Craig's Soil Mechanics

570 Pages·2012·10.753 MB·English

by  Knappett J., Craig R.F.

Craig’s Soil Mechanics
Now in its eighth edition, this bestselling text continues to blend clarity of explanation with
depth of coverage to present students with the fundamental principles of soil mechanics. From
the foundations of the subject through to its application in practice, Craig’s Soil Mechanics
provides an indispensable companion to undergraduate courses and beyond.
Revised and fully reworked throughout, several chapters have been significantly extended
or had fresh topics added to ensure this new edition reflects more than ever the demands of
civil engineering today.
New to this edition:
●● Rewritten throughout in line with Eurocode 7, with reference to other international stand-
ards.
●● Restructuring of the book into two major sections dealing with both the basic concepts
and theories in soil mechanics and the application of these concepts within geotechnical
engineering design.
●● Brand new topics include limit analysis techniques, in- situ testing and foundation systems,

plus additional material on seepage, soil stiffness, the critical state concept and foundation
design.
●● Enhanced pedagogy including a comprehensive glossary of terms, start-o f-chapter learning
objectives, end-o f-chapter summaries, and visual examples of real- life engineering equip-
ment to help students approaching the subject for the first time.
●● An extensive companion website comprising innovative spreadsheet tools for tackling
complex problems, digital datasets to accompany worked examples and problems, solutions
to end- of-chapter problems, weblinks, extended case studies, and more.
Craig’s Soil Mechanics is the definitive text for civil engineering students worldwide.
J. A. Knappett is a lecturer in Civil Engineering at the University of Dundee, UK.
R. F. Craig is a former lecturer in Civil Engineering at the University of Dundee, UK.
Craig’s Soil Mechanics
Eighth edition
J. A. Knappett and R. F. Craig
First published 1974 by E & FN Spon, an imprint of Chapman & Hall
Second edition 1978
Third edition 1983
Fourth edition 1987
Fifth edition 1992
Sixth edition 1997
Seventh edition 2004
This edition published 2012
by Spon Press
2 Park Square, Milton Park, Abingdon, Oxon OX14 4RN
Simultaneously published in the USA and Canada
by Spon Press
711 Third Avenue, New York, NY 10017
Spon Press is an imprint of the Taylor & Francis Group, an informa business
© 1974, 1978, 1983, 1987, 1992, 1997, 2004 R. F. Craig
© 2012 J. A. Knappett
The right of J. A. Knappett to be identified as the author of this work has been
asserted by him in accordance with sections 77 and 78 of the Copyright, Designs and
Patents Act 1988.

Trademark notice: Product or corporate names may be trademarks or registered
trademarks, and are used only for identification and explanation without intent to
infringe.
All rights reserved. No part of this book may be reprinted or reproduced or utilised
in any form or by any electronic, mechanical, or other means, now known or here-
after invented, including photocopying and recording, or in any information
storage or retrieval system, without permission in writing from the publishers.
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library
Library of Congress Cataloging in Publication Data
Knappett, Jonathan.
Craig’s soil mechanics / J. A. Knappett and R. F. Craig. – 8th ed.
p. cm.
Previous ed. under : Soil mechanics / R.F. Craig.
Includes bibliographical references and index.
1. Soil mechanics. I. Craig, R. F. (Robert F.) II. Craig, R. F. (Robert F.) Soil mechanics.
III. Title. IV. Title: Soil mechanics.
TA710.C685 2012
624.1’5136–dc23 2011033710
ISBN: 978-0-415-56125-9 (hbk)
ISBN: 978-0-415-56126-6 (pbk)
ISBN: 978-0-203-86524-8 (ebk)
Typeset in Times and Frutiger
by Wearset Ltd, Boldon, Tyne and Wear
To Lis, for her unending support, patience and inspiration.
Contents
List of figures xii
List of tables xxii
Preface xxiv
Part 1 Development of a mechanical model for soil 1
1 Basic characteristics of soils 3
Learning outcomes 3
1.1 The origin of soils 3
1.2 The nature of soils 6
1.3 Plasticity of fine- grained soils 10
1.4 Particle size analysis 13
1.5 Soil description and classification 14

