Soil Mechanics and Foundations

Cover......Page 1
Title Page......Page 3
Copyright......Page 4
PREFACE......Page 5
ACKNOWLEDGMENTS......Page 6
NOTES FOR STUDENTS AND INSTRUCTORS......Page 7
NOTES FOR INSTRUCTORS......Page 9
CONTENTS......Page 12
1.0 Introduction......Page 19
1.1 Marvels of Civil Engineering—The Hidden Truth......Page 20
1.2 Geotechnical Lessons from Failures......Page 21
2.1 Definitions of Key Terms......Page 23
2.3.2 Plate Tectonics......Page 24
2.3.3 Composition of the Earth’s Crust......Page 25
2.3.5 Geologic Cycle and Geological Time......Page 26
2.4.2 Soil Types......Page 28
2.4.3 Clay Minerals......Page 29
2.4.4 Surface Forces and Adsorbed Water......Page 30
2.4.5 Soil Fabric......Page 31
2.5.1 Particle Size of Coarse-Grained Soils......Page 33
2.5.2 Particle Size of Fine-Grained Soils......Page 34
2.5.3 Characterization of Soils Based on Particle Size......Page 35
2.7 Summary......Page 42
Exercises......Page 43
3.0 Introduction......Page 44
3.4 Phases of a Soils Investigation......Page 45
3.5.1 Soils Exploration Methods......Page 47
3.5.2 Soil Identification in the Field......Page 50
3.5.3 Number and Depths of Boreholes......Page 52
3.5.4 Soil Sampling......Page 53
3.5.5 Groundwater Conditions......Page 54
3.5.7 Types of In Situ or Field Tests......Page 55
3.5.8 Types of Laboratory Tests......Page 61
3.6 Soils Report......Page 64
Exercises......Page 65
4.0 Introduction......Page 66
4.2 Questions to Guide Your Reading......Page 67
4.3 Phase Relationships......Page 68
4.4 Physical States and Index Properties of Fine-Grained Soils......Page 79
4.5.1 Casagrande Cup Method—ASTM D 4318......Page 82
4.5.3 Fall Cone Method to Determine Liquid and Plastic Limits......Page 83
4.5.4 Shrinkage Limit—ASTM D 427 and D 4943......Page 84
4.6 Soil Classification Schemes......Page 88
4.6.2 American Society for Testing and Materials (ASTM) Classification System......Page 89
4.6.3 AASHTO Soil Classification System......Page 92
4.7 Engineering Use Chart......Page 94
4.8 Summary......Page 98
Practical Examples......Page 99
Exercises......Page 101
5.0 Introduction......Page 105
5.3 Basic Concept......Page 106
5.4 Proctor Compaction Test—ASTM D 1140 and ASTM D 1557......Page 107
5.5 Interpretation of Proctor Test Results......Page 109
5.6 Benefits of Soil Compaction......Page 113
5.7 Field Compaction......Page 114
5.8.1 Sand Cone—ASTM D 1556......Page 115
5.8.3 Nuclear Density Meter—ASTM D 2922, ASTM D 5195......Page 118
5.8.4 Comparison Among the Popular Compaction Quality Control Tests......Page 119
Practical Example......Page 120
Exercises......Page 121
6.2 Questions to Guide Your Reading......Page 123
6.3 Head and Pressure Variation in a Fluid at Rest......Page 124
6.4 Darcy’s Law......Page 127
6.5 Empirical Relationships for k......Page 129
6.6 Flow Parallel to Soil Layers......Page 134
6.8 Equivalent Hydraulic Conductivity......Page 135
6.9.1 Constant-Head Test......Page 136
6.9.2 Falling-Head Test......Page 137
6.9.3 Pumping Test to Determine the Hydraulic Conductivity......Page 140
6.10 Groundwater Lowering by Wellpoints......Page 142
Practical Example......Page 144
Exercises......Page 145
7.0 Introduction......Page 149
7.3.1 Normal Stresses and Strains......Page 151
7.3.3 Shear Stresses and Shear Strains......Page 152
7.4.1 Material Responses to Normal Loading and Unloading......Page 153
7.4.2 Material Response to Shear Forces......Page 155
7.4.3 Yield Surface......Page 156
7.5.1 General State of Stress......Page 157
7.5.3 Displacements from Strains and Forces from Stresses......Page 158
7.6.1 Plane Strain Condition......Page 159
7.6.2 Axisymmetric Condition......Page 160
7.7 Anisotropic, Elastic States......Page 163
7.8 Stress and Strain States......Page 164
7.8.1 Mohr’s Circle for Stress States......Page 165
7.8.2 Mohr’s Circle for Strain States......Page 166
7.9.1 The Principle of Effective Stress......Page 169
7.9.2 Effective Stresses Due to Geostatic Stress Fields......Page 170
7.9.3 Effects of Capillarity......Page 171
