Geotechnical engeneering

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<ul><li>1.GEOTECHNICAL ENGINEERING </li></ul><p>2. THIS PAGE IS BLANK 3. Copyright 2006, 1995, 1993 NewAge International (P) Ltd., Publishers Published by New Age International (P) Ltd., Publishers All rights reserved. No part of this ebook may be reproduced in any form, by photostat, microfilm, xerography, or any other means, or incorporated into any information retrieval system, electronic or mechanical, without the written permission of the publisher. All inquiries should be emailed to rights@newagepublishers.com ISBN (10) : 81-224-2338-8 ISBN (13) : 978-81-224-2338-9 PUBLISHING FOR ONE WORLD NEWAGE INTERNATIONAL(P) LIMITED, PUBLISHERS 4835/24,Ansari Road, Daryaganj, New Delhi - 110002 Visit us atwww.newagepublishers.com 4. Dedicated to the memory of My Parenu-in-l_ Smt. Ramalakshmi &amp; Dr. A. Venkat&amp; Subba Bao for ,1Mb- ' - and o/Yeetio,.lo".. and aU 1M meMbue ofmy (Gmjly. 5. THIS PAGE IS BLANK 6. PREFACE TO THE 1'Hnm EDITION With the enthusiastic response to the Second Edition of"GEOTECHNICAL ENGINEERING" from the academic community. the author has undertaken the task of preparing the Third Edition. The important features ofthis Edition are minor revision/additions in Chapters 7. 8, 10, 17 and 18 and change over of the Illustrative Examples and Praclice Problems originally left in the MKS units into the S.I. units so that the book is completely in the S.I. units. This is because the so-caned "Period of Transition" may be considered to have been over. The topics involving minor revision/addition in the respective chapters specificaUy are : Chapter 7 Estimation of the settlement due to secondary compression. Chapter 8 Chapter 10 Chapter 17 Chapter 18 Uses and appli.cations of Skempton'g pore pressure parameters, and "Stress-path" approach and its usefulness. Unifonn load on an annular area (Ring foundation). Reinforced Earth and Geosynthetics, and their applications in geotechnical practice. The art of preparing a soil investigation report. Only brief and elementary treatment of the above has been given. Consequential changes at the appropriate places in the text, contents, answers to nu- merical problems, section numbers, figure numbers, chapter-wise references, and the indices have also been made. A few printing errors noticed in the previous edition have been rectified. The reader is requested to refer to the latest revised versions of the 1.8. Codes mentioned in the book. In view of all these, it is hoped that the bouk would prove even more useful to the stu- dents than the previous edition. The author wishes to thank the geotechnical enbrineenng fraternity for the excellent support given to his book. Finally, the author thanks the Publishers for bringing out this Edition in a relatively short time, while impro.ving the quality of production. Tirupati India Vii C. Venkatramaiah 7. THIS PAGE IS BLANK 8. PREFACE TO THE FIRST EnmON The author does not intend to be apologetic for adding yet another book to the existing list in the field of Geotechnical Engineering. For onc thing, the number ofbooks avaiiable cannot be considered too large, although certain excellent reference books by Stalwarts in the field are available. For another, the number ofbooks by Indian Authors is only a few. Specifically speak. ing, the number ofbooks in this field in the S.I. System ofUnits is small, and books from Indian authors are virtually negligible. This fact, coupled with the author's observation that not many books are available designed specifically to meet the requirements of undergraduate curncu- lum in Civil Engineering and Technology, has been the motivation to undertake this venture. The special features ofthis book are as follows: 1. The S.L System ofUnits is adopted along with the equivalents in the M.K.S. Units in some instances. (A note on the S.l. Units commonly used in Geotechnical Engineer- ing is included). 2. Reference is made to the relevant Indian Standards, wherever applicable, and ex- tracts from these are quoted for the benefit of the student as well a8 the practising engineer. 3. A 'few illustrative problems and problems for practice are given in the M.K.S. Units to facilitate those who continue to use these Units during the transition period. 4. The number of illustrative problems is fairly large compared to that in other books. This aspect would be helpful to the student to appreciate the various types of prob- lems likely to be encountered. 5. The number of problems for practice at the end of each chapter is also fairly large. The answers to the numerical Froblems are given at the end of the book. 6. The illustrative examples and problems are graded carefully with regard to the toughness. 7. A few objective questions are also included at the end. This feature would be useful to students even during their preparation for competitive and other examinations such as GATE. B. "Summary of Main Points", given at the end ofeach Chapter, would be vcr)' helpful to a student trying to brush up his preparatiun on the eve ofthe examination. 