## Principles of Foundation Engineering, Ninth Edition

By Braja M Das and Nagaratnam Sivakugan

**Contents: **

Preface xv

MindTap Online Course xviii

Preface to the SI Edition xxi

About the Authors xxii

1 Introduction 1

1.1

1.2 Foundation Engineering 2

1.3 Soil Exploration 2

1.4 Ground Improvement 3

1.5 Solution Methods 4

1.6 Numerical Modeling 4

1.7 Empiricism 5

1.8 Literature 5

references 6

2 Geotechnical Properties of Soil 8

2.1 Introduction 9

2.2 Grain-Size Distribution 9

2.3 Size Limits for Soil 12

2.4 Weight–Volume Relationships 12

2.5 Relative Density 16

2.6 Atterberg Limits 18

2.7 Liquidity Index 19

2.8 Activity 19

2.9 Soil Classification Systems 20

2.10 Hydraulic Conductivity of Soil 27

2.11 Steady-State Seepage 32

2.12 Effective Stress 33

2.13 Consolidation 36

2.14 Calculation of Primary Consolidation Settlement 41

2.15 Time Rate of Consolidation 42

2.16 Range of Coefficient of Consolidation, cv 48

2.17 Degree of Consolidation Under Ramp Loading 49

2.18 Shear Strength 51

2.19 Unconfined Compression Test 56

2.20 Comments on Friction Angle, f9 57

2.21 Correlations for Undrained Shear Strength, cu 60

2.22 Selection of Shear Strength Parameters 60

2.23 Sensitivity 61

2.24 Summary 62

Problems 62

References 65

3 Natural Soil Deposits and Subsoil Exploration 67

3.1 Introduction 68

Natural Soil Deposits 68

3.2 Soil Origin 68

3.3 Residual Soil 69

3.4 Gravity-Transported Soil 70

3.5 Alluvial Deposits 71

3.6 Lacustrine Deposits 73

3.7 Glacial Deposits 74

3.8 Aeolian Soil Deposits 75

3.9 Organic Soil 76

3.10 Some Local Terms for Soil 76

Subsurface Exploration 77

3.11 Purpose of Subsurface Exploration 77

3.12 Subsurface Exploration Program 77

3.13 Exploratory Borings in the Field 80

3.14 Procedures for Sampling Soil 83

3.15 Split-Spoon Sampling and Standard Penetration Test 83

3.16 Sampling with a Scraper Bucket 92

3.17 Sampling with a Thin-Walled Tube 93

3.18 Sampling with a Piston Sampler 93

3.19 Observation of Water Tables 95

3.20 Vane Shear Test 96

3.21 Cone Penetration Test 100

3.22 Pressuremeter Test (PMT) 108

3.23 Dilatometer Test 111

3.24 Iowa Borehole Shear Test 114

3.25 K0 Stepped-Blade Test 116

3.26 Coring of Rocks 117

3.27 Preparation of Boring Logs 120

3.28 Geophysical Exploration 121

3.29 Subsoil Exploration Report 127

3.30 Summary 128

Problems 129

R eferences 131

4 Instrumentation and Monitoring in Geotechnical Engineering 134

4.1 Introduction 135

4.2 Need for Instrumentation 135

4.3 Geotechnical Measurements 136

4.4 Geotechnical Instruments 137

4.5 Planning an Instrumentation Program 142

4.6 Typical Instrumentation Projects 143

4.7 Summary 143

R eferences 143

5 Soil Improvement and Ground Modification 146

5.1 Introduction 147

5.2 General Principles of Compaction 147

5.3 Empirical Relationships for Compaction 150

5.4 Field Compaction 154

5.5 Compaction Control for Clay Hydraulic Barriers 156

5.6 Vibroflotation 160

5.7 Blasting 164

5.8 Precompression 165

5.9 Sand Drains 170

5.10 Prefabricated Vertical Drains 179

5.11 Lime Stabilization 184

5.12 Cement Stabilization 187

5.13 Fly-Ash Stabilization 189

5.14 Stone Columns 189

5.15 Sand Compaction Piles 194

5.16 Dynamic Compaction 195

5.17 Jet Grouting 198

5.18 Deep Mixing 199

5.19 Summary 201

Problems 201

R eferences 202

6 Shallow Foundations: Ultimate Bearing Capacity 206

6.1 Introduction 207

6.2 General Concept 208

6.3 Terzaghi’s Bearing Capacity Theory 212

6.4 Factor of Safety 216

6.5 Modification of Bearing Capacity Equations for Water Table 217

6.6 The General Bearing Capacity Equation 218

6.7 Other Solutions for Bearing Capacity, Shape, and Depth Factors 225

6.8 Case Studies on Ultimate Bearing Capacity 227

