GEOTECHNICAL ENGINEERING

A Practical Problem Solving Approach

N. Sivakugan I Braja M. Das '~

"-OOJ '. GeoStudio .~ DVD INCLUDED

Geotechnical Engineedng/Civil Engineering

A Titlt in J Ross Pubb~"lill[!,~' Eureka Series

GeoSludio DVD INCLUDED

GEOTECHNICAL ENGINEERING A Practical Problem 'Solving Approach Nagaratnam Sivakugan & Braja M. Das

Geotechnical Engineering:

A Practical Problem Solving

Approach covers all of the major

.geotechnical topics in the simplest

possible way adopting a hands-on

approach with a very strong practical

bias. Engineers arc problem solvers.

Developing problem-solving skills is one

of the key learning outcomes expected

of engineering students and this book

provides just that. 60-70% of the book

is devoted to practical problem solving

and 30-40% covers fundament.al

concepts.

KEY FEATURES • om'J"< carefully selected solved problems with

a wide range of difficulty level- from simple to challenging

• Includes a DVD of th~ Student Edition of GeoStudio that can be used for solving a wide range of geotechnical problems

• Presents the material in the mosl concise manner possible while still including enough detail to solve the problems

• Demonstrates theory mrough practical problem wiving \~~th less reliance on matbcrnatics

• om,r, both soil mechanics and [oandolion engineering in one book

• WYoffers downloadabk PowerPoint slides to assist in classroom instruc60n - available from the Web Added Value™ Download Resource Center at www.jrosspub.com

The books in ·theJ. Ross Publishing Eweka Sen'es are engineering textbooks for a new gencl·ation. Similar to problell1~based learn-

, ing~ ~he subject fnatenai 1S iritegrated "vith exten..<>;ive wurkf:cl ex· amplet;, quizzes. and rcvic\\' exercises. The writing style is lean and simple while. not compromisiflg on the breadth or depth of the subject matter. Books in'the Eweka Selits are written by renowned scholars \vith outstanding university careers who have also made significant contribuliom to teaching and leaming.

JR0167

IS8N: 978-1-60427-010-7

III III 90000

9 781604 270167 1II1111111111111

GEOTECHNICAL ENGINEERING

A Practical Problem Solving Approach

N. Sivakugan I Braja M. Das

J.~OSsJ lPUBLISHING

Copyright © 2010 by J. Ross Publishing. Inc.

ISBN-13: 978-l-60127-01 6-7

Printed and bound in the U.S.A Printed on acid-free paper

Library of Congress Cataloging-in-Publication Data

Sivakugan, Nagaratnam, J 956-Geotechnical engineering: a practical problem solving approach I by Nagaratnam Sivakugan and Braj. M. Das.

p.em. Includes bibliographical references and index. ISBN 978-1-60427-016-7 (pbk. : alk paper) 1. Soil mechanics. 2. Foundations. 3. Earthwork. l. Das. Braja M .•

TA710.S5362009 621.1' 5136-dc22

2009032547

This publication contains information obtained from authentic and highly regarded sources. Reprinted material is used with permission. and sources are indicated. Reasonable effort ha., been made to publiili reliable data and information, but tbe author· and the publi>her cannot assume responsibility for the validity o~ all materials or for tbe consequences of tbeir uSe.

All rights reserved. Neitber tJm; publication nor any part thereof may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic. mechanical, photocopying, recording or otherwise. without the prior written permi>sion of the publisher.

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Direct all inquiries to J. Ross Publishing, Inc., 5765 N. Andrews Way, fort Lauderdale. FL 33309.

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Web: ,,'ww.jrosspub.com

Contents

Preface , ................................................................................................................................................................... ix AbDUl Ihe Authors ................................................................................................................................................ ~i

WAV"''' ................................................................................................................................................................ xiii

Chapter 1 Introduction ........................................................................................................................ 1 1.1 General ............................................................................................................................................................ 1 1.~ Sous ............................................................................................................................................................. .. 1 1.3 Applications .................................................................................................................................................. 3

1.4 Soil Testing ...................................................................................................................................................... 3 15 Geotechnical Literature ................................................................................................................................. 4 1.6 Numerical Modding .................................................................................................................................... 6 Review Exercises ................................................................................................................ ................................ S

Chapter 2 Phase Relations ................................................................................................................. 11 2.1 Inlroduction .................................................................................................................................................. 11 2.2 Definitions ............................................................................................. ....................................................... 11 2.3 Phase Relations ............................................................................................................................................. 13 Work~d Examples ............................................................................................................................................... 16 Review Exercises ...... ............................................................................................................................................ 22

Chapter 3 Soil Classification ............................................................................................................. 27 3.1 Introduction .................................................................................................................................................. 27

