Dedicated to the Cause of Students

FOREWORD Geotechnical Engineering: Principles and Practices of Soil Mechanics and Foundation Engineering is a long title befitting a major work. I am pleased to introduce this superb volume destined for a readership of students, professors, and consultants. What makes this text different from other books on these subjects that appear each year and why am I recommending it to you? I have been working and teaching in the area of geotechnical engineering for 25 years. I have read and used scores of textbooks in my classes and practice. Dr. Murthy's text is by far the most comprehensive text I have found. You will find that his organization of the subject matter follows a logical progression. His example problems are numerous and, like the text, start from fundamental principles and progressively develop into more challenging material. They are the best set of example problems I have seen in a textbook. Dr. Murthy has included ample homework problems with a range of difficulty meant to help the student new to the subject to develop his/her confidence and to assist the experienced engineer in his/her review of the subject and in professional development. As the technical editor I have read the entire manuscript three times. I have been impressed by the coverage, the clarity of the presentation, and the insights into the hows and whys of soil and foundation behavior. Often I have been astonished at Dr. Murthy's near-conversational approach to sharing helpful insights. You get the impression he's right there with you guiding you along, anticipating your questions, and providing instruction and necessary information as the next steps in the learning process. I believe you will enjoy this book and that it will receive a warm welcome wherever it is used. I thank Dr. Murthy for his commitment to write this textbook and for sharing his professional experience with us. I thank him for his patience in making corrections and considering suggestions. I thank Mr. B. J. Clark, Senior Acquisitions Editor at Marcel Dekker Inc., for the opportunity to be associated with such a good book. I likewise express my appreciation to Professor Pierre Foray of 1'Ecole Nationale Superieure d'Hydraulique et de Mecanique de Grenoble, Institut National Polytechnique de Grenoble, France for his enthusiastic and unflagging support while I edited the manuscript. MarkT. Bowers, Ph.D., P. E. Associate Professor of Civil Engineering University of Cincinnati

FOREWORD It gives me great pleasure to write a foreword for Geotechnical Engineering: Principles and Practices of Soil Mechanics and Foundation Engineering. This comprehensive, pertinent and upto-date volume is well suited for use as a textbook for undergraduate students as well as a reference book for consulting geotechnical engineers and contractors. This book is well written with numerous examples on applications of basic principles to solve practical problems. The early history of geotechnical engineering and the pioneering work of Karl Terzaghi in the beginning of the last century are described in Chapter 1. Chapters 2 and 3 discuss methods of classification of soil and rock, the chemical and the mechanical weathering of rock, and soil phase relationships and consistency limits for clays and silts. Numerous examples illustrate the relationship between the different parameters. Soil permeability and seepage are investigated in Chapter 4. The construction of flow nets and methods to determine the permeability in the laboratory and in the field are also explained. The concept of effective stress and the effect of pore water pressure on effective stress are discussed in Chapter 5. Chapter 6 is concerned with stress increase in soil caused by surface load and methods to calculate stress increase caused by spread footings, rafts, and pile groups. Several examples are given in Chapter 6. Consolidation of soils and the evaluation of compressibility in the laboratory by oedometer tests are investigated in Chapter 7. Determination of drained and undrained shear strength by unconfined compression, direct shear or triaxial tests is treated in Chapter 8. The important subject of soil exploration is discussed in Chapter 9, including the use of penetration tests such as SPT and CPT in different countries. The stability of slopes is investigated in Chapter 10. Methods using plain and circular slip surfaces to evaluate stability are described such as the methods proposed by Bishop, Fellenius, Morgenstern, and Spencer. Chapter 11 discusses methods to determine active and passive earth pressures acting on retaining and sheet pile walls. Bearing capacity and settlement of foundation and the evaluation of compressibility in the laboratory by oedometer tests are discussed in Chapters 12, 13, and 14. The effect of inclination and eccentricity of the load on bearing capacity is also examined. Chapter 15 describes different pile types, the concept of critical depth, methods to evaluate the bearing capacity of piles in cohesive and cohesionless soils, and pile-driving formulae. The behavior of laterally loaded piles is investigated in Chapter 16 for piles in sand and in clay. The behavior of drilled pier foundations

