In-depth coverage that spans the full
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“Moreover, the inclusion of theory, measurement techniques and exercises at the end of each chapter provides a comprehensive teaching resource. For a soil scientist beginning to learn about soil mechanics, this textbook would be a very good choice.” (European Journal of Soil Science, 1 August 2010)
"Designed for practitioners and students in civil engineering, geotechnical engineering, structural engineering, and geology, his text is the first to provide an equal and integrated coverage of sedimentary and residual soils and their unique engineering properties." (Book News, December 2009)
Table of Contents
CONTENTS
PREFACE xv
ACKNOWLEDGMENTS xix
1 SOIL FORMATION, COMPOSITION, AND BASIC CONCEPTS 1
1.1 Weathering Processes, Sedimentary and Residual Soils / 1
1.2 Clay Minerals / 3
1.3 Influence of Topography on Weathering Processes / 5
1.4 Factors Governing the Properties of Sedimentary and Residual Soils / 6
1.5 Remolded, or Destructured, Soils / 10
References / 11
2 BASIC DEFINITIONS AND PHASE RELATIONSHIPS 13
2.1 Components of Soil / 13
2.2 Phase Relationships / 14
2.3 Examples in Use of Phase Relationships / 17
2.4 Measurement of Basic Properties / 22
2.4.1 Bulk Density / 22
2.4.2 Water Content / 22
2.4.3 Solid Density and Specific Gravity / 22
Exercises / 24
3 BASIC INDEX TESTS, SOIL CLASSIFICATION AND DESCRIPTION 27
3.1 General / 27
3.1.1 Gravel and Sand / 27
3.1.2 Clay / 28
3.1.3 Silt / 28
3.2 Particle Size and Its Role in Influencing Properties / 28
3.2.1 Measurement of Particle Size / 29
3.3 Plasticity and Atterberg Limits / 31
3.3.1 Determination of Atterberg Limits / 31
3.4 Liquidity Index of Clay and Relative Density of Sand / 35
3.5 Sensitivity, Thixotropy, and Activity of Clays / 36
3.6 Systematic Classification Systems / 37
3.6.1 Unified Soil Classification System / 38
3.6.2 Additional Notes Regarding Classification / 40
3.6.3 Description of In situ (Undisturbed) Characteristics of Soil / 42
3.7 Classification of Residual Soils / 44
3.7.1 Parent Rock / 45
3.7.2 Usefulness of Existing Systems / 45
3.7.3 Classification of Weathering Profile / 46
3.7.4 Importance of Mineralogy and Structure / 47
References / 48
4 STRESS AND PORE PRESSURE STATE IN THE GROUND 49
4.1 Vertical Stress in the Ground / 49
4.2 Pore Pressures above Water Table and Seasonal Variations / 50
4.2.1 Case A: Coarse-Grained Soils / 52
4.2.2 Case B: Low-Permeability Clays / 53
4.2.3 Case C: Medium- to High-Permeability Clays / 53
4.3 Hill Slopes, Seepage, and Pore Pressures / 55
4.4 Significance of the Water Table (or Phreatic Surface) / 56
4.5 Horizontal Stress in Ground / 57
4.6 Worked Examples / 60
4.6.1 Worked Example 1 / 60
4.6.2 Worked Example 2 / 62
References / 64
Exercises / 64
5 STRESSES IN THE GROUND FROM APPLIED LOADS 67
5.1 General / 67
5.2 Elastic Theory Solutions for Stresses Beneath Loaded Areas / 68
References / 74
Exercises / 75
6 PRINCIPLE OF EFFECTIVE STRESS 77
6.1 The Basic Principle / 77
6.2 Applied Stresses, Drained and Undrained Behavior / 80
6.3 Pore Pressure Changes Under Undrained Conditions / 81
6.4 Some Practical Implications of the Principle of Effective Stress / 83
6.4.1 Stress State on Soil Element Below Submerged Surface (Bed of Lake or Seabed) / 83