7.9.4 Effects of Seepage......Page 172
7.10 Lateral Earth Pressure at Rest......Page 179
7.11 Stresses in Soil from Surface Loads......Page 180
7.11.1 Point Load......Page 181
7.11.3 Line Load Near a Buried Earth-Retaining Structure......Page 183
7.11.4 Strip Load......Page 184
7.11.5 Uniformly Loaded Circular Area......Page 185
7.11.6 Uniformly Loaded Rectangular Area......Page 188
7.11.7 Approximate Method for Rectangular Loads......Page 190
7.11.8 Vertical Stress Below Arbitrarily Shaped Area......Page 193
7.11.9 Embankment Loads......Page 195
Practical Examples......Page 196
Exercises......Page 199
8.0 Introduction......Page 204
8.3.2 Deviatoric or Shear Stress......Page 205
8.3.6 Plane Strain, ε₂ = 0......Page 206
8.3.7 Hooke’s Law Using Stress and Strain Invariants......Page 207
8.4.1 Basic Concept......Page 209
8.4.2 Plotting Stress Paths Using Stress Invariants......Page 210
8.4.3 Plotting Stress Paths Using Two-Dimensional Stress Parameters......Page 214
8.4.4 Procedure for Plotting Stress Paths......Page 215
Practical Example......Page 221
Exercises......Page 223
9.0 Introduction......Page 225
9.1 Definitions of Key Terms......Page 226
9.3 Basic Concepts......Page 227
9.3.1 Instantaneous Load......Page 228
9.3.3 Secondary Compression......Page 229
9.3.6 Effective Stress Changes......Page 230
9.3.8 Effects of Vertical Stresses on Primary Consolidation......Page 231
9.3.9 Primary Consolidation Parameters......Page 232
9.3.10 Effects of Loading History......Page 233
9.4.1 Effects of Unloading/Reloading of a Soil Sample Taken from the Field......Page 234
9.4.2 Primary Consolidation Settlement of Normally Consolidated Fine-Grained Soils......Page 235
9.4.4 Procedure to Calculate Primary Consolidation Settlement......Page 236
9.4.5 Thick Soil Layers......Page 237
9.5.1 Derivation of Governing Equation......Page 243
9.5.2 Solution of Governing Consolidation Equation Using Fourier Series......Page 245
9.5.3 Finite Difference Solution of the Governing Consolidation Equation......Page 247
9.6 Secondary Compression Settlement......Page 252
9.7.1 Oedometer Test......Page 253
9.7.2 Determination of the Coefficient of Consolidation......Page 254
9.7.3 Determination of Void Ratio at the End of a Loading Step......Page 256
9.7.4 Determination of the Past Maximum Vertical Effective Stress......Page 257
9.7.6 Determination of the Modulus of Volume Change......Page 258
9.7.7 Determination of the Secondary Compression Index......Page 259
9.8 Relationship Between Laboratory and Field Consolidation......Page 261
9.9 Typical Values of Consolidation Settlement Parameters and Empirical Relationships......Page 263
9.10 Preconsolidation of Soils Using Wick Drains......Page 264
9.11 Summary......Page 267
Practical Examples......Page 268
Exercises......Page 275
10.0 Introduction......Page 279
10.3 Typical Response of Soils to Shearing Forces......Page 280
10.3.1 Effects of Increasing the Normal Effective Stress......Page 283
10.3.2 Effects of Overconsolidation Ratio......Page 284
10.3.4 Effects of Cohesion......Page 285
10.3.5 Effects of Soil Tension......Page 286
10.4 Four Models for Interpreting the Shear Strength of Soils......Page 287
10.4.1 Coulomb’s Failure Criterion......Page 288
10.4.2 Taylor’s Failure Criterion......Page 292
10.4.3 Mohr–Coulomb Failure Criterion......Page 293
10.4.4 Tresca Failure Criterion......Page 295
10.5 Practical Implications of Failure Criteria......Page 296
10.6 Interpretation of the Shear Strength of Soils......Page 298
10.7.2 Shear Box or Direct Shear Test......Page 304
10.7.3 Conventional Triaxial Apparatus......Page 309
10.7.4 Unconfined Compression (UC) Test......Page 311
10.7.5 Consolidated Drained (CD) Compression Test......Page 313
10.7.6 Consolidated Undrained (CU) Compression Test......Page 318
10.7.7 Unconsolidated Undrained (UU) Test......Page 322
10.8 Porewater Pressure Under Axisymmetric Undrained Loading......Page 323
10.9.1 Simple Shear Apparatuses......Page 325
10.9.2 True Triaxial Apparatus......Page 329
