consolidated undrained triaxial test results for block G, anisotropic consolidation and vertical axis. (a) Kf-line. (b) Water content. (c) Undrained strength. 1/“3 obliquity, o N 82 Sample No. G- 10 Consolidation pressure p = O. 70 kg/cm2 K0 = 1. O P Initial dry density = 29. 0 116/1t3 Initial water content = 157. 0% Final water content = 145. 0% 1 1 1 1 l 1 l 1 L 1 1 1 J 1 1 1 1 1 1 g 2 4 6 8 10 12 14 16 18 20 A factor IO 12 axial strain, 1 r .- 1- n I- 1- j- n 7% (9 Figure 5.7.--Stress-strain behavior of consolidated sludge in undrained shear, sample G-lO with the major principal axis horizontal. 83 LSl— N E U >0 1 O . L— 31 a: 355° M Ib (a) l N _ 16H 0.5" (l) 2 45.5 11 E': 0 1...... 16* 0 I I l i O O 5 1.0 1.5 21) '3 +1? _. 1 3 Z pf: 2 , kg/cm 4.? r 06-10 1: 8 140" \ (b) 8 \\ U .130r- \ 8*; \ 3 >120- \‘ 3 a \ \ G-ll .4'0 7‘CL4‘ 8&110— £11 100 I 1 1 1 O 0.5 1.0 1.5 2.0 Consolidation pressure p, kg/cm ..C‘. O 23 1.0-— 8 8N8 {D U "U\ a) no .5“ 0 5" Q g “:1 / "g 0 / (C) :3 / 0 l 1 l L O 0.5 1.0 1.5 2.0 Consolidation pressure p, kg/cm2 Figure 5.8.—-Consolidated undrained triaxial test results for block G, isotropic consolidation, and horizontal axis. (a) Kf-line. (b) Water content. (c) Undrained strength. 84 field stress condition in the laboratory a series of tests were run in which the axial stress, 0], was held constant and deformation was brought about by reducing the lateral stress, 03. Prior to the test, samples were consolidated anisotropically to approximately field conditions based on data from the total pressure cells and a piezometer buried in the landfill. This test procedure perhaps best approximates the loading conditions for a sludge element adjacent to the excavated slope. Data shown in Figure 5.9 for sample C-ll represents an un- drained test with 01 held constant and failed by decreasing 03. Negative pore pressures result for the unloading condition. The higher initial tangent modulus, obtained from the deviator stress versus axial strain curve, perhaps gives the best estimate of the field behavior. The A pore pressure parameter was again close to 0.53. The angle of internal friction was not fully mobilized since complete failure had not occurred. The strain was very small (less than 5 percent) when 03 was decreased to zero. Plane-Strain Shear Tests Plane-strain test specimens were cut from undisturbed block sample E which was obtained during excavation of the slope for the stability study. The plane-strain test results are summarized in Table 5.5. Laboratory data are given in Appendix I, Tables I-36 through I-40. Samples were consolidated anisotropically (Ko = 0.333) to approximate field conditions and then failed in undrained com- pression with pore pressure measurements. A back pressure of l.4l kg/ sq cm was used to ensure full saturation of the sludge and to de-air the space between the membrane and the sample. With this back pressure, 85 Sample No. C-ll Consolidation pressure 2 p = 0.935 kg/cm K = 0.3 o ("‘1 lb \ lb i E .2 23 O l l 1 1 1 O l 2 3 4 5 1.04 N E 4i on .x AM b I 3H 0 1 Z 3 4 5 N 0- I I I E < I .30 I _ ’<- Pore pressure increase 5 / to zero permitted <1 4 0 0.1 . ’/ 1.0 L1 8 g 0.5 L1.- < 0.0 1 1 1 1 1 O 1 2 3 4 5 Axial strain, “/6 Figure 5.9.--Stress-strain behavior of consolidated sludge in undrained shear, sample C-ll with 03 constant and 01 decreasing. 86 4664 464X6464 ummu seesaw-6:64d h Fm.0 00.0 mp._ 0m.0 0.0m v.¢m— <.mm~ mmm.0 No.0 nN—Im 00.0 40.0 NN.N m~.F m.mm om— —.Nm— mmm.0 nm.~ oppum w~.0 0N.0 _¢.¢ 0_.N 0.0m _.m_— m.vmp mmm.0 0N.N nopum 0N.0 No.0 m—.m mm.~ 0.NN ¢.Nm— m.—0P mmm.0 ~¢.— wmum 0N.0 40.0 00.? ¢0.N m.nm 0.0FF ¢.m0— mmm.0 —P.N aqum 0_.0 00.0 0m.m m0.m m.0m NNP 0.0N— mmm.0 _—.N mmnm m_.0 0—.0 m—.m em.p N.0N 0._m_ m.0- mmm.0 F¢.P wmum 0N.0 00.0 No.4 000.0 0.0m —.mmp P.0m— mmm.0 05.0 cram so 0 Eu m 56 m Eu m w AN \ xv AN \ xv \ xv Awoav A&v A&v ox AN \ xv a c 4 =6 4444:66 46e4d 4e444e4 a 64a56m mm 4o spmcmcwm ago mana4m .1 66246462: 4mwp_c4 4:64:00 4646: :owuouwpomcou .m xoo4m co mu—zmmm ummp cwmcmemcmpd use mexmwcp no acmaszm-.m.m m4m 460 .cowum>moxm 66046 meowmn z4mumwumeew .prmucmp 4mucmewgmaxm-1.m4.m mgzmwu 92 NEo\wx .oocmumwmon ocoo Ned}; .xuwcohum 462? 6442/ NR: 4N. Menswear-"om 04 N4 0 v o 0.N 0.4 ~.H 0.0 6.0 my \>\ _ 4 4 4 4 4 4 4 a my... 44m......... 0 44 m m l w“ l w“. o c v . I A|1060?:Copd d 6 \ 1 x 1 owpgm 1.N0 1_N0 1 a mum m 1 44 ‘\\\\ 4|. 3 T.. - 44 Fm m .. n . .. .. . \ ...-4. D a .... m4. 1 o s w -. o .a-. m m.P m mfiflu mean 1 cm .1. 9m 1 00 I. .... 8 \ .100 1 00 \ owpsam IL .1 1 V0 1 «NO . ..\. 4e .. E - 4......H............ 4.58 E 48:4 440 NE} a .4 93 sand blanket was approached. Directly below the middle sand blanket the cone resistance increased with larger values observed for the more highly consolidated bottom half of the lower sludge layer. C. Slope Behavior Slope behavior was monitored in terms of lateral movement, vertical movement, change in pore water pressures, temperature, and total pressure cell readings. Tables, figures and graphs are used to summarize the tabulated data which are given in the Appendices. Lateral Movement Lateral slope movements were monitored using both surface measurements on stakes (Appendix A) and slope indicator data (Appendix 8) obtained using flexible vertical casings and an inclinometer instrument. Surface movements along three lines labeled I, II, and III, are given in Table A-l, Appendix A. Locations of the WX, NY, and NZ positions are given in Figure 4.2 with reference to instrument group locations and the plan view of the experimental slope. Movements in the experimental slope became more evident as the actual slope failure was approached. Tension cracks appeared in the earth surcharge very shortly after completion of the 1:8 slope. Their appearance and location relative to the slope indicator casings are shown in Figure 5.l4. The stake for line II-WZ was lost after the October 28, l972. reading at which time a total surface movement of 3.72 inches (9.45 cm) had been observed. The initial slope failure (Figure 5.l5a) did not occur until four days after the 1:8 slope had been excavated. Shortly thereafter additional failures occurred in the top sludge layer along cracks Scale vert. l-in. = 8-ft. horiz. l-in. = ZO-ft. sloPe indicator casings 5 ft. t0p of slope surcharge . ' -.'-.i“.-2:-.'."-'."-‘:'-.T-'-'-'.'. 3.1%] e --' san sludge bottom 1:8 slope A (b) Figure 5.14 Tension cracks. (a) Photo. (b) Crack locations on October 25, 1972. Figure 5.15 (3.) Initial slope failure, October 29, 1972. (b) Slope c0ndition on November 11, 1972. 96 the slope as shown in Figure 5.l5b. The surface extent of these slope failure areas for three different dates is given in Figure A-l, Ap- pendix A for the l:8 slope. Examination of these slope failures sug- gest that the typical cross-section can be approximated as shown in Figure 5.16. The tension cracks appeared to extend through the earth surcharge down to the upper sand drainage blanket. The failure surface in the sludge approximated a l:l.64 slope (about 58.6 degrees from the horizontal). The failure surface in the sand drainage blankets were approximately as shown in Figure 5.l6. Approximately five months after the excavation (April 7, l973), line III-NZ recorded a total of 7.08 inches (l7.98 cm) of movement for the l:8 slope. The trench was then filled with fresh sludge and surface measurements taken approxi- mately two months later (June l4, l973) showed that the slope had moved back a small amount as shown in Table A-l. Lateral movement at various levels in the landfill is shown very clearly by the slope indicator data summarized in Figure 5.l7a through 5.l7g. Field data are given in Tables B-l through B-l3, Appendix 8. Locations of slope indicator casings A through G were given in Figure 4.l. All movements are referred to the base of each casing which was embedded about l ft. into the natural soil beneath the landfill and to the initial readings taken on September l9, l972. Most of the movement toward the exposed slope occurred in the top sludge layer, reaching a maximum at the landfill surface. Each curve in Figure 5.l7 is identified by the date on which readings were taken. Slope indicator casings A and D also moved significant amounts parallel to the slope as Shown by the data summarized in Figure 5.l7e. For 97 3ft Tension crack 12 ARTHSURCHARGE y = 130.4 pcf 1ft :--ba-F-t 8.2 ft 8 jF—t Failed slope (approximate) [—1 / 1.64/ UPPER SLUDGE LAYER y = 72.6 pcf -SAND . f - avg. ::l(.)0 péf . ... .. . LOWER SLUDGE LAYER Figure 5.l6.--Cross section of l:8 slope, before and after failure. 98 EL‘L'P ZL‘6Z'ZI ZL‘ZI'ZI 22—12-11 ZL‘FI’II 2L‘8'II slope indicator casing.A ZL‘E'II ZL'I'II 22'82‘01 ZL‘9Z'OI ZL'SZ‘OI ZL'EZ'OI ZL'EI'OI 22-61-6L Ln 0\ 8 8O 75 '1; ‘UOIJEAGIS 21-6- -. .. 31:2-:-1\\\\\\\\\\\\\\N2=s2=18\\\\\\\\\\\ \ H o 0 (DO 'U 'U 'U 3 c~ c E G g G . (G 1—1 (6 1—1 «I QH In a: m In In Figure 5.l7.--Lateral movement. (a) Slope indicator casing A. movement north, inches 99 22‘82‘01 SIOpe indicator casing B ZL‘9Z'OI 22-92-01 ZL'EZ'OI 22‘171‘01 22'61'6 :1; ‘uonezx 313 21-61-6 N :35.1\\\\\\W k\\\\\\\\\\\\ 8, [—4 O O‘ Date sludge sand sludge sand Figure 5.l7.--Lateral movement. (b) Slope indicator casing B. movement north, inches 100 EL'L'fi o gL-OI -2 O 2L‘6Z'ZI 213171 ‘11 U DO (I: ZL'S'II '5 m U ZL‘I 'II M 0 +) m .3 'U .5 ZL-sz-OI m a 0 To ZL‘9Z'OI ZL'SZ‘OI ZL'EZ'OI 0 217771 "OI ° 0 O O O O 0 ° 0 o L | 1 ° &\, a\ ZL'6I’6 ' ‘ Ln 0 Ln 0 0‘ 0‘ 00 C13 '1; ‘uotquQIe ZL-6I '6 N Es\\\\\\\\\\\\\\\\‘fik\\\\\\\\\\\\\“fi E [-4 g)” :0 352's '3 '8 “S '3 d . m .H m pi m Qr-Im m a: m m Figure 5.17.--Latera1 movement. (C) 51096 indicator casing C- movement north, inches lOl EL'L'f IZ‘II PU? fI'II EZ'ZI PU? ZI'ZI ZL'S'II ZL‘E'II slope indicator casing I) ZL'I'II ZL'8Z'OI ZL'SZ'OI ZL'EZ'OI ZL‘?I'OI ZL'6I '6 l I o m o o w '1; ‘u0112A319 2L‘6I '6 IDate 1. 9o T/m2 sand sludge sand sludge sand Figure 5.l7.--Lateral movement. (d) Slope indicator casing D. movement north, inches l02 .< co 8 .5 .5 U) m .5 €L'L‘i7 ° 0 . 0 ‘4 v—a +3 8 l :3 O ZL'ZI-ZI 0 _§ fl ZL-Iz-II o o o E 5 ZL-S-II o o ° "* 5 ° ° 8. 9 3 2 a“: 5 2L-9z-01 ° ° : o o o m o E o o g ZL-rI-OI °§§§5 \0 °\ 0 ZL'6I'6 o 0,. °-—o o ZL-H-OI Q :3 OD .c C‘. 2L-9z-0I '5': “I .5). ‘3 3° . a ' :3 3 (D ZL-E-II a 3 .8 g "0 a) .S _,u g 3 ' g ZL-IZ-II .% g .ZL-ZT-ZI EL-L-r 1 1 1 1 Ln 0 In O Ln 0\ 0‘ oo 00 [x '1; ‘uog'eAeIe ”e "-11: ZL‘6I'6 \ fl \:'::' \I-L'E H a; a; .3 a '2 "g '2 g 2 0 CU v—1 (6 r—1 «3 Q v-4 m co co m m Figure 5.l7.--Lateral movement. (e) Slope indicator casings A and D. 103 €L'E‘? EL‘OI‘Z ZL'6Z‘ZI ZL'ZI‘ZI IZ'II PU? fI'II ZL'S'II ZL'E'II 2L'8Z'OI ZL'9Z‘0I ZL'SZ'OI slope indicator casing F ZL'EZ'OI ZL’fI‘OI movement north , inches 2L'6I'6 95 90 85 80 75 EL‘L‘f SL'OI'Z ZL‘6Z‘ZI ZL'ZI'ZI ZL‘IZ'II ZL'BZ'OI ZL‘9Z'OI ZL'SZ'OI ZL'SZ'OI ZL‘VI'OI slope indicator casing E3 movement north, inches ZL-6I-6 ‘ ' o o o o w w '3} ‘uotquQIa iEJ-iéi.\\\\\\\\‘\\\\\\\\‘féiarfl\\\\\\\\;\\\\\\ ZL‘6I'6 1. 9o T/m‘2 Date sand slud sand slud sand Figure 5.l7.--Lateral movement. (f) Slope indicator casings E and F. 104 sl-L-v , EL'OI'Z (J O ZL‘6Z‘ZI 0 go ZL-ZI-zt o '3 0 U 0 H ZL-Iz-II 0 ° % ZL-vI-II -3 ZL'8'II 8 o 3 E ZL-S-II ° '” Q) Q: .2 ZL'SZ'OI w ZL-Ez-OI ZL-vI-OI 0 O o O 0 o . 8\ o 3 2L-6I-6 ‘ °\\\3 0 w '4; ‘uon'eAeIe ZL-6I-6 g - \iozi: \ E4 3) 33 C) O 'U 'U "U 'U 1: °: :3, .2 r: E a D H u: m m m m Figure 5.l7.--Lateral movement. (9) Slope indicator casing G. l. l. 0. 6 movement north, inches 0.4 105 convenient reference the elevations for each sludge layer and sand drainage blanket have been included in Figure 5.17. Vertical Movement Downward movement of the sludge near the exposed slope and any settlement due to consolidation are summarized by elevation readings for the settlement plates given in Tables C-l through C—4, Appendix C. Location and identification of the settlement plates have been given in Figures 4.l and 4.3. In Figure 5.18 the movement in the upper and lower sludge layers is shown by curves labeled (:) - (:) and (:) - (:), respectively. The quantity (:) - (:) equals the elevation of plate 5 minus the elevation of plate 3. The numbers (:), (:), and (:) refer to settlement plates located in the bottom, middle, and top sand drainage blankets, respectively. The largest movement occurred in the softer top sludge layer near the slope as shown by data for instrument group 5. Part of the settlement appears to have been initiated when the middle sand blanket became fully drained due to slope excavation about September 29, l972. Pore Water Pressures Piezometers, identified as to location and number in Figures 4.l and 4.3, gave the data summarized in Figure 5.l9. Field data are given in Tables D-l through D-4, Appendix D. Instrument group 4, closest to the slope, and instrument group 5, about 29 ft. (8.84 m) back from the slope, gave pore water pressures which appear to be . directly related to the reduction of load at the excavated slope. The 3:4 slope was completed on October 13, l972. This unloading of the 106 s ettlement, inches N instrument group 4 o I l l l h I l l 1 N N N N N N S l\ (x N xx N N [x (x Date I I t\ I [\ I I I ' m H m I VT‘ I Vi“ N O\ O [c H N [\ N —-I r—I H N H I I I I I I I I I ' [\ 0‘ O\ O 0 F4 H N N N ' "4 "-4 v—i v—i —I H v (D 0) .2 U C: 0H ...? C‘. E 0.) H ...) 4..) Q) U) (0 0) .-C‘. U C} -H 4.? CI 39’ G) H 4.) ~I-I . o instrument group 8 (D 4 I l I 1 I O 40 80 120 160 200 time, days Figure 5.18.--Settlement in the top,®-@. and bottom,®-®, sludge layers. (a) Instrument groups 4, 6, and 8. s ettlement, inche 5 Date settlement, inches 5 ettlement, inches Figure 5.l8.--Settlement in the tOP.(:) <:> 107 instrument group 3 4 1 I l L 4 I I l _L N N N N N N m [\ l\ N N N Ix (\ [N I\ M I I h l (\ I I I I N -* Ln I V I V!" N O\ o l -—I N I~ N -4 .—I ... N -« I» I I I I I I I I I l °‘ 0‘ 9. 