6.4.2 Force Resisting Sliding of Concrete Gravity Dam / 84
6.4.3 Influence of Rainfall on Slope Stability / 85
6.4.4 Ground Settlement Caused By Lowering Water Table / 86
References / 87
7 PERMEABILITY AND SEEPAGE 89
7.1 General / 89
7.2 Pressure, “Head,” and Total Head / 90
7.3 Darcy’s Law / 92
7.3.1 Notes on Darcy’s Law / 92
7.3.2 Note on Seepage Velocity / 92
7.4 Measurement of Permeability / 93
7.5 General Expression for Seepage in a Soil Mass / 95
7.6 Steady-State Flow, Laplace Equation, and Flow Nets / 97
7.6.1 Flow nets—Conventions Used in Their Construction / 99
7.6.2 Boundary Conditions for Flow Nets / 100
7.6.3 Methods for Solution of Flow Nets / 101
7.6.4 Basic Requirements of Flow Net and Rules for Hand Sketching Flow Nets / 102
7.6.5 Use of Flow Nets for Practical Purposes / 103
7.7 Critical Hydraulic Gradient (and “Quicksand”) / 104
7.7.1 Quicksand / 106
7.7.2 Worked Example / 106
7.8 Unconfined Flow Nets and Approximations in Conventional Formulation / 108
7.9 Use of Filters in Designed Structures / 109
7.10 Vertical Flow Through Single Layers and Multilayers / 111
7.11 Note on Groundwater Studies and Groundwater Mechanics / 113
7.12 Flow into Excavations, Drains, and Wells / 115
References / 117
Exercises / 117
8 COMPRESSIBILITY, CONSOLIDATION, AND SETTLEMENT 121
8.1 General Concepts / 121
8.2 Estimation of Settlement Using Elasticity Theory / 122
8.2.1 Drained and Undrained Behavior / 123
8.2.2 Limitations of Elasticity Theory / 124
8.3 Estimation of Settlement Assuming 1-D Behavior / 124
8.4 Immediate (“Elastic”) Settlement and Long-Term (Consolidation) Settlement / 126
8.4.1 Immediate and Consolidation Settlement in Sands / 126
8.4.2 Immediate and Consolidation Settlement in Clays / 126
8.5 Consolidation Behavior of Clays (and Silts) / 129
8.5.1 Odometer Test / 129
8.5.2 Consolidation Characteristics—Magnitude / 130
8.5.3 Consolidation Behavior–Time Rate / 142
8.6 Estimation of Settlement from Odometer Test Results / 154
8.6.1 Settlement of a Building Foundation / 154
8.6.2 Settlement of Fill on Soft Clay / 160
8.7 Approximations and Uncertainties in Settlement Estimates Based on Odometer Tests / 165
8.7.1 Interpretation of Void Ratio–Stress Curves and Sample Disturbance / 165
8.7.2 Assumptions Regarding Pore Pressure State / 167
8.7.3 Lateral Deformation / 168
8.7.4 Submergence of Fill Loads / 168
8.7.5 Use of Terzaghi Theory of Consolidation for Nonlinear Soils / 168
8.7.6 Influence of Inadequate Data on Actual Soil Conditions / 169
8.8 Allowable Settlement / 170
8.8.1 Total (or Absolute) Settlement / 170
8.8.2 Relative Movement between Structure and Surrounding Ground / 170
8.8.3 Differential Settlement of Buildings / 170
8.9 Radial Flow and Sand (or “Wick”) Drains / 172
8.9.1 Theory for Design of Sand and Wick Drains / 173
8.10 Settlement of Foundations on Sand / 174
8.10.1 Schmertman Method Using Static Cone Penetrometer Results / 175
8.10.2 Burland and Burbidge Method / 176
8.10.3 Worked Example / 178
References / 181
Exercises / 182
9 SHEAR STRENGTH OF SOILS 185
9.1 Basic Concepts and Principles / 185
9.1.1 General Expression for Shear Strength / 186
9.1.2 Undrained Shear Strength (su ) / 187
9.1.3 Relationship between Strength in Terms of Effective Stress and Undrained Strength / 187
