## PREFACE

This textbook is written for an undergraduate course in soil mechanics and foundations. It has three primary

objectives. The fi rst is to present basic concepts and fundamental principles of soil mechanics and

foundations in a simple pedagogy using the students’ background in mechanics, physics, and mathematics.

The second is to integrate modern learning principles, teaching techniques, and learning aids to assist

students in understanding the various topics in soil mechanics and foundations. The third is to provide

a solid background knowledge to hopefully launch students in their lifelong learning of geotechnical

engineering issues.

Some of the key features of this textbook are:

• Topics are presented thoroughly and systematically to elucidate the basic concepts and fundamental

principles without diluting technical rigor.

• A large number of example problems are solved to demonstrate or to provide further insights into

the basic concepts and applications of fundamental principles.

• The solution of each example is preceded by a strategy, which is intended to teach students to

think about possible solutions to a problem before they begin to solve it. Each solution provides a

step-by-step procedure to guide the student in problem solving.

• A “What you should be able to do” list at the beginning of each chapter alerts readers to what

they should have learned after studying each chapter, to help students take responsibility for

learning the material.

• Web-based applications including interactive animations, interactive problem solving, interactive

step-by-step examples, virtual soils laboratory, e-quizzes, and much more are integrated with this

textbook.

With the proliferation and accessibility of computers, programmable calculators, and software,

students will likely use these tools in their practice. Consequently, computer program utilities and

generalized equations that the students can program into their calculators are provided rather than

charts.

The content of the book has been signifi cantly enhanced in the third edition:

• Reorganization of chapters—Several chapters in the second edition are now divided into multiple

chapters for ease of use.

• Enhancement of content—The content of each chapter has been enhanced by adding

updated materials and more explanations. In particular, signifi cant improvements have been

made not only to help interpret soil behavior but also to apply the basic concepts to practical

problems.

• Examples and problems—More examples, with more practical “real-world” situations, and more

problems have been added. The examples have been given descriptive titles to make specifi c

examples easier to locate.

### ACKNOWLEDGMENTS

I am grateful to the many reviewers who offered many valuable suggestions for improving this textbook.

The following persons were particularly helpful in reviewing the third edition: Juan Lopez, geotechnical

engineer, Golder Associates, Houston, TX; Walid Toufi g, graduate student, University of Arizona, Tucson,

AZ; and Ibrahim Adiyaman, graduate student, University of Arizona, Tucson, AZ.

Ms. Jenny Welter, Mr. Bill Webber, and the staff of John Wiley & Sons were particularly helpful

in getting this book completed. Additional resources are available online at www.wiley.com/college/

budhu.

Also available from the Publisher: Foundations and Earth Retaining Structures, by Muni Budhu

ISBN: 978-0471-47012-0

Website: www.wiley.com/college/budhu

A companion lab manual is available from the Publisher: Soil Mechanics Laboratory Manual, by

Michael Kalinski

The soil mechanics course is often accompanied by a laboratory course, to introduce students to common

geotechnical test methods, test standards, and terminology. Michael Kalinski of the University of

Kentucky has written a lab manual introducing students to the most common soil mechanics tests, and

has included laboratory exercises and data sheets for each test. Brief video demonstrations are also

available online for each of the experiments described in this manual.