2 :1 : 2 2 N '5‘ 4- l m 4 1 l l 1 1 1 l 0 4O 80 120 160 200 time, days 0( O o - . . ro o 1 \o z . r®‘© 3 ~ . Instrument group 7 4 J I 1 I I I I L I I 0 4O 80 120 160 200 time, days and bottom,(:)- (:),sludge layers. (b) Instrument groups 3, 5, and7 108 instrument group 4 I .... 2 a A 2 top sludge layer 3 In C U) o H l 04 o I-I o D-l 0 I A l l l l l N N N N N N N m Ix Ix Ix Ix N Ix Ix Ix Ix m Date I I I I l\ I I I I Ix v-l Ln 0 VI‘ I VI‘ N Ch 0 I v—I N -—I N I—I H —I N .—I N I I I l l I I l I I 0‘ 0‘ O O H H N N N VI" PI F! l—( —I l—( r—l ‘ I Initial 6 ft 3‘ slope failure I‘ 'I slope .5; 3'4 fl +§ H 9* 1 8 -———-— + B c a). V +6 E3 ‘4 . . d—I :1 2 4 ° 8 In I +3 2 H 3 1 +2 9* Q‘ .. .. q..." ... “.1 ..."... ..I,_,'_.-..mfi. 2 bottom sludge layer 0 O4 1 . __| Excavation for l:8 slope I I Excavation for 3:4 slope O h I l I L I l I I 1 I 0 40 80 12.0 160 200 time, days Figure 5.l9.--Pore pressure versus time curves. (a) Instrument group 4. 109 29 ft : 0 3m 0 3 u 3 mg 0 N own m +.+.+ w +.*i.m m.“ 8 7 6 .H... 4. 32 ..... n... ....... ...U .9 m... a.“ a m r a I H...“ N... 7 I l... p .... 0 A. 0.0 //n.. r 1 3 1 A. e 8 fi.. y .... a ...9 1 e g d u 1 S p 5 o p t u o r g t n m u r t S n .1 b 2 “mm .ondmmoym ouom mwuxuv MNIOH ..N NnIoNINH NNINH INH Nun“; I: NNIH IHH NhnvNIoH Nbuofi IOH NnImNuo Nun: Io Date bottom sludge layer mum .oMSmmoHQ whom 200 160 120 80 40 time, days (b) Instrument group 5. Figure 5.l9.-~Pore pressure versus time curves. 110 slope is reflected by the decrease in pore pressures in both sludge layers at instrument group 4 and in the bottom sludge layer at instru- ment group 5. The reduction in pore pressure prior to this date was gradual as the excavation progressed. After October 13, 1972, lateral movements toward the slope (Figure 5.17) appear to be the cause of the decrease in observed pore water pressure. The rate of pore water pressure decrease accelerated with excavation for the l:8 slope. The initial decrease in pore water pressure sharply reversed itself after the initial slope failure. Temperature The field data from the thermistors used for temperature measure- ment are tabulated in Table E-l, Appendix E, and are plotted against time in Figure 5.20. The observed temperatures show a pattern indicating that the sludge is responding to air and ground temperatures. Average daily air temperatures and precipitation during the entire project are given in Appendix H. Total Pressure Cells Total sludge pressures measured in the vertical and horizontal directions are tabulated in Table G-l, Appendix G, and plotted against time in Figure 5.2l. The two working cells and adjacent piezometer G7-3 were located in the middle of the lower sludge layer as part of instrument group 7. Original plans had intended that the cell be parallel to the excavated slope, however, the vertical cell was oriented normal to the excavated slope due to the contractor's change in plans. The data in Figure 5.2l show a decrease in total horizontal 111 thermistor ref. elev. o 1 95. 43 ft I 3 91. 43 24" 9 thermistor 5 87° 43 k‘ 7 83' 43 9 79. 43 . A U 16 V “I: A-—— O ' v \ u ' ‘v 9 A Q. I- o \ I4 3 12 - u 3 2 o L' n 2" 8 _ o a o o +3 I— l 4 .. (a) 0 L ! I I I I 9 N N N N Ix N Ix N Ix Ix m I [x I Ix I I [x M Date so I c» I -I N . [\ I [x H M N H O I O\ I I I I I H N o o -4 ._I N I I ,_I ...I .—4 H H N V U o a; 12 h *5 - thermistor ref. elev. 4,; 4 89. 43 ft 8 I— S 6 85. 43 m 8 81.43 g 4 o 77. 43 ... (b) O L 94 I l l 1 1 l l l 0 4O 80 120 160 200 time, days Figure 5.20.--Temperature versus time. (a) Thermistors 1.3.5.7 and 9- (b) Thermistors 4,6,8, and 0. 112 N N N N N [\ N [x [x (I) IN Ix I Ix I I I‘ M I I O\ I H N I [\ \o Ix .... m N —-c o I I I I I I I F‘ I\ C‘ O O "I "" N I I H r—I r—I r-I I—I N <3" Date I I I I I l I I 18 t 16 - _ vertical total pressure1 A !-(-} 4) “ l sand calibration-S 4}__, ‘7 - _§_ 3 water calibration lOb psi horizontal total pressure—\ sand calibrationl - :3 pressure, o~ . 3 a 4 a 9 water calibration pore pressure “HA-AA .. A . w 0 _ I L I I I 4 I l 0 4O 80 120 160 time, days I 200 Figure 5.21.--Horizontal and Vertical total stresses, bottom sludge layer. 113 stress of about 1.4 psi (0.0984 kg/sq cm) during the period that the slope was being excavated. Over a period of time the stress again increased, perhaps due to internal stress adjustments related to creep. Pore pressures in the vicinity of the total pressure cells remained relatively constant during the period of slope excavation. CHAPTER VI ANALYSIS AND DISCUSSION OF PROJECT RESULTS This discussion and interpretation of project data covers laboratory and field results for the stability study on consolidated papermill sludge. The material is presented in three sections: physical pr0perties, strength characteristics, and slope movements and stability of the fibrous organic soil. A. Physical Properties of the Fibrous Organic Soil Physical properties of organic soils and papermill sludges characterize, to some extent, the quality of the material relative to engineering purposes. The properties discussed below include ash content, consistency limits, water content, and unit weights. Ash (or Organic) Content Representative ash contents for undisturbed block samples, given in Table 5.2, are very close to the average reported by Andersland, et_al. (1972), for fresh sludge samples taken during construction of the papermill sludge landfill, approximately one year earlier. These data show that ash contents for the sludge in the landfill range from about 32 percent to about 60 percent. Earlier work (Andersland and Laza, 197l) has shown that organic contents for papermill sludges, 114 115 based on ash contents determined by ASTM test method 0586-63, agree reasonably well with organic contents determined on the basis of the test method given in Agronomy No. 9, section 92-3.3 (Black, 1965). For information, weight loss for papermill sludge samples from blocks C and G, which were first dried to 105°C, have been plotted against temperature in Figure 6.1. The small samples, 6.786l grams for block C and 5.0706 grams for block G, reached essentially a constant weight after one hour at each temperature. These data show no drastic weight loss for temperatures above 300°C. The small weight loss above 400°C may be partly caused by dehydration. Dehydration involves the loss of any water held by the clay mineral. Dehydration curves, given by Grim (l968) for kaolinite clay, show little or no dehydration up to about 400°C. Most of the dehydration takes place between approxi- mately 400 and 525°C with the rest taking place up to approximately 750°C where dehydration is complete. However, part of the weight loss for temperatures above 300°C may also be caused by incomplete burning of the organic material at lower temperatures. The ash (or organic) content of the sludge is shown in the following sections to have some relationship to the consistency limits, water contents, unit weights, and to the shear strength parameter, o. Consistency Limits Organic content of the sludge also influences the consistency limits. Ash content has been plotted against the liquid and plastic limits giving the relationships shown in Figure 6.2. Specifically, as the ash content increased, both the liquid limit and plastic 116 .w new 0 mxuo_n Eocc mw_a5mm mmusz FFPEcmama co» mczuecmqemp msmcm> mmop ugmwszI._.o mcamwa U .oHSHMHomEou o coo cow con 000 com 03» com CON on: o J . q a _ . q _ 4 a . 4 _ . a o _ o O l S D xooflor 80.3 onEmm AN U #003 80.3 03886 O m U moH 953m dams, Aomo um .35: ocO m. o 1 ON 8 ome owpgm Subpommm u; 4 m. S S mmoH paws»? .oIo. I om % H30» mo «coopoml. 0 IO 1.. P 1 IA mm AV 0 I ow m m % mm .2. 0 am. 8 .mmo Hos? . \I s 3: . II c. o w. . m . e E .3. mo 2,0 m we 4 I 0‘ llK/Vl o I. cm I we .mm 000 m m cm. .mmoH mimic? 4 . All mmoH ”E «o? o \ IVA; .hm d 9 130» Mo “coouom 3 mo .3 a 4 4 4. Nw 4 08 I 400 360 320 280 240 200 160 water content, % by wt. 12.0 80 40 117 Fresh pulp and papermill sludge 0 West Carrollton 00 Hamilton (after Andersland and Laza, 1971) AV Chillicothe (after Andersland and Laza, 1971) . 9x" plastic limit 1 l l l l I I 30 4O 50 60 70 8O ash content, % Figure 6.2.-~Relationships between ash content and consistency limits. 118 limits decreased. The greater water retention of the organic material appears to be responsible for the higher liquid and plastic limits at high organic contents (low ash content). The liquid limit data for the three sludges appear to give a consistent relationship with a continuous curve. Plastic limits are more difficult to measure at high organic contents since fibers interfere with crumbling of the thread at the appr0priate water contents. It appears that the dashed curve shown in Figure 6.2 approximates the plastic limit data. The liquid limit and plasticity index have been plotted on the plasticity chart in Figure 6.3. All data points fall in the region designated organic clay with some of the sludge perhaps more closely related to peat (Casagrande, l948, 1966). Water Contents The water content of organic soils and dewatered sludges is unusually high in comparison with inorganic soils. Water contents of the sludge in the landfill after consolidation are summarized in Figure 5.l. The scatter in values appears to be related to variations in organic content of the sludge. Water retention of the sludge is greater for higher organic contents. Also, a small change in organic content will alter the dry weight because of large differences in specific gravity of the ash (clay) as compared to the organic material. Hence, two samples with the same volume of water may show significant differ- ences in percent water content on an oven dry weight basis. Despite the scatter in observed water contents the value for the upper sludge layer dropped from an average of 257 percent for the fresh sludge to a value close to l86 percent for the consolidated sludge. For the lower 119 .mmmcapm Ppwsgmama new a—aa gmmcw Pocm>mm cow mpc_oa moon gum: Aempmxm cowumowwwmmm_u Pwom umwcwczv ucmgu xuw6wumm—QII.m.o mczmwa 3 4 £8: 33: oov - com omm owN ovN CON 00H ON~ ow ov o 7 _ A _ _ _ _ u a _ _ . _ _ _ u _ . . _ o I ow no .m a Ami: .opcmHNMmmU .833 4 I d umom mo won?» mDoTHmcy ow m... m... \\II.I/ I m \ / I 02 x \. a m. \. “P \ \ m \ \ I . \ d1 _ \ I 02 , o \ \ //!II\\ 0 J I OON AN 2 KL .mnwd pom pcmamnopcxx .8“me ofiooflflgu 4 : R; .33 ES ecflmameg. $33 Salaam n. I cofiaounmu «we? 0 IeovN owpgm HZEyommm paw 3.9m gmoyh 120 sludge layer the average water content dropped from an average of 265 percent for the fresh sludge to a value close to 167 percent. These overall changes in water contents agree with settlements reported by Vallee and Andersland (1974). As shown in Figure 6.4, the undrained shear strength increases as the water content is decreased. This relationship is similar to that for inorganic soils (Lambe and Whitman, 1969) where failure water content varies linearly with the logarithm of undrained shear strength. Vertical displacement of the straight lines in Figure 6.4 is dependent on organic content as it relates to equilibrium water contents. Unit Weights During consolidation, the sludge unit weights increased as water drained from the material. Compared to the initial fresh sludge unit weight of 69.7 lb/cu ft. (1116 kg/cu m), the unit weight at elevation 88.8 ft. (27.07 m) increased to 72.6 lb/cu ft. (1162 kg/cu m) for Block B and at elevation 80.9 ft. (24.66 m) increased to 76.5 lb/cu ft. (1225 kg/cu m) for Block F. Block C, taken only 1.3 ft. (0.40m) below Block B, shows a higher unit weight of 74.6 lb/cu ft (1195 kg/cu m) partly because of its greater depth and partly because of more clay (higher ash content) which has a higher specific gravity. For the West Carrollton sludge, the specific gravity can be approxi- mated with a straight line as shown in Figure 6.5. Assuming that the ash is composed of clay minerals having a specific gravity of 2.7 and that the organic material has a specific gravity of 1.54, the average specific gravity of the sludge solids (G) is approximated by the equation 121 .gpmcmcum cmmcm umcwmcuca ecu pcmpcoo capo: :mmzumn mamnmcowHMmeII.¢.m mcsmwa Aao vm\wxv camcouum amonm vmswmuvss c n q m N H m.o v.0 m.o . II I a - - d 1 d I I 11) om I oe I on I ow w 14 a I I om m u 14 a u I OOH 3 mu 9 1 I OHH m u 11 32.: ( .mnma can 0.0m I ONH vamflmuwvafiw 0 .mm Hmuwmv O.wN awesam o.mq I oma acuawsmm n.5N omesam o.Ho :ouaaouumo m.mo I oea umoz o.oq ofiamwuo N 122 .mmuzfim couppoccmu pmmz mg“ cow amsmcowpmpmc pcmucou 5mm I xuw>mcm owmwomamII.m.o mczmma E888 E o< .2388 :8 E 8 om ow cm I M: 3.0me 852: :3 5:2 I o; 3 E388 :2 $-38 8; we :2 5:2 5 its; 658QO I . m 882m c2285 535 o N m o . . u I I I _.~ mu. (cm_mw.T.vm _ A mcmn camcumImmmcum cwcwmcucaII.m.o mc:m_a out .Emuum Hmwxm on. .ammhm Hmmxm m w m N H o OH w 0 V N 0 N A) _ a . ,O _ _ d _ _ _ _ _ , — - 2-0 8383 0 2-0 vacuum 4 VIC onEmm O m; o I“ .a _ cw n. (I a 3.0 I mm s I I I II x. 0.0 // 3 w 0 Z 0 no no L N.H 126 For the two levels of consolidation pressure which are representative of the upper sludge layer (samples C-10 and C-11) normalization gives essentially one curve. Here the ordinate is the stress difference, (0] - 03), divided by the consolidation pressure, p. For comparison, data from sample G-4 has been included to show the different behavior for failure with 01 increasing. The nonlinear behavior shown for samples C-10 and C-11 has been approximated with a bilinear relationship with elastic modulus values of 48.00p and 0.01p. Elastic modulus values take on the same units as the consolidation pressure p. Strength Parameters Shear strength parameters are discussed on both the total and effective stress basis. Total Stress Basis.