VII

viii

Foreword

and the effect of the installation method on bearing capacity and uplift are analyzed in Chapter 17. Foundations on swelling and collapsible soils are treated in Chapter 18 as are methods that can be used to reduce heave. This is an important subject, seldom treated in textbooks. The design of retaining walls is covered in Chapter 19, as well as the different factors that affect active and passive earth pressures. Different applications of geotextiles are covered in this chapter as well as the topic of reinforced earth. Cantilever, anchored, and strutted sheet pile walls are investigated in Chapter 20, as are methods to evaluate stability and the moment distribution. Different soil improvement methods, such as compaction of granular soils, sand compaction piles, vibroflotation, preloading, and stone columns, are described in Chapter 21. The chapter also discusses lime and cement stabilization. Appendix A provides a list of SI units, and Appendix B compares methods that have been proposed. This textbook by Prof. V. N. S. Murthy is highly recommended for students specializing in geotechnical engineering and for practicing civil engineers in the United States and Europe. The book includes recent developments such as soil improvement and stabilization methods and applications of geotextiles to control settlements and lateral earth pressure. Numerous graphs and examples illustrate the most important concepts in geotechnical engineering. This textbook should serve as a valuable reference book for many years to come.

BengtB.Broms, Ph.D. Nanyang Technical University, Singapore (retired).

PREFACE This book has the following objectives: 1. To explain the fundamentals of the subject from theory to practice in a logical way 2. To be comprehensive and meet the requirements of undergraduate students 3. To serve as a foundation course for graduate students pursuing advanced knowledge in the subject There are 21 chapters in this book. The first chapter traces the historical background of the subject and the second deals with the formation and mineralogical composition of soils. Chapter 3 covers the index properties and classification of soil. Chapters 4 and 5 explain soil permeability, seepage, and the effect of water on stress conditions in soil. Stresses developed in soil due to imposed surface loads, compressibility and consolidation characteristics, and shear strength characteristics of soil are dealt with in Chapters 6,7, and 8 respectively. The first eight chapters develop the necessary tools for computing compressibility and strength characteristics of soils. Chapter 9 deals with methods for obtainig soil samples in the field for laboratory tests and for determining soil parameters directly by use of field tests. Chapters 10 to 20 deal with stability problems pertaining to earth embankments, retaining walls, and foundations. Chapter 21 explains the various methods by which soil in situ can be improved. Many geotechnical engineers have not appreciated the importance of this subject. No amount of sophistication in the development of theories will help the designers if the soil parameters used in the theory are not properly evaluated to simulate field conditions. Professors who teach this subject should stress this topic. The chapters in this book are arranged in a logical way for the development of the subject matter. There is a smooth transition from one chapter to the next and the continuity of the material is maintained. Each chapter starts with an introduction to the subject matter, develops the theory, and explains its application to practical problems. Sufficient examples are wor1:ed out to help students understand the significance of the theories. Many homework problems are given at the end of each chapter. The subject matter dealt with in each chapter is restricted to the requirements of undergraduate students. Half-baked theories and unconfirmed test results are not developed in this book. Chapters are up-to-date as per engineering standards. The information provided in Chapter 17 on drilled pier foundations is the latest available at the time of this writing. The design

Preface

of mechanically stabilized earth retaining walls is also current. A new method for predicting the nonlinear behavior of laterally loaded vertical and batter piles is described in Chapter 16. The book is comprehensive, rational, and pertinent to the requirements of undergraduate students. It serves as a foundation course for graduate students, and is useful as a reference book for designers and contractors in the field of geotechnical engineering.

ACKNOWLEDGEMENTS It is my pleasure to thank Marcel Dekker, Inc., for accepting me as a single author for the publication of my book. The man who was responsible for this was Mr. B.J. Clark, the Executive Acquisition Editor. It was my pleasure to work under his guidance. Mr. Clark is a refined gentleman personified, polished, and clear sighted. I thank him cordially for the courtesies and help extended to me during the course of writing the manuscript. I remain ever grateful to him. Writing a book for American Universities by a nonresident of America is not an easy task. I needed an American professor to edit my manuscript and guide me with regards to the requirements of undergraduate students in America. Dr. Mark T. Bowers, Associate Professor of Civil Engineering, University of Cincinnati, accepted to become my consultant and chief editor. Dr. Bowers is a man of honesty and integrity. He is dedicated to the cause of his profession. He worked hard for over a year in editing my book and helped me to streamline to make it acceptable to the undergraduate students of American Universities. I thank Dr. Bowers for the help extended to me. There are many in India who helped me during the course of writing this book. Some provided me useful suggestions and others with references. I acknowledge their services with thanks. The members are: Mr. S. Pranesh