## CONTENTS

PREFACE iii

NOTES FOR STUDENTS AND INSTRUCTORS v

NOTES FOR INSTRUCTORS vii

CHAPTER 1 INTRODUCTION TO SOIL MECHANICS

AND FOUNDATIONS 1

1.0 Introduction 1

1.1 Marvels of Civil Engineering—The Hidden

Truth 2

1.2 Geotechnical Lessons from Failures 3

CHAPTER 2 GEOLOGICAL CHARACTERISTICS AND

PARTICLE SIZES OF SOILS 5

2.0 Introduction 5

2.1 Defi nitions of Key Terms 5

2.2 Questions to Guide Your Reading 6

2.3 Basic Geology 6

2.3.1 Earth’s Profi le 6

2.3.2 Plate Tectonics 6

2.3.3 Composition of the Earth’s Crust 7

2.3.4 Discontinuities 8

2.3.5 Geologic Cycle and Geological Time 8

2.4 Composition of Soils 10

2.4.1 Soil Formation 10

2.4.2 Soil Types 10

2.4.3 Clay Minerals 11

2.4.4 Surface Forces and Adsorbed

Water 12

2.4.5 Soil Fabric 13

2.5 Determination of Particle Size of Soils—

ASTM D 422 15

2.5.1 Particle Size of Coarse-Grained

Soils 15

2.5.2 Particle Size of Fine-Grained Soils 16

2.5.3 Characterization of Soils Based on

Particle Size 17

2.6 Comparison of Coarse-Grained and Fine-

Grained Soils for Engineering Use 24

2.7 Summary 24

Self-Assessment 25

Exercises 25

CHAPTER 3 SOILS INVESTIGATION 26

3.0 Introduction 26

3.1 Defi nitions of Key Terms 27

3.2 Questions to Guide Your Reading 27

3.3 Purposes of a Soils Investigation 27

3.4 Phases of a Soils Investigation 27

3.5 Soils Exploration Program 29

3.5.1 Soils Exploration Methods 29

3.5.2 Soil Identifi cation in the Field 32

3.5.3 Number and Depths of

Boreholes 34

3.5.4 Soil Sampling 35

3.5.5 Groundwater Conditions 36

3.5.6 Soils Laboratory Tests 37

3.5.7 Types of In Situ or Field Tests 37

3.5.8 Types of Laboratory Tests 43

3.6 Soils Report 46

3.7 Summary 47

Self-Assessment 47

Exercises 47

CHAPTER 4 PHYSICAL SOIL STATES AND SOIL

CLASSIFICATION 48

4.0 Introduction 48

4.1 Defi nitions of Key Terms 49

4.2 Questions to Guide Your Reading 49

4.3 Phase Relationships 50

4.4 Physical States and Index Properties of

Fine-Grained Soils 61

4.5 Determination of the Liquid, Plastic, and

Shrinkage Limits 64

4.5.1 Casagrande Cup Method—

ASTM D 4318 64

4.5.2 Plastic Limit Test—ASTM D 4318 65

4.5.3 Fall Cone Method to Determine

Liquid and Plastic Limits 65

4.5.4 Shrinkage Limit—ASTM D 427 and

D 4943 66

4.6 Soil Classifi cation Schemes 70

4.6.1 Unifi ed Soil Classifi cation System 71

4.6.2 American Society for Testing and

Materials (ASTM) Classifi cation

System 71

4.6.3 AASHTO Soil Classifi cation

System 74

4.6.4 Plasticity Chart 76

4.7 Engineering Use Chart 76

4.8 Summary 80

Self-Assessment 81

Practical Examples 81

Exercises 83

CHAPTER 5 SOIL COMPACTION 87

5.0 Introduction 87

5.1 Defi nitions of Key Terms 88

5.2 Questions to Guide Your Reading 88

5.3 Basic Concept 88

5.4 Proctor Compaction Test—ASTM D 1140 and

ASTM D 1557 89

5.5 Interpretation of Proctor Test Results 91

5.6 Benefi ts of Soil Compaction 95

5.7 Field Compaction 96

5.8 Compaction Quality Control 97

5.8.1 Sand Cone—ASTM D 1556 97

5.8.2 Balloon Test—ASTM D 2167 100

5.8.3 Nuclear Density Meter—ASTM

D 2922, ASTM D 5195 100

5.8.4 Comparison Among the Popular

Compaction Quality Control Tests 101

5.9 Summary 102

Self-Assessment 102