6.9 Effect of Soil Compressibility 231

6.10 Eccentrically Loaded Foundations 235

6.11 Ultimate Bearing Capacity Under Eccentric

Loading—One-Way Eccentricity 236

6.12 Bearing Capacity—Two-Way Eccentricity 242

6.13 A Simple Approach for Bearing Capacity with Two-Way

Eccentricity 249

6.14 Bearing Capacity of a Continuous Foundation Subjected

to Eccentrically Inclined Loading 251

6.15 Plane-Strain Correction of Friction Angle 254

6.16 Summary 254

Problems 254

R eferences 256

7 Ultimate Bearing Capacity of Shallow

Foundations: Special Cases 258

7.1 Introduction 259

7.2 Foundation Supported by a Soil with a Rigid Base at Shallow

Depth 259

7.3 Foundations on Layered Clay 266

7.4 Bearing Capacity of Layered Soil: Stronger Soil Underlain

by Weaker Soil (c9 2 f9 soil) 268

7.5 Bearing Capacity of Layered Soil: Weaker Soil Underlain

by Stronger Soil 275

7.6 Continuous Foundation on Weak Clay with a Granular

Trench 278

7.7 Closely Spaced Foundations—Effect on Ultimate Bearing

Capacity 280

7.8 Bearing Capacity of Foundations on Top of a Slope 282

7.9 Bearing Capacity of Foundations on a Slope 285

7.10 Seismic Bearing Capacity and Settlement in Granular

Soil 286

7.11 Foundations on Rock 289

7.12 Ultimate Bearing Capacity of Wedge-Shaped

Foundations 291

7.13 Uplift Capacity of Foundations 293

7.14 Summary 298

Problems 299

References 300

8 Vertical Stress Increase in Soil 302

8.1 Introduction 303

8.2 Stress Due to a Concentrated Load 303

8.3 Stress Due to a Circularly Loaded Area 304

8.4 Stress Due to a Line Load 305

8.5 Stress Below a Vertical Strip Load of Finite Width

and Infinite Length 306

8.6 Stress Below a Horizontal Strip Load of Finite Width

and Infinite Length 310

8.7 Stress Below a Rectangular Area 312

8.8 Stress Isobars 317

8.9 Average Vertical Stress Increase Due to a Rectangularly

Loaded Area 318

8.10 Average Vertical Stress Increase Below the Center of

a Circularly Loaded Area 323

8.11 Stress Increase Under an Embankment 325

8.12 Westergaard’s Solution for Vertical Stress Due

to a Point Load 328

8.13 Stress Distribution for Westergaard Material 330

8.14 Summary 333

Problems 333

R eferences 335

9 Settlement of Shallow Foundations 336

9.1 Introduction 337

9.2 Elastic Settlement of Shallow Foundation on Saturated

Clay ( ms 5 0.5) 337

Elastic Settlement in Granular Soil 339

9.3 Settlement Based on the Theory of Elasticity 339

9.4 Improved Equation for Elastic Settlement 350

9.5 Settlement of Sandy Soil: Use of Strain

Influence Factor 354

9.6 Settlement of Foundation on Sand Based

on Standard Penetration Resistance 361

9.7 Settlement Considering Soil Stiffness Variation

with Stress Level 366

9.8 Settlement Based on Pressuremeter Test (PMT) 370

9.9 Settlement Estimation Using the L1 2 L2 Method 375

9.10 Effect of the Rise of Water Table on Elastic Settlement 378

Consolidation Settlement 380

9.11 Primary Consolidation Settlement Relationships 380

9.12 Three-Dimensional Effect on Primary Consolidation

Settlement 382

9.13 Settlement Due to Secondary Consolidation 386

9.14 Field Load Test 388

9.15 Presumptive Bearing Capacity 389

9.16 Tolerable Settlement of Buildings 390

9.17 Summary 392

Problems 392

R eferences 394

10 Mat Foundations 396

10.1 Introduction 397

10.2 Combined Footings 397

10.3 Common Types of Mat Foundations 401

10.4 Bearing Capacity of Mat Foundations 403

10.5 Differential Settlement of Mats 406

10.6 Field Settlement Observations for Mat Foundations 407

10.7 Compensated Foundation 407

10.8 Structural Design of Mat Foundations 411

10.9 Summary 424

Problems 425

R eferences 425

11 Load and Resistance Factor Design (LRFD) 427

11.1 Introduction 428

11.2 Design Philosophy 429