Dr. K.S.Subba Rao Dr. T.S. Nagaraj

Dr. C. Subba Rao

Managing Director Prism Books Pvt Ltd Bangalore Professor of Civil Engineering Indian Institute of Science Bangalore Professor of Civil Engineering (Emeritus), Indian Institute of Science, Bangalore Professor of Civil Engineering Indian Institute of Technology Kharagpur

Chaitanya Graphics, Bangalore, provided the artwork for the book. I thank Mr S.K. Vijayasimha, the designer, for the excellent job done by him. My son Prakash was associated with the book since its inception. He carried on correspondence with the publishers on my behalf and sent reference books as needed. My wife Sharadamani was mainly responsible for keeping my spirit high during the years I spent in writing the book. I remain grateful to my son and my wife for all they did. I sincerely thank Mr. Brian Black for his continuous efforts in the production of this book. I immensely thank Mr. Janardhan and Mr. Rajeshwar, computer engineers of Aicra Info Mates Pvt Ltd., Hyderabad, for their excellent typesetting work on this book. V.N.S. Murthy

CONTENTS

Foreword

Mark T. Bowers

v

Foreword

Bengt B. Broms

vii

Preface

ix

CHAPTER 1 1.1 1.2 1.3

General Remarks A Brief Historical Development Soil Mechanics and Foundation Engineering

CHAPTER 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9

INTRODUCTION

SOIL FORMATION AND CHARACTERIZATION

Introduction Rock Classification Formation of Soils General Types of Soils Soil Particle Size and Shape Composition of Clay Minerals Structure of Clay Minerals Clay Particle-Water Relations Soil Mass Structure

1 1 2 3

5 5 5 7 7 9 11 11 14 17 XI

xii

Contents

CHAPTER 3 SOIL PHASE RELATIONSHIPS, INDEX PROPERTIES AND CLASSIFICATION 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 3.20 3.21 3.22

Soil Phase Relationships Mass-Volume Relationships Weight-Volume Relationships Comments on Soil Phase Relationships Index Properties of Soils The Shape and Size of Particles Sieve Analysis The Hydrometer Method of Analysis Grain Size Distribution Curves Relative Density of Cohesionless Soils Consistency of Clay Soil Determination of Atterberg Limits Discussion on Limits and Indices Plasticity Chart General Considerations for Classification of Soils Field Identification of Soils Classification of Soils Textural Soil Classification AASHTO Soil Classification System Unified Soil Classification System (USCS) Comments on the Systems of Soil Classification Problems

CHAPTER 4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14

SOIL PERMEABILITY AND SEEPAGE

Soil Permeability Darcy's Law Discharge and Seepage Velocities Methods of Determination of Hydraulic Conductivity of Soils Constant Head Permeability Test Falling Head Permeability Test Direct Determination of k of Soils in Place by Pumping Test Borehole Permeability Tests Approximate Values of the Hydraulic Conductivity of Soils Hydraulic Conductivity in Stratified Layers of Soils Empirical Correlations for Hydraulic Conductivity Hydraulic Conductivity of Rocks by Packer Method Seepage Laplace Equation

19 19 20 24 25 31 32 33 35 43 44 45 47 52 59 67 68 69 69 70 73 76 80

87 87 89 90 91 92 93 97 101 102 102 103 112 114 114

Contents

4.15 4.16 4.17 4.18 4.19 4.20 4.21 4.22

xiii

Flow Net Construction Determination of Quantity of Seepage Determination of Seepage Pressure Determination of Uplift Pressures Seepage Flow Through Homogeneous Earth Dams Flow Net Consisting of Conjugate Confocal Parabolas Piping Failure Problems

CHAPTER 5 5.1 5.2 5.3 5.4 5.5 5.6

EFFECTIVE STRESS AND PORE WATER PRESSURE

Introduction Stresses when No Flow Takes Place Through the Saturated Soil Mass Stresses When Flow Takes Place Through the Soil from Top to Bottom Stresses When Flow Takes Place Through the Soil from Bottom to Top Effective Pressure Due to Capillary Water Rise in Soil Problems