Practical Example 102

Exercises 103

CHAPTER 6 ONE-DIMENSIONAL FLOW OF WATER

THROUGH SOILS 105

6.0 Introduction 105

6.1 Defi nitions of Key Terms 105

6.2 Questions to Guide Your Reading 105

6.3 Head and Pressure Variation in a Fluid at

Rest 106

6.4 Darcy’s Law 109

6.5 Empirical Relationships for k 111

6.6 Flow Parallel to Soil Layers 116

6.7 Flow Normal to Soil Layers 117

6.8 Equivalent Hydraulic Conductivity 117

6.9 Determination of the Hydraulic

Conductivity 118

6.9.1 Constant-Head Test 118

6.9.2 Falling-Head Test 119

6.9.3 Pumping Test to Determine the

Hydraulic Conductivity 122

6.10 Groundwater Lowering by Wellpoints 124

6.11 Summary 126

Self-Assessment 126

Practical Example 126

Exercises 127

CHAPTER 7 STRESSES, STRAINS, AND ELASTIC

DEFORMATIONS OF SOILS 131

7.0 Introduction 131

7.1 Defi nitions of Key Terms 133

7.2 Questions to Guide Your Reading 133

7.3 Stresses and Strains 133

7.3.1 Normal Stresses and Strains 133

7.3.2 Volumetric strain 134

7.3.3 Shear Stresses and Shear Strains 134

7.4 Idealized Stress–Strain Response and

Yielding 135

7.4.1 Material Responses to Normal

Loading and Unloading 135

7.4.2 Material Response to Shear

Forces 137

7.4.3 Yield Surface 138

7.5 Hooke’s Law 139

7.5.1 General State of Stress 139

7.5.2 Principal Stresses 140

7.5.3 Displacements from Strains and Forces

from Stresses 140

7.6 Plane Strain and Axial Symmetric

Conditions 141

7.6.1 Plane Strain Condition 141

7.6.2 Axisymmetric Condition 142

7.7 Anisotropic, Elastic States 145

7.8 Stress and Strain States 146

7.8.1 Mohr’s Circle for Stress States 147

7.8.2 Mohr’s Circle for Strain States 148

7.9 Total and Effective Stresses 150

7.9.1 The Principle of Effective Stress 151

7.9.2 Effective Stresses Due to Geostatic

Stress Fields 152

7.9.3 Effects of Capillarity 153

7.9.4 Effects of Seepage 154

7.10 Lateral Earth Pressure at Rest 161

7.11 Stresses in Soil from Surface Loads 163

7.11.1 Point Load 163

7.11.2 Line Load 165

7.11.3 Line Load Near a Buried Earth-

Retaining Structure 166

7.11.4 Strip Load 166

7.11.5 Uniformly Loaded Circular

Area 168

7.11.6 Uniformly Loaded Rectangular

Area 170

7.11.7 Approximate Method for Rectangular

Loads 172

7.11.8 Vertical Stress Below Arbitrarily

Shaped Area 175

7.11.9 Embankment Loads 177

7.11.10 Infi nite Loads 178

7.12 Summary 178

Self-Assessment 178

Practical Examples 178

Exercises 181

CHAPTER 8 STRESS PATH 186

8.0 Introduction 186

8.1 Defi nitions of Key Terms 187

8.2 Questions to Guide Your Reading 187

8.3 Stress and Strain Invariants 187

8.3.1 Mean Stress 187

8.3.2 Deviatoric or Shear Stress 187

CONTENTS xi

8.3.3 Volumetric Strain 188

8.3.4 Deviatoric or Distortional or Shear

Strain 188

8.3.5 Axisymmetric Condition, s92 5 s93 or

s2 5 s3; ε2 5 ε3 188

8.3.6 Plane Strain, ε2 5 0 188

8.3.7 Hooke’s Law Using Stress and Strain

Invariants 189

8.4 Stress Paths 191

8.4.1 Basic Concept 191

8.4.2 Plotting Stress Paths Using Stress

Invariants 192

8.4.3 Plotting Stress Paths Using Two-

Dimensional Stress Parameters 196

8.4.4 Procedure for Plotting Stress

Paths 197

8.5 Summary 203

Self-Assessment 203

Practical Example 203

