Principles of Geotechnical Engineering Ninth Edition PDF

Braja M. Das | Khaled Sobhan Das _ Braja M. Das | Khaled Sobhan...

Braja M. Das | Khaled Sobhan Das _ Braja M. Das | Khaled Sobhan Sobhan PRINCIPLES OF GEOTECHNICAL ENGINEERING GEOTECHNICAL ENGINEERING Ninth Edition PRINCIPLES OF PRINCIPLES OF To register or access your online learning solution or purchase GEOTECHNICAL ENGINEERING materials for your course, visit www.cengagebrain.com. Ninth Edition Ninth Edition Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  Principles of Geotechnical Engineering Ninth Edition Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  iii Principles of Geotechnical Engineering Ninth Edition BRAJA M. DAS, Dean Emeritus California State University, Sacramento KHALED SOBHAN, Professor Florida Atlantic University Australia Brazil Mexico Singapore United Kingdom United States Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Principles of Geotechnical Engineering, © 2018, 2014 Cengage Learning® Ninth Edition ALL RIGHTS RESERVED. No part of this work covered by the copyright Authors: Braja M. Das and Khaled Sobhan herein may be reproduced or distributed in any form or by any means, Product Director, Global Engineering: except as permitted by U.S. copyright law, without the prior written Timothy L. Anderson permission of the copyright owner. Senior Content Developer: Mona Zeftel For product information and technology assistance, contact us at Product Assistant: Alexander Sham Cengage Learning Customer & Sales Support, 1-800-354-9706. Marketing Manager: Kristin Stine For permission to use material from this text or product, Director, Higher Education Production: submit all requests online at www.cengage.com/permissions. Sharon L. Smith Further permissions questions can be emailed to [email protected]. Content Project Manager: Jana Lewis Production Service: RPK Editorial Services, Inc. Library of Congress Control Number: 2016942336 Copyeditor: Lori Martinsek ISBN: 978-1-305-97093-9 Proofreader: Harlan James Indexer: Braja M. Das Cengage Learning Compositor: MPS Limited 20 Channel Center Street Senior Art Director: Michelle Kunkler Boston, MA 02210 Cover and Internal Designer: USA Harasymczuk Design Cover Image: Felipe Gabaldon, Getty Images Cengage Learning is a leading provider of customized learning solutions Intellectual Property with employees residing in nearly 40 different countries and sales in more than 125 countries around the world. Find your local representative at Analyst: Christine Myaskovsky www.cengage.com. Project Manager: Sarah Shainwald Text and Image Permissions Researcher: Kristiina Paul Cengage Learning products are represented in Canada by Nelson Education Ltd. Manufacturing Planner: Doug Wilke To learn more about Cengage Learning Solutions, visit www.cengage.com/engineering. Purchase any of our products at your local college store or at our preferred online store www.cengagebrain.com. Unless otherwise noted, all items © Cengage Learning. Printed in the United States of America Print Number: 01 Print Year: 2016 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  To Elizabeth Madison, Armaan and Shaiza Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 P R E FA C E Principles of Geotechnical Engineering is intended for use as a text for the introductory course in geotechnical engineering taken by practically all civil engineering students, as well as for use as a reference book for practicing engineers. The book has been revised in 1990, 1994, 1998, 2002, 2006, and 2010. The eighth edition was published in 2014 with coauthor, Khaled Sobhan of Florida Atlantic University. As in the previous editions of the book, this new edition offers a valuable overview of soil properties and mechanics, together with coverage of field practices and basic engineering procedures. It is not the intent of this book to conform to any design codes. The authors appreciate the over over- whelming adoptions of this text in various classrooms and are gratified that it has be- come the market-leading textbook for the course. New to the Ninth Edition This edition includes many new example problems as well as revisions to existing problems. This book now offers more than 185 example problems to ensure understanding. The authors have also added to and updated the book’s end-of-chapter problems throughout. In Chapter 1 on “Geotechnical Engineering: A Historical Perspective,” the list of ISSMGE (International Society for Soil Mechanics and Geotechnical Engineering) technical committees (as of 2013) has been updated. A list of some important geotechnical engineering journals now in publication has been added. Chapter 2 on “Origin of Soil and Grain Size” has a more detailed discussion on U.S. sieve sizes. British and Australian standard sieve sizes have also been added. Chapter 3 on “Weight-Volume Relationships” now offers an expanded dis- cussion on angularity and the maximum and minimum void ratios of granular soils. Students now learn more about the fall cone test used to determine the liquid limit in Chapter 4, which covers “Plasticity and Structure of Soil.” In Chapter 6 on “Soil Compaction,” a newly-developed empirical correlation for maximum dry density and optimum moisture content has been added. In Chapter 7 on “Permeability,” sections on permeability tests in auger holes, hydraulic conductivity of compacted clay soils, and moisture content-unit weight criteria for clay liner construction have been added. Pavlovsky’s solution for seepage through an earth dam has been added to Chapter 8 on “Seepage.” Chapter 10 on “Stresses in a Soil Mass,” has new sections on: Vertical stress caused by a horizontal strip load, Westergaard’s solution for vertical stress due to a point load, and Stress distribution for Westergaard material. Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 viii Preface An improved relationship for elastic settlement estimation has been incor- porated into Chapter 11 on “Compressibility of Soil.” This chapter also has a new section on construction time correction (for ramp loading) of consolida- tion settlement. Chapter 12 on “Shear Strength of Soil” now includes some recently-published correlations between drained angle of friction and plasticity index of clayey soil. Additional content has been included on the relationship between un- drained shear strength of remolded clay with liquidity index. The generalized case for Rankine active and passive pressure (granular backfill) now appears in Chapter 13 on “Lateral Earth Pressure: At-Rest, Rankine, and Coulomb” (Section 13.10). Additional tables for active earth pressure coefficient based on Mononobe-Okabe’s equation have been added. In Chapter 14 on “Lateral Earth Pressure: Curved Failure Surface,” the pas- sive earth pressure coefficient obtained based on the solution by the lower bound theorem of plasticity and the solution by method of characteristics have been summarized. Also, the section on passive force walls with earth- quake forces (Section 14.7) has been expanded. In Chapter 15 on “Slope Stability,” the parameters required for location of the critical failure circle based on Spencer’s analysis have been added. Chapter 16 on “Soil Bearing Capacity for Shallow Foundations,” includes a new section on continuous foundations under eccentrically-inclined load. Chapter 18 is a new chapter titled “An Introduction to Geosynthetics,” which examines current developments and challenges within this robust and rapidly expanding area of civil engineering. In the preparation of an engineering text of this type, it is tempting to include many recent developments relating to the behavior of natural soil deposits found in vari- ous parts of the world that are available in journals and conference proceedings with the hope that they will prove to be useful to the students in their future practice. However, based on many years of teaching, the authors feel that clarity in explaining the fundamentals of soil mechanics is more important in a first course in this area than filling the book with too many details and alternatives. Many of the fine points can be left to an advanced course in geotechnical engineering. This approach is most likely to nurture students’ interest and appreciation in the geotechnical engineering profession at large. Trusted Features Principles of Geotechnical Engineering offers more worked-out problems and fig- ures than any other similar text. Unique in the market, these features offer students ample practice and examples, keeping their learning application-oriented, and help- ing them prepare for work as practicing civil engineers. In addition to traditional end-of-chapter exercises, this text provides challeng- ing critical thinking problems. These problems encourage deeper analyses and drive students to extend their understanding of the subjects covered within each chapter. Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  Preface ix A generous 16-page color insert features distinctive photographs of rocks and rock-forming minerals. These images capture the unique coloring that help geotech- nical engineers distinguish one mineral from another. Each chapter begins with an introduction and concludes with a summary to help students identify what is most important in each chapter. These features clearly preview and reinforce content to guide students and assist them in retaining key concepts. A complete, comprehensive discussion addresses the weathering of rocks. Stu- dents learn about both weathering and the formation of sedimentary and metamor- phic rocks in this thorough presentation. A detailed explanation focuses on the variation of the maximum and minimum void ratios of granular soils. Students examine variations due to grain size, shape, and non-plastic fine contents. Resource Materials A detailed Instructor’s Solutions Manual containing solutions to all end-of-chapter problems and Lecture Note PowerPoint Slides are available via a secure, password- protected Instructor Resource Center at http://sso.cengage.com. Principles of Geotechnical Engineering is also available through MindTap, Cengage Learning’s digital course platform. See the following section on pages xi and xii for more details about this exciting new addition to the book. Acknowledgments We are deeply grateful to Janice Das for her assistance in completing the revi- sion. She has been the driving force behind this textbook since the prepara- tion of the first edition. Thanks to Professor Jiliang Li of Purdue University North Central for pro- viding several important review comments on the eighth edition. The authors would like to thank all of the reviewers and instructors who have pro- vided feedback over the years. In addition we wish to acknowledge and thank our Global Engineering team at Cengage Learning for their dedication to this new book: Timothy Anderson, Product Director; Mona Zeftel, Senior Content Developer; Jana Lewis, Content Project Manager; Kristin Stine, Marketing Manager; Elizabeth Brown and Brittany Burden, Learning Solutions Specialists; Ashley Kaupert, Asso- ciate Media Content Developer; Teresa Versaggi and Alexander Sham, Product As- sistants; and Rose P. Kernan of RPK Editorial Services. They have skillfully guided every aspect of this text’s development and production to successful completion. Braja M. Das Khaled Sobhan Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 M I N D TA P O N L I N E C O U R S E Principles of Geotechnical Engineer- Engineer ing is also available through MindTap, Cengage Learning’s digital course plat- form. The carefully-crafted pedagogy and exercises in this market-leading textbook are made even more effec- tive by an interactive, customizable eBook, automatically graded assess- ments, and a full suite of study tools. As an instructor using MindTap, you have at your fingertips the full text and a unique set of tools, all in an interface designed to save you time. MindTap makes it easy for instructors to build and customize their course, so you can focus on the most relevant material while also lowering costs for your students. Stay connected and informed through real-time student tracking that provides the opportunity to adjust your course as needed based on analyt- ics of interactivity and performance. Algorithmically generated problem sets allow your students maximum practice while you can be assured that each student is being tested by unique problems. Videos of real world sit- uations, geotechnical instruments, and soil and rock materials provide students with knowledge of future field experiences. How does MindTap benefit instructors? You can build and personalize your course by integrating your own con- tent into the MindTap Reader (like lecture notes or problem sets to down- load) or pull from sources such as RSS feeds, YouTube videos, websites, and more. Control what content students see with a built-in learning path that can be customized to your syllabus. MindTap saves you time by pro- viding you and your students with Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 xii MindTap Online Course automatically graded assignments and quizzes, including algorithmically gen- erated problem sets. These problems include immediate, specific feedback, so students know exactly where they need more practice. The Message Center helps you to quickly and easily contact students directly from MindTap. Messages are communicated directly to each student via the communica- tion medium (email, social media, or even text message) designated by the student. StudyHub is a valuable studying tool that allows you to deliver important infor infor- mation and empowers your students to personalize their experience. Instructors can choose to annotate the text with notes and highlights, share content from the MindTap Reader, and create flashcards to help their students focus and succeed. The Progress App lets you know exactly how your students are doing (and where they might be struggling) with live analytics. You can see overall class engagement and drill down into individual student performance, enabling you to adjust your course to maximize student success. How does MindTap benefit your students? The MindTap Reader adds the abilities to have the content read aloud, to print from the reader, and to take notes and highlights while also capturing them within the linked StudyHub App. The MindTap Mobile App keeps students connected with alerts and notifica- tions while also providing them with on-the-go study tools like Flashcards and quizzing, helping them manage their time efficiently. Flashcards are pre-populated to provide a jump start on studying, and students and in- structors can also create customized cards as they move through the course. The Progress App allows students to monitor their individual grades, as well as their level compared to the class average. This not only helps them stay on track in the course but also motivates them to do more, and ultimately to do better. The unique StudyHub is a powerful single- destination studying tool that empowers stu- dents to personalize their experience. They can quickly and easily access all notes and highlights marked in the MindTap Reader, locate bookmarked pages, review notes and Flashcards shared by their instructor, and create custom study guides. To find out more about MindTap go to: www.cengage.com/mindtap. For more information about MindTap for Engineering, or to schedule a dem- onstration, please call (800) 354-9706 or email [email protected]. For those instructors outside the United States, please visit http://www.cengage.com/contact/ to locate your regional office. Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 ABOUT THE AUTHORS Professor Braja Das is Dean Emeritus of the College of Engineering and Com- puter Science at California State University, Sacramento. He received his M.S. in Civil Engineering from the University of Iowa and his Ph.D. in the area of Geo- technical Engineering from the University of Wisconsin. He is the author of several geotechnical engineering texts and reference books and has authored more than 300 technical papers in the area of geotechnical engineering. His primary areas of research include shallow foundations, earth anchors, and geosynthetics. He is a Fellow and Life Member of the American Society of Civil Engineers, Life Member of the American Society for Engineering Education, and an Emeritus Member of the Stabilization of Geometrical Materials and Recycled Materials Committee of the Transportation Research Board of the National Research Council (Washington, D.C.). He has previously served as a member of the editorial board of the Journal of Geotechnical Engineering of ASCE, a member of the Lowland Technology Inter- national journal (Japan), associate editor of the International Journal of Offshore and Polar Engineering (ISOPE), and co-editor of the Journal of Geotechnical and Geological Engineering (Springer, The Netherlands). Presently he is the editor-in- chief of the International Journal of Geotechnical Engineering (Taylor and Francis, U.K.). Dr. Das has received numerous awards for teaching excellence, including the AMOCO Foundation Award, AT&T Award for Teaching Excellence from the American Society for Engineering Education, the Ralph Teetor Award from the Society of Automotive Engineers, and the Distinguished Achievement Award for Teaching Excellence from the University of Texas at El Paso. Dr. Khaled Sobhan is a Professor of Civil, Environmental and Geomatics Engineering at Florida Atlantic University. He received his M.S. degree from The Johns Hopkins University, and his Ph.D. degree from Northwestern University, both in the area of Geotechnical Engineering. His primary research areas include ground improve- ment, geotechnology of soft soils, experimental soil mechanics, and geotechnical aspects of pavement engineering. He served as the Chair of the Chemical and Me- chanical Stabilization committee (AFS90) of the Transportation Research Board (2005–2011), and co-authored the TRB Circular titled Evaluation of Chemical Sta- bilizers: State-of-the-Practice Report (E-C086). He is currently serving as an Associ- ate Editor of ASCE’s Journal of Materials in Civil Engineering, and in the editorial board of the ASTM Geotechnical Testing Journal, Geotechnical and Geological En- gineering (Springer, The Netherlands), and the International Journal of Geotechnical Engineering. He is a recipient of the distinguished Award for Excellence and Innova- tion in Undergraduate Teaching (2006), and the Excellence in Graduate Mentoring Award (2009) from Florida Atlantic University. He has authored/co-authored over 100 technical articles and reports in the area of geotechnical engineering. Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 CONTENTS Preface vii MindTap Online Course xi About the Authors xiii 1 Geotechnical Engineering—A Historical Perspective 1 1.1 Introduction 1 1.2 Geotechnical Engineering Prior to the 18th Century 1 1.3 Preclassical Period of Soil Mechanics (1700–1776) 5 1.4 Classical Soil Mechanics—Phase I (1776–1856) 6 1.5 Classical Soil Mechanics—Phase II (1856–1910) 6 1.6 Modern Soil Mechanics (1910–1927) 7 1.7 Geotechnical Engineering after 1927 8 1.8 End of an Era 13 References 14 2 Origin of Soil and Grain Size 16 2.1 Introduction 16 2.2 Rock Cycle and the Origin of Soil 16 2.3 Rock-Forming Minerals, Rock and Rock Structures 27 2.4 Soil-Particle Size 28 2.5 Clay Minerals 30 2.6 Specific Gravity (Gs) 38 2.7 Mechanical Analysis of Soil 39 2.8 Particle-Size Distribution Curve 48 2.9 Particle Shape 55 2.10 Summary 57 Problems 57 References 63 3 Weight–Volume Relationships 64 3.1 Introduction 64 3.2 Weight–Volume Relationships 64 3.3 Relationships among Unit Weight, Void Ratio, Moisture Content, and Specific Gravity 68 3.4 Relationships among Unit Weight, Porosity, and Moisture Content 72 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 xvi Contents 3.5 Relative Density 80 3.6 Comments on emax and emin 83 3.7 Correlations between emax, emin, emax 2 emin, and Median Grain Size (D50) 85 3.8 Summary 88 Problems 88 References 94 4 Plasticity and Structure of Soil 95 4.1 Introduction 95 4.2 Liquid Limit (LL) 95 4.3 Plastic Limit (PL) 105 4.4 Plasticity Index 107 4.5 Shrinkage Limit (SL) 108 4.6 Liquidity Index and Consistency Index 113 4.7 Activity 114 4.8 Plasticity Chart 117 4.9 Soil Structure 118 4.10 Summary 123 Problems 124 References 127 5 Classification of Soil 129 5.1 Introduction 129 5.2 Textural Classification 130 5.3 Classification by Engineering Behavior 132 5.4 AASHTO Classification System 132 5.5 Unified Soil Classification System 136 5.6 Comparison between the AASHTO and Unified Systems 139 5.7 Summary 150 Problems 151 References 155 6 Soil Compaction 156 6.1 Introduction 156 6.2 Compaction—General Principles 157 6.3 Standard Proctor Test 158 6.4 Factors Affecting Compaction 162 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  Contents xvii 6.5 Modified Proctor Test 165 6.6 Empirical Relationships 167 6.7 Structure of Compacted Clay Soil 177 6.8 Effect of Compaction on Cohesive Soil Properties 178 6.9 Field Compaction 181 6.10 Specifications for Field Compaction 186 6.11 Determination of Field Unit Weight of Compaction 188 6.12 Evaluation of Soils as Compaction Material 195 6.13 Special Compaction Techniques 195 6.14 Summary 204 Problems 205 References 210 7 Permeability 212 7.1 Introduction 212 7.2 Bernoulli’s Equation 212 7.3 Darcy’s Law 215 7.4 Hydraulic Conductivity 217 7.5 Laboratory Determination of Hydraulic Conductivity 218 7.6 Relationships for Hydraulic Conductivity—Granular Soil 226 7.7 Relationships for Hydraulic Conductivity—Cohesive Soils 232 7.8 Directional Variation of Permeability 238 7.9 Equivalent Hydraulic Conductivity in Stratified Soil 239 7.10 Permeability Test in the Field by Pumping from Wells 244 7.11 Permeability Test in Auger Holes 248 7.12 Hydraulic Conductivity of Compacted Clayey Soils 250 7.13 Moisture Content—Unit Weight Criteria for Clay Liner Construction 252 7.14 Summary 253 Problems 254 References 259 8 Seepage 261 8.1 Introduction 261 8.2 Laplace’s Equation of Continuity 261 8.3 Flow Nets 263 8.4 Seepage Calculation from a Flow Net 265 8.5 Flow Nets in Anisotropic Soil 271 8.6 Mathematical Solution for Seepage 274 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 xviii Contents 8.7 Uplift Pressure under Hydraulic Structures 276 8.8 Seepage through an Earth Dam on an Impervious Base 277 8.9 L. Casagrande’s Solution for Seepage through an Earth Dam 280 8.10 Pavlovsky’s Solution for Seepage through an Earth Dam 282 8.11 Filter Design 286 8.12 Summary 290 Problems 290 References 294 9 In Situ Stresses 295 9.1 Introduction 295 9.2 Stresses in Saturated Soil without Seepage 295 9.3 Stresses in Saturated Soil with Upward Seepage 301 9.4 Stresses in Saturated Soil with Downward Seepage 304 9.5 Seepage Force 306 9.6 Heaving in Soil Due to Flow around Sheet Piles 309 9.7 Use of Filters to Increase the Factor of Safety against Heave 315 9.8 Effective Stress in Partially Saturated Soil 318 9.9 Capillary Rise in Soils 319 9.10 Effective Stress in the Zone of Capillary Rise 322 9.11 Summary 325 Problems 325 References 330 10 Stresses in a Soil Mass 331 10.1 Introduction 331 10.2 Normal and Shear Stresses on a Plane 332 10.3 The Pole Method of Finding Stresses along a Plane 336 10.4 Stresses Caused by a Point Load 338 10.5 Vertical Stress Caused by a Vertical Line Load 341 10.6 Vertical Stress Caused by a Horizontal Line Load 343 10.7 Vertical Stress Caused by a Vertical Strip Load (Finite Width and Infinite Length) 345 10.8 Vertical Stress Caused by a Horizontal Strip Load 350 10.9 Linearly Increasing Vertical Loading on an Infinite Strip 354 10.10 Vertical Stress Due to Embankment Loading 356 10.11 Vertical Stress Below the Center of a Uniformly Loaded Circular Area 360 Copyright 2018 Cengage Learning. 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WCN 02-200-203  Contents xix 10.12 Vertical Stress at Any Point below a Uniformly Loaded Circular Area 362 10.13 Vertical Stress Caused by a Rectangularly Loaded Area 366 10.14 Influence Chart for Vertical Pressure 372 10.15 Westergaard’s Solution for Vertical Stress Due to a Point Load 375 10.16 Stress Distribution for Westergaard Material 378 10.17 Summary 381 Problems 382 References 389 11 Compressibility of Soil 390 11.1 Introduction 390 11.2 Contact Pressure and Settlement Profile 391 11.3 Relations for Elastic Settlement Calculation 393 11.4 Improved Relationship for Elastic Settlement 396 11.5 Fundamentals of Consolidation 405 11.6 One-Dimensional Laboratory Consolidation Test 409 11.7 Void Ratio–Pressure Plots 412 11.8 Normally Consolidated and Overconsolidated Clays 415 11.9 Effect of Disturbance on Void Ratio–Pressure Relationship 419 11.10 Calculation of Settlement from One-Dimensional Primary Consolidation 420 11.11 Correlations for Compression Index (Cc) 422 11.12 Correlations for Swell Index (Cs) 424 11.13 Secondary Consolidation Settlement 431 11.14 Time Rate of Consolidation 434 11.15 Construction Time Correction of Consolidation Settlement 444 11.16 Determination of Coefficient of Consolidation 447 11.17 Calculation of Consolidation Settlement under a Foundation 454 11.18 Methods for Accelerating Consolidation Settlement 456 11.19 Summary 459 Problems 460 References 467 12 Shear Strength of Soil 469 12.1 Introduction 469 12.2 Mohr–Coulomb Failure Criterion 469 12.3 Inclination of the Plane of Failure Caused by Shear 471 Copyright 2018 Cengage Learning. 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WCN 02-200-203 xx Contents 12.4 Laboratory Test for Determination of Shear Strength Parameters 473 12.5 Direct Shear Test 473 12.6 Drained Direct Shear Test on Saturated Sand and Clay 478 12.7 General Comments on Direct Shear Test 481 12.8 Triaxial Shear Test-General 486 12.9 Consolidated-Drained Triaxial Test 487 12.10 Consolidated-Undrained Triaxial Test 497 12.11 Unconsolidated-Undrained Triaxial Test 505 12.12 Unconfined Compression Test on Saturated Clay 509 12.13 Empirical Relationships between Undrained Cohesion (cu) and Effective Overburden Pressure (o9) 511 12.14 Sensitivity and Thixotropy of Clay 512 12.15 Strength Anisotropy in Clay 514 12.16 Vane Shear Test 516 12.17 Other Methods for Determining Undrained Shear Strength 523 12.18 Shear Strength of Unsaturated Cohesive Soils 523 12.19 Summary 526 Problems 527 References 533 13 Lateral Earth Pressure: At-Rest, Rankine, and Coulomb 535 13.1 Introduction 535 13.2 At-Rest, Active, and Passive Pressures 535 13.3 Earth Pressure At-Rest 538 13.4 Earth Pressure At-Rest for Partially Submerged Soil 540 13.5 Lateral Pressure on Unyeilding Retaining Walls from Surcharges—Based on Theory of Elasticity 545 13.6 Rankine’s Theory of Active Pressure 549 13.7 Theory of Rankine’s Passive Pressure 552 13.8 Yielding of Wall of Limited Height 554 13.9 Rankine Active and Passive Pressure with Sloping Backfill 555 13.10 A Generalized Case for Rankine Active and Passive Pressure—Granular Backfill 558 13.11 Diagrams for Lateral Earth-Pressure Distribution against Retaining Walls with Vertical Back 561 13.12 Coulomb’s Active Pressure 575 13.13 Coulomb’s Passive Pressure 581 13.14 Active Force on Retaining Walls with Earthquake Forces 582 13.15 Common Types of Retaining Walls in the Field 594 Copyright 2018 Cengage Learning. 