11.3 Allowable Stress Design (ASD) 431

11.4 Limit State Design (LSD) and Partial Safety

Factors 432

11.5 Load and Resistance Factor Design (LRFD) 433

11.6 Summary 436

Problems 436

R eferences 437

12 Pile Foundations 438

12.1 Introduction 439

12.2 Pile Materials 440

12.3 Continuous Flight Auger (CFA) Piles 450

12.4 Point Bearing and Friction Piles 451

12.5 Installation of Piles 452

12.6 Pile Driving 453

12.7 Load Transfer Mechanism 458

12.8 Equations for Estimating Pile Capacity 461

12.9 Meyerhof’s Method for Estimating Qp 463

12.10 Vesic’s Method for Estimating Qp 466

12.11 Coyle and Castello’s Method for Estimating Qp

in Sand 469

12.12 Correlations for Calculating Qp with SPT and CPT Results

in Granular Soil 473

12.13 Frictional Resistance (Qs) in Sand 474

12.14 Frictional (Skin) Resistance in Clay 480

12.15 Ultimate Capacity of Continuous Flight Auger Pile 485

12.16 Point Bearing Capacity of Piles Resting on Rock 487

12.17 Pile Load Tests 493

12.18 Elastic Settlement of Piles 497

12.19 Laterally Loaded Piles 502

12.20 Pile-Driving Formulas 514

12.21 Pile Capacity for Vibration-Driven Piles 520

12.22 Wave Equation Analysis 521

12.23 Negative Skin Friction 524

Group Piles 528

12.24 Group Efficiency 528

12.25 Ultimate Capacity of Group Piles in Saturated Clay 531

12.26 Elastic Settlement of Group Piles 534

12.27 Consolidation Settlement of Group Piles 536

12.28 Piles in Rock 538

12.29 Summary 539

Problems 539

References 543

13 Drilled-Shaft Foundations 546

13.1 Introduction 547

13.2 Types of Drilled Shafts 547

13.3 Construction Procedures 548

13.4 Other Design Considerations 554

13.5 Load Transfer Mechanism 555

13.6 Estimation of Load-Bearing Capacity 556

13.7 Load-Bearing Capacity in Granular Soil 558

13.8 Load-Bearing Capacity in Granular Soil Based

on Settlement 561

13.9 Load-Bearing Capacity in Clay 568

13.10 Load-Bearing Capacity in Clay Based on Settlement 570

13.11 Settlement of Drilled Shafts at Working Load 575

13.12 Lateral Load-Carrying Capacity—

Characteristic Load

and Moment Method 576

13.13 Drilled Shafts Extending into Rock 583

13.14 Summary 588

Problems 589

R eferences 590

14 Piled Rafts: An Overview 592

14.1 Introduction 593

14.2 Load-Settlement Plots of Unpiled and Piled Rafts Under

Different Design Conditions 594

14.3 Poulos–Davis–Randolph Simplified Design Method 595

14.4 Case Study: Burj Khalifa Tower in Dubai 600

14.5 Summary 602

Problems 602

R eferences 602

15 Foundations on Difficult Soil 603

15.1 Introduction 604

Collapsible Soil 604

15.2 Definition and Types of Collapsible Soil 604

15.3 Physical Parameters for Identification 606

15.4 Procedure for Calculating Collapse Settlement 608

15.5 Foundations in Soil Not Susceptible

to Wetting 609

15.6 Foundations in Soil Susceptible to Wetting 611

Expansive Soil 612

15.7 General Nature of Expansive Soil 612

15.8 Unrestrained Swell Test 615

15.9 Swelling Pressure Test 617

15.10 Classification of Expansive Soil on the Basis

of Index Tests 621

15.11 Foundation Considerations for Expansive Soil 624

15.12 Construction on Expansive Soil 626

Sanitary Landfills 630

15.13 General Nature of Sanitary Landfills 630

15.14 Settlement of Sanitary Landfills 631

15.15 Summary 633

Problems 633

R eferences 634

16 Lateral Earth Pressure 638

16.1 Introduction 639

16.2 Lateral Earth Pressure at Rest 640

Active Pressure 644

16.3 Rankine Active Earth Pressure 644

16.4 A Generalized Case for Rankine Active Pressure—Granular

Backfill 649

16.5 Generalized Case for Rankine Seismic Active Earth

Pressure—Granular Backfill 653

16.6 Rankine Active Pressure with Vertical Wall Backface

and Inclined c9 2 f9 Soil Backfill 655