CHAPTER 6 STRESS DISTRIBUTION IN SOILS DUE TO SURFACE LOADS 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 6.12

Introduction Boussinesq's Formula for Point Loads Westergaard's Formula for Point Loads Line Loads Strip Loads Stresses Beneath the Corner of a Rectangular Foundation Stresses Under Uniformly Loaded Circular Footing Vertical Stress Beneath Loaded Areas of Irregular Shape Embankment Loadings Approximate Methods for Computing cr Pressure Isobars Problems

CHAPTER 7 7.1 7.2 7.3

COMPRESSIBILITY AND CONSOLIDATION

Introduction Consolidation Consolidometer

116 120 122 123 126 127 131 138

143 143 145 146 147 149 170

173 173 174 175 178 179 181 186 188 191 197 198 203

207 207 208 212

xiv

Contents

7.4 7.5 7.6 7.7 7.8 7.9 7.10 7.11 7.12 7.13 7.14

The Standard One-Dimensional Consolidation Test Pressure-Void Ratio Curves Determination of Preconsolidation Pressure e-logp Field Curves for Normally Consolidated and Overconsolidated Clays of Low to Medium Sensitivity Computation of Consolidation Settlement Settlement Due to Secondary Compression Rate of One-dimensional Consolidation Theory of Terzaghi Determination of the Coefficient of Consolidation Rate of Settlement Due to Consolidation Two- and Three-dimensional Consolidation Problems Problems

CHAPTERS 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 8.10 8.11 8.12 8.13 8.14 8.15 8.16 8.17 8.18 8.19 8.20 8.21 8.22 8.23 8.24 8.25

SHEAR STRENGTH OF SOIL

Introduction Basic Concept of Shearing Resistance and Shearing Strength The Coulomb Equation Methods of Determining Shear Strength Parameters Shear Test Apparatus Stress Condition at a Point in a Soil Mass Stress Conditions in Soil During Triaxial Compression Test Relationship Between the Principal Stresses and Cohesion c Mohr Circle of Stress Mohr Circle of Stress When a Prismatic Element is Subjected to Normal and Shear Stresses Mohr Circle of Stress for a Cylindrical Specimen Compression Test Mohr-Coulomb Failure Theory Mohr Diagram for Triaxial Compression Test at Failure Mohr Diagram for a Direct Shear Test at Failure Effective Stresses Shear Strength Equation in Terms of Effective Principal Stresses Stress-Controlled and Strain-Controlled Tests Types of Laboratory Tests Shearing Strength Tests on Sand Unconsolidated-Undrained Test Unconfined Compression Tests Consolidated-Undrained Test on Saturated Clay Consolidated-Drained Shear Strength Test Pore Pressure Parameters Under Undrained Loading Vane Shear Tests

213 214 218 219 219 224 233 240 242 243 247

253 253 253 254 255 256 260 262 263 264 265 266 268 269 270 274 275 276 276 278 284 286 294 296 298 300

Contents

8.26 8.27 8.28 8.29

xv

Other Methods for Determining Undrained Shear Strength of Cohesive Soils The Relationship Between Undrained Shear Strength and Effective Overburden Pressure General Comments Questions and Problems

CHAPTERS SOIL EXPLORATION 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9 9.10 9.11 9.12 9.13 9.14 9.15 9.16 9.17

Introduction Boring of Holes Sampling in Soil Rock Core Sampling Standard Penetration Test SPT Values Related to Relative Density of Cohesionless Soils SPT Values Related to Consistency of Clay Soil Static Cone Penetration Test (CPT) Pressuremeter The Flat Dilatometer Test Field Vane Shear Test (VST) Field Plate Load Test (PUT) Geophysical Exploration Planning of Soil Exploration Execution of Soil Exploration Program Report Problems

CHAPTER 10 10.1 10.2 10.3 10.4 10.5 10.6 10.7 10.8 10.9 10.10 10.11 10.12 10.13

STABILITY OF SLOPES

Introduction General Considerations and Assumptions in the Analysis Factor of Safety Stability Analysis of Infinite Slopes in Sand Stability Analysis of Infinite Slopes in Clay Methods of Stability Analysis of Slopes of Finite Height Plane Surface of Failure Circular Surfaces of Failure Failure Under Undrained Conditions ((f>u = 0) Friction-Circle Method Taylor's Stability Number Tension Cracks Stability Analysis by Method of Slices for Steady Seepage