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WCN 02-200-203  Contents xxi 13.16 Summary 598 Problems 600 References 604 14 Lateral Earth Pressure: Curved Failure Surface 606 14.1 Introduction 606 14.2 Retaining Walls with Friction 606 14.3 Properties of a Logarithmic Spiral 608 14.4 Procedure for Determination of Passive Earth Pressure (Pp)—Cohesionless Backfill 610 14.5 Coefficient of Passive Earth Pressure (Kp) 612 14.6 Caquot and Kerisel Solution for Passive Earth Pressure (Granular Backfill) 617 14.7 Passive Force on Walls with Earthquake Forces 621 14.8 Braced Cuts—General 625 14.9 Determination of Active Thrust on Bracing Systems of Open Cuts—Granular Soil 627 14.10 Determination of Active Thrust on Bracing Systems for Cuts—Cohesive Soil 629 14.11 Pressure Variation for Design of Sheetings, Struts, and Wales 630 14.12 Summary 633 Problems 634 References 637 15 Slope Stability 638 15.1 Introduction 638 15.2 Factor of Safety 640 15.3 Stability of Infinite Slopes 641 15.4 Infinite Slope with Steady-state Seepage 644 15.5 Finite Slopes—General 648 15.6 Analysis of Finite Slopes with Plane Failure Surfaces (Culmann’s Method) 648 15.7 Analysis of Finite Slopes with Circular Failure Surfaces—General 652 15.8 Mass Procedure—Slopes in Homogeneous Clay Soil with  5 0 653 15.9 Slopes in Clay Soil with  5 0; and cu Increasing with Depth 662 15.10 Mass Procedure—Slopes in Homogeneous c9 2 9 Soil 665 15.11 Ordinary Method of Slices 671 15.12 Bishop’s Simplified Method of Slices 680 15.13 Stability Analysis by Method of Slices for Steady-State Seepage 682 Copyright 2018 Cengage Learning. 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WCN 02-200-203 xxii Contents 15.14 Solutions for Steady-State Seepage 685 15.15 Fluctuation of Factor of Safety of Slopes in Clay Embankment on Saturated Clay 699 15.16 Summary 703 Problems 703 References 709 16 Soil Bearing Capacity for Shallow Foundations 710 16.1 Introduction 710 16.2 Ultimate Soil-Bearing Capacity for Shallow Foundations 712 16.3 Terzaghi’s Ultimate Bearing Capacity Equation 713 16.4 Effect of Groundwater Table 717 16.5 Factor of Safety 719 16.6 General Bearing Capacity Equation 723 16.7 Ultimate Load for Shallow Footings Under Eccentric Load (One-Way Eccentricity) 729 16.8 Continuous Footing Under Eccentrically Inclined Load 734 16.9 Bearing Capacity of Sand Based on Settlement 740 16.10 Summary 742 Problems 742 References 746 17 Subsoil Exploration 748 17.1 Introduction 748 17.2 Planning for Soil Exploration 749 17.3 Boring Methods 750 17.4 Common Sampling Methods 754 17.5 Sample Disturbance 759 17.6 Correlations for N60 in Cohesive Soil 760 17.7 Correlations for Standard Penetration Number in Granular Soil 761 17.8 Other In Situ Tests 767 17.9 Vane Shear Test 767 17.10 Borehole Pressuremeter Test 767 17.11 Cone Penetration Test 769 17.12 Rock Coring 774 17.13 Soil Exploration Report 776 17.14 Summary 776 Problems 778 References 781 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  Contents xxiii 18 An Introduction to Geosynthetics 783 18.1 Introduction 783 18.2 Geotextile 784 18.3 Geogrid 789 18.4 Geomembrane 795 18.5 Geonet 799 18.6 Geosynthetic Clay Liner 801 18.7 Summary 803 References 803 Answers to Selected Problems 805 Index 815 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  CHAPTER 1 Geotechnical Engineering— A Historical Perspective 1.1 Introduction For engineering purposes, soil is defined as the uncemented aggregate of mineral grains and decayed organic matter (solid particles) with liquid and gas in the empty spaces between the solid particles. Soil is used as a construction material in various civil engineering projects, and it supports structural foundations. Thus, civil engineers must study the properties of soil, such as its origin, grain-size distribution, ability to drain water, compressibility, strength, and its ability to support structures and resist deformation. Soil mechanics is the branch of science that deals with the study of the physical properties of soil and the behavior of soil masses subjected to various types of forces. Soils engineering is the application of the principles of soil mechanics to practical problems. Geotechnical engineering is the subdiscipline of civil engineering that involves natural materials found close to the surface of the earth. It includes the application of the principles of soil mechanics and rock mechanics to the design of foundations, retaining structures, and earth structures. 1.2 Geotechnical Engineering Prior to the 18th Century The record of a person’s first use of soil as a construction material is lost in antiquity. In true engineering terms, the understanding of geotechnical engineering as it is known today began early in the 18th century (Skempton, 1985). For years, the art of geotechnical engineering was based on only past experiences through a succession 1 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 2 Chapter 1 | Geotechnical Engineering—A Historical Perspective Table 1.1 Major Pyramids in Egypt Pyramid/Pharaoh Location Reign of Pharaoh Djoser Saqqara 2630–2612 b.c. Sneferu Dashur (North) 2612–2589 b.c. Sneferu Dashur (South) 2612–2589 b.c. Sneferu Meidum 2612–2589 b.c. Khufu Giza 2589–2566 b.c. Djedefre Abu Rawash 2566–2558 b.c. Khafre Giza 2558–2532 b.c. Menkaure Giza 2532–2504 b.c. of experimentation without any real scientific character. Based on those experimen- tations, many structures were built—some of which have crumbled, while others are still standing. Recorded history tells us that ancient civilizations flourished along the banks of rivers, such as the Nile (Egypt), the Tigris and Euphrates (Mesopotamia), the Huang Ho (Yellow River, China), and the Indus (India). Dykes dating back to about 2000 b.c. were built in the basin of the Indus to protect the town of Mohenjo Dara (in what became Pakistan after 1947). During the Chan dynasty in China (1120 b.c. to 249 b.c.) many dykes were built for irrigation purposes. There is no evidence that measures were taken to stabilize the foundations or check erosion caused by floods (Kerisel, 1985). Ancient Greek civilization used isolated pad footings and strip-and-raft foundations for building structures. Beginning around 2700 b.c., sev- eral pyramids were built in Egypt, most of which were built as tombs for the country’s Pharaohs and their consorts during the Old and Middle Kingdom periods. Table 1.1 lists some of the major pyramids identified through the Pharaoh who ordered it built. As of 2008, a total of 138 pyramids have been discovered in Egypt. Figure 1.1 Figure 1.1 A view of the pyramids at Giza. (Courtesy of Janice Das, Henderson, Nevada) Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  1.2 Geotechnical Engineering Prior to the 18th Century 3 shows a view of the three pyramids at Giza. The construction of the pyramids posed formidable challenges regarding foundations, stability of slopes, and construction of underground chambers. With the arrival of Buddhism in China during the Eastern Han dynasty in 68 a.d., thousands of pagodas were built. Many of these structures were constructed on silt and soft clay layers. In some cases the foundation pressure exceeded the load-bearing capacity of the soil and thereby caused extensive struc- tural damage. One of the most famous examples of problems related to soil-bearing capacity in the construction of structures prior to the 18th century is the Leaning Tower of Pisa in Italy (See Figure 1.2). Construction of the tower began in 1173 a.d. when the Republic of Pisa was flourishing and continued in various stages for over 200 years. The structure weighs about 15,700 metric tons and is supported by a circular base having a diameter of 20 m (< 66 ft). The tower has tilted in the past to the east, north, west, and, finally, to the south. Recent investigations showed that a weak clay layer existed at a depth of about 11 m (< 36 ft) below the ground surface compression of which caused the tower to tilt. It became more than 5 m (< 16.5 ft) out of plumb Figure 1.2 Leaning Tower of Pisa, Italy (Courtesy of Braja M. Das, Henderson, Nevada) Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 4 Chapter 1 | Geotechnical Engineering—A Historical