Exercises 205

CHAPTER 9 ONE-DIMENSIONAL CONSOLIDATION

SETTLEMENT OF FINE-GRAINED SOILS 207

9.0 Introduction 207

9.1 Defi nitions of Key Terms 208

9.2 Questions to Guide Your Reading 209

9.3 Basic Concepts 209

9.3.1 Instantaneous Load 210

9.3.2 Consolidation Under a Constant

Load—Primary Consolidation 211

9.3.3 Secondary Compression 211

9.3.4 Drainage Path 212

9.3.5 Rate of Consolidation 212

9.3.6 Effective Stress Changes 212

9.3.7 Void Ratio and Settlement Changes

Under a Constant Load 213

9.3.8 Effects of Vertical Stresses on Primary

Consolidation 213

9.3.9 Primary Consolidation

Parameters 216

9.3.10 Effects of Loading History 215

9.3.11 Overconsolidation Ratio 216

9.3.12 Possible and Impossible Consolidation

Soil States 216

9.4 Calculation of Primary Consolidation

Settlement 216

9.4.1 Effects of Unloading/Reloading

of a Soil Sample Taken from the

Field 216

9.4.2 Primary Consolidation Settlement of

Normally Consolidated Fine-Grained

Soils 217

9.4.3 Primary Consolidation Settlement

of Overconsolidated Fine-Grained

Soils 218

xii CONTENTS

9.4.4 Procedure to Calculate Primary

Consolidation Settlement 218

9.4.5 Thick Soil Layers 219

9.5 One-Dimensional Consolidation

Theory 225

9.5.1 Derivation of Governing

Equation 225

9.5.2 Solution of Governing Consolidation

Equation Using Fourier Series 227

9.5.3 Finite Difference Solution of

the Governing Consolidation

Equation 229

9.6 Secondary Compression Settlement 234

9.7 One-Dimensional Consolidation Laboratory

Test 235

9.7.1 Oedometer Test 235

9.7.2 Determination of the Coeffi cient of

Consolidation 236

9.7.2.1 Root Time Method (Square

Root Time Method) 236

9.7.2.2 Log Time Method 237

9.7.3 Determination of Void Ratio at the

End of a Loading Step 238

9.7.4 Determination of the Past Maximum

Vertical Effective Stress 239

9.7.5 Determination of Compression

and Recompression Indices 240

9.7.6 Determination of the Modulus of

Volume Change 240

9.7.7 Determination of the Secondary

Compression Index 241

9.8 Relationship Between Laboratory and Field

Consolidation 243

9.9 Typical Values of Consolidation

Settlement Parameters and Empirical

Relationships 245

9.10 Preconsolidation of Soils Using Wick

Drains 246

9.11 Summary 249

Self-Assessment 250

Practical Examples 250

Exercises 257

CHAPTER 10 SHEAR STRENGTH OF SOILS 261

10.0 Introduction 261

10.1 Defi nitions of Key Terms 262

10.2 Questions to Guide Your Reading 262

10.3 Typical Response of Soils to Shearing

Forces 262

10.3.1 Effects of Increasing the Normal

Effective Stress 265

10.3.2 Effects of Overconsolidation Ratio 266

10.3.3 Effects of Drainage of Excess

Porewater Pressure 267

10.3.4 Effects of Cohesion 267

10.3.5 Effects of Soil Tension 268

10.3.6 Effects of Cementation 269

10.4 Four Models for Interpreting the Shear

Strength of Soils 269

10.4.1 Coulomb’s Failure Criterion 270

10.4.2 Taylor’s Failure Criterion 274

10.4.3 Mohr–Coulomb Failure Criterion 275

10.4.4 Tresca Failure Criterion 277

10.5 Practical Implications of Failure Criteria 278

10.6 Interpretation of the Shear Strength of

Soils 280

10.7 Laboratory Tests to Determine Shear Strength