3.2 Coarse-Grained Soils .................................................. ... .............................................................................. 27

3.3 Fine-Grained Soils ..................................................................................................................................... 32 3.4 Soil Classification ......................................................................................................................................... 37 Worked Examples ............................................................................................................................................... .41 Review Exercise .................................................................................................................................................. .11

Chapter 4 Compaction ..................................................................................................................... ..49 4.1 lntroduction .................................................................................................................................................. 49 1.2 Variables in Compaction ............................................................................................................................ 50 4.3 Laboratory Tests ........................................................................................................................................... 52 4.4 Field Compaction. Specification, and Control ........................................................................................ 55 Worked Examples .............................................................................................................................................. 59 Review Exercises ................................................................................................................................................. 62

v

vi Contents

Chapter 5 Effective Stress, Total Stress, and Pore Water Pressure ................................................... 65 5.1 Introduction .................................................................................................................................................. 65 5.2 Effective Stress Principle ............................................................................................................................ 65 5.3 Vertical Nurmal Stresses Due (0 Overburden ......................................................................................... 66 5.4 Capillary Effects in Soils ............................................................................................. , ............................... 68

Worked Examples ....................................................................................................... , ........................................ 70

Review Exercises ................................................................................................................................................. 71

Chapter 6 Permeability and Seepage ................................................................................................. 73 6.1 Introduction .................................................................................................................................................. 73 6.2 Bernoulli's Jiquation .................................................................................................................................. 73 6.3 Darcy's Law .............. ..................................................................................................................................... 76 6.4 Laboratory and field Permeability Tests .................................................................................................. 77 6.5 Stresses in Soils Due to Flow ...................................................................................................................... 81 6.6 Seepage .......................................................................................................................................................... 82 6.7 Design of Granular Fiiters .......................................................................................................................... 86 6.8 Equivalent Permeabilities for One·dimensional Flow ............................................................................ 87 6.9 Seepage AnalYSis U,ing SEEPIW ............................................................................................................. 89 Worked Examples ................................................................................................................................................ 94 Re\~ew Exercises ................................................................................................................................................ 103

Chapter 7 Vertical Stresses Bene.th Loaded Are ........................................................................... 115 7.1 lntroduclion ................................................................................................................................................ 115 7.2 Stresses Due to Point Loads ..................................................................................................................... 116 7.3 Stresses Due to Line Loads ...................... " ............................................................................................... 118

7.1 Stresses Under the Comer of a Uniform Rectanl,'lllar l.oad ................................................................ 118 7.5 2:1 Distribution Method ......................................................................................................................... 123 7.6 Pressure Isobars Under Flexible Uniform Loads .................................................................................. 124 7.7 Newmark's Chart.. ...................................................................................................................................... 124 7.8 Stress Computations Using SIGMA/W ........................................................ .......................................... 129 Worked Examples.. ............................................................................................................................................ 133 Review Exercises ............................................................................................................................................... 136

Chapter 8 Consolidation .................................................................................................................. 139 8.1 Introduc(ion ...................................................................................................... , ......................................... \39 8.2 One-dimensional Consolidation ............................................................................................................. 140 8.3 Consolidation Test ........................................................................ ............................................................ 143 8.4 Camputation of Final Consolidation Settlemeot. ................................................................................ 150

8.5 Time Rate of Consolidation ............................. , ....................................................................................... 153 8.6 Secondary Compression ........................................................................................................................... 159 Worked E.,.mplcs ............................................................................................................................................. 165 Review Exec\:lscs ............................................ ____ ___ ........ , ............................................. , ... .,._,. ............................. 175

Contents vii

ChapteJ' 9 Shear Strength ................................................................................................................. 181 9.1 Introduction ............................................................................................................................................. 181 9.2 Mohr Cirdes ............................................................................................................................................ 11>1 9 .3 Mohr-Coulomb Fail" re Criterion ......................................................................................................... 186 904 A Common Loading $ltuation .............................................................................................................. 187 9.5 Mohr Cirdes and Failure Envelopes in Terms of" and 'T ................................................................ 190 9.6 Drained and Undrained Loading Situations ....................................................................................... 191

9.7 Triaxial Test .......................................................................................................................................... 193 98 Direct Shear Test................................................................... .. .................................................. 200 9.9 Skempton's Pore Pressure Parameters ................................................................................................ 202 9.10 O'J -(1, Relatiollship at I'ailure ............................................................................................................... 205 9.11 Stress Paths ............................................................................................................................................... 206 Worked Examples ............................................................................................................................................. 21 0 I(eview Exercises ............................................................................................................................................... 217