Perspective with the 54 m (< 179 ft) height (about a 5.5 degree tilt). The tower was closed in 1990 because it was feared that it would either fall over or collapse. It recently has been stabilized by excavating soil from under the north side of the tower. About 70 metric tons of earth were removed in 41 separate extractions that spanned the width of the tower. As the ground gradually settled to fill the resulting space, the tilt of the tower eased. The tower now leans 5 degrees. The half-degree change is not noticeable, but it makes the structure considerably more stable. Figure 1.3 is an example of a similar problem. The towers shown in Figure 1.3 are located in Bologna, Italy, and they were built in the 12th century. The tower on the left is usually referred to as the Garisenda Tower. It is 48 m (< 157 ft) in height and weighs about 4210 metric tons. It has tilted about 4 degrees. The tower on the right is the Asinelli Tower, which is 97 m high and weighs 7300 metric tons. It has tilted about 1.3 degrees. After encountering several foundation-related problems during construction over centuries past, engineers and scientists began to address the properties and Figure 1.3 Tilting of Garisenda Tower (left) and Asinelli Tower (right) in Bologna, Italy (Courtesy of Braja M. Das, Henderson, Nevada) Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  1.3 Preclassical Period of Soil Mechanics (1700–1776) 5 behaviors of soils in a more methodical manner starting in the early part of the 18th century. Based on the emphasis and the nature of study in the area of geotechni- cal engineering, the time span extending from 1700 to 1927 can be divided into four major periods (Skempton, 1985): 1. Preclassical (1700 to 1776 a.d.) 2. Classical soil mechanics—Phase I (1776 to 1856 a.d.) 3. Classical soil mechanics—Phase II (1856 to 1910 a.d.) 4. Modern soil mechanics (1910 to 1927 a.d.) Brief descriptions of some significant developments during each of these four peri- ods are presented below. 1.3 Preclassical Period of Soil Mechanics (1700–1776) This period concentrated on studies relating to natural slope and unit weights of various types of soils, as well as the semiempirical earth pressure theories. In 1717, a French royal engineer, Henri Gautier (1660–1737), studied the natural slopes of soils when tipped in a heap for formulating the design procedures of retaining walls. The natural slope is what we now refer to as the angle of repose. According to this study, the natural slope of clean dry sand and ordinary earth were 318 and 458, respectively. Also, the unit weight of clean dry sand and ordinary earth were recommended to be 18.1 kN/m3 (115 lb/ft3) and 13.4 kN/m3 (85 lb/ft3), respectively. No test results on clay were reported. In 1729, Bernard Forest de Belidor (1671–1761) published a text- book for military and civil engineers in France. In the book, he proposed a theory for lateral earth pressure on retaining walls that was a follow-up to Gautier’s (1717) original study. He also specified a soil classification system in the manner shown in the following table. Unit weight Classification kN/m 3 lb/ft3 Rock — — Firm or hard sand, compressible sand 16.7 to 18.4 106 to 117 Ordinary earth (as found in dry locations) 13.4 85 Soft earth (primarily silt) 16.0 102 Clay 18.9 120 Peat — — The first laboratory model test results on a 76-mm-high (< 3 in.) retaining wall built with sand backfill were reported in 1746 by a French engineer, Francois Gadroy (1705–1759), who observed the existence of slip planes in the soil at failure. Gadroy’s study was later summarized by J. J. Mayniel in 1808. Another notable con- tribution during this period is that by the French engineer Jean Rodolphe Perronet (1708–1794), who studied slope stability around 1769 and distinguished between in- tact ground and fills. Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 6 Chapter 1 | Geotechnical Engineering—A Historical Perspective 1.4 Classical Soil Mechanics—Phase I (1776–1856) During this period, most of the developments in the area of geotechnical engineering came from engineers and scientists in France. In the preclassical period, practically all theoretical considerations used in calculating lateral earth pressure on retaining walls were based on an arbitrarily based failure surface in soil. In his famous paper presented in 1776, French scientist Charles Augustin Coulomb (1736–1806) used the principles of calculus for maxima and minima to determine the true position of the sliding surface in soil behind a retaining wall. In this analysis, Coulomb used the laws of friction and cohesion for solid bodies. In 1790, the distinguished French civil engi- neer, Gaspard Clair Marie Riche de Prony (1755–1839) included Coulomb’s theory in his leading textbook, Nouvelle Architecture Hydraulique (Vol. 1). In 1820, special cases of Coulomb’s work were studied by French engineer Jacques Frederic Francais (1775–1833) and by French applied mechanics professor Claude Louis Marie Henri Navier (1785–1836). These special cases related to inclined backfills and backfills supporting surcharge. In 1840, Jean Victor Poncelet (1788–1867), an army engineer and professor of mechanics, extended Coulomb’s theory by providing a graphical method for determining the magnitude of lateral earth pressure on vertical and in- clined retaining walls with arbitrarily broken polygonal ground surfaces. Poncelet was also the first to use the symbol  for soil friction angle. He also provided the first ultimate bearing-capacity theory for shallow foundations. In 1846 Alexandre Collin (1808–1890), an engineer, provided the details for deep slips in clay slopes, cutting, and embankments. Collin theorized that in all cases the failure takes place when the mobilized cohesion exceeds the existing cohesion of the soil. He also observed that the actual failure surfaces could be approximated as arcs of cycloids. The end of Phase I of the classical soil mechanics period is generally marked by the year (1857) of the first publication by William John Macquorn Rankine (1820–1872), a professor of civil engineering at the University of Glasgow. This study provided a notable theory on earth pressure and equilibrium of earth masses. Rankine’s theory is a simplification of Coulomb’s theory. 1.5 Classical Soil Mechanics—Phase II (1856–1910) Several experimental results from laboratory tests on sand appeared in the literature in this phase. One of the earliest and most important publications is one by French engineer Henri Philibert Gaspard Darcy (1803–1858). In 1856, he published a study on the permeability of sand filters. Based on those tests, Darcy defined the term coef- ficient of permeability (or hydraulic conductivity) of soil, a very useful parameter in geotechnical engineering to this day. Sir George Howard Darwin (1845–1912), a professor of astronomy, conducted laboratory tests to determine the overturning moment on a hinged wall retaining sand in loose and dense states of compaction. Another noteworthy contribution, which was published in 1885 by Joseph Valentin Boussinesq (1842–1929), was the development of the theory of stress distribution under load bearing areas in a ho- mogeneous, semiinfinite, elastic, and isotropic medium. In 1887, Osborne Reynolds Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  1.6 Modern Soil Mechanics (1910–1927) 7 (1842–1912) demonstrated the phenomenon of dilatancy in sand. Other nota- ble studies during this period are those by John Clibborn (1847–1938) and John Stuart Beresford (1845–1925) relating to the flow of water through sand bed and uplift pressure. Clibborn’s study was published in the Treatise on Civil Engineering, Vol. 2: Irrigation Work in India, Roorkee, 1901 and also in Technical Paper No. 97, Government of India, 1902. Beresford’s 1898 study on uplift pressure on the Narora Weir on the Ganges River has been documented in Technical Paper No. 97, Government of India, 1902. 