10.9.3 Hollow-Cylinder Apparatus......Page 330
10.10.2 The Standard Penetration Test (SPT)......Page 331
10.12 Empirical Relationships for Shear Strength Parameters......Page 332
Practical Examples......Page 334
Exercises......Page 338
11.0 Introduction......Page 342
11.2 Questions to Guide Your Reading......Page 343
11.3.1 Parameter Mapping......Page 344
11.3.3 Soil Yielding......Page 346
11.3.4 Prediction of the Behavior of Normally Consolidated and Lightly Overconsolidated Soils Under Drained Condition......Page 347
11.3.5 Prediction of the Behavior of Normally Consolidated and Lightly Overconsolidated Soils Under Undrained Condition......Page 350
11.3.6 Prediction of the Behavior of Heavily Overconsolidated Soils Under Drained and Undrained Condition......Page 353
11.3.8 Critical State Boundary......Page 355
11.3.10 Effects of Effective and Total Stress Paths......Page 356
11.4.1 Yield Surface......Page 357
11.4.2 Critical State Parameters......Page 358
11.5.1 Drained Triaxial Test......Page 363
11.5.2 Undrained Triaxial Test......Page 365
11.6 Modifications of CSM and Their Practical Implications......Page 379
11.7.1 Relationship Between Normalized Yield (peak) Shear Stress and Critical State Shear Stress Under Triaxial Drained Condition......Page 383
11.7.2 Relationship Among the Tension Cutoff, Mean Effective Stress, and Preconsolidation Stress......Page 385
11.7.3 Relationship Among Undrained Shear Strength, Critical State Friction Angle, and Preconsolidation Ratio......Page 387
11.7.4 Relationship Between the Normalized Undrained Shear Strength at the Critical State for Normally Consolidated and Overconsolidated Fine-Grained Soils......Page 388
11.7.5 Relationship Between the Normalized Undrained Shear Strength of One-Dimensionally Consolidated or K[sub o]-Consolidated and Isotropically Consolidated Fine-Grained Soils......Page 389
11.7.6 Relationship Between the Normalized Undrained Shear Strength at Initial Yield and at Critical State for Overconsolidated Fine-Grained Soils Under Triaxial Test Condition......Page 392
11.7.7 Undrained Shear Strength Under Direct Simple Shear (plane strain) Condition......Page 394
11.7.8 Relationship Between Direct Simple Shear Tests and Triaxial Tests......Page 395
11.7.9 Relationship for the Application of Drained and Undrained Conditions in the Analysis of Geosystems......Page 396
11.7.10 Relationship Among Excess Porewater Pressure, Preconsolidation Ratio, and Critical State Friction Angle......Page 399
11.7.13 Compressibility Indices (λ and C[sub(c)] and Plasticity Index......Page 400
11.7.15 Summary of Relationships Among Some Soil Parameters from CSM......Page 401
11.8 Soil Stiffness......Page 407
11.9.1 Volumetric Strains......Page 411
11.9.2 Shear Strains......Page 413
11.10 Calculated Stress–Strain Response......Page 417
11.10.2 Undrained Compression Tests......Page 418
11.11 Application of CSM to Cemented Soils......Page 425
11.12 Summary......Page 426
Practical Examples......Page 427
Exercises......Page 436
12.0 Introduction......Page 440
12.1 Definitions of Key Terms......Page 441
12.2 Questions to Guide Your Reading......Page 442
12.3 Allowable Stress and Load and Resistance Factor Design......Page 443
12.4.1 Soil Response to a Loaded Footing......Page 444
12.4.2 Conventional Failure Surface Under Footing......Page 446
12.5 Collapse Load Using the Limit Equilibrium Method......Page 447
12.6 Bearing Capacity Equations......Page 449
12.7 Mat Foundations......Page 461
12.8 Bearing Capacity of Layered Soils......Page 463
12.9 Building Codes Bearing Capacity Values......Page 465
12.10 Settlement......Page 466
12.11.1 Immediate Settlement......Page 468
12.11.2 Primary Consolidation Settlement......Page 472
12.12.1 Standard Penetration Test (SPT)......Page 475
12.12.2 Cone Penetration Test (CPT)......Page 478
12.12.3 Plate Load Test (PLT)......Page 481
12.13 Shallow Foundation Analysis Using CSM......Page 482
12.13.1 Heavily Overconsolidated Fine-Grained Soil......Page 483
12.13.2 Dense, Coarse-Grained Soils......Page 489