16.7 Coulomb’s Active Earth Pressure 658

16.8 Lateral Earth Pressure Due to Surcharge 665

16.9 Active Earth Pressure for Earthquake Conditions—Granular

Backfill 668

16.10 Active Earth Pressure for Earthquake Condition (Vertical

Backface of Wall and c9 2 f9 Backfill) 672

Passive Pressure 676

16.11 Rankine Passive Earth Pressure 676

16.12 Rankine Passive Earth Pressure—Vertical Backface and

Inclined Backfill 679

16.13 Coulomb’s Passive Earth Pressure 681

16.14 Comments on the Failure Surface Assumption for

Coulomb’s Pressure Calculations 683

16.15 Caquot and Kerisel Solution for Passive Earth Pressure

(Granular Backfill) 684

16.16 Solution for Passive Earth Pressure by the Lower Bound

Theorem of Plasticity (Granular Backfill) 686

16.17 Passive Force on Walls with Earthquake Forces 688

16.18 Summary 691

Problems 691

R eferences 693

17 Retaining Walls 694

17.1 Introduction 695

Gravity and Cantilever Walls 697

17.2 Proportioning Retaining Walls 697

17.3 Application of Lateral Earth Pressure Theories

to Design 698

17.4 Stability of Retaining Walls 699

17.5 Check for Overturning 701

17.6 Check for Sliding Along the Base 703

17.7 Check for Bearing Capacity Failure 706

17.8 Construction Joints and Drainage from Backfill 714

17.9 Comments on Design of Retaining Walls

and a Case Study 717

17.10 Gravity Retaining-Wall Design for Earthquake

Conditions 720

Mechanically Stabilized Retaining Walls 722

17.11 Soil Reinforcement 723

17.12 Considerations in Soil Reinforcement 723

17.13 General Design Considerations 727

17.14 Retaining Walls with Metallic Strip Reinforcement 728

17.15 Step-by-Step-Design Procedure Using Metallic Strip

Reinforcement 734

17.16 Retaining Walls with Geotextile Reinforcement 738

17.17 Retaining Walls with Geogrid Reinforcement—

General 744

17.18 Design Procedure for Geogrid-Reinforced Retaining

Wall 746

17.19 Summary 748

Problems 749

R eferences 750

18 Sheet-Pile Walls 752

18.1 Introduction 753

18.2 Construction Methods 756

18.3 Cantilever Sheet-Pile Walls 757

18.4 Cantilever Sheet Piling Penetrating Sandy Soil 758

18.5 Special Cases for Cantilever Walls Penetrating a Sandy

Soil 764

18.6 Cantilever Sheet Piling Penetrating Clay 767

18.7 Special Cases for Cantilever Walls Penetrating Clay 772

18.8 Cantilever Sheet Piles Penetrating Sandy Soil—A Simplified

Approach 775

18.9 Anchored Sheet-Pile Walls 779

18.10 Free Earth Support Method for Penetration of Sandy

Soil—A Simplified Approach 780

18.11 Free Earth Support Method for Penetration of Sandy

Soil—Net Lateral Pressure Method 782

18.12 Design Charts for Free Earth Support Method (Penetration

into Sandy Soil) 785

18.13 Moment Reduction for Anchored Sheet-Pile Walls

Penetrating into Sand 789

18.14 Computational Pressure Diagram Method for Penetration

into Sandy Soil 792

18.15 Field Observations for Anchor Sheet-Pile Walls 795

18.16 Free Earth Support Method for Penetration of Clay 797

18.17 Anchors 802

18.18 Holding Capacity of Deadman Anchors 804

18.19 Holding Capacity of Anchor Plates in Sand 804

18.20 Holding Capacity of Anchor Plates in Clay

(f 5 0 Condition) 811

18.21 Ultimate Resistance of Tiebacks 811

18.22 Summary 812

Problems 812

R eferences 813

19 Braced Cuts 814

19.1 Introduction 815

19.2 Braced-Cut Analysis Based on General Wedge Theory 817

19.3 Pressure Envelope for Braced-Cut Design 820

19.4 Pressure Envelope for Cuts in Layered Soil 822

19.5 Design of Various Components of a Braced Cut 823

19.6 Case Studies of Braced Cuts 831

19.7 Bottom Heave of a Cut in Clay 835

19.8 Stability of the Bottom of a Cut in Sand 839

19.9 Lateral Yielding of Sheet Piles and Ground

Settlement 843

19.10 Summary 845

Problems 845