1.6 Modern Soil Mechanics (1910–1927) In this period, results of research conducted on clays were published in which the fundamental properties and parameters of clay were established. The most notable publications are described next. Around 1908, Albert Mauritz Atterberg (1846–1916), a Swedish chemist and soil scientist, defined clay-size fractions as the percentage by weight of particles smaller than 2 microns in size. He realized the important role of clay particles in a soil and the plasticity thereof. In 1911, he explained the consistency of cohesive soils by de- fining liquid, plastic, and shrinkage limits. He also defined the plasticity index as the difference between liquid limit and plastic limit (see Atterberg, 1911). In October 1909, the 17-m (56-ft) high earth dam at Charmes, France, failed. It was built between 1902 and 1906. A French engineer, Jean Fontard (1884–1962), carried out investigations to determine the cause of failure. In that context, he con- ducted undrained double-shear tests on clay specimens (0.77 m2 in area and 200 mm thick) under constant vertical stress to determine their shear strength parameters (see Frontard, 1914). The times for failure of these specimens were between 10 to 20 minutes. Arthur Langley Bell (1874–1956), a civil engineer from England, worked on the design and construction of the outer seawall at Rosyth Dockyard. Based on his work, he developed relationships for lateral pressure and resistance in clay as well as bear- ing capacity of shallow foundations in clay (see Bell, 1915). He also used shear-box tests to measure the undrained shear strength of undisturbed clay specimens. Wolmar Fellenius (1876–1957), an engineer from Sweden, developed the sta- bility analysis of undrained saturated clay slopes (that is,  5 0 condition) with the assumption that the critical surface of sliding is the arc of a circle. These were elab- orated upon in his papers published in 1918 and 1926. The paper published in 1926 gave correct numerical solutions for the stability numbers of circular slip surfaces passing through the toe of the slope. Karl Terzaghi (1883–1963) of Austria (Figure 1.4) developed the theory of con- solidation for clays as we know today. The theory was developed when Terzaghi was teaching at the American Robert College in Istanbul, Turkey. His study spanned a five-year period from 1919 to 1924. Five different clay soils were used. The liquid limit of those soils ranged between 36 and 67, and the plasticity index was in the range of 18 to 38. The consolidation theory was published in Terzaghi’s celebrated book Erdbaumechanik in 1925. Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 8 Chapter 1 | Geotechnical Engineering—A Historical Perspective Figure 1.4 Karl Terzaghi (1883–1963) (SSPL via Getty Images) 1.7 Geotechnical Engineering after 1927 The publication of Erdbaumechanik auf Bodenphysikalisher Grundlage by Karl Terzaghi in 1925 gave birth to a new era in the development of soil mechanics. Karl Terzaghi is known as the father of modern soil mechanics, and rightfully so. Terzaghi was born on October 2, 1883 in Prague, which was then the capital of the Austrian province of Bohemia. In 1904 he graduated from the Technische Hochschule in Graz, Austria, with an undergraduate degree in mechanical engineering. After graduation he served one year in the Austrian army. Following his army service, Terzaghi studied one more year, concentrating on geological subjects. In January 1912, he received the degree of Doctor of Technical Sciences from his alma mater in Graz. In 1916, he accepted a teaching position at the Imperial School of Engineers in Istanbul. After the end of World War I, he accepted a lectureship at the American Robert College in Istanbul (1918–1925). There he began his research work on the behavior of soil and settlement of clay and on the failure due to piping in sand under dams. The publication Erdbaumechanik is primarily the result of this research. Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  1.7 Geotechnical Engineering after 1927 9 In 1925, Terzaghi accepted a visiting lectureship at Massachusetts Institute of Technology, where he worked until 1929. During that time, he became recognized as the leader of the new branch of civil engineering called soil mechanics. In October 1929, he returned to Europe to accept a professorship at the Technical University of Vienna, which soon became the nucleus for civil engineers interested in soil me- chanics. In 1939, he returned to the United States to become a professor at Harvard University. The first conference of the International Society of Soil Mechanics and Foundation Engineering (ISSMFE) was held at Harvard University in 1936 with Karl Terzaghi presiding. The conference was possible due to the conviction and ef- forts of Professor Arthur Casagrande of Harvard University. About 200 individu- als representing 21 countries attended this conference. It was through the inspira- tion and guidance of Terzaghi over the preceding quarter-century that papers were brought to that conference covering a wide range of topics, such as Effective stress Shear strength Testing with Dutch cone penetrometer Consolidation Centrifuge testing Elastic theory and stress distribution Preloading for settlement control Swelling clays Frost action Earthquake and soil liquefaction Machine vibration Arching theory of earth pressure For the next quarter-century, Terzaghi was the guiding spirit in the development of soil mechanics and geotechnical engineering throughout the world. To that effect, in 1985, Ralph Peck wrote that “few people during Terzaghi’s lifetime would have disagreed that he was not only the guiding spirit in soil mechanics, but that he was the clearing house for research and application throughout the world. Within the next few years he would be engaged on projects on every continent save Australia and Antarctica.” Peck continued with, “Hence, even today, one can hardly improve on his contemporary assessments of the state of soil mechanics as expressed in his sum- mary papers and presidential addresses.” In 1939, Terzaghi delivered the 45th James Forrest Lecture at the Institution of Civil Engineers, London. His lecture was enti- tled “Soil Mechanics—A New Chapter in Engineering Science.” In it, he proclaimed that most of the foundation failures that occurred were no longer “acts of God.” Following are some highlights in the development of soil mechanics and geo- technical engineering that evolved after the first conference of the ISSMFE in 1936: Publication of the book Theoretical Soil Mechanics by Karl Terzaghi in 1943 (Wiley, New York) Publication of the book Soil Mechanics in Engineering Practice by Karl Terzaghi and Ralph Peck in 1948 (Wiley, New York) Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 10 Chapter 1 | Geotechnical Engineering—A Historical Perspective Publication of the book Fundamentals of Soil Mechanics by Donald W. Taylor in 1948 (Wiley, New York) Start of the publication of Geotechnique, the international journal of soil me- chanics in 1948 in England After a brief interruption for World War II, the second conference of ISSMFE was held in Rotterdam, The Netherlands, in 1948. There were about 600 partici- pants, and seven volumes of proceedings were published. In this conference, A. W. Skempton presented the landmark paper on  5 0 concept for clays. Following Rotterdam, ISSMFE conferences have been organized about every four years in different parts of the world. The aftermath of the Rotterdam conference saw the growth of regional conferences on geotechnical engineering, such as European Regional Conference on Stability of Earth Slopes, Stockholm (1954) First Australia–New Zealand Conference on Shear Characteristics of Soils (1952) First Pan American Conference, Mexico City (1960) Research conference on Shear Strength of Cohesive Soils, Boulder, Colorado, (1960) Two other important milestones between 1948 and 1960 are (1) the publication of A. W. Skempton’s paper on A and B pore pressure parameters, which made effec- tive stress calculations more practical for various engineering works, and (2) publi- cation of the book entitled The Measurement of Soil Properties in the Triaxial Text by A. W. Bishop and B. J. Henkel (Arnold, London) in 1957. By the early 1950s, computer-aided finite difference and finite element solutions were applied to various types of geotechnical engineering problems. When the proj- ects become more sophisticated with complex boundary conditions, it is no longer possible to apply closed-form solutions. Numerical modeling, using a finite element (e.g. Abaqus, Plaxis) or finite difference (e.g. Flac) software, is becoming increasingly popular in the profession. The dominance of numerical modeling in geotechnical en- gineering will continue in the next few decades due to new challenges and advances in the modelling techniques. Since the early days, the profession of geotechnical en- gineering has come a long way and has matured. It is now an established branch of civil engineering, and thousands of civil engineers declare geotechnical engineering to be their preferred area of speciality. In 1997, the ISSMFE was changed to ISSMGE (International Society of Soil Mechanics and Geotechnical Engineering) to reflect its true scope. These interna- tional conferences have been instrumental for exchange of information regarding new developments and ongoing research activities in geotechnical engineering. Table 1.2 gives the location and year in which each conference of ISSMFE/ISSMGE was held. In 1960, Bishop, Alpan, Blight, and Donald provided early guidelines and exper- imental results for the factors controlling the strength of partially saturated cohesive soils. Since that time advances have been made in the study of the behavior of un- saturated