Engineering rock mechanics: part 2 II l ustrative worked examples CHILE Continuous, Homogeneous, Isotropic and Linearly Elastic DIANE Discontinuous, Inhomogeneous, Anisotropic and Not-Elastic Frontispiece Part of the concrete foundation beneath a multi-storey car park on the Island of Jersey in the Channel Islands Engineering rock mechanics: part 2 Illustrative worked examples John R Harrison Senior Lecturer in Engineering Rock Mechanics Imperial College of Science, Technology and Medicine University of London, UK and John A. Hudson FREng Professor of Engineering Rock Mechanics Imperial College of Science, Technology and Medicine University of London, UK Pergamon UK Elsevier Science Ltd, The Boulevard, Longford Lane, Kidlington, Oxford OX5 lGB, UK USA Elsevier Science Inc., 665 Avenue of the Americas, New York, NY 10010 , USA JAPAN Elsevier Science Japan, Higashi Azabu 1- chome Building 4F, 1-9-15 , Higashi Azabu, Minato-ku, Tokyo 106, Japan Copyright @ 2000 J.P. Harrison and J.A. Hudson All Rights Resewed. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic tape, mechanical, photocopying, recording or otherwise, without permission in writing from the publishers. First edition 2000 Library of Congress Cataloging-in Publication Data A catalog record from the Library of Congress has been applied for. British library Cataloguing in Publication Data A catalog record from the British Library has been applied for. ISBN: 0 08 043010 4 Disclaimer No responsibility is assumed by the Authors or Publisher for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or op- eration of any methods, products, instructions or ideas contained in the material herein. Printed in The Netherlands For all our past, present andhture students and colleagues at Imperial College About the authors Dr J.P. Harrison John Harrison graduated in civil engineering from Imperial College, University of London, and then worked for some years in the civil engineering industry for both contracting and consulting organisations. This was interspersed by studies leading to a Master’s degree, also from Imperial College, in Engineering Rock Mechanics. He was appointed Lecturer in Engineering Rock Mechanics at Imperial College in 1986, then obtained his Ph.D. in 1993, and became Senior Lecturer in 1996. He currently directs undergraduate and postgraduate teaching of en- gineering rock mechanics within the Huxley School of the Environment, Earth Sciences and Engineering. His personal research interests are in the characterisation and behaviour of discontinuous rock masses, an exten- sion of his earlier Ph.D. work at Imperial College on novel mathematical methods applied to the analysis of discontinuity geometry. Professor J.A. Hudson FREng John Hudson graduated in 1965 from the Heriot-Watt University, U.K. and obtained his Ph.D. at the University of Minnesota, U.S.A. He has spent his professional career in engineering rock mechanics - as it applies to civil, mining and environmental engineering - in consulting, research, teaching and publishing and has been awarded the D.Sc. degree for his contributions to the subject. In addition to authoring many scientific papers, he edited the 1993 five-volume ”Comprehensive Rock Engineering” compendium, and currently edits the International Journal of Rock Mechanics and Mining Sciences. From 1983 to the present, Professor Hudson has been affiliated with Imperial College as Reader and Professor. He is also a Principal of Rock Engineering Consultants, actively engaged in applying engineering rock mechanics principles and techniques to relevant engineering practice worldwide. In 1998, he was elected as a Fellow of the Royal Academy of Engineering in the U.K. Contents Preface xi Units and Symbols xiii - Part A Illustrative worked examples Questions and answers 1 Introduction 1.1 The subject of engineering rock mechanics 1.2 Questions and answers: introduction 1.3 Additional points 2 Geological setting 13 2.1 Rock masses 13 2.2 Questions and answers: geological setting 19 2.3 Additional points 26 3 Stress 27 3.1 Understanding stress 27 3.2 Questions and answers: stress 30 3.3 Additional points 37 4 In situ rock stress 39 4.1 The nature of in situ rock stress 39 4.2 Questions and answers: in situ rock stress 42 4.3 Additional points 56 5 Strain and the theory of elasticity 57 5.1 Stress and strain are both tensor quantities 57 5.2 Questions and answers: strain and the theory of elasticity 60 5.3 Additional points 68 6 Intact rock defonnability, strength and failure 71 6.1 Intact rock 71 6.2 Questions and answers: intact rock 74 6.3 Additional points 87