9.2 Measurement of Shear Strength / 190
9.2.1 Direct Shear Test (or Shear Box Test) / 190
9.2.2 Triaxial Test / 191
9.2.3 Mohr’s Circle of Stress / 193
9.2.4 Use of Mohr’s Circle for Plotting Triaxial Test Results / 195
9.2.5 Soil Behavior in Consolidated Undrained and Drained Tests / 197
9.2.6 Area Correction in Triaxial Tests / 199
9.2.7 Failure Criteria in Terms of Principal Stresses / 200
9.2.8 Determination of Angle of Failure Plane / 201
9.2.9 Worked Example / 201
9.3 Practical Use of Undrained Strength and Effective Strength Parameters / 203
9.4 Shear Strength and Deformation Behavior of Sand / 204
9.5 Residual Strength of Clays / 206
9.5.1 Measurement of Residual Strength / 208
9.6 Stress Path Concept / 209
9.7 Pore Pressure Parameters A and B / 211
9.8 Shear Strength and Deformation Behavior of Clay / 212
9.8.1 Behavior of Fully Remolded Clay / 212
9.8.2 Behavior of Undisturbed Sedimentary Clays / 214
9.8.3 Behavior of Residual Soils / 221
9.8.4 Failure Criterion and Determination of c_ and φ from Consolidated Undrained Tests / 224
9.9 Typical Values of Effective Strength Parameters for Clays and Silts and Correlations with Other Properties / 225
9.10 Undrained Strength of Undisturbed and Remolded Soils / 228
9.10.1 Sedimentary Clays / 228
9.10.2 Remolded Soils / 230
9.10.3 Residual Soils / 231
9.11 Measurement of Undrained Shear Strength / 232
9.11.1 Unconfined Compression test / 232
9.11.2 Vane Test / 232
References / 232
Exercises / 233
10 SITE INVESTIGATIONS, FIELD TESTING, AND PARAMTER CORRELATIONS 235
10.1 Overview / 235
10.2 Drilling / 235
10.2.1 Hand Auguring / 236
10.2.2 Machine Drilling / 236
10.2.3 Continuous Coring with Single-Tube Core Barrel (Also Known as Open Barrel) / 238
10.2.4 Rotary Drilling Using Core Barrels / 238
10.2.5 Wash Drilling / 239
10.2.6 Percussion Boring / 239
10.3 Undisturbed Sampling Using Sample Tubes / 239
10.4 Block Sampling / 241
10.5 Investigation Pits (or Test Pits) / 242
10.6 In Situ Testing / 242
10.6.1 Limitations of Drilling and Undisturbed Sampling / 242
10.6.2 Standard Penetration Test (Dynamic Test) / 243
10.6.3 Dutch Static Cone Penetration Test CPT / 246
10.6.4 Shear Vane Test / 249
10.7 Correlations between In Situ Test Results and Soil Properties / 250
10.7.1 SPT N Values and CPT Values / 250
10.7.2 Undrained Shear Strength of Clay / 251
10.7.3 Relative Density of Sand / 252
10.7.4 Stiffness Modulus of Sand / 253
References / 254
11 STABILITY CONCEPTS AND FAILURE MECHANISMS 257
11.1 Basic Concepts / 257
11.2 Stability of Slopes / 259
11.3 Bearing Capacity / 261
11.4 Retaining Walls / 262
11.5 Further Observations / 264
11.5.1 Safety Factors, Load Factors, and Strength Reduction Factors / 264
11.5.2 Questions of Deformation Versus Stability / 264
References / 265
12 BEARING CAPACITY AND FOUNDATION DESIGN 267
12.1 Bearing Capacity / 267
12.1.1 Bearing Capacity in Terms of Effective Stress / 270
12.1.2 Bearing Capacity in Terms of Total Stress (Undrained Behavior) / 270
12.1.3 Eccentric and Inclined Loads / 270
12.2 Shallow Foundations on Clay / 272
12.2.1 Use of Undrained Shear Strength / 272
12.2.2 Application of Factor of Safety / 272
12.2.3 Bearing Capacity Versus Settlement Tolerance in Design of Foundations / 273