R eferences 846

Answers to Problems 847

Index 851

MindTap Online Course xviii

Preface to the SI Edition xxi

About the Authors xxii

1 Introduction 1

1.1

**Geotechnical Engineering**21.2 Foundation Engineering 2

1.3 Soil Exploration 2

1.4 Ground Improvement 3

1.5 Solution Methods 4

1.6 Numerical Modeling 4

1.7 Empiricism 5

1.8 Literature 5

references 6

2 Geotechnical Properties of Soil 8

2.1 Introduction 9

2.2 Grain-Size Distribution 9

2.3 Size Limits for Soil 12

2.4 Weight–Volume Relationships 12

2.5 Relative Density 16

2.6 Atterberg Limits 18

2.7 Liquidity Index 19

2.8 Activity 19

2.9 Soil Classification Systems 20

2.10 Hydraulic Conductivity of Soil 27

2.11 Steady-State Seepage 32

2.12 Effective Stress 33

2.13 Consolidation 36

2.14 Calculation of Primary Consolidation Settlement 41

2.15 Time Rate of Consolidation 42

2.16 Range of Coefficient of Consolidation, cv 48

2.17 Degree of Consolidation Under Ramp Loading 49

2.18 Shear Strength 51

2.19 Unconfined Compression Test 56

2.20 Comments on Friction Angle, f9 57

2.21 Correlations for Undrained Shear Strength, cu 60

2.22 Selection of Shear Strength Parameters 60

2.23 Sensitivity 61

2.24 Summary 62

Problems 62

References 65

3 Natural Soil Deposits and Subsoil Exploration 67

3.1 Introduction 68

Natural Soil Deposits 68

3.2 Soil Origin 68

3.3 Residual Soil 69

3.4 Gravity-Transported Soil 70

3.5 Alluvial Deposits 71

3.6 Lacustrine Deposits 73

3.7 Glacial Deposits 74

3.8 Aeolian Soil Deposits 75

3.9 Organic Soil 76

3.10 Some Local Terms for Soil 76

Subsurface Exploration 77

3.11 Purpose of Subsurface Exploration 77

3.12 Subsurface Exploration Program 77

3.13 Exploratory Borings in the Field 80

3.14 Procedures for Sampling Soil 83

3.15 Split-Spoon Sampling and Standard Penetration Test 83

3.16 Sampling with a Scraper Bucket 92

3.17 Sampling with a Thin-Walled Tube 93

3.18 Sampling with a Piston Sampler 93

3.19 Observation of Water Tables 95

3.20 Vane Shear Test 96

3.21 Cone Penetration Test 100

3.22 Pressuremeter Test (PMT) 108

3.23 Dilatometer Test 111

3.24 Iowa Borehole Shear Test 114

3.25 K0 Stepped-Blade Test 116

3.26 Coring of Rocks 117

3.27 Preparation of Boring Logs 120

3.28 Geophysical Exploration 121

3.29 Subsoil Exploration Report 127

3.30 Summary 128

Problems 129

R eferences 131

4 Instrumentation and Monitoring in Geotechnical Engineering 134

4.1 Introduction 135

4.2 Need for Instrumentation 135

4.3 Geotechnical Measurements 136

4.4 Geotechnical Instruments 137

4.5 Planning an Instrumentation Program 142

4.6 Typical Instrumentation Projects 143

4.7 Summary 143

R eferences 143

5 Soil Improvement and Ground Modification 146

5.1 Introduction 147

5.2 General Principles of Compaction 147

5.3 Empirical Relationships for Compaction 150

5.4 Field Compaction 154

5.5 Compaction Control for Clay Hydraulic Barriers 156

5.6 Vibroflotation 160

5.7 Blasting 164

5.8 Precompression 165

5.9 Sand Drains 170

5.10 Prefabricated Vertical Drains 179

5.11 Lime Stabilization 184

5.12 Cement Stabilization 187

5.13 Fly-Ash Stabilization 189

5.14 Stone Columns 189

5.15 Sand Compaction Piles 194

5.16 Dynamic Compaction 195

5.17 Jet Grouting 198

5.18 Deep Mixing 199

5.19 Summary 201

Problems 201

R eferences 202

6 Shallow Foundations: Ultimate Bearing Capacity 206

6.1 Introduction 207

6.2 General Concept 208

6.3 Terzaghi’s Bearing Capacity Theory 212

6.4 Factor of Safety 216

6.5 Modification of Bearing Capacity Equations for Water Table 217

6.6 The General Bearing Capacity Equation 218

6.7 Other Solutions for Bearing Capacity, Shape, and Depth Factors 225

6.8 Case Studies on Ultimate Bearing Capacity 227

6.9 Effect of Soil Compressibility 231