1.6 Phase relationships 22
1.7 Soil compaction 26
Summary 35
Problems 35
References 36
Further reading 37
2 Seepage 39
Learning outcomes 39
2.1 Soil water 39
2.2 Permeability and testing 41
2.3 Seepage theory 46
2.4 Flow nets 51
2.5 Anisotropic soil conditions 57
2.6 Non- homogeneous soil conditions 59
2.7 Numerical solution using the Finite Difference Method 60
2.8 Transfer condition 63
2.9 Seepage through embankment dams 64
2.10 Filter design 73
Summary 74
vii
Contents
Problems 74
References 77
Further reading 78
3 Effective stress 79
Learning outcomes 79
3.1 Introduction 79
3.2 The principle of effective stress 80
3.3 Numerical solution using the Finite Difference Method 83
3.4 Response of effective stress to a change in total stress 83
3.5 Effective stress in partially saturated soils 87
3.6 Influence of seepage on effective stress 87
3.7 Liquefaction 91
Summary 98
Problems 98
References 100
Further reading 100
4 Consolidation 101
Learning outcomes 101
4.1 Introduction 101
4.2 The oedometer test 102
4.3 Consolidation settlement 109
4.4 Degree of consolidation 112
4.5 Terzaghi’s theory of one- di mensional consolidation 115
4.6 Determination of coefficient of consolidation 121
4.7 Secondary compression 126
4.8 Numerical solution using the Finite Difference Method 127
4.9 Correction for construction period 131
4.10 Vertical drains 136
4.11 Pre-loading 140
Summary 142
Problems 142
References 143
Further reading 144
5 Soil behaviour in shear 145
Learning outcomes 145
5.1 An introduction to continuum mechanics 145
5.2 Simple models of soil elasticity 149
5.3 Simple models of soil plasticity 152
5.4 Laboratory shear tests 156
5.5 Shear strength of coarse- grained soils 168
5.6 Shear strength of saturated fine- grained soils 174
viii
Contents
5.7 The critical state framework 183
5.8 Residual strength 188
5.9 Estimating strength parameters from index tests 189
Summary 195
Problems 196
References 197
Further reading 199
6 Ground investigation 201
Learning outcomes 201
6.1 Introduction 201
6.2 Methods of intrusive investigation 203
6.3 Sampling 210
6.4 Selection of laboratory test method(s) 215
6.5 Borehole logs 216
6.6 Cone Penetration Testing (CPT) 218
6.7 Geophysical methods 222
6.8 Contaminated ground 227
Summary 228
References 229
Further reading 229
7 In- situ testing 231
Learning outcomes 231
7.1 Introduction 231
7.2 Standard Penetration Test (SPT) 232
7.3 Field Vane Test (FVT) 236
7.4 Pressuremeter Test (PMT) 240
7.5 Cone Penetration Test (CPT) 252
7.6 Selection of in- situ test method(s) 260
Summary 261
Problems 262
References 265
Further reading 266
Part 2 Applications in geotechnical engineering 267
8 Shallow foundations 269
Learning outcomes 269
8.1 Introduction 269
8.2 Bearing capacity and limit analysis 271
8.3 Bearing capacity in undrained materials 273
8.4 Bearing capacity in drained materials 285
8.5 Stresses beneath shallow foundations 295
ix
Contents
8.6 Settlements from elastic theory 300
8.7 Settlements from consolidation theory 304
8.8 Settlement from in- situ test data 311
8.9 Limit state design 316
Summary 323
Problems 324
References 325
Further reading 326
9 Deep foundations 327
Learning outcomes 327
9.1 Introduction 327
9.2 Pile resistance under compressive loads 331
9.3 Pile resistance from in-s itu test data 340
9.4 Settlement of piles 341
9.5 Piles under tensile loads 349
9.6 Load testing 350
9.7 Pile groups 353
9.8 Negative skin friction 358
Summary 359
Problems 359
References 361
Further reading 362
10 Advanced foundation topics 365
Learning outcomes 365
10.1 Introduction 365
10.2 Foundation systems 366
10.3 Shallow foundations under combined loading 380
10.4 Deep foundations under combined loading 389
Summary 398
Problems 399
References 400
Further reading 401
11 Retaining structures 403
Learning outcomes 403
11.1 Introduction 403
11.2 Limiting earth pressures from limit analysis 404
11.3 Earth pressure at rest 415
11.4 Gravity retaining structures 418
11.5 Coulomb’s theory of earth pressure 429
11.6 Backfilling and compaction- induced earth pressures 434
11.7 Embedded walls 436
x
Contents
11.8 Ground anchorages 447
11.9 Braced excavations 452
11.10 Diaphragm walls 456
11.11 Reinforced soil 458
Summary 460
Problems 461
References 464
Further reading 465
12 Stability of self-s upporting soil masses 467
Learning outcomes 467
12.1 Introduction 467
12.2 Vertical cuttings and trenches 468
12.3 Slopes 472
12.4 Embankment dams 487
12.5 An introduction to tunnels 490
Summary 495
Problems 496
References 498
Further reading 499
13 Illustrative cases 501
Learning outcomes 501
13.1 Introduction 501
13.2 Selection of characteristic values 502

13.3 Field instrumentation 506
13.4 The observational method 514
13.5 Illustrative cases 515
Summary 517
References 517
Further reading 518
Principal symbols 519
Glossary 527
Index 543
xi