12.2.4 Worked Examples / 274
12.3 Shallow Foundations on Sand / 276
12.3.1 Use of Bearing Capacity Theory / 276
12.3.2 Empirical Methods for Foundations on Sand / 277
12.4 Pile Foundations / 278
12.4.1 Basic Concepts and Pile Types / 278
12.4.2 Pile-Bearing Capacity—Basic Formula and Methods of Estimation / 281
12.4.3 Bearing Capacity of Piles in Clay / 282
12.4.4 Bearing Capacity of Piles in Sand / 285
12.4.5 Pile Group Behavior / 286
12.4.6 Lateral Load Capacity of Piles / 289
References / 303
Exercises / 304
13 EARTH PRESSURE AND RETAINING WALLS 307
13.1 Coulomb Wedge Analysis / 307
13.2 At-Rest Pressure, Active Pressure, Passive Pressure, and Associated Deformations / 312
13.3 Rankine Earth Pressures / 312
13.4 Influence of Wall Friction / 316
13.5 Earth Pressure Coefficients / 316
13.6 Total Stress Analysis / 317
13.7 Maximum Height of Unsupported Vertical Banks or Cuts / 317
13.8 Construction Factors Influencing Earth Pressures on Retaining Walls / 319
13.9 Propped (Strutted) Trenches / 321
13.10 Retaining-Wall Design Example / 322
13.11 Sheet Pile (and Similar) Retaining Walls / 329
13.11.1 FreeStanding and Propped Cantilever Walls / 329
13.12 Reinforced-Earth Walls / 337
13.12.1 Concept and General Behavior / 337
13.12.2 Reinforcement Types / 338
13.12.3 Basic Design Procedures / 339
13.12.4 Other Matters / 349
References / 351
Exercises / 351
14 STABILITY OF SLOPES 355
14.1 Introduction / 355
14.2 Analysis Using Circular Arc Failure Surfaces / 357
14.2.1 Circular Arc Analysis Using Total Stresses / 359
14.2.2 Circular Arc Analysis in Terms of Effective Stresses / 360
14.2.3 Example Calculation Using Bishop Method / 362
14.2.4 Bishop’s Method for Submerged Slopes / 363
14.3 Stability Analysis of Infinite Slopes / 366
14.4 Short- and Long-Term Stability of Built Slopes / 368
14.4.1 Excavated Slopes / 369
14.4.2 Embankments on Soft Clays / 371
14.5 Stability Analysis for Earth Dams / 377
14.5.1 Estimation of Pore-Water Pressures During or at End of Construction / 377
14.5.2 Full-Reservoir Steady-State Seepage Condition / 379
14.5.3 Rapid Drawdown Pore Pressures / 380
14.6 Influence of Climate and Weather on Stability of Slopes / 381
14.7 Stability Analysis Using Noncircular Failure Surfaces / 385
References / 387
Exercises / 387
15 SOIL COMPACTION 391
15.1 Earthworks and Soil Compaction / 391
15.2 Compaction Behavior of Soils / 391
15.3 Control of Compaction / 397
15.3.1 Traditional Method of Compaction Control / 397
15.3.2 Alternative Compaction Control Based on Undrained Shear Strength and Air Voids / 397
15.4 Difficulties in Compacting Clays / 401
15.4.1 Soils Considerably Wetter Than Optimum Water Content / 401
15.4.2 Soils That Soften During Compaction / 401
15.5 Compaction of Granular and Non-Plastic Materials / 402
References / 404
16 SPECIAL SOIL TYPES 405
16.1 General Comments / 405
16.2 Partially Saturated Soils / 406
16.2.1 Occurrence / 406
16.2.2 Measurements of Degree of Saturation / 407
16.2.3 Mechanics of Partially Saturated Soils / 408
16.3 Expansive or Swelling Clays / 415
16.3.1 Basic Concepts of Expansive Behavior / 415
16.3.2 Estimation of Swelling Pressure and Swell Magnitude / 416
16.3.3 Estimation of Swell Magnitude / 420
16.4 Collapsing Soils / 421
References / 424
INDEX 425