6.10 Eccentrically Loaded Foundations 235

6.11 Ultimate Bearing Capacity Under Eccentric

Loading—One-Way Eccentricity 236

6.12 Bearing Capacity—Two-Way Eccentricity 242

6.13 A Simple Approach for Bearing Capacity with Two-Way

Eccentricity 249

6.14 Bearing Capacity of a Continuous Foundation Subjected

to Eccentrically Inclined Loading 251

6.15 Plane-Strain Correction of Friction Angle 254

6.16 Summary 254

Problems 254

R eferences 256

7 Ultimate Bearing Capacity of Shallow

Foundations: Special Cases 258

7.1 Introduction 259

7.2 Foundation Supported by a Soil with a Rigid Base at Shallow

Depth 259

7.3 Foundations on Layered Clay 266

7.4 Bearing Capacity of Layered Soil: Stronger Soil Underlain

by Weaker Soil (c9 2 f9 soil) 268

7.5 Bearing Capacity of Layered Soil: Weaker Soil Underlain

by Stronger Soil 275

7.6 Continuous Foundation on Weak Clay with a Granular

Trench 278

7.7 Closely Spaced Foundations—Effect on Ultimate Bearing

Capacity 280

7.8 Bearing Capacity of Foundations on Top of a Slope 282

7.9 Bearing Capacity of Foundations on a Slope 285

7.10 Seismic Bearing Capacity and Settlement in Granular

Soil 286

7.11 Foundations on Rock 289

7.12 Ultimate Bearing Capacity of Wedge-Shaped

Foundations 291

7.13 Uplift Capacity of Foundations 293

7.14 Summary 298

Problems 299

References 300

8 Vertical Stress Increase in Soil 302

8.1 Introduction 303

8.2 Stress Due to a Concentrated Load 303

8.3 Stress Due to a Circularly Loaded Area 304

8.4 Stress Due to a Line Load 305

8.5 Stress Below a Vertical Strip Load of Finite Width

and Infinite Length 306

8.6 Stress Below a Horizontal Strip Load of Finite Width

and Infinite Length 310

8.7 Stress Below a Rectangular Area 312

8.8 Stress Isobars 317

8.9 Average Vertical Stress Increase Due to a Rectangularly

Loaded Area 318

8.10 Average Vertical Stress Increase Below the Center of

a Circularly Loaded Area 323

8.11 Stress Increase Under an Embankment 325

8.12 Westergaard’s Solution for Vertical Stress Due

to a Point Load 328

8.13 Stress Distribution for Westergaard Material 330

8.14 Summary 333

Problems 333

R eferences 335

9 Settlement of Shallow Foundations 336

9.1 Introduction 337

9.2 Elastic Settlement of Shallow Foundation on Saturated

Clay ( ms 5 0.5) 337

Elastic Settlement in Granular Soil 339

9.3 Settlement Based on the Theory of Elasticity 339

9.4 Improved Equation for Elastic Settlement 350

9.5 Settlement of Sandy Soil: Use of Strain

Influence Factor 354

9.6 Settlement of Foundation on Sand Based

on Standard Penetration Resistance 361

9.7 Settlement Considering Soil Stiffness Variation

with Stress Level 366

9.8 Settlement Based on Pressuremeter Test (PMT) 370

9.9 Settlement Estimation Using the L1 2 L2 Method 375

9.10 Effect of the Rise of Water Table on Elastic Settlement 378

Consolidation Settlement 380

9.11 Primary Consolidation Settlement Relationships 380

9.12 Three-Dimensional Effect on Primary Consolidation

Settlement 382

9.13 Settlement Due to Secondary Consolidation 386

9.14 Field Load Test 388

9.15 Presumptive Bearing Capacity 389

9.16 Tolerable Settlement of Buildings 390

9.17 Summary 392

Problems 392

R eferences 394

10 Mat Foundations 396

10.1 Introduction 397

10.2 Combined Footings 397

10.3 Common Types of Mat Foundations 401

10.4 Bearing Capacity of Mat Foundations 403

10.5 Differential Settlement of Mats 406

10.6 Field Settlement Observations for Mat Foundations 407

10.7 Compensated Foundation 407

10.8 Structural Design of Mat Foundations 411

10.9 Summary 424

Problems 425

R eferences 425

11 Load and Resistance Factor Design (LRFD) 427

11.1 Introduction 428

11.2 Design Philosophy 429

11.3 Allowable Stress Design (ASD) 431