9. Chapter-wise references are given; this is CODl,!idered a better way to encourage fur- ther reading than a big Bibliography at the end. Note: References are invited to the latest editions ofthesc specifications for further details. These standards are available from Indian Standards Institution, New Delhi and it.s Regional Branch and In- epection Offices at Ahmedabad, Bangalorc. Bhopal. llhubaneshwar. Bombay, Calcutta. Chandigarh, Hyderabad, Jaipur. Kanpur, Madras, Patnn. Pune and Trivilndrum. ix 9. x PREFACE 10. The sequence of topics and subtopics is sought to ~ made as logical as possible. Symbols and Nomenclature adopted are such that they are consistent (without sig- nificant variation from Chapter to Chapter), while being in close agreement with the intemational1y standardized ones.This would go a long way in minimising the possi- ble confusion in the mind ofthe student. 11. The various theories, formulae, and schools of thought are given in the most logical sequence, laying greater emphasis on those that are most commonly used, or are more sound from a scientific point ofview. 12. The author does not pretend to claim any originality for the material; however, he does claim some degree of special effort in the style of presentation, in the degree of lucidity sought to be imparted, and in his efforts to combine the good features of previous books in the field. An sources are properly acknowledged. The book has been designed as a Text-book to meet the needs ofundergraduate curricula ofIndian Universities in the two conventional courses-"Soil Mechanics" and "Foundation Engi- neering". Since a text always includes a little more than what is required, a few topics marked by asterisks may be omitted on first reading or by undergraduates depending on the needs ora specific syllabus. The author wishes to express his grateful thanks and acknowledgements to: (i) The Indian Standards 1nstitution, for according permission to include extracts from a number ofrelevant Indian Standard Codes ofPractice in the field of Geotechnical Engineering ; (it) The authors and publishers ofvariou8 Technical papers and books, referred to in the appropriate places; and. (iti) The Sri Venkateswara University, for permission to include questions and problems from their University Question Papers in the subject (some cases, in a modified system ofUnite). The author specially acknowledges his colleague, Prof. K. Venkata Ramana, for critically going through most ofthe Manuscript and offering valuable suggestions for improvement. Efforts wil1 be made to rectify errors, if any, pointed out by readers, to whom the author would be grateful. Suggestions for improvement are also welcome. The author thanks the publishers for bringing out the book nicely. The author places on record the invaluable RUpport and unstinted encoUragement re- ceived from his wife, Mrs. Lakshmi Suseela, and his daughters, Ms. Sarada and Ms. Usha Padmini, during the period of preparation of the manuscript. Tirupati India C. Venkatramaiah 10. PuRPoSE AND ScOPE OF THE BOOK 'GEOTECHNICAL ENGINEERING' There are not many books which cover both soil mechanics and foundation engineering which a student can use for his paper on Geotechnical Engineering. This paper is studied compulsorily and available books, whatever few are there, have not been found satisfactory. Students are compelled to refer to three or four books to meet their requirements. The author has been prompted by the lack of a good comprehensive textbook to write this present work. He has made a sincere effort to sum up his experience of thirty three years of teaching in the present book. The notable features ofthe book are as follows: 1. The S.1. (Standard International) System of Units, which is a modification of the Metric System of units, is adopted. A note on the S.l. Units is included by way of elucidation. The reader is requested to refer to the latest revised versions of the 1.8. codes men- tioned in the book. 2. Reference is made to the relevant Indian Standards, wherever applicable. 3. The number of illustrative problems as well as the number of practice problems:is made as large as possible so as to cover the various types of problems likely to be encountered. The problems are carefully graded with regard to their toughness, 4. A few "objective questions" are also included. 5. "Summary of Main Points" is given at the end of each Chapter. 6. References are given at the end of each Chapter. 7. Symbols and nomenclature adopted are mostly consistent, while being in close agree- ment with the internationally standardised. ones. 8. The sequencc oftopics and subtopics is made as logical as possible. 9. The author does not pretend to claim any originality for the material, the sources being appropriately acknowledged; however, he does claim some degree of it in the presentation, in the degree of lucidity sought to be imparted, and in his efforts to combine the good features of previous works in this field, In view of the meagre number ofbooks in this field in S.I. Units, this can be expected to be a valuable contributio~ to the existing literature. xl 11. THIS PAGE IS BLANK 12. .