--For saturated samples the diameter of the failure stress circle for a given test is the same whether it is plotted in terms of total or effective stresses. This leads to a useful con- cept, called the 5 = 0 condition, which is valid for conditions associ— ated with complete lack of drainage (Terzaghi and Peck, 1968). This condition was approximated in the sludge landfill immediately after excavation since the low permeability of the sludge retarded drainage; as a consequence the decrease in pore pressures due to unloading required several days to dissipate. Samples C-10, 11, and 14 in Figure 6.8 and C-11 in Figure 5.9 showed little deformation until the negative pore pressure change was permitted to dissipate. The undrained shear strength may be evaluated on the basis of triaxial tests (effective or total stress basis), unconfined compression 127 tests, and vane shear tests. The results of triaxial tests on isotropically consolidated fresh sludge samples U-3 and U-l, in terms of total stresses, are expressed as the value of undrained strength cu plotted against consolidation pressure p in Figures 5.3c and 5.4c. For the normally consolidated samples the ratio cu/p appears to be constant, its value dependent to some extent on the sludge organic content. The results of triaxial tests on anisotropically consoli- dated (Ko = 0.3) undisturbed sludge samples G and E, in terms of total stresses, are expressed as the value of undrained strength cu plotted against consolidation pressure p in Figures 5.6c and 5.llc. For the same vertical consolidation pressure, larger undrained strengths were obtained for the anisotropically consolidated sludge in comparison to samples consolidated with isotropic consolidation. The ratio cu/p has increased over the values obtained for the fresh sludge with isotropic consolidation. These differences appear to be related to structural anisotropy of the sludge. Unconfined compression tests on undisturbed samples generally provide shear strengths for use in the total stress analysis for slope stability and provide information on the anisotropy of the consolidated sludge. Data summarized in Table 5.4 and plotted in Figure 5.12 show that the sludge was significantly weaker when failed in the horizontal direction as compared to the vertical. The natural alignment of fibers in the horizontal direction form a plane of weakness which may be the reason for the lower strength. The two curves in Figure 5.12 can be normalized when the respective unconfined compression strengths are 128 divided by the effective overburden pressure p0. For example, taking the vertical unconfined compression strengths, cu/p equals 0.49 for sample Blocks G and C. The unconfined compressive strengths are significantly lower than the undrained vane shear strengths shown by data plotted in Figure 5.l3a. This lower strength is due partly to physical disturbance in sampling and sample preparation for laboratory testing. For soft clays with low to medium sensitivity Parry (1971) states that the physical disturbance and stress change are sufficient to reduce the laboratory shear strength below field values. Sensitivity of the sludge, equal to the undisturbed vane strength divided by the remolded vane strength, was very low (about 1.40) as shown by the data in Figure 5.l3a. The vane shear strength to overburden pressure is reasonably constant. Some variation would be expected since ash contents, given in Table 5.2 for Blocks B, C, F, and G were not com- pletely uniform. Blocks B and C at close to the same elevation and different ash contents contain significantly different water contents due primarily to different organic contents. The Dutch cone penetration test was less sensitive to increase in shear strength with depth than the vane shear test (Figure 5.13b). Effective Stress Basis.--Since pore pressures were measured during triaxial and plane strain testing, the effective strength parameters can be determined using the Mohr-Coulomb failure theory. The maximum stress circles will be tangent to the rupture line defined by Coulomb's equation (Equation 2.7). Consider first the triaxial test results on fresh sludge samples U-l, U-Z, and &-3, summarized in Table 5.4. These samples 129 were consolidated with an all-around pressure and failed by increasing the deviator stress for conditions of no drainage. The data plotted in Figures 5.3a and 5.4a give the Kf lines from which the angle of internal friction and the cohesion were obtained on an effective stress basis. These 5 values along with sample organic contents are summarized in Table 5.3. Additional data from Andersland and Laza (1971) for fresh sludge sample H-2 has been included. A plot of 5 versus organic content, Figure 6.7, suggests a linear relationship when comparisons are made using data obtained by a given test procedure. This agreement is quite good considering the accuracy of the organic content determinations. At lower organic contents the angle of internal friction appears to approach a value representative of the non-organic constuents in the papermill sludge. Extrapolation to zero organic content for the Hamilton sludge gives an angle of internal friction equal to about 24 degrees, close to a value of 25 degrees reported for kaolin clay by Gibbs, gt_al; (1960) and Olson (1974). Differences in fiber size and fiber orientation between the two sludges, represented in Figure 6.7, appear to be responsible for the different slopes and intercepts. If sludge decomposition is represented by a decrease in organic content, then for the same effective normal stress there will be a reduction in shear strength in a sludge landfill. Water content has been plotted against all-around consolidation pressure in Figures 5.3b and 5.4b. With the higher organic content, sample U-3, a greater reduction in water content is observed for the same consolidation pressure. At the same time the higher organic 130 .mwmmn mmmcum m>_uomcwm .cowpowcw Pmccmpcw we mpmcm mcu co ucmucoo uwcmmco mo mocmzpocHII.n.m mczmwa $3 capo Kc .«coucoo omcmwpo ox 3 cm 3 om ON 2 o I. _ _ _ _ _ _ o e I 2 Q"... m. :2: .83 2; 3328.2. .853 I cm 0 NIE oHQEom .OMJO £038.03 0 H U 030 £82830 ~83 o \\ I om m. \ I 50.3 ompgm Amouh \\ w I 3. H u. I om w m. U L 00 I %w_ I ox w. on I mow % S 131 content is responsible for a greater water retention at a given con- solidation pressure. For the undisturbed sludge samples, anisotropic consolidation was used to approximate the field stress condition of no lateral yield. Data from the total pressure cells, buried in the landfill (Figure 5.21), gave a ratio of horizontal to vertical effective stress (Eh/5v = K0) close to 0.3. Consolidation under this stress ratio followed by increasing the deviator stress to failure gave the data summarized in Figure 5.8. For the same organic content, an apparent increase in the angle of internal friction is noted for the anisotropi- cally consolidated sludge. A reduced angle of internal friction (Figure 5.8) was obtained when the sample axis was changed to the horizontal. These differences appear to be related to structural anisotropy of the sludge. A form of structural anisotropy tends to develop in sludge when fibers align themselves at right angles to the direction of the major principal stress during field consolidation. To more closely approximate the field strain condition during excavation, anisotropically consolidated plane strain shear tests were also run on the undisturbed sludge samples. Triaxial results are correlated with plane—strain results for Block E in Table 5.5 and in Figure 5.11. The angle of internal friction, 5, was found to be 74.9 degrees for both types of tests on Block E. However, the plane strain tests indicated undrained strengths approximately 25 percent greater than those shown by triaxial tests consolidated under similar conditions. 132 organic fiber + —————————————— -- - -- - - - - - - -_2_=_=_‘-——— (a) m o a 8 m fibrous organic soil 1.: --- ———————————————————— __—_-_—..—— — — H ’ u—I' ‘— 'U ’ m / ’ m / / 0 II, // clay-water matrix ’- axial strain A (b) A,/’///1(ir (b7 so};X 0 3 1%P§& 9 e O sitifi ¢ 0) ‘- (fl-3‘] H m m .c U) , 4A.- effective normal stress Figure 6.8.--Composite action of a clay-water matrix with organic fibers. (a) stress-strain curves. (b) failure envelope. 133 Figure 6.8 shows the concept behind a fiber reinforced material composed of a clay-water matrix interwoven with organic fibers. Figure 6.8a shows the probable stress strain behavior of the clay-water matrix, the organic fiber, and the composite action of the clay-water matrix reinforced with organic fibers. The higher modulus of elasticity of the fibers provides the primary stiffening action to the matrix as the composite deforms. Figure 6.8a also shows the effect on the failure envelope (or strength) by adding organic fibers to the clay-water matrix and Figure 6.8b helps explain the large 6 values of the paper- mill sludge. More research is needed to define the influence of fiber size and fiber orientation on the shear strength parameters and whether these parameters (effective stress basis) correctly model field shear strengths of a fibrous organic soil (sludge). C. Movement and Stability of the Experimental Cut Slopes Movement and stability of the experimental cut slopes in the papermill sludge are discussed under four headings: slope movements, development of failure zones, slope failure, and stability analysis for the failure surface. Slope Movements Field monitoring provided data on both lateral and vertical movements at a number of locations adjacent to the excavated slope. The lateral movements were measured by using surface stakes (Table A-1) and slope indicator casings (Figure 5.17). The surface measurements 134 provided data which were in agreement with the upper level of the slope indicator casings. In addition to movement towards the slope all casings showed some movement away from the east or west dikes (Figure 5.l7e). The resultant movements close to the landfill surface (elevation 94.6 ft. = 28.83m) for casings A through D are shown in Figure 6.9. The rate of movement was very much dependent on the stress release or excavation for the slope. The rate of movement for each casing is shown in Figure 6.10 by plotting lateral movement versus time. The low movement rate after completion of the 3:4 slope sug- gests that the sludge was relatively stable for this slope configuration. The highest movement rate occurred immediately after excavating the 1:8 slope. Rates decreased when partial slope failures occurred and reversed direction when fresh sludge was placed adjacent to the slope at the end of the field portion of the study. Vertical movement (Figure 5.18) monitored by settlement plates was largest in the upper sludge layer adjacent to the excavated slope. A large part of this settlement appears to have been caused by consoli- dation related to complete drainage of the middle sand blanket when the slope was excavated on September 29, 1972. Increased settlement rates are observed for the top sludge layer at all instrument groups after this date. Development of Failure Zones Sludge movement occurred as the excavation progressed and as stresses were reduced to zero on this slope. Stress conditions within the slope change during excavation. Failure zones develop in those .maopm paucmewcmaxm meg com cow9m>moxm cmucm new newczv .um m.¢m cowpm>mxm um mucmEm>oE mcwmmOII.m.m mcamwa O O wfimmo MPINIV \ IIIIIIIIIII NwImI: ‘|I‘ IIIIIIIIIl-IIIIIIII NNIONIOH Np Iva IOH Nu IOH Io ~0qu mcwmmu wnwmmu um ON .CH m .I. .5 H "mucoEocon you ofimom 3 ON a ON fiaoz 136 .< copmowucw maopm Amy .ocmsm>oe Pmcmpmp mo mumcImswaI.O~.o mcamwm m>m~c .053 mm. MN: m? oase.aa<..nmm ~xo~.omo. Nxoa.>oz. Npoa.oon. Nno_.aaam «Q N. .O~ PONL 0 ON «2 o Om ON I O~ Om ON 1 q 1. da q q q d — — _ q q q . oIO IIIIOIII . d‘IIIIIIIQ. 00mm 0 a, a w ... / I I_ m / \IQII # d .....A 6‘“ B u .9 w I I. w 0 o ..H No / w w m S / .|\ o ..OI. (l p 1N w / \I0\ 70 .V W... J \\ 1. «x m m I. .. 9 mm. 8 w 0/ w.n m Im / \ ”Comm .../20 u m 1 dll‘I‘I‘b‘ an S 8 m. wSmMo .Ho mod 5 omo m D D S PM 4 . u .U . H Law 2 o I u : m.w.m DIW sd 1. ammo 3U 1.1.... 9 11 n O 9. a S 112 I d D 8 JG "H O a a u. c on ps 9 a l q [...—I 0 T. U 1.8 m. U w. Jim m a 8 Us a I a u w m I O mm IIQIIIQ . GI) 41 l?) uInI all e vw mm II?) )011 m QIIII oI 38.3. 5 w. é) 137 adots no 19 paa'etd )0 /@ ’9 qv / 0—1 / efipnls / // / .. lJ 5{ qsax; ——u-/ f ‘ \ i g H‘I adots {73 g ado] 5: —--° [BAOLUOJ amp [2111.1 12d —->-o slupe indicator casing B 11' 0 snupu; ‘ qn nu iumu O.'\OlU 10 30 Feb. Apr. June '73 Dec. 1972 1972 Nov. 1972 Oct. Sept. 1972 '73 '73 time, days (b) Slope indicator 3. Figure 6.10.-Time-rate of laterai movement. 138 E: -< v _ //€d0[s uo paseId /fi /fi I? -‘ H aSpnIs qsaI;——>/ / ‘F’ g f Q/ Q/ d " l\ 2.; \\ \ ‘ ‘ .. (K Q A § : g f) 2 \ \ L“ i i I N F ox l—‘ 8 3 Q o <1: 0‘ >' 3 '0 (1 pure 3 sfiugsea . uaamqaq azoldwoo E "1’ I: o >' 3 pue g sBugsea uaa/maq 2 axnue} ado1s {'egqgu; —-> 8“ adoIS U _ o no N .5 :3 "3 c» 8 17:; BdOIS —-> ° F: {J :9: [EAOUUQJ amp [epxed —-—o 2 8 '0 E o O 8‘ m N .—. xx "1 O J % O U) I 1 1 l l 1 ’N saqou; 'quou auauxaAow Figure 6.10.--Time-rate of laterai movement. (c) Siope indicator C. 139 .o .oomuwuc. mao_m Rev «gov .053 mp. mu. mu. .ucwsm>os ngmump we mpmgumewhu-.o_.o mgzawu 2.3 .3... jun NR: .80 NR: .82 ES .30 NE doom v“ ..n h owipmwlh 0 ON O~ o Om ON O~ Om ON . .. <-. «A < a q O.On.a q a _ q q . o o . o o O .m5 0 o o oo o 0 GI 0 G o o o \‘lQ-IIIIII . o m 0 O I \I n o cm H o.~mo \ 1 O O 0/ . w o S // \\\\Q‘ll Aw vm O 0 S m. a...“ ”1‘ m .d m. 1 N n O mm o o .m ”.0. w H “w m m o/ . . a 9 a .... / o J m 0d 8 Mv\“ s U . 0 U u flmw m.n m,m A o s o P o .80 8 u m. H ...... e u. .198 s o n 1. I u. 0 p3 qd I P. t v“ "..‘: g 9 9 3 Val”. I. T m. . o [ 9, n O NO w m o w.o m. / u. P . mm a / i a . s d‘llllll'bl'll C. O a my} 0 .wo c u U Q @223 heumua 5 0&0 m a n . .w . H n.m e 1 m.a . u an QIIIIOIIII-éI‘ . S o.vo g L.. by u oulll.@.llLf 3 < O.vw O sanUI 113139 quauznAn-v- 140 June '73 pure {1 sSu1s23 ueamaq enaIduxoa 9.1mm; BdOIS 3 pue q sfiugsea use/m 3.1131112; adols 12111u1 3dO[S //%0 pa and //O /P '59 i/P afipnts / M“ r 1 a 1i 1. m \ \ 4 o -...e’ ....o’ —-—O’ l A 1 fl/ (I o q 9 8:1 adots» we adots ._..° 1211011191 amp 0 {cured ' slope indicato'g casing F D P“? H ° sSugseo o uaamaq axnne; ad0[s 19111“! SIOpe indicator casing E Vi adots —.