11.4 Limit State Design (LSD) and Partial Safety

Factors 432

11.5 Load and Resistance Factor Design (LRFD) 433

11.6 Summary 436

Problems 436

R eferences 437

12 Pile Foundations 438

12.1 Introduction 439

12.2 Pile Materials 440

12.3 Continuous Flight Auger (CFA) Piles 450

12.4 Point Bearing and Friction Piles 451

12.5 Installation of Piles 452

12.6 Pile Driving 453

12.7 Load Transfer Mechanism 458

12.8 Equations for Estimating Pile Capacity 461

12.9 Meyerhof’s Method for Estimating Qp 463

12.10 Vesic’s Method for Estimating Qp 466

12.11 Coyle and Castello’s Method for Estimating Qp

in Sand 469

12.12 Correlations for Calculating Qp with SPT and CPT Results

in Granular Soil 473

12.13 Frictional Resistance (Qs) in Sand 474

12.14 Frictional (Skin) Resistance in Clay 480

12.15 Ultimate Capacity of Continuous Flight Auger Pile 485

12.16 Point Bearing Capacity of Piles Resting on Rock 487

12.17 Pile Load Tests 493

12.18 Elastic Settlement of Piles 497

12.19 Laterally Loaded Piles 502

12.20 Pile-Driving Formulas 514

12.21 Pile Capacity for Vibration-Driven Piles 520

12.22 Wave Equation Analysis 521

12.23 Negative Skin Friction 524

Group Piles 528

12.24 Group Efficiency 528

12.25 Ultimate Capacity of Group Piles in Saturated Clay 531

12.26 Elastic Settlement of Group Piles 534

12.27 Consolidation Settlement of Group Piles 536

12.28 Piles in Rock 538

12.29 Summary 539

Problems 539

References 543

13 Drilled-Shaft Foundations 546

13.1 Introduction 547

13.2 Types of Drilled Shafts 547

13.3 Construction Procedures 548

13.4 Other Design Considerations 554

13.5 Load Transfer Mechanism 555

13.6 Estimation of Load-Bearing Capacity 556

13.7 Load-Bearing Capacity in Granular Soil 558

13.8 Load-Bearing Capacity in Granular Soil Based

on Settlement 561

13.9 Load-Bearing Capacity in Clay 568

13.10 Load-Bearing Capacity in Clay Based on Settlement 570

13.11 Settlement of Drilled Shafts at Working Load 575

13.12 Lateral Load-Carrying Capacity—

Characteristic Load

and Moment Method 576

13.13 Drilled Shafts Extending into Rock 583

13.14 Summary 588

Problems 589

R eferences 590

14 Piled Rafts: An Overview 592

14.1 Introduction 593

14.2 Load-Settlement Plots of Unpiled and Piled Rafts Under

Different Design Conditions 594

14.3 Poulos–Davis–Randolph Simplified Design Method 595

14.4 Case Study: Burj Khalifa Tower in Dubai 600

14.5 Summary 602

Problems 602

R eferences 602

15 Foundations on Difficult Soil 603

15.1 Introduction 604

Collapsible Soil 604

15.2 Definition and Types of Collapsible Soil 604

15.3 Physical Parameters for Identification 606

15.4 Procedure for Calculating Collapse Settlement 608

15.5 Foundations in Soil Not Susceptible

to Wetting 609

15.6 Foundations in Soil Susceptible to Wetting 611

Expansive Soil 612

15.7 General Nature of Expansive Soil 612

15.8 Unrestrained Swell Test 615

15.9 Swelling Pressure Test 617

15.10 Classification of Expansive Soil on the Basis

of Index Tests 621

15.11 Foundation Considerations for Expansive Soil 624

15.12 Construction on Expansive Soil 626

Sanitary Landfills 630

15.13 General Nature of Sanitary Landfills 630

15.14 Settlement of Sanitary Landfills 631

15.15 Summary 633

Problems 633

R eferences 634

16 Lateral Earth Pressure 638

16.1 Introduction 639

16.2 Lateral Earth Pressure at Rest 640

Active Pressure 644

16.3 Rankine Active Earth Pressure 644

16.4 A Generalized Case for Rankine Active Pressure—Granular

Backfill 649

16.5 Generalized Case for Rankine Seismic Active Earth

Pressure—Granular Backfill 653

16.6 Rankine Active Pressure with Vertical Wall Backface

and Inclined c9 2 f9 Soil Backfill 655

16.7 Coulomb’s Active Earth Pressure 658