12.14 Horizontal Elastic Displacement and Rotation......Page 503
12.15 Summary......Page 504
Practical Examples......Page 505
Exercises......Page 524
13.1 Definitions of Key Terms......Page 527
13.2 Questions to Guide Your Reading......Page 528
13.3 Types of Piles and Installations......Page 529
13.3.5 Composites......Page 530
13.3.6 Pile Installation......Page 532
13.4 Basic Concept......Page 533
13.5 Load Capacity of Single Piles......Page 539
13.6 Pile Load Test (ASTM D 1143)......Page 540
13.7.1 α-Method......Page 549
13.7.2 β-Method......Page 550
13.8 Pile Load Capacity of Driven Piles Based on SPT and CPT Results......Page 557
13.8.2 CPT......Page 558
13.9 Load Capacity of Drilled Shafts......Page 562
13.10 Pile Groups......Page 564
13.11 Elastic Settlement of Piles......Page 570
13.12 Consolidation Settlement Under a Pile Group......Page 572
13.13 Procedure to Estimate Settlement of Single and Group Piles......Page 573
13.14 Settlement of Drilled Shafts......Page 577
13.15 Piles Subjected to Negative Skin Friction......Page 578
13.16 Pile-Driving Formulas and Wave Equation......Page 580
13.17 Laterally Loaded Piles......Page 581
13.18 Micropiles......Page 585
Practical Examples......Page 586
Exercises......Page 593
14.1 Definitions of Key Terms......Page 597
14.3 Two-Dimensional Flow of Water Through Porous Media......Page 598
14.4.2 Flownet for Isotropic Soils......Page 601
14.4.3 Flownet for Anisotropic Soil......Page 603
14.5.3 Static Liquefaction, Heaving, Boiling, and Piping......Page 604
14.5.6 Uplift Forces......Page 605
14.6 Finite Difference Solution for Two-Dimensional Flow......Page 610
14.7 Flow Through Earth Dams......Page 616
14.8 Soil Filtration......Page 620
Practical Examples......Page 621
Exercises......Page 624
15.0 Introduction......Page 628
15.2 Questions to Guide Your Reading......Page 629
15.3 Basic Concepts of Lateral Earth Pressures......Page 630
15.4 Coulomb’s Earth Pressure Theory......Page 638
15.5 Rankine’s Lateral Earth Pressure for a Sloping Backfill and a Sloping Wall Face......Page 641
15.6 Lateral Earth Pressures for a Total Stress Analysis......Page 643
15.7 Application of Lateral Earth Pressures to Retaining Walls......Page 645
15.8 Types of Retaining Walls and Modes of Failure......Page 648
15.9.1 Translation......Page 651
15.9.4 Deep-Seated Failure......Page 652
15.9.6 Procedures to Analyze Rigid Retaining Walls......Page 653
15.10.1 Analysis of Sheet Pile Walls in Uniform Soils......Page 661
15.10.3 Consideration of Tension Cracks in Fine-Grained Soils......Page 663
15.10.4 Methods of Analyses......Page 664
15.10.6 Analysis of Anchored Sheet Pile Walls......Page 666
15.11 Braced Excavation......Page 677
15.12 Mechanical Stabilized Earth Walls......Page 684
15.12.2 Stability of Mechanical Stabilized Earth Walls......Page 685
15.13.1 Modular Gravity Walls......Page 693
Practical Examples......Page 694
Exercises......Page 700
16.1 Definitions of Key Terms......Page 705
16.3 Some Types of Slope Failure......Page 706
16.4.1 Erosion......Page 707
16.4.6 Construction Activities......Page 709
16.5 Infinite Slopes......Page 710
16.7 Rotational Slope Failures......Page 715
16.8.1 Bishop’s Method......Page 717
16.8.2 Janbu’s Method......Page 720
16.8.3 Cemented Soils......Page 721
16.9 Application of the Method of Slices......Page 722
16.10 Procedure for the Method of Slices......Page 723
16.11.1 Taylor’s Method......Page 731
16.11.2 Bishop–Morgenstern Method......Page 732
16.12 Factor of Safety (FS)......Page 733
Practical Example......Page 734
Exercises......Page 737
APPENDIX A: A COLLECTION OF FREQUENTLY USED SOIL PARAMETERS AND CORRELATIONS......Page 741
APPENDIX B: DISTRIBUTION OF VERTICAL STRESS AND ELASTIC DISPLACEMENT UNDER A UNIFORM CIRCULAR LOAD......Page 748
APPENDIX C: DISTRIBUTION OF SURFACE STRESSES WITHIN FINITE SOIL LAYERS......Page 749
APPENDIX D: LATERAL EARTH PRESSURE COEFFICIENTS (KERISEL AND ABSI, 1990)......Page 752
REFERENCES......Page 756
INDEX......Page 760