Parameters 286

10.7.1 A Simple Test to Determine Friction

Angle of Clean, Coarse-Grained

Soils 286

10.7.2 Shear Box or Direct Shear Test 286

10.7.3 Conventional Triaxial

Apparatus 291

10.7.4 Unconfi ned Compression (UC)

Test 293

10.7.5 Consolidated Drained (CD)

Compression Test 295

10.7.6 Consolidated Undrained (CU)

Compression Test 300

10.7.7 Unconsolidated Undrained (UU)

Test 304

10.8 Porewater Pressure Under Axisymmetric

Undrained Loading 305

10.9 Other Laboratory Devices to Measure Shear

Strength 307

10.9.1 Simple Shear Apparatuses 307

10.9.2 True Triaxial Apparatus 311

10.9.3 Hollow-Cylinder Apparatus 312

10.10 Field Tests 313

10.10.1 Vane Shear Test (VST) 313

10.10.2 The Standard Penetration Test

(SPT) 313

10.10.3 Cone Penetrometer Test (CPT) 314

10.11 Specifying Laboratory Strength Tests 314

10.12 Empirical Relationships for Shear Strength

Parameters 314

10.13 Summary 316

Self-Assessment 316

Practical Examples 316

Exercises 320

CHAPTER 11 A CRITICAL STATE MODEL TO

INTERPRET SOIL BEHAVIOR 324

11.0 Introduction 324

11.1 Defi nitions of Key Terms 325

11.2 Questions to Guide Your Reading 325

11.3 Basic Concepts 326

11.3.1 Parameter Mapping 326

11.3.2 Failure Surface 328

CONTENTS xiii

11.3.3 Soil Yielding 328

11.3.4 Prediction of the Behavior of

Normally Consolidated and Lightly

Overconsolidated Soils Under

Drained Condition 329

11.3.5 Prediction of the Behavior of

Normally Consolidated and Lightly

Overconsolidated Soils Under

Undrained Condition 332

11.3.6 Prediction of the Behavior of Heavily

Overconsolidated Soils Under Drained

and Undrained Condition 335

11.3.7 Prediction of the Behavior of Coarse-

Grained Soils Using CSM 337

11.3.8 Critical State Boundary 337

11.3.9 Volume Changes and Excess

Porewater Pressures 338

11.3.10 Effects of Effective and Total Stress

Paths 338

11.4 Elements of the Critical State Model 339

11.4.1 Yield Surface 339

11.4.2 Critical State Parameters 340

11.4.2.1 Failure Line in (p9, q)

Space 340

11.4.2.2 Failure Line in (p9, e)

Space 342

11.5 Failure Stresses from the Critical State

Model 345

11.5.1 Drained Triaxial Test 345

11.5.2 Undrained Triaxial Test 347

11.6 Modifi cations of CSM and Their Practical

Implications 361

11.7 Relationships from CSM that Are of Practical

Signifi cance 365

11.7.1 Relationship Between Normalized

Yield (peak) Shear Stress and Critical

State Shear Stress Under Triaxial

Drained Condition 365

11.7.2 Relationship Among the Tension

Cutoff, Mean Effective Stress, and

Preconsolidation Stress 367

11.7.3 Relationship Among Undrained

Shear Strength, Critical State

Friction Angle, and Preconsolidation

Ratio 369

11.7.4 Relationship Between the Normalized

Undrained Shear Strength at

the Critical State for Normally

Consolidated and Overconsolidated

Fine-Grained Soils 370

11.7.5 Relationship Between the Normalized

Undrained Shear Strength of One-

Dimensionally Consolidated or

Ko-Consolidated and Isotropically

Consolidated Fine-Grained

Soils 371

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 374

11.7.7 Undrained Shear Strength Under

Direct Simple Shear (plane strain)