302 304 310 311

317 317 318 322 325 327 330 330 332 343 349 351 3 51 352 358 359 361 362

365 365 367 368 371 372 376 376 378 380 382 389 393 393

xvi

Contents

10.14 10.15 10.16 10.17 10.18

Bishop's Simplified Method of Slices Bishop and Morgenstern Method for Slope Analysis Morgenstern Method of Analysis for Rapid Drawdown Condition Spencer Method of Analysis Problems

CHAPTER 11 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 11.10 11.11 11.12 11.13 11.14 11.15

LATERAL EARTH PRESSURE

Introduction Lateral Earth Pressure Theory Lateral Earth Pressure for at Rest Condition Rankine's States of Plastic Equilibrium for Cohesionless Soils Rankine's Earth Pressure Against Smooth Vertical Wall with Cohesionless Backfill Rankine's Active Earth Pressure with Cohesive Backfill Rankine's Passive Earth Pressure with Cohesive Backfill Coulomb's Earth Pressure Theory for Sand for Active State Coulomb's Earth Pressure Theory for Sand for Passive State Active Pressure by Culmann's Method for Cohesionless Soils Lateral Pressures by Theory of Elasticity for Surcharge Loads on the Surface of Backfill Curved Surfaces of Failure for Computing Passive Earth Pressure Coefficients of Passive Earth Pressure Tables and Graphs Lateral Earth Pressure on Retaining Walls During Earthquakes Problems

CHAPTER 12 SHALLOW FOUNDATION I: ULTIMATE BEARING CAPACITY 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 12.10 12.11 12.12 12.13

Introduction The Ultimate Bearing Capacity of Soil Some of the Terms Defined Types of Failure in Soil An Overview of Bearing Capacity Theories Terzaghi's Bearing Capacity Theory Skempton's Bearing Capacity Factor NC Effect of Water Table on Bearing Capacity The General Bearing Capacity Equation Effect of Soil Compressibility on Bearing Capacity of Soil Bearing Capacity of Foundations Subjected to Eccentric Loads Ultimate Bearing Capacity of Footings Based on SPT Values (N) The CPT Method of Determining Ultimate Bearing Capacity

400 403 405 408 411

419 419 420 421 425 428 440 449 452 455 456 458 462 464 467 476

481 481 483 483 485 487 488 493 494 503 509 515 518 518

Contents

xvii

12.14 Ultimate Bearing Capacity of Footings Resting on Stratified Deposits of Soil 12.15 Bearing Capacity of Foundations on Top of a Slope 12.16 Foundations on Rock 12.17 Case History of Failure of the Transcona Grain Elevator 12.18 Problems

CHAPTER 13 SHALLOW FOUNDATION II: SAFE BEARING PRESSURE AND SETTLEMENT CALCULATION 13.1 13.2 13.3 13.4 13.5 13.6 13.7 13.8 13.9 13.10 13.11 13.12 13.13 13.14 13.15

Introduction Field Plate Load Tests Effect of Size of Footings on Settlement Design Charts from SPT Values for Footings on Sand Empirical Equations Based on SPT Values for Footings on Cohesionless Soils Safe Bearing Pressure from Empirical Equations Based on CPT Values for Footings on Cohesionless Soil Foundation Settlement Evaluation of Modulus of Elasticity Methods of Computing Settlements Elastic Settlement Beneath the Corner of a Uniformly Loaded Flexible Area Based on the Theory of Elasticity Janbu, Bjerrum and Kjaernsli's Method of Determining Elastic Settlement Under Undrained Conditions Schmertmann's Method of Calculating Settlement in Granular Soils by Using CPT Values Estimation of Consolidation Settlement by Using Oedometer Test Data Skempton-Bjerrum Method of Calculating Consolidation Settlement (1957) Problems

CHAPTER 14 SHALLOW FOUNDATION III: COMBINED FOOTINGS AND MAT FOUNDATIONS 14.1 14.2 14.3 14.4 14.5

Introduction Safe Bearing Pressures for Mat Foundations on Sand and Clay Eccentric Loading The Coefficient of Subgrade Reaction Proportioning of Cantilever Footing