° I'ezxowax - 0 9x19 191112d 1‘ ‘5’» \ 1 \ \ \ 1 J 8 L 1 1 1 1 1 ’ 1 1 1 1 " NOWQV‘NCNOCDOVNO '-:O'O'O'o 44555:; saqaug 'prou menus/10m Feb.Apr. ‘73 NOV. 1972 Dec. 1972 Oct. 1972 Sept.1972 time, days (e) S1ope indicator casings E and F. Figure 6.10.-Time rate of 1atera1 movement. 141 BdOIS f) ur) [JBDEId 9 I afianS qsaJ; / ————-» a put: {1 s‘dugsna unomaq 0101111110.) Jump} OdOIS 3 pull ‘d 551.1152.) uaamioq axnue} adop; [121211111 slope indicator casing G 14 30 20 O m O N 1 1 1 1 1 1 1 1 1 ’ NHOOWI‘Om 44.455555 auout ‘ quou ‘1uauzaAoux f‘J . I Oct. 1972 Nov. 1072 Dcc.1‘ Sept. 197 2 time, days (f) S1ope indicator G. Figure 6.10.-Time-rate of 1atera1 movement. 142 regions where the maximum shear stress values exceed the undrained shear strength of the sludge. It is helpful to show these zones in a graphic manner. These zones can be determined by use of the finite element method of analysis (Dunlop, Duncan, and Seed, 1968). For a slope excavated in the dry, both the earth and water pressures would be reduced to zero on the excavated slope. For analysis of these slopes, it was necessary to consider both the changes in earth and water pressures during excavation. This may be done by working with total stresses. At a depth y below the surface of a horizontal deposit with unit weight v, the initial total stresses may be expressed as 0 =Y'.Y (6-2) (6.3) Q 11 7Q Q where 0y and ox are the total vertical and horizontal stresses and K is a total stress earth pressure coefficient. Field data (Figure 5.18) has shown that K was close to 0.4 just prior to excavation. It was convenient to consider the initial strains and displacements, before excavation, as being zero but with non-zero stresses. The stress- strain relationships for the sludge (Figures 5.9 and 6.6) were obtained from consolidated-undrained triaxial tests using test procedures which simulated field stress conditions existing before and during excavation of the slope. Plane strain deformation has been assumed for the excavated slope since the distance normal to the section analyzed (Figure 6.lla) 143 (a) xunit width 4.— .— all. ‘ fl ‘ ’ ‘ ’ fl ‘- fl ‘ fl ’ ’ fl '- ’ ’ fi ‘0 ‘ fl ‘- d ’- ‘- I I I I I I I L. ..--+—-1——1-— 1 I to be I I 1,1 ex avate l sludge I.‘l"‘—I"‘"|""r" . earth %L__L__L__"\ ' 7 1 Ir 11 l?— '1 1* natural soil + lower sand blanket (C) excavation lifts elev. _[} 9$lft 78. 1 ft Figure 6.ll.--(a) Excavated slope showing the section to be analyzed. (6) Finite element idealization of slope cross-section. (c) Typical finite element configuration of the slope showing the excavation sequence. 144 was about five times the thickness of the sludge plus sand blankets (Dunlop, gt_al;, 1968). Field measurements of slope movement, given in Appendix B and summarized in Figure 6.9 for elevation 94.6 ft. (28.83m), close to the excavation indicated that the assumption of plane strain deformation was reasonable near the center line of the slope. Along this line the movements were perpendicular to the slope. A finite element idealization of the slope cross-section in Figure 6.llb includes boundaries representative of field conditions. The top and slope surfaces are free surfaces. Loads applied to the top surface nodes simulate the earth surcharge. Points along these boundaries are free to move in the vertical and horizontal directions. Since the sludge was very soft in comparison with the dike material and the natural soil below the landfill, it was assumed that these boundaries were fixed as shown in Figure 6.llb. The dike was far enough from the slope so that shear stresses could be assumed equal to zero. Field data showed that there was no vertical movement of the bottom surface and that there was no reason to suspect any hori- zontal movement of the firm base of the landfill. The finite element configuration of the slope with simulation of the excavation by removal of elements has been illustrated in Figure 6.llc. The slope cross-section was represented by 252 rec- tangular elements with a total of 279 nodes. The basic element used was a quadrilateral composed of four constant strain triangles. Rec- tangles were used throughout with the exception of the region immedi- ately adjacent to the sloping face, where triangles and trapezoids (Figure 6.llb) were employed alternately. This scheme of elements 145 was well-suited to simulation of slope excavation by the removal of elements outside the slope and it was convenient for automatic mesh generation within the computer. The analyses were conducted in a series of steps. Eight steps were used to represent slope excavation. The stress-strain curve for any particular element was approximated by a bilinear curve (Figure 6.6), consisting of two straight line portions corresponding to the two values of modulus. Material numbers and properties for each row of elements are given in Table 6.l. Material 9 is the number assigned to elements after failure, and material 10 is the number assigned to elements which are being or have been removed. The computer program given by Dunlop, §t_al;_(1968) was used to obtain the results summarized in Figure 6.l2 showing the develop- ment of failure zones in the experimental slope for simulated excaVation depths of 6, 10, and 14 feet. Failure has been defined by the bilinear curve in Figure 6.6, and a total horizontal strain of 10 percent. A simulated excavation depth to 6 ft., Figure 6.12, shows that a small failure zone has developed behind the slope. A small tension zone now exists behind the crest of the slope. Additional excavation to lo ft. alters stress conditions sufficiently so that the failure zone now extends farther behind the slope and to a greater depth. The tension zone has increased in size. At this stage the overall factor of safety against slope failure would be approaching unity. Excavation to 14 ft. shows the failure zone extending to the slope surface and behind the crest. Failure along the unsupported slope could be predicted and did occur. Line A-A in Figure 6.l2 shows the location 146 . on “:5th cm CBOAm uofifimgon camoumnmmopum 9.3 09 coEmEMXOAnEm umoczwm \ul I- u- mnv .O ~O .O O OH 1- ..- mnvd H0.0 21:. 0 v .O m KOO mnv .O .Oomhn mu .3. w v.0 H2. mnvd .OONON. mhdb h v.0 m.mmO mnvO .OOONO mhél. 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Mm 0 O OO 0 SS .32 MR; 029.. m2; .332 A .501 aov was Eov 4 .3 0.0L co0ump0n00u £0800 03G cofimfinfio A080» 000G 00000300000 .0800 000a 30.0% 0wmn0>< 0.0.0 0O000>< nonm 0O000>< Av0sd0unoov ZOHH 0. 0000 0. 0000 1. 4061 0. 0000 3. 5154 3. 5154 15. 1956 0. 0762 1. 9826 0. 0156 4. 9064 2. 9389 19. 0512 0. 1524 2. 6295 0. 0311 4. 7198 2. 2920 21. 3192 0. 2286 3. 1005 0. 0467 4. 4941 1. 8210 23. 5872 0. 3048 3. 4380 0. 0622 4. 3927 1. 4835 25. 4016 0. 3810 3. 6911 0. 0778 4. 3114 1. 2304 26. 9892 0. 4572 3. 8739 0. 0934 4. 2659 1. 0476 28. 4407 0. 5334 4. 0427 0.1089 4. 2121 0. 8789 30. 1644 0. 6096 4. 1833 0.1245 4. 2117 O. 7382 31. 7520 O. 6858 4. 3028 0. 1401 4. 2100 0. 6187 33. 5664 0. 7620 4. 4153 0.1556 4. 2341 0. 5062 35. 2901 0. 8382 4. 4997 0. 1712 4. 2689 0. 4218 37.1952 0. 9144 4. 6051 0.1867 4. 2950 0. 3164 39. 6900 0. 9906 4. 7106 0. 2023 4. 3751 0. 2109 F1 and E3 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 221 TABLE I-6. TRIAXIAL TEST DATA, SAMPLE U-3-1 Axial consolidation pressure = 0. 703 kg/cm2 with Ko = 1 61f = 3. 017 kg/cmZ Initial water content = 310. 0% 83f = 2. 109 kg/cmz Final Water content = 150. 9% uf = 2. 109 kg/cmZ Initial dry density = 18. 94 pcf Af = 0.77 cu = 0.454 kg/cm2 Load Displace- Pore Axial _ _ ment pressuiée strain 0'1 2 0'3 2 (kg) (cm) (kg/cm ) (kg/cm ) 132/cm ) 0. 0000 0. 0000 1. 4061 0. 0000 0. 7031 0. 7031 2. 9484 0. 0483 l. 5678 0. 0106 0. 8242 0. 5414 4.1278 0. 1194 1. 7014 0. 0262 0. 7975 0. 4078 4. 8989 0. 1753 1. 8139 0. 0385 0. 7520 0. 2953 5. 3525 0. 2337 1. 8842 0. 05 14 0. 7173 0. 2250 5. 5339 0. 2921 1. 9053 0. 0642 0. 7060 0. 2039 6. 2143 0. 3505 1. 9545 0. 0770 0. 7108 0. 1547 6. 6679 0. 4089 1. 9721 0. 0899 0. 7256 0. 1371 7. 0308 0. 4674 2. 0037 0. 1027 0. 7172 0. 1055 7.5298 0.5258 2.0389 0. 1156 0. 7161 0.0703 7. 9380 0. 5817 2. 0459 0. 1278 0. 7346 0. 0633 8. 5277 0. 6401 2. 0730 0. 1407 0. 7456 0. 0352 9. 0720 0. 6985 2. 0811 0. 1535 0. 7727 0. 0281 9. 5256 0. 7315 2. 0951 0.1608 0. 7892 0. 0141 10. 3421 0. 8153 2. 0986 0.1792 0. 8337 0. 0105 11. 1132 0. 8738 2.1057 0. 1921 0. 8742 0. 0035 11. 7029 0. 9093 2. 1092 0. 1999 0. 9080 0. 0000 12. 8369 0. 9906 2. 1092 0. 2177 0. 9737 0. 0000 ‘ h 01 and .53 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 222 TABLE 1-7. TRIAXIAL TEST DATA, SAMPLE U-3-2 Axial consolidation pressure = 0. 703 kg/cm2 with Ko = 1 61f = 3. 351 kg/cm‘2 Initial water content = 306. 0% 03f = 2. 109 kg/cm2 Final water content = 147. 4% uf = 2. 151 kg/cmz Initial dry density = 18. 39 pcf Af = 0. 60 cu = 0.621 kg/enn2 Load Displace- Pore Axial _ _ ment pressulée strain 0'1 2 0'3 2 (kg) (cm) (lsggm ) (lsg/cm ) (kg/cm ) 0. 0000 0. 0000 1. 4061 0. 0000 0. 7031 0. 7031 3. 8556 0. 0686 1. 7506 0. 0161 0. 7349 0. 3586 5. 4432 0. 1499 1. 8701 0. 0352 0. 7600 0. 2390 6. 4411 0. 2134 1. 9475 0. 0501 0. 7686 0.1617 7. 2576 0. 2819 2. 0037 0. 0662 0. 7777 0. 1055 8. 1648 0. 3632 2. 0459 0. 0853 0. 8041 0. 0633 9. 0720 0. 4293 2. 0775 0. 1008 0. 8408 0. 0316 9. 7524 0. 4978 2. 1057 0. 1169 0. 8578 0. 0035 10. 8864 0. 5791 2.1232 0.1360 0. 9190 -0. 0141 11. 5668 0. 6375 2. 1373 0. 1497 0. 9475 -0. 0281 12. 7008 0. 7087 2.1443 0. 1664 1. 0150 -0. 0352 14. 2884 0. 7798 2.1479 0.1832 1.1191 -0. 0387 15. 6492 0. 8509 2. 15 14 0. 1999 l. 1999 -0. 0422 F1 and :3 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 223 TABLE I-9. TRIAXIAL TEST DATA, SAMPLE U-3-5 Axial consolidation pressure = 3. 515 kg/cm‘2 with K0 2 1 0'1 = 7. 966 kg/em‘2 Initial water content = 255. 0% f 03 = 4. 921 kg/cmZ Final water content = 97. 5% f uf = 4. 696 kg/cm2 Initial dry density = 20. 32 pcf Af = 1.08 c = 1.522 kg/ennZ 11 Load Displace- Pore Axial _ _ ment pressure strain 0'1 03 2 ' 2 2 (kg) (cm) 1kg/cm ) Lkg/crn ) (kg/cmj 0. 0000 0. 0000 1. 4061 0. 0000 3. 5154 3. 5154 7. 3483 0. 0762 2. 0334 0. 0163 3. 9938 2. 9881 10. 7957 0.1524 2. 4010 0. 0327 3. 9736 2. 5205 12. 6101 0. 2261 2. 8826 0. 0485 3. 7085 2. 0389 14. 3791 0. 3023 3. 2341 0. 0648 3. 5585 1. 6874 15.4224 0. 3759 3.5294 0.0806 3. 3650 1. 3921 16. 4203 O. 4572 3. 7403 0. 0980 3. 2420 1.1812 18. 1440 0. 5258 3. 9583 0. 1127 3. 2032 0. 9632 19. 2780 0. 6020 4. 1481 0. 1291 3. 1095 0. 7734 21. 0924 O. 6756 4. 2747 0. 1449 3. 1565 0. 6468 22. 9068 0. 7544 4. 4504 0.1617 3. 1428 0. 4711 23. 8140 0. 8280 4. 5418 O. 1775 3. 1049 0. 3797 26. 3088 0. 9017 4. 6543 0.1933 3. 2201 0. 2672 27. 2160 0. 9144 4. 6965 0. 1961 3. 2694 0. 2250 F1 and 0'3 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 225 TABLE I-3. TRIAXIAL TEST DATA, SAMPLE U-1-12 Axial consolidation pressure 2 2. 109 kg/cmZ with K0 = 1 61f = 5. 919 kg/cm2 Initial water content 2 194. 4% 03f = 3. 515 kg/cmz Final water content 2 94. 3% uf = 3. 452 kg/em2 Initial dry density = 25. 75 pcf Af = o. 85 cu = 1. 265 kg/em2 Load Displace- Pore Axial _ _ ment pressure strain 0'1 0'3 (kg) (cml (kg/cm2> (kgzcmz) 0g/cm2) 0. 0000 0. 0000 1. 4061 0. 0000 2. 1092 2. 1092 7. 2576 0. 0737 1. 6170 0. 0147 2. 7554 1. 8983 10. 7957 0.1473 1. 9404 0. 0294 2. 8308 1. 5749 12. 2472 0. 2256 2. 2428 0. 0450 2. 6744 1. 2726 13. 6080 0. 2972 2. 4678 0. 0592 2. 5819 1. 0476 14. 6059 0. 3734 2. 6506 0. 0744 2. 4850 0. 8648 15. 7399 0. 4470 2. 7982 0. 0891 2. 4355 0. 7171 16. 6471 0. 5207 2. 9177 0.1038 2. 3857 0. 5976 17. 7811 0. 5944 3. 0232 0.1185 2. 3707 0. 4922 18. 9605 0. 6706 3.1076 0. 1337 2. 3764 0. 4078 19. 9584 0. 7442 3. 1990 0. 1484 2. 3535 0. 3164 21. 3192 0. 8179 3. 2693 0. 1630 2. 3846 0. 2461 22. 5893 0. 8941 3. 3396 0.1782 2. 4006 0. 1758 23. 6779 0. 9677 3. 3958 0. 1929 2. 4099 0. 1195 25. 3109 1. 0414 3. 4521 0. 2076 2. 4670 0. 0633 P and .0.- equal the major and minor effective principal stresses, respectively. 1 3 Failure taken at maximum deviator stress or at 20 percent axial strain. 219 TABLE I-4. TRIAXIAL TEST DATA, SAMPLE U-1-13 Axial consolidation pressure = 3.515 kg/cm2 with KO = 1 01f = 8. 768 kg/cm2 Initial water content 2 180. 2% 03f = 4. 921 kg/cmz Final water content = 84. 2% uf = 4. 668 kg/cmz Initial dry density = 27. 47 pcf Af = 0. 85 cu = 1.923 kg/cnn2 Load Displace- Pore Axial _ _ ment pressurze strain 0'1 2 03 2 (kg) (cml (man ) (kg/cm ) JRB/Cm ) 0. 0000 0. 0000 1. 4061 0. 0000 3. 5154 ' 3. 5154 15. 4224 0. 0762 2. 0389 0. 0157 4. 7638 2. 8826 18. 8244 0. 1524 2. 65 76 0. 0314 4. 5234 2. 2639 20. 8656 0. 2286 3. 0865 0. 0471 4. 2990 1. 8350 22. 7707 0. 3048 3. 4099 0. 0628 4. 1562 1. 5116 24. 4944 0. 3810 3. 6560 0. 0785 4. 0626 1. 2655 26. 3088 0. 4572 3. 8528 0. 0943 4. 0217 1. 0687 27. 7603 0. 5334 4. 0075 0. 1100 3. 9759 0. 9140 29. 2572 0. 6096 4. 1581 0. 1257 3. 9434 0. 7734 30. 9355 0. 6858 4. 2747 0. 1414 3. 9385 0. 6468 31. 8881 0. 7620 4. 3590 0. 1571 3. 8934 0. 5625 34. 8365 0. 8382 4. 4926 0. 1728 4. 0000 0. 4289 36. 7416 O. 9144 4. 5770 0. 1885 4. 0394 0. 3445 39. 0096 0. 9906 4. 6684 0. 2042 4. 1001 0. 2531 E1 and :3 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 220 TABLE I-5. TRIAXIAL TEST DATA, SAMPLE U-2-21 Axial consolidation pressure = 3. 515 kg/cm2 with Ko 2 1 (71f 1' 9. 086 kg/cm2 Initial water content : 215. 0% 03f = 4. 921 kg/cmz Final water content I 94. 2% uf = 4. 711 kg/cm2 Initial dry density = 23. 86 pcf Af = 0.79 cu = 2. 082 kg/cm2 Load Displace- Pore Axial _ _ ment pressurze strain 01 2 0'3 2 (kg) (can (kgzcm; (kg/cm ) (kg/cm ) 0. 0000 0. 0000 1. 4061 0. 0000 3. 5154 3. 5154 15. 1956 0. 0762 1. 9826 0. 0156 4. 9064 2. 9389 19. 0512 0.1524 2. 6295 0. 0311 4. 7198 2. 2920 21. 3192 0. 2286 3. 1005 0. 0467 4. 4941 l. 8210 23. 5872 0. 3048 3. 4380 0. 0622 4. 3927 1. 4835 25. 4016 0. 3810 3. 6911 0. 0778 4. 3114 1. 2304 26. 9892 0. 45 72 3. 8739 0. 