Chapter 10 Lateral Earth Pressnres ................................................................................................. 225 10.1 Introduction ............................................................................................................................................. 225 10.2 At·rest State .............................................................................................................................................. 226 10.3 Rankine's Earth Pressure Theory ........................................................................................................... 230 lOA Coulomb's Earth Pressure Theory ......................................................................................................... 237 Worked E~amples ........ , .......................................................................................................................... , .......... 210 Review Exercises ............................................................................................................................................... 216

Chapter 11 Site Investigation ....................... , ................................................................................. 251

11.1 Introduction ............................................................................................................................................. 251 11.2 Drilling arid Sampling .......................................................................................................................... .253

11.3 In Situ Tests ................................................. , .. " ........................................................................................ 257 1104 Laboratory Tests ....................................................................................................................................... 276

11.5 Site Investigation Report... ...................................................................................................................... 276 Worked Examples .............................................................................................................................................. 280 Review Exercises ................................................................................................................................................ 283

Chapter 12 Shallow Foundalions ................................................................................................... 289 12.1 Introduction ....... , ..................................................................................................................................... 289 12.2 Design Criteria ......................................................................................................................................... 290 12.3 Bearing Capacity of i\ Shallow Foundation .......................................................................................... 291 12.4 Pressure Distributions Beneath Eccentrically Loaded Footings ....................................................... 30J 12.5 Introduction to Raft Foundation Design ............................................................................................. 304 12.6 Settlement in a Granular Soil ................................................................................................................. 310

12.7 Settlement in a Cohesive Soil ................................................................................................................. 319 Worked Ex.mples .............................................................................................................................................. 325 Review Exercises ...... , ......................................................................................................................................... 33'1

Vlii Contents

Chapter 13 Deep Foundatinns ......................................................... _ ............................................. 341 13.1 Introduction ............................................................................................................................................. 341 13.2 Pile Materials .............................................................................. _ ............................................................. 342 13.3 Pile Installation ....................................................................................................... _ ................................ 345 13.4 Load Carrying Capacity of a Pile-Static Analysis ............................................................................. 347 13.5 Pile-Driving Formulae ............................................................................................................................ 354 13.6 Pile Load 'fest ...... , .......... " ... ~ .. ~ ... " .... ".,,.,--.. -<"H.,~ .. ~.' ..... ,, •..•. ............................. <0"" ... " ... ;0" •• ," .•.• ,.,, ....... 355 13.7 Settlement of a Pile .................................................................................................................................. 357 13.8 Pile Group ................................................................................................................................................. 361 Worked E.xamples ........................................................................................... " ................................................ .365 Review Exercises .................................................................................................. " ............................................ 373

Chapter 14 Earth Retaining Sttuctures .............................................................................. m .......... 377 14.1 Introduction ............................................................................................................................................. 377 14.2 Design of Retaining Walls ...................................................................................................................... 379 14.3 Cantilever Sheet Piles .............................................................................................................................. 385 14.4 Anchored Sheet Piles .............. , ................................................................................................................ 395 14.5 Braced ExcavatiOllS ................................................ , ................................................................................. 399 WOTked Examples ............................................................................................................................................. .404 Review £xercises ................................................................................................................................................ 415

Chapter 15 Slope Stability ................................................................................................................ 421 15.1 Introduction ............................................................................................................................................. 421 15.2 Slope Failure and Safety Factor .............................................................................................................. 422 15.3 Stability of Homogeneous Undrained Slopes ...................................................................................... 423 15.4 Taylor's Stability Charts for c' -q,' Soils ................................................................................................. 427 15.5 Infinite Slopes .................................. , ...................................................................................................... ..429 15.6 Method of Slices .......................................................................................................................... , ............ 432 15.7 Stability Analysis Using SLOPE/W ........................................................................................................ 435 Worked Examples ............................................................................................................................................. .443 Review Exerdses ................................................................................................................................................ 449

Chapter 16 Vibrations of Fowtdations ........................................................................................... .453 16.1 Introduction .................................................................................. m ....................................................... .453 16.2 Vibration Theory-General .............................................................................. , .................................... .454 16.3 Shear Modulus and Poisson's Ratio ........................................................................................................ 463 16.4 VeTtical Vlbration of Foundations- Analog Solution ........ _ ............................ , ......... , ....................... .465 16.5 Rocking Vibration of Foundations ............................................ , ........................................................... .469 16.6 Sliding Vibration of Foundations ...................... _ ............................................................................... , ... 475 16.7 Torsional Vibration of !'oundations ....................................................................................................... 478 Review Exercises ................................................................................................................... , ........................... .483

Index ..................................... · .. · .. · ...... • ................................................. , ............................................. 487