521 529 532 533 536

545 545 548 554 555 558 559 561 562 564 565 568 569 575 576 580

585 585 587 588 588 591

xviii

Contents

14.6

Design of Combined Footings by Rigid Method (Conventional Method) 14.7 Design of Mat Foundation by Rigid Method 14.8 Design of Combined Footings by Elastic Line Method 14.9 Design of Mat Foundations by Elastic Plate Method 14.10 Floating Foundation 14.11 Problems

CHAPTER 15 DEEP FOUNDATION I: PILE FOUNDATION 15.1 15.2 15.3 15.4 15.5 15.6

Introduction Classification of Piles Types of Piles According to the Method of Installation Uses of Piles Selection of Pile Installation of Piles

PART A-VERTICAL LOAD BEARING CAPACITY OF A SINGLE VERTICAL PILE 15.7 15.8 15.9 15.10 15.11 15.12 15.13 15.14 15.15 15.16 15.17 15.18 15.19 15.20 15.21 15.22 15.23 15.24 15.25

General Considerations Methods of Determining Ultimate Load Bearing Capacity of a Single Vertical Pile General Theory for Ultimate Bearing Capacity Ultimate Bearing Capacity in Cohesionless Soils Critical Depth Tomlinson's Solution for Qbin Sand Meyerhof's Method of Determining Qbfor Piles in Sand Vesic's Method of Determining Qb Janbu's Method of Determining Qb Coyle and Castello's Method of Estimating Qbin Sand The Ultimate Skin Resistance of a Single Pile in Cohesionless Soil Skin Resistance Qfby Coyle and Castello Method (1981) Static Bearing Capacity of Piles in Clay Soil Bearing Capacity of Piles in Granular Soils Based on SPT Value Bearing Capacity of Piles Based on Static Cone Penetration Tests (CPT) Bearing Capacity of a Single Pile by Load Test Pile Bearing Capacity from Dynamic Pile Driving Formulas Bearing Capacity of Piles Founded on a Rocky Bed Uplift Resistance of Piles

592 593 594 595 595 603

605 605 605 606 608 609 610

613 613 617 618 620 621 622 624 625 628 628 629 631 631 635 652 663 666 670 671

Contents

xix

PART B-PILE GROUP 15.26 Number and Spacing of Piles in a Group 15.27 Pile Group Efficiency 15.28 Vertical Bearing Capacity of Pile Groups Embedded in Sands and Gravels 15.29 Settlement of Piles and Pile Groups in Sands and Gravels 15.30 Settlement of Pile Groups in Cohesive Soils 15.31 Allowable Loads on Groups of Piles 15.32 Negative Friction 15.33 Uplift Capacity of a Pile Group 15.34 Problems

CHAPTER 16 DEEP FOUNDATION II: BEHAVIOR OF LATERALLY LOADED VERTICAL AND BATTER PILES 16.1 16.2 16.3 16.4

Introduction Winkler's Hypothesis The Differential Equation Non-dimensional Solutions for Vertical Piles Subjected to Lateral Loads 16.5 p-y Curves for the Solution of Laterally Loaded Piles 16.6 Broms' Solutions for Laterally Loaded Piles 16.7 A Direct Method for Solving the Non-linear Behavior of Laterally Loaded Flexible Pile Problems 16.8 Case Studies for Laterally Loaded Vertical Piles in Sand 16.9 Case Studies for Laterally Loaded Vertical Piles in Clay 16.10 Behavior of Laterally Loaded Batter Piles in Sand 16.11 Problems

CHAPTER 17 DEEP FOUNDATION III: DRILLED PIER FOUNDATIONS 17.1 17.2 17.3 17.4 17.5 17.6 17.7 17.8

Introduction Types of Drilled Piers Advantages and Disadvantages of Drilled Pier Foundations Methods of Construction Design Considerations Load Transfer Mechanism Vertical Bearing Capacity of Drilled Piers The General Bearing Capacity Equation for the Base Resistance

=

"

674 674 676 678 681 689 690 692 694 696

699 699 700 701 704 706 709 716 722 725 731 739

741 741 7 41 743 743 751 752 754 755

xx

Contents

17.9 17.10 17.11 17.12 17.13 17.14 17.15 17.16 17.17 17.18 17.19

Bearing Capacity Equations for the Base in Cohesive Soil Bearing Capacity Equation for the Base in Granular Soil Bearing Capacity Equations for the Base in Cohesive IGM or Rock The Ultimate Skin Resistance of Cohesive and Intermediate Materials Ultimate Skin Resistance in Cohesionless Soil and Gravelly Sands Ultimate Side and Total Resistance in Rock Estimation of Settlements of Drilled Piers at Working Loads Uplift Capacity of Drilled Piers Lateral Bearing Capacity of Drilled Piers Case Study of a Drilled Pier Subjected to Lateral Loads Problems