Condition 376

11.7.8 Relationship Between Direct Simple

Shear Tests and Triaxial Tests 377

11.7.9 Relationship for the Application of

Drained and Undrained Conditions in

the Analysis of Geosystems 378

11.7.10 Relationship Among Excess Porewater

Pressure, Preconsolidation Ratio, and

Critical State Friction Angle 381

11.7.11 Undrained Shear Strength of Clays at

the Liquid and Plastic Limits 382

11.7.12 Vertical Effective Stresses at the

Liquid and Plastic Limits 382

11.7.13 Compressibility Indices (l and Cc) and

Plasticity Index 382

11.7.14 Undrained Shear Strength, Liquidity

Index, and Sensitivity 383

11.7.15 Summary of Relationships Among

Some Soil Parameters from CSM 383

11.8 Soil Stiffness 389

11.9 Strains from the Critical State Model 393

11.9.1 Volumetric Strains 393

11.9.2 Shear Strains 395

11.10 Calculated Stress–Strain Response 399

11.10.1 Drained Compression Tests 400

11.10.2 Undrained Compression Tests 400

11.11 Application of CSM to Cemented Soils 407

11.12 Summary 408

Self-Assessment 409

Practical Examples 409

Exercises 418

CHAPTER 12 BEARING CAPACITY OF SOILS AND

SETTLEMENT OF SHALLOW FOUNDATIONS 422

12.0 Introduction 422

12.1 Defi nitions of Key Terms 423

12.2 Questions to Guide Your Reading 424

12.3 Allowable Stress and Load and Resistance

Factor Design 425

12.4 Basic Concepts 426

12.4.1 Soil Response to a Loaded

Footing 426

12.4.2 Conventional Failure Surface Under a

Footing 428

12.5 Collapse Load Using the Limit Equilibrium

Method 429

12.6 Bearing Capacity Equations 431

12.7 Mat Foundations 443

12.8 Bearing Capacity of Layered Soils 445

12.9 Building Codes Bearing Capacity Values 447

12.10 Settlement 448

12.11 Settlement Calculations 450

12.11.1 Immediate Settlement 450

12.11.2 Primary Consolidation

Settlement 454

12.12 Determination of Bearing Capacity and

Settlement of Coarse-Grained Soils from

Field Tests 457

12.12.1 Standard Penetration Test (SPT) 457

12.12.2 Cone Penetration Test (CPT) 460

12.12.3 Plate Load Test (PLT) 463

12.13 Shallow Foundation Analysis Using CSM 464

11.13.1 Heavily Overconsolidated

Fine-Grained Soil 465

12.13.2 Dense, Coarse-Grained Soils 471

12.14 Horizontal Elastic Displacement and

Rotation 485

12.15 Summary 486

Self-Assessment 487

Practical Examples 487

Exercises 506

CHAPTER 13 PILE FOUNDATIONS 509

13.0 Introduction 509

13.1 Defi nitions of Key Terms 509

13.2 Questions to Guide Your Reading 510

13.3 Types of Piles and Installations 511

13.3.1 Concrete Piles 512

13.3.2 Steel Piles 512

13.3.3 Timber Piles 512

13.3.4 Plastic Piles 512

13.3.5 Composites 512

13.3.6 Pile Installation 514

13.4 Basic Concept 515

13.5 Load Capacity of Single Piles 521

13.6 Pile Load Test (ASTM D 1143) 522

13.7 Methods Using Statics for Driven Piles 531

13.7.1 a-Method 531

13.7.1.1 Skin Friction 531

13.7.1.2 End Bearing 531

13.7.2 b-Method 532

13.7.2.1 Skin Friction 532

13.7.2.2 End Bearing 534

13.8 Pile Load Capacity of Driven Piles Based on

SPT and CPT Results 539

13.8.1 SPT 540

13.8.2 CPT 540

13.9 Load Capacity of Drilled Shafts 544

13.10 Pile Groups 546

13.11 Elastic Settlement of Piles 552

13.12 Consolidation Settlement Under a Pile

Group 554

xiv CONTENTS

13.13 Procedure to Estimate Settlement of Single

and Group Piles 555

13.14 Settlement of Drilled Shafts 559

13.15 Piles Subjected to Negative Skin

Friction 560

13.16 Pile-Driving Formulas and Wave

Equation 562

13.17 Laterally Loaded Piles 563

13.18 Micropiles 567

13.19 Summary 568

Self-Assessment 568

Practical Examples 568

Exercises 575

CHAPTER 14 TWO-DIMENSIONAL FLOW OF WATER

THROUGH SOILS 579

14.0 Introduction 579