soils as related to strength and compressibility and other factors affecting construction of earth-supported and earth-retaining structures. ISSMGE has several technical committees, and these committees organize or co- sponsor several conferences around the world. A list of these technical committees Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  1.7 Geotechnical Engineering after 1927 11 Table 1.2 Details of ISSMFE (1936–1997) and ISSMGE (1997–present) Conferences Conference Location Year I Harvard University, Boston, U.S.A. 1936 II Rotterdam, the Netherlands 1948 III Zurich, Switzerland 1953 IV London, England 1957 V Paris, France 1961 VI Montreal, Canada 1965 VII Mexico City, Mexico 1969 VIII Moscow, U.S.S.R. 1973 IX Tokyo, Japan 1977 X Stockholm, Sweden 1981 XI San Francisco, U.S.A. 1985 XII Rio de Janeiro, Brazil 1989 XIII New Delhi, India 1994 XIV Hamburg, Germany 1997 XV Istanbul, Turkey 2001 XVI Osaka, Japan 2005 XVII Alexandria, Egypt 2009 XVIII Paris, France 2013 XIX Seoul, Korea 2017 (scheduled) (2010–2013) is given in Table 1.3. ISSMGE also conducts International Seminars (formerly known as Touring Lectures), which have proved to be an important ac- tivity; these seminars bring together practitioners, contractors, and academics, both on stage and in the audience, to their own benefit irrespective of the region, size, or wealth of the Member Society, thus fostering a sense of belonging to the ISSMGE. Soils are heterogeneous materials that can have substantial variability within a few meters. The design parameters for all geotechnical projects have to come from a site investigation exercise that includes field tests, collecting soil samples at various locations and depths, and carrying out laboratory tests on these samples. The labora- tory and field tests on soils, as for any other materials, are carried out as per standard methods specified by ASTM International (known as American Society for Testing and Materials before 2001). ASTM standards (http://www.astm.org) cover a wide range of materials in more than 80 volumes. The test methods for soils, rocks, and aggregates are bundled into the two volumes—04.08 and 04.09. Geotechnical engineering is a relatively young discipline that has witnessed sub- stantial developments in the past few decades, and it is still growing. These new de- velopments and most cutting-edge research findings are published in peer reviewed international journals before they find their way into textbooks. Some of these geo- technical journals are (in alphabetical order): Canadian Geotechnical Journal (NRC Research Press in cooperation with the Canadian Geotechnical Society) Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 12 Chapter 1 | Geotechnical Engineering—A Historical Perspective Table 1.3 List of ISSMGE Technical Committees (November, 2013) Technical committee Category number Technical committee name Fundamentals TC101 Laboratory Stress Strength Testing of Geomaterials TC102 Ground Property Characterization from In-Situ Tests TC103 Numerical Methods in Geomechanics TC104 Physical Modelling in Geotechnics TC105 Geo-Mechanics from Micro to Macro TC106 Unsaturated Soils Applications TC201 Geotechnical Aspects of Dykes and Levees, Shore Protection and Land Reclamation TC202 Transportation Geotechnics TC203 Earthquake Geotechnical Engineering and Associated Problems TC204 Underground Construction in Soft Ground TC205 Safety and Surviability in Geotechnical Engineering TC206 Interactive Geotechnical Design TC207 Soil-Structure Interaction and Retaining Walls TC208 Slope Stability in Engineering Practice TC209 Offshore Geotechnics TC210 Dams and Embankments TC211 Ground Improvement TC212 Deep Foundations TC213 Scour and Erosion TC214 Foundation Engineering for Difficult Soft Soil Conditions TC215 Environmental Geotechnics TC216 Frost Geotechnics Impact TC301 Preservation of Historic Sites on Society TC302 Forensic Geotechnical Engineering TC303 Coastal and River Disaster Mitigation and Rehabilitation TC304 Engineering Practice of Risk Assessment and Management TC305 Geotechnical Infrastructure for Megacities and New Capitals Geotechnical and Geoenvironmental Engineering (American Society of Civil Engineers) Geotechnical and Geological Engineering (Springer, Germany) Geotechnical Testing Journal (ASTM International, USA) Geotechnique (Institute of Civil Engineers, UK) International Journal of Geomechanics (American Society of Civil Engineers) Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  1.8 End of an Era 13 International Journal of Geotechnical Engineering (Taylor and Francis, UK) Soils and Foundations (Elsevier on behalf of the Japanese Geotechnical Society) For a thorough literature review on a research topic, these journals and the proceed- ings of international conferences (e.g. ICSMGE, see Table 1.2) would be very valuable. The references cited in each chapter in this book are listed at the end of the chapter. 1.8 End of an Era In Section 1.7, a brief outline of the contributions made to modern soil mechanics by pioneers such as Karl Terzaghi, Arthur Casagrande, Donald W. Taylor, Alec W. Skempton, and Ralph B. Peck was presented. The last of the early giants of the profession, Ralph B. Peck, passed away on February 18, 2008, at the age of 95. Professor Ralph B. Peck (Figure 1.5) was born in Winnipeg, Canada to American parents Orwin K. and Ethel H. Peck on June 23, 1912. He received B.S. and Ph.D. degrees in 1934 and 1937, respectively, from Rensselaer Polytechnic Institute, Troy, New York. During the period from 1938 to 1939, he took courses from Arthur Casagrande at Harvard University in a new subject called “soil mechanics.” From Figure 1.5 Ralph B. Peck (Photo courtesy of Ralph B. Peck) Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 14 Chapter 1 | Geotechnical Engineering—A Historical Perspective 1939 to 1943, Dr. Peck worked as an assistant to Karl Terzaghi, the “father” of mod- ern soil mechanics, on the Chicago Subway Project. In 1943, he joined the University of Illinois at Champaign–Urban and was a professor of foundation engineering from 1948 until he retired in 1974. After retirement, he was active in consulting, which included major geotechnical projects in 44 states in the United States and 28 other countries on five continents. Some examples of his major consulting proj- ects include Rapid transit systems in Chicago, San Francisco, and Washington, D.C. Alaskan pipeline system James Bay Project in Quebec, Canada Heathrow Express Rail Project (U.K.) Dead Sea dikes His last project was the Rion-Antirion Bridge in Greece. On March 13, 2008, The Times of the United Kingdom wrote, “Ralph B. Peck was an American civil engineer who invented a controversial construction technique that would be used on some of the modern engineering wonders of the world, including the Channel Tunnel. Known as ‘the godfather of soil mechanics,’ he was directly responsible for a succes- sion of celebrated tunneling and earth dam projects that pushed the boundaries of what was believed to be possible.” Dr. Peck authored more than 250 highly distinguished technical publications. He was the president of the ISSMGE from 1969 to 1973. In 1974, he received the National Medal of Science from President Gerald R. Ford. Professor Peck was a teacher, mentor, friend, and counselor to generations of geotechnical engineers in every country in the world. The 16th ISSMGE Conference in Osaka, Japan (2005) was the last major conference of its type that he would attend. This is truly the end of an era. References Atterberg, A. M. (1911). “Über die physikalische Bodenuntersuchung, und über die Plasti- zität de Tone,” International Mitteilungen für Bodenkunde, Verlag für Fachliteratur. G.m.b.H. Berlin, Vol. 1, 10–43. Belidor, B. F. (1729). La Science des Ingenieurs dans la Conduite des Travaux de Fortification et D’Architecture Civil, Jombert, Paris. Bell, A. L. (1915). “The Lateral Pressure and Resistance of Clay, and Supporting Power of Clay Foundations,” Min. Proceeding of Institute of Civil Engineers, Vol. 199, 233–272. Bishop, A. W., Alpan, I., Blight, G. E., and Donald, I. B. (1960). “Factors Controlling the Strength of Partially Saturated Cohesive Soils.” Proceedings. Research Conference on Shear Strength of Cohesive Soils, ASCE, 502–532. Bishop, A. W. and Henkel, B. J. (1957). The Measurement of Soil Properties in the Triaxial Test, Arnold, London. Boussinesq, J. V. (1885). Application des Potentiels â L’Etude de L’Équilibre et du Mouvement des Solides Élastiques, Gauthier-Villars, Paris. Collin, A. (1846). Recherches Expérimentales sur les Glissements Spontanés des Terrains Argileux Accompagnées de Considérations sur Quelques Principes de la Mécanique Terrestre, Carilian-Goeury, Paris. Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  References 15 Coulomb, C. A. (1776). “Essai sur une Application des Règles de Maximis et Minimis à Quelques Problèmes de Statique Relatifs à L’Architecture,” Mèmoires de la Mathèmatique et de Phisique, présentés à l’Académie Royale des Sciences, par divers savans, et lûs dans sés Assemblées, De L’Imprimerie Royale, Paris, Vol. 7, Annee 1793, 343–382. Darcy, H. P. G. (1856). Les Fontaines Publiques de la Ville de Dijon, Dalmont, Paris. Darwin, G. H. (1883). “On the Horizontal Thrust of a Mass of Sand,” Proceedings, Institute of Civil Engineers, London, Vol. 71, 350–378. Fellenius, W. (1918). “Kaj-och Jordrasen I Göteborg,” Teknisk Tidskrift. Vol. 48, 17–19. Francais, J. F. (1820). “Recherches sur la Poussée de Terres sur la Forme et Dimensions des Revêtments et sur la Talus D’Excavation,” Mémorial de L’Officier du Génie, Paris, Vol. IV, 157–206. Frontard, J. (1914). “Notice sur L’Accident de la Digue de Charmes,” Anns. Ponts et Chaussées 9th Ser., Vol. 23, 173–292. Gadroy, F. (1746). Mémoire sur la Poussée des Terres, summarized by Mayniel, 1808. Gautier, H. (1717). Dissertation sur L’Epaisseur des Culées des Ponts... sur L’Effort et al Pesanteur des Arches... et sur les Profiles de Maconnerie qui Doivent Supporter des Chaussées, des Terrasses, et des Remparts. Cailleau, Paris. Kerisel, J. (1985). “The History of Geotechnical Engineering up until 1700,” Proceedings, XI International Conference on Soil Mechanics and Foundation Engineering, San Francisco, Golden Jubilee Volume, A. A. Balkema, 3–93. Mayniel, J. J. (1808). Traité Experimentale, Analytique et Pratique de la Poussé des Terres. Colas, Paris. Navier, C. L. M. (1839). Leçons sur L’Application de la Mécanique à L’Establissement des Constructions et des Machines, 2nd ed., Paris. Peck, R. B. (1985). “The Last Sixty Years,” Proceedings, XI International Conference on Soil Mechanics and Foundation Engineering, San Francisco, Golden Jubilee Volume, A. A. Balkema, 123–133. Poncelet, J. V. (1840). Mémoire sur la Stabilité des Revêtments et de seurs Fondations, Bachelier, Paris. Prony, G. C. M. L. R. (1790), Nouvelle Architecture Hydraulique, contenant l’ art d’élever l’eau au moyen de différentes machines, de construire dans ce fluide, de le diriger, et générale- ment de l’appliquer, de diverses manières, aux besoins de la sociétè, FirminDidot, Paris. Rankine, W. J. M. (1857). “On the Stability of Loose Earth,” Philosophical Transactions, Royal Society, Vol. 147, London. Reynolds, O. (1887). “Experiments Showing Dilatency, a Property of Granular Material Possibly Connected to Gravitation,” Proceedings, Royal Society, London, Vol. 11, 354–363. Skempton, A. W. (1948). “The  5 0 Analysis of Stability and Its Theoretical Basis,” Proceedings, II International Conference on Soil Mechanics and Foundation Engineering, Rotterdam, Vol. 1, 72–78. Skempton, A. W. (1954). “The Pore Pressure Coefficients A and B,” Geotechnique, Vol. 4, 143–147. Skempton, A. W. (1985). “A History of Soil Properties, 1717–1927,” Proceedings, XI International Conference on Soil Mechanics and Foundation Engineering, San Francisco, Golden Jubilee Volume, A. A. Balkema, 95–121. Taylor, D. W. (1948). Fundamentals of Soil Mechanics, John Wiley, New York. Terzaghi, K. (1925). Erdbaumechanik auf Bodenphysikalisher Grundlage, Deuticke, Vienna. Terzaghi, K. (1939). “Soil Mechanics—A New Chapter in Engineering Science,” Institute of Civil Engineers Journal, London, Vol. 12, No. 7, 106–142. Terzaghi, K. (1943). Theoretical Soil Mechanics, John Wiley, New York. Terzaghi, K., and Peck, R. B. (1948). Soil Mechanics in Engineering Practice, John Wiley, New York. Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 CHAPTER 2 Origin of Soil and Grain Size 2.1 Introduction In general, soils are formed by weathering of rocks. The physical properties of soil are dictated primarily by the minerals that constitute the soil particles and, hence, the rock from which it is derived. In this chapter we will discuss the following: The formation of various types of rocks, the origins of which are the solidifi- cation of molten magma in the mantle of the earth Formation of soil by mechanical and chemical weathering of rock Determination of the distribution of particle sizes in a given soil mass Composition of the clay minerals. The clay minerals provide the plastic prop- erties of a soil mass The shape of various particles in a soil mass 2.2 Rock Cycle and the Origin of Soil The mineral grains that form the solid phase of a soil aggregate are the product of rock weathering. The size of the individual grains varies over a wide range. Many of the phys- ical properties of soil are dictated by the size, shape, and chemical composition of the grains. To better understand these factors, one must be familiar with the basic types of rock that form the earth’s crust, the rock-forming minerals, and the weathering process. On the basis of their mode of origin, rocks can be divided into three basic types: igneous, sedimentary, and metamorphic. Figure 2.1 shows a diagram of the formation cycle of different types of rock and the processes associated with them. This is called the rock cycle. Brief discussions of each element of the rock cycle follow. 16 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  2.2 Rock Cycle and the Origin of Soil 17 ,C ementation, Crystallizat tion ion m pac Co Sediments Sedimentary Tr rock an spo rtati o n, Erosio Weathering Metamorphism n, Metamorphic Igneous rock rock Me ltin g Magma Figure 2.1 Rock cycle Igneous rock Igneous rocks are formed by the solidification of molten magma ejected from deep within the earth’s mantle. After ejection by either fissure eruption or volcanic eruption, some of the molten magma cools on the surface of the earth. Sometimes magma ceases its mobility below the earth’s surface and cools to form intrusive igne- ous rocks that are called plutons. Intrusive rocks formed in the past may be exposed at the surface as a result of the continuous process of erosion of the materials that once covered them. The types of igneous rock formed by the cooling of magma depend on factors such as the composition of the magma and the rate of cooling associated with it. After conducting several laboratory tests, Bowen (1922) was able to explain the re- lation of the rate of magma cooling to the formation of different types of rock. This explanation—known as Bowen’s reaction principle—describes the sequence by which new minerals are formed as magma cools. The mineral crystals grow larger and some of them settle. The crystals that remain suspended in the liquid react with the remaining melt to form a new mineral at a lower temperature. This process continues until the entire body of melt is solidified. Bowen classified these reac- tions into two groups: (1) discontinuous ferromagnesian reaction series, in which Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 18 Chapter 2 | Origin of Soil and Grain Size Lower resistance Crystallization at to weathering higher temperature Olivine Calcium feldspar Augite Hornblende Sodium feldspar se fer D o cla ro isco g i ma nt pla ies gn inu es ou Biotite (black mica) o us r ser ian s u a tin sp se rie C on feld s Orthoclase (potassium feldspar) Muscovite (white mica) Higher resistance Crystallization at to weathering Quartz lower temperature Figure 2.2 Bowen’s reaction series the minerals formed are different in their chemical composition and crystalline structure, and (2) continuous plagioclase feldspar reaction series, in which the min- erals formed have different chemical compositions with similar crystalline struc- tures. Figure 2.2 shows Bowen’s reaction series. The chemical compositions of the minerals are given in Table 2.1. Figure 2.3 is a scanning electron micrograph of a fractured surface of quartz showing glass-like fractures with no discrete planar cleavage. Figure 2.4 is a scanning electron micrograph that shows basal cleavage of individual mica grains. Thus, depending on the proportions of minerals available, different types of igneous rock are formed. Granite, gabbro, and basalt are some of the common types of igneous rock generally encountered in the field. Table 2.2 shows the general com- position of some igneous rocks. Table 2.1 Composition of Minerals Shown in Bowen’s Reaction Series Mineral Composition Olivine (Mg, Fe)2SiO4 Augite Ca, Na(Mg, Fe, Al)(Al, Si2O6) Hornblende Complex ferromagnesian silicate of Ca, Na, Mg, Ti, and Al Biotite (black mica) K(Mg, Fe)3AlSi3O10(OH)2 Plagioclase 5 calcium feldspar sodium feldspar Ca(Al2Si2O8) Na(AlSi3O8) Orthoclase (potassium feldspar) K(AlSi3O8) Muscovite (white mica) KAl3Si3O10(OH)2 Quartz SiO2 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203  2.2 Rock Cycle and the Origin of Soil 19 Figure 2.3 Scanning electron micrograph of fractured surface of quartz showing glass-like fractures with no discrete planar surface (Courtesy of David J. White, Iowa State University, Ames, Iowa) Figure 2.4 Scanning electron micrograph showing