CHAPTER 18 FOUNDATIONS ON COLLAPSIBLE AND EXPANSIVE SOILS 18.1

General Considerations

PART A-COLLAPSIBLE SOILS 18.2 18.3 18.4 18.5 18.6

General Observations Collapse Potential and Settlement Computation of Collapse Settlement Foundation Design Treatment Methods for Collapsible Soils

PART B-EXPANSIVE SOILS 18.7 18.8 18.9 18.10 18.11 18.12 18.13 18.14 18.15 18.16 18.17 18.18 18.19

Distribution of Expansive Soils General Characteristics of Swelling Soils Clay Mineralogy and Mechanism of Swelling Definition of Some Parameters Evaluation of the Swelling Potential of Expansive Soils by Single Index Method Classification of Swelling Soils by Indirect Measurement Swelling Pressure by Direct Measurement Effect of Initial Moisture Content and Initial Dry Density on Swelling Pressure Estimating the Magnitude of Swelling Design of Foundations in Swelling Soils Drilled Pier Foundations Elimination of Swelling Problems

756 756 759 760 763 764 765 777 779 787 787

791 791

793 793 795 796 799 800

800 800 801 803 804 804 806 812 813 814 817 817 827 828

Contents

xxi

CHAPTER 19 CONCRETE AND MECHANICALLY STABILIZED EARTH RETAINING WALLS

833

PART A-CONCRETE RETAINING WALLS

833

19.1 19.2 19.3 19.4 19.5

Introduction Conditions Under Which Rankine and Coulomb Formulas Are Applicable to Retaining Walls Under the Active State Proportioning of Retaining Walls Earth Pressure Charts for Retaining Walls Stability of Retaining Walls

PART B-MECHANICALLY STABILIZED EARTH RETAINING WALLS 19.6 19.7 19.8 19.9 19.10 19.11 19.12 19.13

General Considerations Backfill and Reinforcing Materials Construction Details Design Considerations for a Mechanically Stabilized Earth Wall Design Method External Stability Examples of Measured Lateral Earth Pressures Problems

CHAPTER 20 20.1 20.2 20.3 20.4 20.5 20.6 20.7 20.8 20.9 20.10 20.11 20.12 20.13 20.14 20.15

SHEET PILE WALLS AND BRACED CUTS

Introduction Sheet Pile Structures Free Cantilever Sheet Pile Walls Depth of Embedment of Cantilever Walls in Sandy Soils Depth of Embedment of Cantilever Walls in Cohesive Soils Anchored Bulkhead: Free-Earth Support Method—Depth of Embedment of Anchored Sheet Piles in Granular Soils Design Charts for Anchored Bulkheads in Sand Moment Reduction for Anchored Sheet Pile Walls Anchorage of Bulkheads Braced Cuts Lateral Earth Pressure Distribution on Braced-Cuts Stability of Braced Cuts in Saturated Clay Bjerrum and Eide Method of Analysis Piping Failures in Sand Cuts Problems

833 833 835 836 839 849 849 851 855 857 859 863 875 877

881 881 883 883 885 896 908 913 916 925 931 935 938 940 945 945

Contents

XXII

CHAPTER 21 21.1 21.2 21.3 21.4 21.5 21.6 21.7 21.8 21.9 21.10 21.11

SOIL IMPROVEMENT

Introduction Mechanical Compaction Laboratory Tests on Compaction Effect of Compaction on Engineering Behavior Field Compaction and Control Compaction for Deeper Layers of Soil Preloading Sand Compaction Piles and Stone Columns Soil Stabilization by the Use of Admixtures Soil Stabilization by Injection of Suitable Grouts Problems

951 951 952 953 959 962 973 974 980 981 983 983

APPENDIX A

SI UNITS IN GEOTECHNICAL ENGINEERING

987

APPENDIX B

SLOPE STABILITY CHARTS AND TABLES

993

REFERENCES

1007

INDEX

1025