0934 4. 2659 1. 0476 28. 4407 0. 5334 4. 0427 0.1089 4. 2121 0. 8789 30.1644 0. 6096 4. 1833 0.1245 4. 2117 0. 7382 31. 7520 0. 6858 4. 3028 0. 1401 4. 2100 0. 6187 33. 5664 0. 7620 4. 4153 0.1556 4. 2341 0. 5062 35. 2901 0. 8382 4. 4997 0. 1712 4. 2689 0. 4218 37.1952 0. 9144 4. 6051 0.1867 4. 2950 0. 3164 39. 6900 0. 9906 4. 7106 0. 2023 4. 3751 0. 2109 E and}. 1 3 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 221 TABLE I-6. TRIAXIAL TEST DATA, SAMPLE U-3-1 Axial consolidation pressure = 0. 703 kg/cm2 with Ko = 1 01f = 3. 017 kg/cm2 Initial water content = 310. 0% 03f = 2. 109 kg/cm2 Final Water content 2 150. 9% uf = 2. 109 kg/cnn‘Z initial dry density = 18. 94 pcf Af = 0.77 cu = 0. 454 kg/cnnZ Load Displace- Pore Axial _ _ ment pressurze strain 0'1 2 0'3 2 kg) (cm) (kg/cm ) (kg/cm ) lkg/cm ) 0.0000 0.0000 1.4061 0.0000 0.7031 0.7031 2.9484 0.0483 1.5678 0.0106 0.8242 0.5414 4.1278 0.1194 1.7014 0.0262 0.7975 0.4078 4.8989 0.1753 1.8139 0.0385 0.7520 0.2953 5.3525 0.2337 1.8842 0.0514 0.7173 0.2250 5.5339 0.2921 1.9053 0.0642 0.7060 0.2039 6.2143 0.3505 1.9545 0.0770 0.7108 0.1547 6.6679 0.4089 1.9721 0.0899 0.7256 0.1371 7.0308 0.4674 2.0037 0.1027 0.7172 0.1055 7.5298 0.5258 2.0389 0.1156 0.7161 0.0703 7.9380 0.5817 2.0459 0.1278 0.7346 0.0633 8.5277 0.6401 2.0730 0.1407 0.7456 0.0352 9.0720 0.6985 2.0811 0.1535 0.7727 0.0281 9.5256 0.7315 2.0951 0.1608 0.7892 0.0141 10.3421 0.8153 2.0986 0.1792 0.8337 0.0105 11.1132 0.8738 2.1057 0.1921 0.8742 0.0035 11.7029 0.9093 2.1092 0.1999 0.9080 0.0000 12.8369 0.9906 2.1092 0.2177 0.9737 0.0000 ‘_ F1 and 0:3 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 222 TABLE I-7. TRIAXIAL TEST DATA, SAMPLE U-3-2 Axial consolidation pressure 2 0. 703 kg/cmZ with Ko = 1 01f == 3. 351 kg/cm2 Initial water content = 306. 0% 03f = 2. 109 kg/cmZ Final water content = 147. 4% uf = 2. 151 kg/cmZ initial dry density = 18. 39 pcf Af = 0. 60 cu = o. 621 kg/cm2 Load Displace- Pore Axial _ _ ment pressurze strain 0'1 2 (r3 2 (kg) (cm) (kg/cm ) (lg/cm ) (kg/cm ) 0. 0000 0. 0000 1. 4061 0. 0000 0. 7031 0. 7031 3. 8556 0. 0686 1. 7506 0. 0161 0. 7349 0. 3586 5. 4432 0. 1499 1. 8701 0. 0352 0. 7600 0. 2390 6. 4411 0. 2134 1. 9475 0. 0501 0. 7686 0. 1617 7. 2576 0. 2819 2. 0037 0. 0662 0. 7777 0.1055 8. 1648 0. 3632 2. 0459 0. 0853 0. 8041 0. 0633 9. 0720 0. 4293 2. 0775 0. 1008 0. 8408 0. 0316 9. 7524 0. 4978 2. 1057 0. 1169 0. 8578 0. 0035 10. 8864 0. 5791 2.1232 0. 1360 0. 9190 -0. 0141 11. 5668 0. 6375 2. 1373 0. 1497 0. 9475 -0. 0281 12. 7008 0. 7087 2. 1443 0. 1664 1. 0150 -0. 0352 14. 2884 0. 7798 2. 1479 0. 1832 1.1191 -0. 0387 15. 6492 0. 8509 2. 1514 0. 1999 1. 1999 -0. 0422 0'1 and :3 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 223 TABLE 1-8. TRAIXIAL TEST DATA, SAMPLE U-3-3 Axial consolidation pressure = 1. 406 kg/cmZ with Ko = 1 01f = 5. 781 kg/cm2 Initial water content : 276. 2% 63f = 2. 81 kg/cm2 Final water content = 118. 8% uf = 2. 755 kg/crn2 initial dry density = 19.23 pcf Af = o. 45 cu = 1. 485 kg/cm2 Load Displace- Pore Axial _ _ ment pressure strain 0'1 03 (kg) (cm) (kg/cmz) (kg/cmz) (kg/cm?) 0. 0000 0. 0000 1. 4061 0. 0000 1. 4062 1. 4062 8. 6184 O. 0584 1. 8701 0. 0135 1. 9213 0. 9421 12. 2018 0. 1168 2. 2568 0. 0270 1. 9227 0. 5554 14.5152 0.1753 2. 3553 0.0406 2.0609 0.4570 16. 2389 0.2337 2.4607 0.0541 2. 1206 0. 3515 17.6904 0.2921 2.5592 0.0676 2. 1528 0.2531 18. 9605 0. 3480 2. 6124 0. 0805 2. 1976 0. 1898 20.4120 0.4064 2.6716 0.0941 2.2703 0.1406 21. 7728 0. 4648 2. 7068 0. 1076 2. 3433 0. 1055 23. 5872 0. 5232 2. 7244 0. 1211 2. 4754 0. 0879 24. 9480 0. 5817 2. 7420 0. 1346 2. 5568 0. 0703 26. 3088 0. 6401 2. 7420 0. 1481 2. 6514 0. 0703 28.1232 0. 6960 2. 7490 0. 1611 2. 7805 0. 0633 29. 4840 0. 7569 2. 7490 0. 1752 2. 8641 0. 0633 30. 8448 0. 8153 2. 7550 0. 1887 2. 9383 0. 05 62 32. 2056 0. 8611 2. 7550 0. 1993 3. 0262 0. 0562 0:1 and 03 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 224 TABLE I-9. TRIAXIAL TEST DATA, SAMPLE U-3-5 Axial consolidation pressure = 3. 515 kg/cmZ with Ko = 1 1 3 0'1 = 7. 966 kg/cm2 Initial water content = 255. 0% f (73 = 4. 921 kg/cmZ Final water content = 97. 5% f uf = 4. 696 kg/cm2 Initial dry density = 20. 32 pcf Af = 1.08 cu = 1.522 kg/cm‘2 Load Displace- Pore Axial _ _ ment pressure strain 01 0'3 2 ' 2 2 4kg) (cm) 1kg/Cm ) (kg/cm 1 (Elem-J 0. 0000 0. 0000 1. 4061 0. 0000 3. 5 154 3. 5 154 7. 3483 0. 0762 2. 0334 0. 0163 3. 9938 2. 9881 10. 7957 0.1524 2. 4010 0. 0327 3. 9736 2. 5205 12. 6101 0. 2261 2. 8826 0. 0485 3. 7085 2. 0389 14. 3791 0. 3023 3. 2341 0. 0648 3. 5585 l. 6874 15.4224 0. 3759 3.5294 0.0806 3. 3650 l. 3921 16. 4203 0. 4572 3. 7403 0. 0980 3. 2420 1. 1812 18. 1440 0. 5258 3. 9583 0. 1127 3. 2032 0. 9632 19. 2780 0. 6020 4. 1481 0.1291 3. 1095 0. 7734 21. 0924 0. 6756 4. 2747 0. 1449 3. 15 65 0. 6468 22. 9068 0. 7544 4. 4504 0. 1617 3. 1428 0. 4711. 23. 8140 0. 8280 4. 5418 O. 1775 3. 1049 0. 3797 26. 3088 0. 9017 4. 6543 0. 1933 3. 2201 0. 2672 27. 2160 0. 9144 4. 6965 0. 1961 3. 2694 0. 2250 F and; equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 225 TABLE I-10. TRIAXIAL TEST DATA, SAMPLE U-3-6 Axial consolidation pressure 2 2. 109 kg/cmz with Ko == 1 01f = 4. 531 kg/cm2 Initial water content 2 285. 8% 0'3 = 2. 109 kg/cnn2 Final water content = 122. 8% f uf = 2. 189 kg/cmZ Initial dry density = 18. 63 pcf Af = 0. 90 cu = 1. 200 kg/cm2 Load Displace- Pore Axial _ _ ment pressure strain 01 0'3 2 2 2 1kg) (cm) (kg/cm; (kglcm ) 1kg/cm ) 0. 0000 0. 0000 1. 4061 0. 0000 2. 1092 2.1092 7.1669 0. 0737 1. 7928 0. 0158 2. 6145 1. 7225 9. 8431 0. 1473 2.1936 0. 0316 2. 5272 l. 3218 11. 5668 0. 2256 2. 4748 0. 0483 2. 4325 1. 0406 12. 7008 0. 2972 2. 6857 0. 0637 2. 3334 0. 8296 13. 6987 0. 3734 2. 8474 0. 0800 2. 2616 0. 6679 15. 0595 0. 4470 2. 9870 0. 0958 2. 2492 0. 5273 16. 2842 0. 5207 3. 1146 0. 1146 2. 2302 0. 4008 17.2368 0.5944 3.2201 0. 1274 2.1973 0.2953 18. 2347 0. 6706 3. 3044 0. 1437 2. 1854 0. 2109 19. 5955 0. 7442 3. 3958 0. 1595 2. 2022 0. 1195 20. 8656 0. 8179 3. 4732 0. 1753 2. 2182 0. 0422 22.4532 0.8941 3.5294 0.1916 2.2812 -0.0141 23. 9501 0. 9677 3. 5716 0. 2074 2. 3442 -0. 0562 E1 and 0'3 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 226 TABLE I-11. TRIAXIAL TEST DATA, SAMPLE U-3-7 Axial consolidation pressure = 1. 406 kg/cmZ with Ko = 1 01f == 4. 693 kg/cm2 Initial water content 2 289. 6% 03f = 2. 812 kg/cmz Final water content 2 127. 0% uf '2 2. 777 kg/cm2 Initial dry density = 18. 30 pcf Af = 0. 73 cu = 0. 940 kg/cnn2 Load Displace- Pore Axial _ _ ment pressure strain 01 03 (kg) (cm) (kg/cmz) (kg/cmz) (kg/cmz) 0. 0000 0. 0000 1. 4061 0. 0000 l. 4062 1. 4062 l. 8144 0.0152 1.4413 0.0032 1.6028 1. 3710 3. 6288 0. 0305 1. 5116 0. 0063 1. 7627 l. 3007 4. 5360 0. 0432 1. 5819 0. 0090 1. 8064 1. 2304 5. 4432 0. 0584 1. 6522 0. 0121 1. 8491 1.1601 6.1236 0.0737 1.7225 0.0153 1. 8624 1.0896 6. 4411 0. 0889 1. 7858 0. 0185 1. 8366 1. 0265 7.1215 0.1041 1. 8385 0. 0216 l. 8666 0. 9738 7. 6205 0.1245 1. 9264 0. 0259 1. 8371 0. 8859 8.1648 0.1473 1. 9861 0. 0305 l. 8403 0. 8261 9. 2988 0. 2256 2.1584 0. 0469 1. 7895 0. 6539 10.2060 0.2972 2.2779 0.0618 1.7613 0.5343 11.1132 0. 3734 2. 3693 0. 0776 1. 7564 0. 4429 12. 0204 0. 4479 2. 4467 0. 0929 1. 7627 0. 3656 12. 7462 0. 5207 2. 5170 0.1082 1. 7518 0. 2953 13. 6080 0. 5944 2. 5731 0.1236 1. 7673 0. 2390 14. 5152 0. 6706 2. 6295 0.1394 1. 7835 0. 1828 15. 4224 0. 7442 2. 6787 0. 1547 1. 8041 0. 1336 16. 3296 0. 8179 2. 7138 0.1700 1. 8351 0. 0984 17. 2368 0. 8941 2. 7560 0.1859 1. 8544 O. 0562 18. 3708 0. 9677 2. 7771 0. 2012 l. 9156 0. 0352 1 F and .073 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 227 TABLE I-12. TRIAXIAL TEST DATA, SAMPLE U-3-8 Axial consolidation pressure = 3. 515 kg/cmz with KO = 1 01 = 9. 127 kg/cm2 Initial water content 2 293. 6% f 0'3 2 4. 921 kg/cm2 Final water content = 111. 0% f uf = 4. 844 kg/cm2 Initial dry density = 18. 22 pcf Af = 0. 82 cu = 2. 102 kg/cm2 Load Displace- Pore Axial __ __ ment pressure strain 01 0'3 2 ' 2 2 1kg) (cm) (kglcm ) (kg/cm ) (kg/cm ) 0. 0000 0. 0000 1. 4061 0. 0000 3. 5 154 3. 5 154 12. 6554 0. 0762 2. 1443 0. 0170 4. 4755 2. 7772 16. 3750 0. 1499 2. 8474 0. 0334 4. 2349 2. 0741 19. 0512 0. 2261 3. 2622 0. 0504 4.1290 1. 6593 21. 0924 0. 2997 3. 5716 0. 0669 4. 0370 1. 3499 23. 1336 0. 3759 3. 8317 0. 0839 3. 9832 1. 0898 25. 3109 0. 4521 4. 0637 0.1008 3. 9648 0. 8578 26. 8531 0. 5258 4. 2325 0. 1173 3. 9251 0. 6890 28. 8036 0. 6020 4. 3942 0. 1343 3. 9316 0. 5273 30. 8448 0. 6782 4. 5629 0. 15 13 3. 9326 0. 3586 33. 3396 0. 75 18 4. 6965 0. 1677 4. 0133 0. 2250 35. 8344 0. 8280 4. 7668 0. 1847 4. 1433 0. 1547 38. 5560 0. 9017 4. 8442 0. 2011 4. 2824 0. 0773 0" and? equal the major and minor effective principal stresses, respectively. 1 Failure taken at maximum deviator stress or at 20 percent axial strain. 228 TABLE I-13. TRIAXIAL TEST DATA, SAMPLE G-3 Axial consolidation pressure = l. 173 kg/cm2 with K0 = 0. 3 Angle between direction of compression and horizontal = 90 degrees 01f = 4. 566 kg/cm2 Initial water content = 159. 1% 03f = 3. 164 kg/cm2 Final water content = 142. 0% uf = 3. 123 kg/cmZ Initial dry density = 20. 45 pcf Af = 0. 45 cu = 0. 701 kg/cm2 Load Displace- Pore Axial _ _ ment pressure strain 01 0'3 (kg) (ch (kg/cmz) 1kg/cm2) (kg/cmz) 15. 4200 0. 0000 2. 8123 0. 0000 1. 0641 0. 3515 16. 3296 0. 0102 2. 8264 0. 0013 1. 0913 0. 3375 17. 4636 0. 0178 2. 8615 0. 0022 1.1077 0. 3023 18. 1440 0. 0279 2. 8756 0. 0035 1. 1240 0. 2883 18. 5976 0. 0305 2. 8826 0. 0038 1. 1375 0. 2812 19. 0512 0. 0381 2. 8896 0. 0047 1.1506 0. 2742 21. 4099 0. 0787 2. 9178 0. 0098 1. 2260 0. 2461 22. 9975 0.1295 2. 9529 0. 0161 1. 2568 0. 2109 24. 4944 0.1778 3. 0513 0. 0221 1. 2196 0.1125 25. 4016 O. 2388 3. 0738 0. 0296 1. 2292 0. 0900 26. 3088 0. 2997 3. 0935 0. 0372 1. 2411 0. 0703 27. 2160 0. 3581 3.1090 0. 0444 1. 2568 0. 0548 28. 8036 0. 4521 3.1287 0. 0561 1. 2917 0. 0352 29. 4840 0. 5461 3. 1391 0. 0678 1. 2950 0. 0246 30. 3912 0. 6401 3.1463 0. 0794 1. 3107 0. 0176 31.2984 0. 7366 3.1484 0.0914 1. 3298 0.0155 31. 8427 0. 8331 3. 1477 0.1034 1. 3358 0. 0162 33. 5664 1. 0287 3. 1392 0. 1276 1. 3780 0. 0246 35. 3808 1. 2217 3. 1287 0. 15 16 1. 4225 0. 0352 36. 2880 1. 3208 3. 1231 0. 1639 1. 4431 0. 0408 E1 and 0'3 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 229 TABLE 1-14. TRIAXIAL TEST DATA, SAMPLE G-4 Axial consolidation pressure = 1. 173 kg/cm2 with Ko = 0. 3 Angle between direction of compression and horizontal = 90 degrees 01f = 4. 983 kg/cm2 Initial water content = 157. 7% 03f = 3. 164 kg/cm2 Final water content = 134. 0% uf = 3. 155 kg/cmZ Initial dry density = 24. 58 pcf Af = 0. 30 cu = 0. 910 kg/cm‘2 Load Displace- Pore Axial _ _ ment pressure strain 01 03 (kg) 1cm) (kg/cmz) (kgzcmz) (kg/cmz) 15. 6500 0. 0000 2. 8123 0. 0000 1. 0333 0. 3515 15. 6492 0. 0102 2. 8123 0. 0010 1. 0327 0. 3515 17. 6904 0. 0203 2. 8404 0. 0021 1. 0928 0. 3234 19. 9584 0. 0381 2. 8756 0. 0039 1.1547 0. 2883 21. 5460 0. 0559 2. 8932 0. 0057 l. 2043 0. 2707 22. 4532 0. 0737 2. 9079 0. 0075 1. 2271 0. 2559 25. 8552 0. 1676 2. 9599 0. 0171 1. 3113 0. 2039 27. 6696 0. 2616 2. 9965 0. 0268 1. 3409 O. 1673 29.1211 0. 3556 3. 0303 0. 0364 l. 3565 0.1336 30. 7541 0. 4521 3. 05 84 0. 0462 1. 3837 0. 1055 31. 7520 0.5512 3.0795 0.0564 1. 3901 0.0844 32. 8860 0. 6477 3. 0978 0. 0662 1. 4043 0. 0661 34. 3375 0. 7442 3. 1090 0. 0761 l. 4374 0. 0548 35. 3808 0. 8407 3. 1202 0. 0860 1. 4529 0. 0436 36. 5 148 0. 9373 3. 1273 0. 0958 1. 4753 0. 0366 37. 6488 1. 0363 3.1322 0. 1060 1. 4985 0. 0316 38. 9642 1. 1328 3. 1371 0. 1159 1. 5280 0. 0267 41. 6405 1. 4275 3. 1427 0. 1460 1. 5709 0. 0211 44. 4528 1. 5240 3. 1484 0.1559 1. 6508 0. 0155 47. 6280 1. 7221 3.1498 0. 1761 1. 7241 0. 0141 50. 8032 1. 9202 3.1533 0. 1964 1. 7898 0. 0105 52. 6176 2. 0193 3.1547 0. 2065 1. 8287 0. 0091 :1 and .0.-3 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 230 TABLE I-15. TRIAXIAL TEST DATA, SAMPLE G-S Axial consolidation pressure = 1. 173 kg/cmz with Ko = 0. 3 Angle between direction of compression and horizontal = 90 degrees 0'1 = 5. 073 kg/cm‘Z Initial water content = 153.7% f 03 = 3. 164 kg/cmZ Final water content = 130. 0% f uf = 3. 149 kg/cm2 Initial dry density = 21. 95 pcf Af = 0. 30 cu = 0. 954 kg/cm2 Load Displace- Pore Axial _ _ ment pressure strain 01 0'3 2 2 2 (kg) (cm) (kg/cm ) (kglcm ) (kg/cm ) 15. 6500 0. 0000 2. 8123 0. 0000 1. 1543 0. 3515 20. 8656 0. 0305 2. 8791 0. 0032 1. 3532 0. 2847 23. 6779 0. 0864 2. 9389 0. 0092 1. 4303 0. 2250 25. 4016 0.1372 2. 9726 0. 0146 1. 4772 0. 1912 26. 5356 0. 1905 2. 9965 0. 0203 1. 5030 0. 1673 27. 3067 0. 2388 3. 0162 0. 0254 1. 5149 0. 1476 30. 7541 0. 4978 3. 0809 0. 0530 1. 5793 0. 0830 33. 4757 0. 7518 3.1153 0. 0800 l. 6308 0. 0485 36. 2880 1. 0084 3. 1322 0. 1073 1. 6959 0. 0316 39. 2364 1. 2824 3. 1406 0. 1343 1. 7682 0. 0232 42. 6384 1. 5215 3.1442 0. 1619 1. 8557 0. 0197 45. 8136 1. 7755 3.1491 0.1889 1. 9239 0. 0148 45. 2693 2. 0295 3. 1385 0. 2159 1. 8489 0. 0253 F and-o: equal the major and minor effective principal stresses, respectively. 1 Failure taken at maximum deviator stress or at 20 percent axial strain. 231 TABLE I-16. TRIAXIAL TEST DATA, SAMPLE G-6 Axial consolidation pressure 2 2. 343 kg/cm2 with Ko = 0. 3 Angle between direction of compression and horizontal = 90 degrees 7. 694 kg/cm2 Initial water content = 157. 2% q H f 0'3 = 3. 504 kg/cm2 Final water content 2 115. 0% f uf = 3. 469 kg/cm2 initial dry density = 23.53 pcf Af = 0. 24 cu = 2. 095 kg/cmz Load Displace- Pore Axial _ _ ment pressure strain 0'1 0'3 2 2 2 (kg) (cmi tkchm ) (kg/cm ) tkglcm ) 33. 5680 0. 0000 2. 8123 0. 0000 2. 1508 0. 7030 49. 4424 0. 0406 3. 0303 0. 0052 2. 6070 0. 485 1 55. 3392 0. 0914 3.1709 0. 0117 2. 7039 0. 3445 58.5144 0.1372 3.2412 0.0176 2. 7542 0.2742 60. 7824 0. 1905 3. 2904 0. 0244 2. 7832 0. 2250 62. 5968 0. 2438 3. 3291 0. 0313 2. 8024 0. 1863 70. 7616 0.5029 3.4155 0.0645 2. 9557 0.0998 79. 3800 0. 