16.8 Lateral Earth Pressure Due to Surcharge 665

16.9 Active Earth Pressure for Earthquake Conditions—Granular

Backfill 668

16.10 Active Earth Pressure for Earthquake Condition (Vertical

Backface of Wall and c9 2 f9 Backfill) 672

Passive Pressure 676

16.11 Rankine Passive Earth Pressure 676

16.12 Rankine Passive Earth Pressure—Vertical Backface and

Inclined Backfill 679

16.13 Coulomb’s Passive Earth Pressure 681

16.14 Comments on the Failure Surface Assumption for

Coulomb’s Pressure Calculations 683

16.15 Caquot and Kerisel Solution for Passive Earth Pressure

(Granular Backfill) 684

16.16 Solution for Passive Earth Pressure by the Lower Bound

Theorem of Plasticity (Granular Backfill) 686

16.17 Passive Force on Walls with Earthquake Forces 688

16.18 Summary 691

Problems 691

R eferences 693

17 Retaining Walls 694

17.1 Introduction 695

Gravity and Cantilever Walls 697

17.2 Proportioning Retaining Walls 697

17.3 Application of Lateral Earth Pressure Theories

to Design 698

17.4 Stability of Retaining Walls 699

17.5 Check for Overturning 701

17.6 Check for Sliding Along the Base 703

17.7 Check for Bearing Capacity Failure 706

17.8 Construction Joints and Drainage from Backfill 714

17.9 Comments on Design of Retaining Walls

and a Case Study 717

17.10 Gravity Retaining-Wall Design for Earthquake

Conditions 720

Mechanically Stabilized Retaining Walls 722

17.11 Soil Reinforcement 723

17.12 Considerations in Soil Reinforcement 723

17.13 General Design Considerations 727

17.14 Retaining Walls with Metallic Strip Reinforcement 728

17.15 Step-by-Step-Design Procedure Using Metallic Strip

Reinforcement 734

17.16 Retaining Walls with Geotextile Reinforcement 738

17.17 Retaining Walls with Geogrid Reinforcement—

General 744

17.18 Design Procedure for Geogrid-Reinforced Retaining

Wall 746

17.19 Summary 748

Problems 749

R eferences 750

18 Sheet-Pile Walls 752

18.1 Introduction 753

18.2 Construction Methods 756

18.3 Cantilever Sheet-Pile Walls 757

18.4 Cantilever Sheet Piling Penetrating Sandy Soil 758

18.5 Special Cases for Cantilever Walls Penetrating a Sandy

Soil 764

18.6 Cantilever Sheet Piling Penetrating Clay 767

18.7 Special Cases for Cantilever Walls Penetrating Clay 772

18.8 Cantilever Sheet Piles Penetrating Sandy Soil—A Simplified

Approach 775

18.9 Anchored Sheet-Pile Walls 779

18.10 Free Earth Support Method for Penetration of Sandy

Soil—A Simplified Approach 780

18.11 Free Earth Support Method for Penetration of Sandy

Soil—Net Lateral Pressure Method 782

18.12 Design Charts for Free Earth Support Method (Penetration

into Sandy Soil) 785

18.13 Moment Reduction for Anchored Sheet-Pile Walls

Penetrating into Sand 789

18.14 Computational Pressure Diagram Method for Penetration

into Sandy Soil 792

18.15 Field Observations for Anchor Sheet-Pile Walls 795

18.16 Free Earth Support Method for Penetration of Clay 797

18.17 Anchors 802

18.18 Holding Capacity of Deadman Anchors 804

18.19 Holding Capacity of Anchor Plates in Sand 804

18.20 Holding Capacity of Anchor Plates in Clay

(f 5 0 Condition) 811

18.21 Ultimate Resistance of Tiebacks 811

18.22 Summary 812

Problems 812

R eferences 813

19 Braced Cuts 814

19.1 Introduction 815

19.2 Braced-Cut Analysis Based on General Wedge Theory 817

19.3 Pressure Envelope for Braced-Cut Design 820

19.4 Pressure Envelope for Cuts in Layered Soil 822

19.5 Design of Various Components of a Braced Cut 823

19.6 Case Studies of Braced Cuts 831

19.7 Bottom Heave of a Cut in Clay 835

19.8 Stability of the Bottom of a Cut in Sand 839

19.9 Lateral Yielding of Sheet Piles and Ground

Settlement 843

19.10 Summary 845

Problems 845

R eferences 846

Answers to Problems 847

Index 851