14.1 Defi nitions of Key Terms 579

14.2 Questions to Guide Your Reading 580

14.3 Two-Dimensional Flow of Water Through

Porous Media 580

14.4 Flownet Sketching 583

14.4.1 Criteria for Sketching Flownets 583

14.4.2 Flownet for Isotropic Soils 583

14.4.3 Flownet for Anisotropic Soil 585

14.5 Interpretation of Flownet 586

14.5.1 Flow Rate 586

14.5.2 Hydraulic Gradient 586

14.5.3 Static Liquefaction, Heaving, Boiling,

and Piping 586

14.5.4 Critical Hydraulic Gradient 587

14.5.5 Porewater Pressure Distribution 587

14.5.6 Uplift Forces 587

14.6 Finite Difference Solution for Two-

Dimensional Flow 592

14.7 Flow Through Earth Dams 598

14.8 Soil Filtration 602

14.9 Summary 603

Self-Assessment 603

Practical Examples 603

Exercises 606

CHAPTER 15 STABILITY OF EARTH-RETAINING

STRUCTURES 610

15.0 Introduction 610

15.1 Defi nitions of Key Terms 611

15.2 Questions to Guide Your Reading 611

15.3 Basic Concepts of Lateral Earth

Pressures 612

15.4 Coulomb’s Earth Pressure Theory 620

15.5 Rankine’s Lateral Earth Pressure for a Sloping

Backfi ll and a Sloping Wall Face 623

15.6 Lateral Earth Pressures for a Total Stress

Analysis 625

15.7 Application of Lateral Earth Pressures to

Retaining Walls 627

15.8 Types of Retaining Walls and Modes of

Failure 630

15.9 Stability of Rigid Retaining Walls 633

15.9.1 Translation 633

15.9.2 Rotation 634

15.9.3 Bearing Capacity 634

15.9.4 Deep-Seated Failure 634

15.9.5 Seepage 635

15.9.6 Procedures to Analyze Rigid

Retaining Walls 635

15.10 Stability of Flexible Retaining Walls 643

15.10.1 Analysis of Sheet Pile Walls in

Uniform Soils 643

15.10.2 Analysis of Sheet Pile Walls in Mixed

Soils 645

15.10.3 Consideration of Tension Cracks in

Fine-Grained Soils 645

15.10.4 Methods of Analyses 646

15.10.5 Analysis of Cantilever Sheet Pile

Walls 648

15.10.6 Analysis of Anchored Sheet Pile

Walls 648

15.11 Braced Excavation 659

15.12 Mechanical Stabilized Earth Walls 666

15.12.1 Basic Concepts 667

15.12.2 Stability of Mechanical Stabilized

Earth Walls 667

15.13 Other Types of Retaining Walls 675

15.13.1 Modular Gravity Walls 675

15.13.2 In Situ Reinforced Walls 676

15.13.3 Chemically Stabilized Earth Walls

(CSE) 676

15.14 Summary 676

Self-Assessment 676

Practical Examples 676

Exercises 682

CHAPTER 16 SLOPE STABILITY 687

16.0 Introduction 687

16.1 Defi nitions of Key Terms 687

16.2 Questions to Guide Your Reading 688

16.3 Some Types of Slope Failure 688

16.4 Some Causes of Slope Failure 689

16.4.1 Erosion 689

16.4.2 Rainfall 691

16.4.3 Earthquakes 691

16.4.4 Geological Features 691

16.4.5 External Loading 691

16.4.6 Construction Activities 691

16.4.6.1 Excavated Slopes 691

16.4.6.2 Fill Slopes 692

16.4.7 Rapid Drawdown 692

CONTENTS xv

16.5 Infi nite Slopes 692

16.6 Two-Dimensional Slope Stability Analyses 697

16.7 Rotational Slope Failures 697

16.8 Method of Slices 699

16.8.1 Bishop’s Method 699

16.8.2 Janbu’s Method 702

16.8.3 Cemented Soils 703

16.9 Application of the Method of Slices 704

16.10 Procedure for the Method of Slices 705

16.11 Stability of Slopes with Simple Geometry 713

16.11.1 Taylor’s Method 713

16.11.2 Bishop–Morgenstern Method 714

16.12 Factor of Safety (FS) 715

16.13 Summary 716

Self-Assessment 716

Practical Example 716

Exercises 719

APPENDIX A A COLLECTION OF FREQUENTLY USED

SOIL PARAMETERS AND CORRELATIONS 723

APPENDIX B DISTRIBUTION OF VERTICAL STRESS

AND ELASTIC DISPLACEMENT UNDER A UNIFORM

CIRCULAR LOAD 730

APPENDIX C DISTRIBUTION OF SURFACE STRESSES

WITHIN FINITE SOIL LAYERS 731

APPENDIX D LATERAL EARTH PRESSURE

COEFFICIENTS (KERISEL AND ABSI, 1990) 734

REFERENCES 738

INDEX 742

xvi CONTENTS