7366 3. 4451 0. 0945 3. 1714 0. 0703 86.1840 0. 9601 3. 4556 0. 1231 3. 3201 0. 0598 92. 0808 1. 1862 3. 4605 0.1521 3. 4231 0. 0548 114. 3072 1. 4326 3. 4662 0. 1837 4. 0747 0. 0492 123. 8328 1. 6891 3. 4732 0. 2166 4. 2274 0. 0422 .51 and :3 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. TABLE I-17. TRIAXIAL TEST DATA, SAMPLE G-7 Unconfined compression test Angle between direction of compression and horizontal = 90 degrees 01f = 0. 637 kg/cm2 Initial water content = 158. 6% 03f = 0 kg/cm2 Final water content 2 158. 6% cu = 0. 318 kg/cm2 initial dry density = 27.52 pcf Load Displace- Pore Axial ment pressure strain 0'1 (73 (kg) (cm) (kg/mi (kglcmzl (kg/cm?) 0. 0000 0. 0000 -- 0. 0000 0. 0000 0. 0000 2. 1773 0. 0457 0. 0036 0. 1062 3.1752 0. 0914 0. 0073 0.1543 3. 9917 0.1321 0. 0105 0.1899 4. 8989 0. 1829 0. 0145 0. 2293 5. 6246 0. 2337 0. 0185 0. 2632 8.6184 0.4851 0.0385 0. 3916 10. 9318 0. 7391 0. 0587 0. 4896 12. 6101 0. 9957 0.0790 0.5544 13.5173 1. 2522 0.0994 0. 5818 13. 6987 1.5062 0.1196 0.5763 13. 6987 1. 7602 0.1397 0. 5698 13.5173 1. 9990 0.1587 0.5567 13.1544 2. 2327 0.1772 0. 5298 15. 6492 2. 4663 0. 1958 0. 6160 16. 3296 2. 5603 0. 2032 0. 6368 0' and 0' equal the major and minor tota1 principal stresses, respectively. 1 Failure taken at maximum deviator stress or at 20 percent axial strain. 233 TABLE I-18. TRIAXIAL TEST DATA, SAMPLE G-8 Unconfined compres sion test Angle between direction of compression and horizontal = 90 degrees 01f = 0. 644 kg/cm2 Initial water content = 158. 6% 03f = 0 kg/cm2 Final water content 2 158. 6% cu = 0. 322 kg/crn2 initial dry density = 24. 15 pcf Load Displace- Pore Axial ment pressure strain 01 03 4kg) (cm) jg/cmz) 1kg/cm5 (kg/cmz) 0. 0000 0. 0000 -- 0. 0000 0. 0000 0. 0000 2.1773 0.457 0.0038 0.1128 2. 9484 0. 0940 0. 0079 0. 1520 3. 7422 0.1321 0. 0111 0.1923 4. 3546 0.1829 0. 0153 0. 2228 5.0803 0.2337 0.0196 0. 2568 8.4823 0.4851 0. 0406 0. 4229 10. 8864 0. 7391 0.0619 0.5307 12. 6554 0. 9957 0. 0833 0. 6028 13. 8348 1. 2522 0. 1048 0. 6435 13.5173 1.5062 0.1261 0.6138 9. 8885 1. 7602 0. 1473 0. 4381 10. 4328 1. 9990 0.1673 0. 4514 9. 0720 2. 2327 0.1869 0. 3833 9. 2988 2. 4663 0. 2064 0. 3834 01 and 03 equal the major and minor tota1 principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 234 TABLE I-19. TRIAXIAL TEST DATA, SAMPLE G-9 Axial consolidation pressure = O. 696 kg/cm2 with Ko = 0. 3 Angle between direction of compression and horizontal = 90 degrees 01f = 3. 992 kg/cmZ Initial water content = 157. 2% 03f = 3. 023 kg/cmZ Final water content 2 153. 0% uf = 3. 002 kg/cm‘Z initial dry density = 26. 92 pcf Af = o. 40 cu = 0. 484 kg/cnn2 Load Displace- Pore Axial _ _ ment pressure strain (71 0'3 4kg) gm) aka/mg) (kg/cmz) (kg/cmz) 9. 9547 0. 0000 2. 8123 0. 0000 0. 6943 0. 2109 12. 9276 0. 0508 2. 8756 0. 0041 0. 7986 0. 1476 13. 8348 0. 0965 2. 8967 0. 0077 0. 8206 0. 1266 14. 5152 0. 1321 2. 9107 0. 0106 0. 8386 0. 1125 14. 9688 0. 1905 2. 9220 0. 0153 0. 8465 0. 1012 15. 2863 0. 2388 2. 9318 0. 0191 0. 8494 0. 0914 16. 7832 0. 4928 2. 9607 0. 0395 0. 8776 0. 0626 18. 0533 0. 7442 2. 9782 0. 0596 0. 9033 0. 0450 19. 0966 1. 0058 2. 9895 0. 0806 0. 9214 0. 0337 20. 4120 1. 2649 2. 9986 0. 1013 0. 9520 0. 0246 21. 3192 1. 5240 3. 0021 0. 1221 0. 9673 0. 0211 22. 2264 1. 7831 3. 0028 0. 1428 0. 9836 0. 0204 22. 9068 2. 0422 3. 0021 0. 1636 0. 9897 0. 0211 23. 4058 2. 2911 2. 9881 O. 1835 1. 0013 0. 0352 23. 6779 2. 5425 0. 29670 0. 2037 1. 0095 0. 0562 0'1 and 0‘3 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 235 TABLE I-20. TRIAXIAL TEST DATA, SAMPLE G-10 Axial consolidation pressure = 0. 703 kg/cm2 with Ko = 1. 0 Angle between direction of compression and horizontal = 0 degrees 01 = 4. 413 kg/cm2 Initial water content = 157. 0% f 0'3 = 3. 515 kg/cnn2 Final water content = 145. 0% f uf = 3. 325 kg/cmz initial dry density = 22.53 pcf Af = 0. 57 Cu = 0. 449 kg/cm2 Load Displace- Pore Axial _ __ ment pressure strain 0'1 03 2 2 2 1kg) (cm) (kg/cm ) Ikg/cm ) (kglcm ) 0. 0000 0. 0000 2. 8123 0. 0000 0. 7030 0. 7030 4. 0824 0. 0330 2. 9529 0. 0030 0. 7985 0. 5625 6. 4411 0. 0864 3. 0162 0. 0079 0. 8698 0. 4992 7. 9380 0. 1372 3. 0549 0. 0125 0. 9151 0. 4605 8. 8452 0. 1880 3. 0830 0. 0171 0. 9366 0. 4324 9. 6163 0. 2388 3.1076 0. 0218 0. 9533 0. 4078 12. 2472 0. 5004 3. 1849 0. 0456 1. 0083 0. 3304 13. 6080 0. 7620 3. 2271 0. 0695 1. 0226 0. 2883 14. 7420 1. 0211 3. 2552 0. 0931 1. 0355 0. 2601 15. 8760 1. 2802 3. 2763 0.1167 1. 0523 0. 2390 16. 8739 1. 5392 3. 2974 0. 1404 1. 05 92 0. 2180 17. 9172 1. 7958 3. 3150 0. 1637 1. 0693 0. 2004 19. 0512 2. 0549 3. 3255 0.1874 1. 0877 0.1898 19. 2780 2.1590 3. 3326 0. 1969 1. 0807 0. 1828 0.1 and 03 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 236 11 I II. I 111) I. . TABLE I-21. TRIAXIAL TEST DATA, SAMPLE G-ll Axial consolidation pressure = 2. 109 kg/cm2 with Ko = 1. 0 Angle between direction of compression and horizontal = 0 degrees 01 = 7. 151 kg/cm2 Initial water content 2 160. 0% f 03 = 4. 920 kg/cmZ Final water content : 114.0% f uf = 4. 492 kg/cm2 initial dry density = 23. 74 pcf Af = 0. 75 cu = 1. 115 kg/cm2 Load Displace- Pore Axial _ _ ment pressure strain 0'1 03 2 Z 2 (kg) (cm) (kg/cm ) (kg/cml (kg/cm ) 0. 0000 0. 0000 2. 8123 0. 0000 2. 1092 2. 1092 12. 7008 0. 0533 3. 0935 0. 0047 2. 6795 l. 8280 16. 3296 0. 0183 3. 3045 0. 0072 2. 7091 1. 6171 19. 0512 0. 1600 3. 4802 0. 0141 2. 7064 1. 4413 20. 8656 0. 2108 3. 5857 0. 0186 2. 7151 1. 3359 22.5893 0.2616 3. 6912 0.0231 2. 7168 1.2304 27. 2160 0. 5232 3. 9794 0. 0462 2. 6905 0. 9421 30. 3912 0. 7849 4. 1411 0. 0694 2. 6855 0. 7804 32. 2056 1. 0465 4. 2325 0. 0925 2. 6577 0. 6890 34. 2468 1. 3081 4. 2888 0. 1156 2. 6729 0. 6328 36. 0612 1. 5697 4. 3591 0. 1387 2. 6545 0. 5625 37. 8756 1. 8313 4. 4153 0.1618 2. 6445 0. 5062 39. 9168 2. 0930 4. 4645 0. 1849 216484 0. 4570 42. 1848 2. 3520 4. 5067 0. 2078 2. 6657 0. 4148 P and 0 equal the major and minor effective principal stresses, respectively. 1 Failure taken at maximum deviator stress or at 20 percent axial strain. 237 TABLE 1-22. TRIAXIAL TEST DATA, SAMPLE G-12 Unconfined comp re s sion test Angle between direction of compression and horizontal = 0 degrees 0*] = 0. 404 kg/cm2 Initial water content = 158. 6% f 03 = 0 kg/cm2 Final water content 2 158. 6% f cu = 0. 202 kg/cmz Initial dry density = 19. 92 pcf Load Displace- Pore Axial ment pressure strain 01 0'3 2 2 2 (kg) (cm) ikg/cm ) (kg/cm ) (kg/cm ) 0. 0000 0. 0000 -- 0. 0000 0. 0000 0. 0000 1. 9958 0. 0406 0. 0043 0. 0973 3.0391 0.0965 0.0103 0.1473 3. 6742 0. 1473 0. 0157 0. 1771 4. 3092 0. 1905 0. 0203 0. 2067 4. 7628 0. 2388 0. 0254 0. 2272 6. 8040 0. 4928 0. 0524 0. 3156 8. 0741 0. 7442 0. 0792 0. 3639 8. 9359 1. 0033 0. 1068 0. 3907 9. 5256 1. 2624 O. 1343 0. 4036 9.5256 1.5189 0.1616 0.3909 8. 7091 1. 7780 0. 1892 0. 3456 7. 4844 l. 9329 0. 2057 0. 2910 0'1 and 03 equal the major and minor tota1 principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 238 TABLE I-23. TRIAXIAL TEST DATA, SAMPLE G-ZO Axial consolidation pressure = 2. 341 kg/cm2 with K0 = 0. 3 Undrained test with 0' constant and 0' decreasing. 1 3 Initial water content = 159. 0% Final water content = 122. 0% Initial dry density = 24. 37 pcf pore Axial _ __ 01 03 pressure strain 01 03 Jkg/cmzL (kg /cm2L (lgg/cmz) (kg/cmz) (kg/cmz) 5.135 3.5154 2.8123 0.000 2.3412 0.7031 5.1535 3.4893 2.8123 0.001 2.3412 0.6770 5.1535 3.4429 2.8123 0.001 2.3412 0.6306 5.1535 3.3965 2.7947 0.001 2.3588 0.6018 5.1535 3.3501 2.7772 0.002 2.3763 0.5729 5.1535 3.2580 2.7420 0.003 2.4115 0.5160 5.1535 3.1666 2.7068 0.005 2.4467 0.4598 5.1535 3.0745 2.6506 0.006 2.5029 0.4239 5.1535 2.9986 2.7420 0.035 2.4115 0.2566 5.1535 2.9185 2.7772 0.048 2.3763 0.1413 5.1535 2.8362 2.7772 0.057 2.3763 0.0590 5.1535 2.8158 2.7596 0.085 2.3939 0.0562 5.2027 2.8123 2.8123a 0.087 2.3904 0.0000 5.2630b 2.8123 2.8123 0.091 2.4507 0 5.3504b 2.8123 2.8123 0.094 2.5381 0 5.5051b 2.8123 2.8123 0.127 2.6928 0 5.5683b 2.8123 2.8123 0.136 2.7560 0 a . . . . Pore pressure increased to initial backpressure. Small increases in axial stress. Deformation rate approximately zero when test was terminated. 239 TABLE 1-24. TRIAXIAL TEST DATA, SAMPLE G-21 Axial consolidation pressure 2 0. 703 kg/cm2 with KO 2 0. 3 Undrained test with 01 constant and 03 decreasing. Initial water content Final water content 2 135. 0% Initial dry density = 31. 26 pcf 0' 0_ pore axial -O-_ 3 1 3 pressure strain 1 3 (kg/cmz) (kg/cmz) (kg/cmz) (kg/cmz) (kg/cmz) 3.5153 3.0232 2.8123 0.000 0.7030 0.2109 3.5153 2.9628 2,7807 0.003 0.7346 0.1821 3.5153 2.9121 2.7561 0.007 0.7592 0.1560 3.5153 2.8622 2.7279 0.009 0.7874 0.1343 3.5153 2,8158 2.7139 0.024 0.8014 0.1019 3.5153 2.8123 2.8123a 0.025 0.7030 0.0000 3.5153 2.8123 2.81233 0.101 0.7030 0.0000 a . . . . Pore pressure increased to initial backpressure. Deformation rate approximately zero when test was terminated. 240 TABLE I-13. TRIAXIAL TEST DATA, SAMPLE G-3 Axial consolidation pressure = l. 173 kg /cnn2 with KO = 0. 3 Angle between direction of compression and horizontal = 90 degrees 01f = 4. 566 kg/cmZ Initial water content = 159. 1% 03f = 3. 164 kg/cm2 Final water content = 142. 0% uf = 3. 123 kg/cm2 Initial dry density = 20. 45 pcf Af = 0. 45 cu = 0. 701 kg/cmZ Load Displace- Pore Axial _ _ ment pressure strain 0'1 03 (kgl (ch (kg/cmz) ikg/cmz) _Lk2/cm2) 15. 4200 0. 0000 2. 8123 0. 0000 1. 0641 0. 3515 16. 3296 0. 0102 2. 8264 0. 0013 1. 0913 0. 3375 17. 4636 0. 0178 2. 8615 0. 0022 1. 1077 0. 3023 18. 1440 0. 0279 2. 8756 0. 0035 1. 1240 0. 2883 18.5976 0.0305 2. 8826 0.0038 1. 1375 0.2812 19. 0512 0. 0381 2. 8896 0. 0047 1. 1506 0. 2742 21. 4099 0. 0787 2. 9178 0. 0098 1. 2260 0. 2461 22. 9975 0.1295 2. 9529 0. 0161 1. 2568 0. 2109 24. 4944 0. 1778 3. 0513 0. 0221 1. 2196 0. 1125 25. 4016 0. 2388 3. 0738 0. 0296 l. 2292 0. 0900 26. 3088 0. 2997 3. 0935 0. 0372 1. 2411 0. 0703 27. 2160 0. 3581 3. 1090 0. 0444 l. 2568 0. 0548 28. 8036 0. 4521 3. 1287 0. 0561 1. 2917 0. 0352 29. 4840 0. 5461 3. 1391 0. 0678 1. 2950 0. 0246 30. 3912 0. 6401 3.1463 0. 0794 1. 3107 0. 0176 31. 2984 0. 7366 3. 1484 0. 0914 1. 3298 0. 0155 31. 8427 0. 8331 3. 1477 0.1034 1. 3358 0. 0162 33. 5664 1. 0287 3. 1392 0. 1276 1. 3780 0. 0246 35. 3808 1. 2217 3. 1287 0. 1516 l. 4225 0. 0352 36. 2880 1. 3208 3. 1231 0. 1639 1. 4431 0. 0408 ‘0'- and; equal the major and minor effective principal stresses, respectively. 1 3 Failure taken at maximum deviator stress or at 20 percent axial strain. 229 TABLE I-14. TRIAXIAL TEST DATA, SAMPLE G-4 Axial consolidation pressure = 1. 173 kg/cm2 with Ko = 0. 3 Angle between direction of compression and horizontal = 90 degrees 01f = 4. 983 kg/cm2 Initial water content = 157. 7% 03f = 3. 164 kg/cmZ Final water content 2 134. 0% uf = 3. 155 kg/cmZ initial dry density = 24.58 pcf Af = 0. 30 cu = 0. 910 kg/cmZ Load Displace- Pore Axial _ _ ment pressure strain 01 0'3 1kg) (cm) (kg/cmz) (kg/cmz) (kg/cmz) 15.6500 0.0000 2.8123 0.0000 1.0333 0.3515 15.6492 0.0102 2.8123 0.0010 1.0327 0.3515 17.6904 0.0203 2.8404 0.0021 1.0928 0.3234 19.9584 0.0381 2.8756 0.0039 1.1547 0.2883 21.5460 0.0559 2.8932 0.0057 1.2043 0.2707 22.4532 0.0737 2.9079 0.0075 1.2271 0.2559 25.8552 0.1676 2.9599 0.0171 1.3113 0.2039 27.6696 0.2616 2.9965 0.0268 1.3409 0.1673 29.1211 0.3556 3.0303 0.0364 1.3565 0.1336 30.7541 0.4521 3.0584 0.0462 1.3837 0.1055 31.7520 0.5512 3.0795 0.0564 1.3901 0.0844 32.8860 0.6477 3.0978 0.0662 1.4043 0.0661 34.3375 0.7442 3.1090 0.0761 1.4374 0.0548 35.3808 0.8407 3.1202 0.0860 1.4529 0.0436 36.5148 0.9373 3.1273 0.0958 1.4753 0.0366 37.6488 1.0363 3.1322 0.1060 1.4985 0.0316 38.9642 1.1328 3.1371 0.1159 1.5280 0.0267 41.6405 1.4275 3.1427 0.1460 1.5709 0.0211 44. 4528 1. 5240 3. 1484 0. 1559 1. 6508 0. 0155 47.6280 1.7221 3.1498 0.1761 1.7241 0.0141 50.8032 1.9202 3.1533 0.1964 1.7898 0.0105 52.6176 2.0193 3.1547 0.2065 1.8287 0.0091 0:1 and 33 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 230 TABLE I-15. TRIAXIAL TEST DATA, SAMPLE G-5 Axial consolidation pressure = 1. 173 kg/cm2 with K() = 0. 3 Angle between direction of compression and horizontal = 90 degrees 0'l = 5. 073 kg/cm2 Initial water content = 153. 7% f 0'3 = 3. 164 kg/cm2 Final water content 2 130. 0% f uf = 3. 149 kg/cmZ initial dry density = 21. 95 pcf Af = 0. 30 cu = 0.954 kg/crn2 Load Displace- Pore Axial _ __ ment pressure strain 01 0'3 2 2 (kg) (cm) (kg/cm ) (kg/cm ) (kg/cmz) 15. 6500 0. 0000 2. 8123 0. 0000 1. 1543 0. 3515 20. 8656 0. 0305 2. 8791 0. 0032 1. 3532 0. 2847 23. 6779 0. 0864 2. 9389 0. 0092 1. 4303 0. 2250 25. 4016 0.1372 2. 9726 0. 0146 1. 4772 0. 1912 26. 5356 0. 1905 2. 9965 0. 0203 1. 5030 0. 1673 27. 3067 0. 2388 3. 0162 0. 0254 1. 5 149 0. 1476 30. 7541 0. 4978 3. 0809 0. 0530 1. 5793 0. 0830 33. 4757 0. 75 18 3. 1153 0. 0800 1. 6308 0. 0485 36. 2880 1. 0084 3. 1322 0. 1073 1. 6959 0. 0316 39. 2364 1. 2824 3. 1406 0.1343 1. 7682 0. 0232 42. 6384 1. 5215 3.1442 0.1619 1. 8557 0. 0197 45. 8136 1. 7755 3. 1491 0. 1889 1. 9239 0. 0148 45. 2693 2. 0295 3. 1385 0. 2159 1. 8489 0. 0253 .0: and; 1 3 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 231 TABLE 1-16. TRIAXIAL TEST DATA, SAMPLE G~6 Axial consolidation pressure 2 2. 343 kg/cm2 with Ko = 0. 3 Angle between direction of compression and horizontal = 90 degrees 01 = 7. 694 kg/cmZ Initial water content 2 157. 2% f 0'3 = 3.504 kg/crn2 Final water content = 115.0% f uf = 3.469 kg/cm2 Initial dry density = 23.53 pcf Af = 0. 24 cu = 2.095 kg/cnn‘Z Load Displace- Pore Axial _ _ ment pressure strain 01 (I3 2 2 2 (kg) Lem) (kchm ) (kg/cm ) (kglcm ) 33. 5680 0. 0000 2. 8123 0. 0000 2. 1508 0. 7030 49. 4424 0. 0406 3. 0303 0. 0052 2. 6070 0. 4851 55. 3392 0. 0914 3.1709 0. 0117 2. 7039 0. 3445 58. 5144 0.1372 3. 2412 0. 0176 2. 7542 0. 2742 60. 7824 0. 1905 3. 2904 0. 0244 2. 7832 0. 2250 62. 5968 0. 2438 3. 3291 0. 0313 2. 8024 0.1863 70. 7616 0.5029 3.4155 0.0645 2. 9557 0.0998 79. 3800 0. 7366 3. 4451 0. 0945 3. 1714 0. 