Preface

We both have been quite successful as geotechnkal engineering teachers. In Geotechnical Engi­neering: A Practical Problem Solving Approach, we have tried to cover every major geotechnical topic in the simplest way possible. We have adopted a hands-on approach with a stCGng, prac­tical bias. You willlcam the material through several worked examples that take geotechnkal engineering principles and apply them to realistic problems that you are likely to encounter in real-life field situations. This is our attempt to write a straightforward, no-nonsense, geotechni­cal engineering textbook that will appeal to a new generation of students. This is said with no disrespect to the variety of geotechnical engineering textbooks already available---each serves

a purpose. . ~~ 'f'

We have used a few symbols to facilitate quick referenciug and to call your at- ....... rj): tention to key concepts. This symbol appears at the end of a chapter wherever it is·",,; .. necessary to emphaSize a partkular point and your need to understand it. ~ern' del'

There are a few thoughtfully selected review exercises at the end of each chap- '" tec, and answers are given whenever possible. Remember, when you practice as a professional engineer you will not get to see the solutions! You will simply design with confidence and have it checked by a colleague. The degree of difficolty in­creases with each review exercise. The symbol shown here appears beside the most challenging problems.

We also try to IHLrturC the habit of self-learning through exercises that re­late to topks not covered in this book. Here, you are expected to surf the Web; or even better, refer to library books. The knowledge obtained from both the research activity and the material itself will complement the mate­rial from this book and is an integral part of learning. Such research-type questions are identified by the symbol shown here. Today, the www is at your fingertips, so this should not be a problem. There are many dedicated Web sites for geotechnical re­sources and reference materials (e.g., Center for Integrating Information on Geoengineer­ing at http://www.geoengineer.org). Give proper references for research-type questions in your short essays. Sites like Wildpedia (http://en.wikipedia.org) and YouTube (http://www .youtube.com) can provide useful information including images and video clips. To obtain the best references, you mnst go to the library and conduct a proper literature search using appro­priate key words.

ix

x Preface

We have included eight quizzes to test your comprehension, These are closed­book quizzes that should he completed within the specified times, They are de­sigll~d to make you think and show you what YOll have missed,

The site investigation chapter has a slightly different layout. lhe nature of this topic is quite descriptive and less rejiant on problem solving. It is good to have a dear idea of what the different in situ testing devices look like. For this reason, we

have induded several quality photographs. The purpose of the site investigation exercise is to derive the soil pa rameters from the in situ test data. A wide range of empirical correlations that are used in practice are summarized in this chapter. Tests are included that are rarely covered in traditional textbooks-such as the borehole shear test and the Ko stepped blade test-and are followed by review questions that encourage the reader to review other SOurces of literature and hence nurture the habit of research.

Fotmdation Engineerlng is one of the main areas of geotechnical engineering; therefore, considerable effort was directed toward Chapters 12 and 13. which cover the topics of bearing capacity and settlements of shallow and deep foundations.

This is not a place for uS to document everything we know in geotechnical engineering, We realize that this is your first geotechnical engineering book and have endeavored (0 give sufficient breadth and depth covering all major topiCS in soil mechanics and foundation engineering.

A free DVD containing the Student Edition of GeoStudio is included with this book. It is a powerful software suite that can be used for solving a wide range of geotechnical problems and is a useful complement to traditional learning. We are grateful to Mr. Paul Bryden and the GeoStudio team for their advice and s~lpport.

We are grateful LO the following people who have contributed either by feviewing 'hapters from the book and proViding suggestions for improvement Dr. Jay Amcratunga. Colfey Geo­technics; Ms. Julie Lovisa. James Cook University; Kieralee Rankine, Golder Associates; and Shailesh Singh, Colfey Gcotechnks; or by providing photogr~phs or data: Dr. Jay Ameratunga, Coffey Geotechnics; Mr. Mark Arnold, Douglas Parlners; Mr. Martyn Ellis, PMC. UK; Profes­sor Robin Fell, University of New South Wales; Dr. Chris Haberfield. Golder Associates; Profes­sor Silvano Marchetti, University of LAquila, Italy; Dr. Kandiah Firapakaran, ColTey Geotech­nics: Dr. Kirralee Rankine, Golder Associates; Dr. Kelda Rankine. Golder Associates; Dr. Ajant. Saehan.lIT Kanpur. India: Mr. Leonard Sands, Venezuela; Dr. Shailesh Singh, ColIey Geotech­nics; Mr. Bruce Stewart, Douglas Partner.; Professor David White, Iowa State University.

We wish to thank Mrs. Janke Das and Mrs. Rohini Siwkugan, who provided manuscript preparation and proofreading assistance. Finally, we wish to thank Mr. Tim Pletscher of). Ross Publishing for his prompt response to all our questions and for his valnable contributions at various stages.

N. Sivakugan and B. M. Das