- CONTENTS Preface to the Third Edition i Preface to the First Edition ii Purpose and Scope of the Book iv 1 SOIL AND SOIL MECHANICS 1 1.1 Introduction 1 1.2 Development or SoH Mechanics 2 1.3 Fields of Application of Soil mechanics 3 1.4 Soil Formation 4 1.5 Residual and Transported Soils 6 1.6 Some Commonly Used Soil Designations 7 1.7 Structure of Soils 8 1.8 Texture of Soils 9 1.9 Major Soil Deposits of India 9 Summary ofMain Points 10 References 10 Questions 11 2 COMPOSITION OF SOIL TERMINOLOGY AND DEFINITIONS 12 2.1 Composition of Soil 12 2.2 Basic Terminology 13 2.3 Certain Important Relationships 17 2.4 Illustrative Examples 21 Summary of Main Points 27 References 27 Questions and Problems 28 3 INDEX PROPERTIES AND CLASSIFICATION TeSTS 30 3.1 Introduction 30 3.2 Soil Colour 30 3.3 Particle Shape 31 3.4 Specific Gravity ofSoil Solids 31 3.5 Water Content 34 xIII 13. xlv 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 Density Index 37 In.-Situ Unit Weight 41 Particle Size Distribution (Mechanical Analysis) 45 Consistency ofClay So4a 68 Activity ofClays 71 Unconfined CompreSHion Strength and Senaitivity ofClaya 72 Thixotropy of Clays 73 Illustrative Examples 73 Summary of Main Points sa References 88 Questions and Problema 89 4 IDENTIFICATION AND CLASSIFICATION OF SOILS 92 4.1 Introduction 92 4.2 Field Identification of Soils 92 4.3 Soil Classification- The Need 94 4.4 Engineering Soil Cla88ification-~l'hle Fe,atures ~. 4.5 Classification Systems-More Co~on Ones 95 4.6 Illustrative Examples 105 Summary of Main Points 109 References 110 Questions and Problems 110 5 SOIL MOISTURe-PERMEABILITY AND CAPILLARITY 112 5.1 Introduction 112 5.2 Soil Moisture and Modes ofOccurrence 112 5.3 Neutral and Effective Pressures 11" 5.4 Flow ofWater Through Soil-Permeability 116 5.5 Determination of Permeability 121 5.6 Factors Affecting Permeabllity 130 5.7 Values ofPenneability 134 5.B Permeability of Layered Soils 134 *5.9 Capillarity 136 5.10 Illustrative Examples 147 Summary of.Main Points' 160 References 161 Questions and Problems 162 6 SeEPAGE AND FLOW'NETS 165 6.1 Introduction 165 6.2 Flow Net for One-dimensional Flow 165 CONTENTS 14. CONTENTS KY 6.3 Flow Net for Two-Dimensional Flow 168 6.4 Basic Equation for Seepage 172 *6.5 Seepage Through Non-Homogeneous and Anisotropic Soil 176 6.6 Top Flow Line in an Earth Dam 178 *6.7 Radial Flow Nets 187 6.8 Methods of Obtaining Flow Nets 190 6.9 Quicksand 192 6.10 Seepage Forces 193 6.11 Effective Stress in a Soil Mass Under Seepage 194 6.12 lIlustrative Examples 194 Summary of Main Point8 199 References 199 Questions and Problems 200 7 COMPRESSIBILITY AND CONSOLIDATION OF SOILS 202 7.1 Introduction 202 7.2 Compressibility ofSoils 202 7.3 A Mechanistic Model for Consolidation 220 7.4 Ten:agW's Theory of One-dimensional Consolidation 224 7.5 Solution ofTerzaghi's Equation for One-dimensional Consolidation 228 7.6 Graphical Presentation of Consolidation Relationships 231 7.7 Evaluation of Coefficient of Consolidation from Odometer Test Data 234 *7.8 Secondary Consolidation 238 7.9 Illustrative Examples 240 Summary of Main Points 248 References 248 Question,; and Problems 249 8 SHEARING STRENGTH OF SOILS 253 8.1 Introduction 253 8.2 Friction 253 8.3 Principal Planes and Principal Stresses-Mohr's Circle 255 8.4 Strength Theories for Soils 260 8.5 Shearing Strength-A Function of Effective Stress 263 *8.6 Hvorslev's True Shear Parameters 264 8.7 Types of Shear Tp.sts Basod on Drainage Conditions 265 B.8 Shearing Strength Tests 266 *8.9 Pore Pressure Parameters 280 *8.10 Stress-Path Approach 282 8.11 Shearing Characteristics of Sand~ 285 8.12 Shearing Characteristics of Clays 290 15. xvi 9 10 8.13 lIJustrative Examples 297 Summary of Main Points 312 References 313 Questions and Prob1ems 314 STABILITY OF EARTH SLOPES 318 9.1 Introduction 318 9.2 Infinite Slopes 318 9.3 Finite Slopes 325 9.4 Illustrative Examples 342 Summary of Main Points 349 References 350 Questions and Problems 350 STRESS DISTRIBUTION IN SOIL 10.1 Introduction 352 10.2 Point Load 353 10.3 Line Load 361 10.4 Strip Load 363 352 10.5 Uniform Load on Circular Area 366 10.6 Uniform. Load on Rectangular Area 370 10.7 UniConn Load on Irregular Areas-Newmark's Chart 374 10.8 Approximate Methods 377 10.9 lIluMtrative Examples 378 Summary of Main Points 386 References 387 Questions and Problems 388 11 SETTLEMENT ANALYSIS 390 1.1 Introduction 390 11.2 Data for Settlement Analysia 390 11.3 Settlement 393 11.4 Corrections to Computed Settlement 399 11.5 Further Factors Affecting Settlement 401 11.6 Other Factors Pertinent to Settlement .c04- 11.7 Settlement Records 407 11.8 Contact Pressure and Active Zone From Pressure Bulb Concept 407 11.9 Dlustrative ExampJes 411 Summary of Main Points 419 Reference8 420 Que8tions and Problems 4...</p>

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