0703 86.1840 0. 9601 3. 4556 0.1231 3. 3201 0. 0598 92. 0808 1. 1862 3. 4605 0. 1521 3. 4231 0. 0548 114. 3072 1. 4326 3. 4662 0. 1837 4. 0747 0. 0492 123. 8328 1. 6891 3. 4732 0. 2166 4. 2274 0. 0422 E1 and 03 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 232 TABLE I-17. TRIAXIAL TEST DATA, SAMPLE G-7 Unconfined compression test Angle between direction of compression and horizontal = 90 degrees 01f = 0. 637 kg/cmZ Initial water content 2 158. 6% 03f = 0 kg/cm2 Final water content = 158. 6% Cu = 0. 318 kg/cm2 Initial dry density = 27. 52 pcf Load Displace- Pore Axial ment pressure strain 01 0'3 (kg) (cm) (kgzcng (kgLCmZJ (kg/cmz) 0. 0000 0. 0000 -- 0. 0000 0. 0000 0. 0000 2.1773 0. 0457 0. 0036 0. 1062 3.1752 0. 0914 0. 0073 0.1543 3. 9917 0. 1321 0. 0105 0. 1899 4. 8989 0. 1829 0. 0145 0. 2293 5. 6246 0. 2337 0. 0185 0. 2632 8.6184 0.4851 0.0385 0.3916 10. 9318 O. 7391 0. 05 87 0. 4896 12. 6101 0. 9957 0. 0790 0. 5544 13.5173 1.2522 0.0994 0. 5818 13. 6987 1. 5062 0.1196 0. 5763 13. 6987 1. 7602 0.1397 0. 5698 13. 5173 1. 9990 0.1587 0. 5567 13.1544 2. 2327 0.1772 0. 5298 15. 6492 2. 4663 0. 1958 0. 6160 16. 3296 2. 5603 0. 2032 0. 6368 0‘1 and 03 equal the major and minor tota1 principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 233 TABLE I-18. TRIAXIAL TEST DATA, SAMPLE G-8 Unconfined compres sion test Angle between direction of compression and horizontal = 90 degrees 01f = 0. 644 kg/cm2 Initial water content = 158. 6% 03f = 0 kg/cmZ Final water content 2 15 8. 6% cu = 0. 322 kg/cnn2 initial dry density = 24. 15 pcf Load Displace- Pore Axial ment pressure strain 0'1 03 (kg) (cm) (kg/cmz) 4kg/cm2) (kg/ml) 0. 0000 0. 0000 -- 0. 0000 0. 0000 0. 0000 2.1773 0. 457 0. 0038 0.1128 2. 9484 0. 0940 0. 0079 0. 1520 3. 7422 0.1321 0. 0111 0.1923 4. 3546 0.1829 0. 0153 0. 2228 5.0803 0.2337 0.0196 0. 2568 8. 4823 0. 4851 0. 0406 0. 4229 10. 8864 0. 7391 0.0619 0.5307 12. 6554 0. 9957 0. 0833 0. 6028 13. 8348 1. 2522 0. 1048 0. 6435 13.5173 1.5062 0. 1261 0.6138 9. 8885 1. 7602 0. 1473 0. 4381 10. 4328 1. 9990 0. 1673 0. 4514 9. 0720 2. 2327 0. 1869 0. 3833 9. 2988 2. 4663 0. 2064 0. 3834 0' lands equal the major and minor tota1 principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 234 TABLE I-19. TRIAXIAL TEST DATA, SAMPLE G-9 Axial consolidation pressure 2 0. 696 kg/cm2 with Ko = 0. 3 Angle between direction of compression and horizontal = 90 degrees 01 = 3. 992 kg/cmZ Initial water content = 157. 2% f 0'3 = 3. 023 kg/cm2 Final water content = 153. 0% f uf = 3.002 kg/cnn2 initial dry density = 26. 92 pcf Af = 0. 40 cu = o. 484 kg/crn2 Load Displace- Pore Axial _ _ ment pressure strain 01 0'3 2 2 2 Akgi Em) (kglcm ) (kg/cm ) (kg/cm ) 9. 9547 0. 0000 2. 8123 0. 0000 0. 6943 0. 2109 12. 9276 0. 0508 2. 8756 0. 0041 0. 7986 0. 1476 13. 8348 O. 0965 2. 8967 0. 0077 0. 8206 0. 1266 14. 5152 0.1321 2. 9107 0. 0106 0. 8386 0.1125 14. 9688 0. 1905 2. 9220 0. 0153 0. 8465 0. 1012 15. 2863 0. 2388 2. 9318 0. 0191 0. 8494 0. 0914 16. 7832 0. 4928 2. 9607 0. 0395 0. 8776 0. 0626 18. 0533 0. 7442 2. 9782 0. 0596 0. 9033 0. 0450 19.0966 1.0058 2. 9895 0.0806 0. 9214 0.0337 20. 4120 1. 2649 2. 9986 0. 1013 0. 9520 0. 0246 21. 3192 1. 5240 3. 0021 0. 1221 0. 9673 0. 0211 22. 2264 1. 7831 3. 0028 0. 1428 0. 9836 0. 0204 22. 9068 2. 0422 3. 0021 0. 1636 0. 9897 0. 0211 23. 4058 2. 2911 2. 9881 0. 1835 1. 0013 0. 0352 23. 6779 2. 5425 0. 29670 0. 2037 l. 0095 0. 0562 0'1 and; equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 235 TABLE I-20. TRIAXIAL TEST DATA, SAMPLE G-10 Axial consolidation pressure = 0. 703 kg/cnn‘Z with Ko = l. 0 Angle between direction of compression and horizontal = 0 degrees 01 = 4. 413 kg/cm2 Initial water content 2 157. 0% f 0'3 = 3. 515 kg/cm2 Final water content 2 145. 0% f uf = 3. 325 kg/cm2 Initial dry density = 22.53 pcf Af = 0. 57 cu = 0.449 kg/cnn2 Load Displace- Pore Axial _ __ ment pressure strain 01 0'3, 2 2 2 (kg) (cm) 1kg/crn ) (kg/cm ) (kg/cm ) 0. 0000 0. 0000 2. 8123 0. 0000 0. 7030 0. 7030 4. 0824 0. 0330 2. 9529 0. 0030 0. 7985 0. 5625 6. 4411 0. 0864 3. 0162 0. 0079 0. 8698 0. 4992 7. 9380 0. 1372 3. 0549 0. 0125 0. 9151 0. 4605 8. 8452 0. 1880 3. 0830 0. 0171 0. 9366 0. 4324 9. 6163 0. 2388 3.1076 0. 0218 0. 9533 0. 4078 12. 2472 0. 5004 3. 1849 0. 0456 1. 0083 0. 3304 13. 6080 0. 7620 3. 2271 0. 0695 l. 0226 0. 2883 14. 7420 1. 0211 3. 2552 0. 0931 1. 0355 0. 2601 15. 8760 1. 2802 3. 2763 0.1167 1. 0523 0. 2390 16. 8739 1. 5392 3. 2974 0. 1404 1. 05 92 0. 2180 17. 9172 1. 7958 3. 3150 0. 1637 1. 0693 0. 2004 19. 0512 2. 0549 3. 3255 0. 1874 1. 0877 0.1898 19. 2780 2.1590 3. 3326 0. 1969 1. 0807 0. 1828 31 and 33 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 236 TABLE 1-21. TRIAXIAL TEST DATA, SAMPLE G-ll Axial consolidation pressure = 2. 109 kg/cm2 with K0 = 1. 0 Angle between direction of compression and horizontal = 0 degrees 01 = 7. 151 kg/cm2 Initial water content = 160. 0% f 0'3 = 4. 920 kg/crn2 Final water content = 114.0% f uf = 4. 492 kg/cm2 Initial dry density = 23. 74 pcf Af = 0. 75 c = 1. 115 kg/cmz 11 Load Displace- Pore Axial _ _ ment pressure strain 0'1 0'3 2 2 2 (kg) (cm) (kg/cm ) (kg/cm; (kg/cm ) 0. 0000 0. 0000 2. 8123 0. 0000 2. 1092 2. 1092 12. 7008 0. 0533 3. 0935 0. 0047 2. 6795 l. 8280 16.3296 0.0183 3.3045 0.0072 2.7091 1.6171 19. 0512 0.1600 3. 4802 0. 0141 2. 7064 1. 4413 20.8656 0.2108 3.5857 0.0186 2.7151 1.3359 22.5893 0.2616 3. 6912 0.0231 2.7168 1.2304 27. 2160 0. 5232 3. 9794 0. 0462 2. 6905 0. 9421 30. 3912 0. 7849 4. 1411 0. 0694 2. 6855 0. 7804 32. 2056 1. 0465 4. 2325 0. 0925 2. 6577 0. 6890 34. 2468 1. 3081 4. 2888 0.1156 2. 6729 0. 6328 36. 0612 1. 5697 4. 3591 0.1387 2. 6545 0. 5625 37. 8756 1. 8313 4. 4153 0.1618 2. 6445 0. 5062 39. 9168 2. 0930 4. 4645 0. 1849 216484 0. 4570 42. 1848 2. 3520 4. 5067 0. 2078 2. 6657 0. 4148 I; and 7; equal the major and minor effective principal stresses, respectively. 1 3 Failure taken at maximum deviator stress or at 20 percent axial strain. 237 TABLE 1-22. TRIAXIAL TEST DATA, SAMPLE G-12 Unconfined compression test Angle between direction of compression and horizontal = 0 degrees 0’] = 0. 404 kg/cmZ Initial water content = 158. 6% f 03 = 0 kg/cm2 Final water content 2 158. 6% f cu = 0. 202 kg/cmz initial dry density = 19. 92 pcf Load Displace- Pore Axial ment pressure strain 01 (I3 2 2 2 (kg) (cm) Lkg/cm ) (kg/cm ) (kg/cm ) 0. 0000 0. 0000 -- 0. 0000 0. 0000 0. 0000 1. 9958 0. 0406 0. 0043 0. 0973 3. 0391 0. 0965 0. 0103 0. 1473 3. 6742 0. 1473 0. 0157 0. 1771 4. 3092 0. 1905 0. 0203 0. 2067 4. 7628 0. 2388 0. 0254 0. 2272 6. 8040 0. 4928 0. 0524 0. 3156 8. 0741 0. 7442 0. 0792 0. 3639 8. 9359 1. 0033 0. 1068 0. 3907 9. 5256 1. 2624 0.1343 0. 4036 9.5256 1.5189 0.1616 0.3909 8. 7091 1. 7780 0. 1892 0. 3456 7. 4844 1. 9329 0. 2057 0. 2910 01 and 03 equal the major and minor tota1 principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 238 TABLE I-23. TRIAXIAL TEST DATA, SAMPLE G-20 Axial consolidation pressure = 2. 341 kg/cm2 with KO = 0. 3 Undrained test with 01 constant and 03 decreasing. Initial water content 2 159. 0% Final water content = 122. 0% Initial dry density = 24. 37 pcf pore Axial _ _ 0'1 03 pressure strain 0'1 03 0.4/man (kg/cmz) (kg/cmz) (kg/cmz) (kg/cmz) 5.135 3. 5154 2. 8123 0. 000 2. 3412 0. 7031 5.1535 3. 4893 2. 8123 0. 001 2. 3412 0. 6770 5.1535 3. 4429 2. 8123 0. 001 2. 3412 0.6306 5.1535 3. 3965 2. 7947 0. 001 2. 3588 0. 6018 5.1535 3. 3501 2. 7772 0. 002 2. 3763 0. 5729 5. 1535 3. 2580 2. 7420 0. 003 2. 4115 0. 5 160 5. 1535 3. 1666 2. 7068 0. 005 2. 4467 0. 4598 5. 1535 3. 0745 2. 6506 0. 006 2. 5029 0. 4239 5. 1535 2. 9986 2. 7420 0. 035 2. 4115 0. 2566 5.1535 2. 9185 2. 7772 0. 048 2. 3763 0.1413 5.1535 2. 8362 2. 7772 0. 057 2. 3763 0. 0590 5.1535 2.8158 2.7596 0.085 2.3939 0.0562 5. 2027 2. 8123 2. 8123a 0. 087 2. 3904 0. 0000 5. 2630‘” 2. 8123 2. 8123 0. 091 2. 4507 o 5. 3504b 2. 8123 2. 8123 0.094 2. 5381 0 5. 5051‘” 2. 8123 2. 8123 0.127 2. 6928 o 5. 5683b 2. 8123 2. 8123 0. 136 2. 7560 0 a I I O I Pore pressure increased to Initial backpressure. b O I I Small increases in ax1a1 stress. Deformation rate approximately zero when test was terminated. 239 TABLE 1-24. TRIAXIAL TEST DATA, SAMPLE G-Zl Axial consolidation pressure = 0. 703 kg/cm2 with K0 = 0. 3 Undrained test with 0'l constant and 0' decreasing. 3 Initial water content Final water content = 135. 0% Initial dry density = 31. 26 pcf 0' 0 pore axial 0 7; 1 3 pressure strain 1 3 (kg/cmz) (kg/cmz) (kg/cmz) (kchmZ) (kg/cmz) 3.5153 3.0232 2. 8123 0. 000 0.7030 0. 2109 3.5153 2. 9628 2,7807 0.003 0.7346 0.1821 3.5153 2.9121 2.7561 0. 007 0.7592 0.1560 3.5153 2. 8622 2.7279 0. 009 0.7874 0.1343 3.5153 2,8158 2.7139 0.024 0.8014 0.1019 3.5153 2. 8123 2. 8123a 0. 025 0.7030 0.0000 3.5153 2.8123 2.8123a 0.101 0.7030 0.0000 a . . . . Pore pressure increased to initial backpressure. Deformation rate approximately zero when test was terminated. 240 TABLE I-25. TRIAXIAL TEST DATA, SAMPLE C-2 Unconfined compression test Angle between direction of compression and horizontal = 90 degrees 01f = 0. 268 kg/cm: Initial water content = 162% 03f = 0 kg/cm Final water content 2 162% Cu = 0. 134 kg/cm2 Initial dry density = 28. 17 pcf Load Displace— Pore Axial ment pressure strain 01 0'3 (kg) (cm) (kg/cmz) (kglcmz) (kgAcmz) 0. 0000 0. 0025 -- 0. 0000 0. 0000 0. 0000 1. 8144 0. 0813 0. 0086 0. 0800 2. 4494 0. 1321 0. 0141 0. 1074 2. 9484 0. 1829 0. 0195 0. 1286 3. 4474 0. 2337 0. 0249 0. 1495 3. 8556 0. 2896 0. 0308 0. 1662 5. 3525 0. 5334 0. 0567 0. 2246 6. 2143 0. 7849 0. 0835 0. 2534 6. 7586 1. 0414 0. 1108 0. 2673 6. 8494 1. 1430 0. 1216 0. 2676 6. 3504 1. 2954 0. 1378 0. 2436 01 and 0'3 equal the major and minor tota1 principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 241 TABLE I-26. TRIAXIAL TEST DATA, SAMPLE C-3 Unconfined compression test Angle between direction of compression and horizontal = 90 degrees “If = 0. 311 kg/cm2 Initial water content = 157% 0'3 = 0 kg/cm2 Final water content = 157% f cu = 0. 156 kg/cm2 initial dry density = 28. 83 pcf Load Displace- Pore Axial ment pressure strain 0'1 0'3 2 2 2 (kg) (cm) (kg/cm ) (kg/cm ) 113.2ch 0. 0000 0. 0025 -- 0. 0000 0. 0000 0. 0000 1. 2701 0. 0813 0. 0073 0. 0709 1.7464 0.1321 0.0119 0.0970 2. 1773 0. 1829 0. 0164 0. 1203 2. 5402 0. 2337 O. 0210 0. 1397 2. 9030 0. 2896 0. 0260 0. 1589 4.2638 0.5334 0.0479 0.2281 5. 1710 0. 7849 0. 0705 0. 2701 5.7154 1.0414 0. 0935 0.2911 6. 1690 1. 2954 0. 1163 0. 3064 6. 3504 1. 4224 0. 1277 0. 3113 6. 3958 1. 5494 0. 1391 0. 3094 6. 3050 1. 65 10 0. 1482 0. 3018 (r and 0' equal the major and minor tota1 principal stresses, respectively. 1 3 Failure taken at maximum deviator stress or at 20 percent axial strain. 242 TABLE 1-27. TRIAXIAL TEST DATA, SAMPLE C-4 Unconfined compre ssion test Angle between direction of compression and horizontal = 90 degrees 01 = 0. 204 kg/cm‘2 Initial water content 2 163% f 03f = 0 kg/cm2 Final water content 2 163% cu = 0. 102 kg/cm2 Initial dry density = 27. 64 pcf Load Displace- Pore Axial ment pressure strain 01 0'3 2 2 2 (kg) (cml Ikg/cmj (kg/cm ) (kglcm ) 0. 0000 0. 0025 -- 0. 0000 0. 0000 0. 0000 1. 2247 0. 0813 0. 0069 0. 0637 1. 6330 0. 1321 0. 0113 0. 0846 1. 9505 0. 1829 0. 0156 0. 1006 2.1773 0. 2337 0. 0200 0. 1118 2. 4494 0. 2896 0. 0247 0. 1251 3. 4020 0. 5334 0. 0456 0. 1701 3. 9917 0. 7849 0. 0670 0. 195 1 4. 2638 1. 0414 0. 0889 0. 2035 4. 2185 0. 1684 0. 0998 0. 1989 3. 9917 1. 2954 0. 1106 0. 1860 0'1 and 03 equal the major and minor tota1 principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 243 TABLE I-28. TRIAXIAL TEST DATA, SAMPLE C-5 Unconfined compression test Angle between direction of compression and horizontal = 0 degrees 0'1 = 0. 189 kg/cm2 Initial water content = 169% f 0'3 = 0 kg/cm2 Final water content = 169% f cu = o. 094 kg/cmZ Initial dry density = 27. 73 pcf Load Displace- Pore Axial ment pressure strain 01 03 2 2 2 (kg) (cm) _1kg/cm ) 1kchm ) (141cm ) 0. 0000 0. 0025 -- 0. 0000 0. 0000 0. 0000 1. 4969 0. 0813 0. 0079 0. 0736 1. 9051 0. 1321 0.0129 0.0932 2. 1773 0. 1829 0. 0178 0. 1059 2. 4041 0. 2337 0. 0228 0.1164 2. 6309 0. 2896 0. 0282 0. 1266 3. 4474 0. 5334 0. 05 19 0. 16 19 3. 9463 0. 7849 0. 0764 0. 1805 4. 2412 1. 0414 0. 1014 0. 1888 4. 2638 1.1684 0. 1138 0. 1872 4. 1731 1. 2954 0. 1261 0. 1806 0.1 and 0'3 equal the major and minor tota1 principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 244 TABLE 1-29. TRIAXIAL TEST DATA, SAMPLE C-6 Unconfined compression test Angle between direction of compression and horizontal = 0 degrees 0'1 - 0. 152 kg/cmz Initial water content = 169% f (73 = 0 kg/cm2 Final water content 2 169% f cu = 0. 076 kg/cmz Initial dry density = 27. 75 pcf Load Displace- Pore Axial ment pressure strain 0'1 03 2 2 2 (kg) (cm) (kg/cm ) 044cm ) (kgzcm ) 0. 0000 0. 0025 -- 0. 0000 0. 0000 0. 0000 0. 9072 0. 0813 0. 0075 0. 0483 1. 3608 0.1321 0. 0122 0. 0722 1. 5876 0. 1829 0. 0169 0. 0838 1. 7690 0. 2337 0. 0216 0. 0929 1. 9505 0. 2896 0. 0267 O. 1019 2. 5402 0. 5334 0. 0493 0. 1297 2. 9030 0. 7849 0. 0725 0. 1446 3.1298 1. 0414 0. 0962 0. 1519 3. 1298 1. 1684 0. 1079 0. 1499 2. 9030 1. 2954 0. 1196 0. 1372 0'1 and 0'3 equal the major and minor tota1 principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 245 TABLE 1—30. TRIAXIAL TEST DATA, SAMPLE C-7 Unconfined compression test Angle between direction of compression and horizontal = 45 degrees a’lf — 0. 208 kg/cmZ Initial water content = 170% 03f = 0 kg/cm2 Final water content : 170% cu = 0. 104 kg/cm2 Initial dry density = 28. 35 pcf Load Displace- Pore Axial ment pressure strain 0'1 0'3 LkgL (can (kg/cmzL (kgAmzi (lg/mi 0. 0000 0. 0025 -- 0. 0000 0. 0000 0. 0000 1. 2701 0. 0813 0. 0069 0. 0648 1.6330 0. 1321 0.0113 0.0829 1. 8824 0. 1829 0. 0156 0. 0951 Z. 1092 0. 2337 0. 0199 0. 106 1 2. 3360 0. 2896 0. 0247 0. 1170 3. 0845 0. 5334 0. 0455 0. 15 12 3. 6515 0. 7849 0. 0669 0. 1749 3. 9917 1. 0414 0. 0888 0. 1867 4. 3546 1. 2954 0. 1104 0. 1989 4. 6721 1. 5494 0. 1321 0. 2082 4. 6948 1. 65 10 0. 1408 0. 207 1 4. 4453 1. 8034 0. 1537 0. 1931 0'1 and (r3 equal the major and minor tota1 principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 246 TABLE I-31. TRIAXIAL TEST DATA, SAMPLE C-8 Unconfined compres sion test Angle between direction of compression and horizontal = 45 degrees 0'l = 0. 249 kg/cmz Initial water content = 169% 1' 03 = 0 kg/cm2 Final water content = 16 9% f cu — 0. 124 kg/cm‘2 Initial dry density = 27. 75 pcf Load Displace- Pore Axial ment pressure strain 0'1 0'3 2 (kg) (9311 (kg/cm ) (kg [cm2) (kg [cm2) 0. 0000 0. 0025 -- 0. 0000 0. 0000 0. 0000 0. 7258 0. 0813 0. 0074 0. 0374 1. 3608 0. 1321 0. 0120 0. 0699 1. 8144 0. 1829 0. 0166 0. 0927 2. 2000 0. 2337 0. 0212 0. 1119 2. 5402 0. 2896 0. 0263 0. 1285 3. 9917 0. 5334 0. 0485 0. 1974 4. 8082 0. 7849 0. 0714 0. 2320 5. 2618 1. 0414 0. 0947 0. 2475 5. 3525 1. 1684 0. 1062 0. 2486 5.2618 1.2954 0. 1178 0.2412 01 and 03 equal the major and minor tota1 principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 247 TABLE I-32. TRIAXIAL TEST DATA, SAMPLE C-9 Unconfined compres sion test Angle between direction of compression and horizontal = 90 degrees 01f = 0. 265 kg/cm2 Initial water content = 178% 03f = 0 kg/cm‘2 Final water content = 178% cu = 0. 132 kg/cnnZ Initial dry density = 25. 72 pcf Load Displace- Pore Axial ment pressure strain (1'1 03 (kg) (cm) (kgzcmz) (kgAmz) (kg/cm?) 0. 0000 0. 0025 -- 0. 0000 0. 0000 0. 0000 0. 9072 0. 0559 0. 0056 0. 0445 1.5196 0.1118 0.0113 0.0741 1. 9732 0. 1626 0. 0164 0. 0958 2. 3587 0. 2134 0. 0216 0. 1139 2. 8123 0. 2667 0. 0269 0. 1350 3. 6742 0. 3988 0. 0403 0. 1740 4. 2638 0. 5334 0. 0539 0. 1990 4. 8082 0. 6604 0. 0667 0. 2214 5. 2618 0. 7849 0. 0793 0. 2390 5. 8968 1. 0363 0. 1047 0. 2605 6. 0782 1. 1633 0. 1175 0. 2646 6.1690 1. 2903 0. 1303 0. 2647 6. 1690 1. 3411 0. 1355 0. 2631 5.5793 1.5519 0.1568 0. 2321 5. 3525 1. 6002 0. 1616 0. 2214 0'1 and 0'3 equal the major and minor tota1 principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 248 TABLE I-33. TRIAXIAL TEST DATA, SAMPLE C-10 Axial consolidation pressure = 0. 7030 kg/cmz with K0 2 0. 3 Undrained test with 01 constant and 03 decreasing. Initial water content 2 177. 0% Final water content 2 150. 0% Initial dry density = 26. 94 pcf a 0 pore axial 7‘- 6: 1 3 pressure strain 1 3 (kg/cmz) (kg/cmZ (kgzcmz) (kg/cmz) (kg/cmz) 3.5153 3. 0232 2. 8123 0.0000 0.703 0. 2109 3. 5 153 2. 9881 2. 7982 0. 0005 0. 7171 0. 1899 3.5153 2.9620 2.7912 0.0019 0.7241 0.1708 3. 5153 2. 9360 2. 7877 0. 0045 0. 7276 0. 1483 3.5153 2.9107 2.7912 0.0059 0. 7241 0. 1195 3. 5153 2. 8854 2. 7912 0. 0091 0. 7241 0. 0942 3.5153 2. 8594 2.7912 0.0147 0. 7241 0.0682 3. 5153 2. 8341 2. 7771 0. 0249 0. 7382 0. 0570 3.5153 2. 8123 2.7560 0.0340 0.7593 0. 0563 3.5153 2.8123 2.8123a 0.2591 0.7030 0.0000 a . . . . Pore pressure increased to initial backpressure. Deformation rate approximately zero when test was terminated. 249 TABLE 1-34. TRIAXIAL TEST DATA, SAMPLE C-ll Axial consolidation pressure = 0. 9350 kg/cmZ with K0 = 0. 3 Undrained test with 01 constant and 0'3 decreasing. Initial water content = 174. 5% Final water content = 133. 5% Initial dry density 2 27. 30 pcf 0' 0_ pore axial E F 1 3 pressure strain 1 3 (kg/cmz) (kg/cmz) (kgzcmz) (kg/cmz) (kg/cmz) 3. 7474 3. 0935 2. 8123 0. 0000 0. 9351 0. 2812 3. 7474 3. 0626 2. 7982 0. 0003 0. 9490 0. 2644 3.7474 3. 0373 2.7912 0.0011 0 9561 0.2461 3. 7474 3. 0113 2. 7631 0. 0023 0. 9631 0. 2482 3. 7474 2. 9859 2. 7560 0. 0043 0. 9701 0. 2299 3. 7474 2. 9606 2. 7490 0. 0057 0. 9772 0. 2116 3. 7474 2. 9353 2. 7476 0. 0094 0. 9997 0. 1877 3. 7474 2. 9107 2. 7279 0.0114 1.0193 0. 1715 3. 7474 2. 8854 2.7139 0. 0143 1.0334 0. 1715 3. 7474 2. 8608 2. 6998 0. 0174 1. 0475 0. 1610 3. 7474 2. 8376 2. 6963 0. 0209 1. 0509 0. 1413 3.7474 2.8123 2.7174a 0.0437 1.0298 0.0949 3.7474 2.8123 2.8123b 0.0509 0.9351 0.000 aSmall leak permitted dissipation of reduced pore pressure. Pore pressure increased to initial backpressure. Deformation rate approximately zero when test was terminated. 250 TABLE 1-35. TRIAXIAL TEST DATA, SAMPLE C-14 Axial consolidation pressure = 2. 3430 kg/cm2 with Ko = 0. Undrained test with 0'1 constant and 03 decreasing. Initial water content 2 174. 3% Final water content 2 104. 3% Initial dry density = 27. 26 pcf 0 0 pore axial 0 E 1 3 pressure strain 1 3 (kg/cmfl (kg/cmz) (kg/cm: Gig/cm?) (kglcmz) 5.1553 3.5153 2. 8123 0.0000 2.343 0.703 5.1553 3. 4873 2. 8113 0. 0004 2. 344 0. 676 5. 1553 3. 4313 2. 7983 0. 0007 2. 357 O. 633 5.1553 3. 3743 2. 7843 0. 0012 2. 371 0. 590 5.1553 3. 3253 2.7633 0.0014 2.392 0.562 5.1553 3. 2763 2.7353 0.0018 2.420 0.541 5.1553 3. 2203 2. 7173 0. 0025 2. 438 0. 503 5.1553 3.1633 2. 6793 0. 0032 2. 476 0. 484 5. 1553 3. 1143 2. 6643 0. 0035 2. 491 0. 450 5.1553 3. 0583 2. 6433 0. 0046 2. 512 0. 415 5.1553 3. 0093 2. 6123 0. 0053 2. 543 0. 397 5.1553 2. 9603 2. 6013 0. 0065 2. 554 0. 359 5.1553 2.9033 2.5733 0.0081 2.582 0.330 5.1553 2. 8543 2. 5483 0. 0098 2. 607 0. 306 5.1553 2.8123 2.5313 0.0109 2.624 0.281 5.1553 2.8123 2.8123a 0.1193 2.343 0.0000 a . . . . Pore pressure increased to initial backpressure. Deformation rate approximately zero when test was terminated. 251 TABLE 1-36. PLANE STRAIN TEST DATA, SAMPLE E-l. Axial consolidation pressure 0.703 kg/cm2 with KO = 0.33 61 = 4.662 kg/cm2 Initial water content = 174.1% f 03 = 3.046 kg/cm2 Final water content = 153.1% f uf = 3.046 kg/cm2 Initial dry density = 26.3 pcf Af = 0.20 cu = 0.808 kg/cm2 Load Displace- Pore Axial _ _ ment pressure strain 0 0 2 1 2 3 2 (kg) (cm) (kg/cm ) (kg/cm ) (kg/cm ) 9.3169 0.0000 2.8123 0.0000 .7030 .2341 14.0616 .0330 2.8925 .0050 .8582 1540 17.4182 .1168 2.9775 .0176 .9302 .0689 18.7337 .2159 2.9951 .0325 .9636 .0513 20.0945 .3150 3.0120 .0473 .9979 .0345 21.6821 .4089 3.0268 .0615 1.0439 0197 24.0862 .5334 3.0324 .0802 1.1291 .0141 26.3088 .6731 3.0352 .1012 1.2014 .0112 28.8943 .7874 3.0802 .1184 1.2906 .0084 31.5252 .8890 3.0408 .1336 1.3803 .0056 34.7911 1.0033 3.0465 .1508 1.4870 .0000 38.5560 1.1125 3.0465 .1672 1.6160 .0000 5] and 53 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 252 TABLE I-37. PLANE STRAIN TEST DATA, SAMPLE E-2. 2 Axial consolidation pressure 1.407 kg/cm with K0 = 0.33 01f = 6.370 kg/cm2 Initial water content = 170.3% 03f = 3.281 kg/cm2 Final water content = 131.6% uf = 3.178 kg/cm2 Initial dry density = 26.2 pcf Af ' 0.17 cu = 1.545 kg/cm2 Load Displace- Pore Axial _ _ ment pressuge strain 01 2 03 2 (kg) (cm) (kg/cm ) (kg/cm ) (kg/cm ) 18.6384 0.0000 2.8123 0.0000 1.4067 .4690 27.2160 .0254 2.9951 .0043 1.6495 .2862 34.0200 .1143 3.1357 .0194 1.8239 .1455 35.3808 .1778 3.1639 .0302 1.8437 .1174 37.1952 .2286 3.1744 .0388 1.9055 .1069 39.0096 .2921 3.1955 .0496 1.9510 .0858 51.2776 .3632 3.2061 .0617 2.0238 .0752 44.4528 .4369 3.2166 .0742 2.1352 .0647 46.7208 .5080 3.2201 .0863 2.2089 .0612 49.4424 .5842 3.2271 .0993 2.2948 .0541 52.1640 .6604 3.2271 .1122 2.3841 .0541 54.8856 .7264 3.2342 .1234 2.4677 .0471 61.6896 .8763 3.2342 .1489 2.6887 .0471 70.7616 1.0160 3.2061 .1746 3.0208 .0752 76.2048 1.1430 3.1779 .1942 3.1928 .1034 01 and 53 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 253 TABLE 1-38. PLANE STRAIN TEST DATA. SAMPLE E-3. Axial consolidation pressure 2.109 kg/cm2 with KO = 0.33 61f = 8.816 kg/cm2 Initial water content = 170.0% 03f = 3.515 kg/cm2 Final water content = 122. % uf = 3.515 kg/cm2 Initial dry density = 26.5 pcf Af = 0.18 cu = 2.650 kg/cm2 Load Displace- Pore Axial _ _ ment pressuge strain 01 2 03 2 (kg) (cm) (kg/cm ) (kg/cm ) (kg/cm ) 27.9418 0.0000 2.8123 0.0000 2.1091 .7031 34.0200 .0127 2.9529 .0025 2.2701 .5625 44.4528 .0254 3.1498 .0049 2.5914 .3656 53.5248 .0762 3.3467 .0147 2.8224 .1687 58.5144 .1270 3.4381 .0245 2.9495 .0773 62.5968 .1905 3.4943 .0368 3.0550 .0211 66.6792 .2540 3.5154 .0491 3.1906 0.0000 70.7616 .3302 3.5154 .0638 3.3335 0.0000 76.2048 .4064 3.5154 .0785 3.5335 0.0000 81.6480 .4826 3.5154 .0932 3.7255 0.0000 86.1840 .5563 3.5154 .1074 3.8707 0.0000 92.9880 .6274 3.5154 .1212 4.1120 0.0000 104.3280 .7747 3.5154 .1496 4.4641 0.0000 117.9360 .9169 3.5154 .1771 4.8833 0.0000 131.5440 1.0312 3.5154 .1992 5.3007 0.0000 5] and 63 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 254 TABLE 1-39. PLANE STRAIN TEST DATA, SAMPLE E-4. Axial consolidation pressure 2.109 kg/cm2 with K0 = 0.33 01f = 7.588 kg/cm2 Initial water content = 167.4% 03f = 3.515 kg/cm2 Final water content = 119.6% uf = 3.501 kg/cm2 Initial dry density = 27.5 pcf Af = 0.25 cu = 2.037 kg/cm2 Load Displace- Pore Axial _ _ ment pressuge strain 01 2 03 2 (kg) (cm) (kg/cm ) (kg/cm ) (kg/cm ) 27.9418 0.0000 2.8123 0.0000 2.1089 .7031 33.1128 .0127 2.9881 .0024 2.1894 .5273 39.9168 .0254 3.1498 .0047 2.3645 .3656 45.3600 .0762 3.2975 .0142 2.4679 .2180 48.0816 .1270 3.3748 - .0236 2.5027 .1406 49.8960 .1905 3.4170 .0354 2.5200 .0984 53.0712 .2540 3.4451 .0472 2.6145 .0703 57.1536 .3302 3.4662 .0613 2.7484 .0492 60.7824 .4064 3.4803 .0755 2.8624 .0352 64.4112 .4826 3.4873 .0897 2.9783 .0281 68.9472 .5563 3 4943 .1033 3.1316 .0211 73.4832 .6274 3.5013 .1166 3.2804 .0141 83.4624 .7747 3.5084 .1439 3.6020 .0070 90.7200 .9169 3.5013 .1703 3.8010 .0141 99.7920 1.0160 3.5013 .1887 4.0873 .0141 5] and 63 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 255 TABLE I-40. PLANE STRAIN TEST DATA, SAMPLE E-S. Axial consolidation pressure 1.408 kg/cm2 with KO = 0.33 01f = 6.421 kg/cm2 Initial water content = 161.9% 03f = 3.281 kg/cm2 Final water content = 132.4% uf = 3.258 kg/cm2 Initial dry density = 27.0 pcf Af = 0.20 cu = 1.57 kg/cm2 Load Displace- Pore Axial _ _ ment pressuge strain 01 2 03 2 (kg) (cm) (kg/cm ) (kg/cm 1 (kg/cm ) 18.6430 0.0000 2.8123 0.0000 1.4075 .4690 22.6800 .0508 2.9108 .0099 1.5010 .3705 25.8552 .1143 2.9529 .0222 1.6011 .3283 32.6592 .1778 3.1006 .0345 1.7681 .1807 36.2880 .2286 3.1498 .0444 1.8772 .1315 39.4632 .2921 3.1814 .0567 1.9739 .0998 42.6384 .3607 3.2061 .0700 2.0715 .0752 45.3600 .4318 3.2201 .0838 2.1534 .0612 48.0816 .5080 3.2271 .0986 2.2361 .0541 51.7104 .5842 3.2342 .1133 2.3552 .0471 55.3392 .6604 3.2412 .1281 2.4690 .0401 58.9680 .7239 3.2412 .1404 2.5917 .0401 68.0400 .8763 3.2588 .1700 2.8654 .0225 77.1120 1.0160 3.2588 .1971 3.1392 .0225 86.1840 1.1684 3.2588 .2267 3.3776 .0225 90.7200 1.2243 3.2623 .2375 3.5012 .0190 5] and 53 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 256 TABLE I-4l. TRIAXIAL TEST DATA. SAMPLE E-lD. Axial consolidation pressure 2.291 kg/cm2 with Ko = 0.33 o] = 7.895 kg/cm2 Initial water content = 174.8% 03 = 3.515 kg/cm2 Final water content = 117.1% uf = 3.487 kg/cm2 Initial dry density = 26.6 pcf Af = 0.24 cu = 2.190 kg/cm2 Load Displace- Pore Axial _ _ ment pressuge strain 011 2 03 2 (kg) (cm) (kg/cm ) (kg/cm ) (kg/cm ) 27.9418 0.0000 2 8123 0.0000 2.2910 .7031 40.8240 .0508 3.1217 .0067 2.6982 .3937 47.1744 .1143 3.2623 .0150 2.8938 .2531 49.8960 .1778 3.2061 .0233 3.0788 .3094 52.6176 .2286 3.3889 .0300 3.0271 .1266 54.4320 .2921 3.4170 .0383 3.0733 .0984 57.6072 .3607 3.4881 .0473 3.1963 .0773 59.8752 .4318 3.4521 .0566 3.2733 .0633 62.5968 .5080 3.4592 .0666 3.3767 .0562 65.3184 .5842 3.4662 .0766 3.4770 .0492 68.9472 .6604 3.4732 .0866 3.6212 .0422 72.5760 .7239 3 4732 .0949 3.7753 .0422 79.8336 .8763 3.4732 .1148 4.0580 .0422 88.9056 1 0160 3.4873 .1332 4.4077 .0281 90.7200 1.1938 3.4943 .1565 4.3699 .0211 5] and 53 equal the major and minor effective principal stresses, respectively. axial strain. 257 Failure taken at maximum deviator stress or at 20 percent TABLE I-42. TRAIXIAL TEST DATA, SAMPLE E-ll. Axial consolidation pressure 1.366 kg/cm2 with K0 = 0.33 01 = 5.548 kg/cm2 Initial water content = 172.1% f 03 = 3.281 kg/cmz Final water content = 130 % f uf = 3.276 kg/cm2 Initial dry density = 27.5 pcf - _ 2 Af — 0.34 cu - 1.134 kg/cm Load Displace- Pore Axial _ _ ment pressure strain 01 03 (kg) (cm) (kg/cm?) (kg/cm 1 (kg/cmz) 18.6430 0.0000 2.8123 0.0000 1.3657 .4690 24.4944 .0508 2.9318 .0067 1.5198 .3494 27.2160 .1143 3.0162 .0150 1.5545 .2651 29.0304 .1778 3.0795 .0234 1.5655 .2018 29.9376 .2286 3.1287 .0301 1.5493 .1526 30.8448 .2921 3.1639 .0385 1.5441 .1174 32.2056 .3607 3.1850 .0475 1.5719 .0963 33.3396 .4318 3.2061 .0569 1.5878 .0752 34.4736 .5080 3.2201 .0669 1.6085 .0612 35.8344 .5842 3.2342 .0769 1.6382 .0471 38.5560 .7239 3.2482 .0953 1.7109 .0330 41.2776 .8763 3.2553 .1154 1.7825 .0260 44.9064 1.0160 3.2623 .1338 1.8901 .0190 48.9888 1.1684 3.2623 .1538 2.0130 .0190 52.6176 1.3208 3.2693 .1739 2.1028 .0120 58.9680 1.5240 3.2764 .2007 2.2723 .0049 5] and 63 equal the major and minor effective principal stresses, respectively. Failure taken at maximum deviator stress or at 20 percent axial strain. 258 TABLE I-43. TRIAXIAL TEST DATA, SAMPLE E-12. Axial consolidation pressure 0.670 kg/cm2 with Ko = 0.33 2 01f = 4.222 kg/cm Initial water content = 173.4% 03f = 3.046 kg/cm2 Final water content = 154.4% uf = 3.044 kg/cm2 Initial dry density = 26.9 pcf Af = 0.31 cu = 0.588 kg/cm2 Load Displace- Pore Axial _ _ ment pressuge strain 01 2 03 2 (kg) (cm) (kg/cm ) (kg/cm ) (kg/cm ) 9.2988 0.0000 2.8123 0.0000 .6701 .2341 13.1544 .0508 2.8967 .0058 .7629 .1498 14.5152 .1143 2.9318 .0129 .7863 .1146 15.4224 .1778 2.9529 .0201 .8019 .0935 16.3296 .2286 2.9670 .0259 .8251 .0794 16.7832 .2921 2.9881 .0331 .8191 .0584 17.6904 .4318 3.0092 .0489 .8260 .0373 19.0512 .5740 3.0233 .0650 .8582 .0232 20.1852 .7239 3.0303 .0820 .8848 .0162 21.7728 .8763 3.0373 .0993 .9285 .0091 22.9068 1.0160 3.0443 .1151 .9524 .0021 24.4944 1.1684 3.0443 .1324 .9984 .0021 25.8552 1.3208 3.0443 .1496 1.0328 .0021 28.1232 1.5265 3.0443 .1729 1.0925 .0021 29.4840 1.6510 3.0443 .1870 1.1258 .0021 31.7520 1.8542 3.0443 .2100 1.1780 .0021 5] and 53 equal the major and minor effective principal stresses, respective1y. Failure taken at maximum deviator stress or at 20 percent axial strain. 259 "I1111111111111111111111111111111111111ES