ROCK SLOPE STABILITY 2ND EDITION CHARLES A. KLICHE ROCK SLOPE STABILITY 2ND EDITION CHARLES A. KLICHE Published by the Society for Mining, Metallurgy & Exploration Copyright © 2018 Society of Mining, Metallurgy & Exploration. All rights reserved. !SME_RockSlopeStab_2ndEd_TitlePg_L2.indd 1 6/29/18 7:02 AM Society for Mining, Metallurgy & Exploration (SME) 12999 E. Adam Aircraft Circle Englewood, Colorado, USA 80112 (303) 948-4200 / (800) 763-3132 www.smenet.org The Society for Mining, Metallurgy & Exploration (SME) is a professional society whose more than 15,000 members represents all professionals serving the minerals industry in more than 100 countries. SME members include engineers, geologists, metallurgists, educators, students and researchers. SME advances the worldwide mining and underground construction community through information exchange and professional development. Copyright © 2018 Society for Mining, Metallurgy & Exploration All Rights Reserved. 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No part of this publication 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 permission of the publisher. ISBN 978-0-87335-369-4 eBook 978-0-87335-370-0 Library of Congress Cataloging-in-Publication Data Names: Kliche, Charles A., 1951- author. Title: Rock slope stability / Charles A. Kliche. Description: Second edition. | Englewood, Colorado : Society for Mining, Metallurgy & Exploration, [2019] | Includes bibliographical references and index. Identifiers: LCCN 2018017397 (print) | LCCN 2018017699 (ebook) | ISBN 9780873353700 | ISBN 9780873353694 Subjects: LCSH: Rock slopes. | Rock mechanics. | Ground control (Mining) | Stability. Classification: LCC TA706 (ebook) | LCC TA706 .K62 2019 (print) | DDC 624.1/5132--dc23 LC record available at https://lccn.loc.gov/2018017397 Copyright © 2018 Society of Mining, Metallurgy & Exploration. All rights reserved. Contents PREFACE v ACKNOWLEDGMENTS vii ABOUT THE AUTHOR ix CHAPTER 1 BASIC CONCEPTS 1 Slope Stability as an Engineering Issue 1 Terminology 2 Slope Failure Causes and Processes 7 General Modes of Slope Failure in Rock Masses 11 Mechanical Approaches to Stability Analysis 15 CHAPTER 2 ROCK MASS PROPERTIES 35 Engineering Properties of Discontinuities 35 Shear Strength of Discontinuities 42 Geologic Data Collection 55 Hemispherical Projection Techniques 57 Engineering Rock Mass Classification Schemes 87 CHAPTER 3 GROUNDWATER 115 Groundwater Flow Within Rock Masses 115 Influence of Groundwater on Slope Stability 122 Evaluation of Groundwater Conditions in Slopes 125 Slope Dewatering 141 Cone of Depression 141 CHAPTER 4 THE ROCKFALL HAZARD RATING SYSTEM 149 Significance of the Rockfall Problem 149 Origins of the Rockfall Hazard Rating System 150 Overview 153 Slope Survey and Preliminary Rating 154 Detailed Rating Phase 156 iii Copyright © 2018 Society of Mining, Metallurgy & Exploration. All rights reserved. iv ROCK SLOPE STABILITY CHAPTER 5 KINEMATIC SLOPE STABILITY ANALYSIS 165 Markland Test for Plane Shear Failure 165 Markland Test for Toppling Failure 169 Computer-Aided Kinematic Analysis 169 Friction Cone Concept 173 CHAPTER 6 KINETIC SLOPE STABILITY: ANALYSIS OF SHEAR FAILURE—PLANE SHEAR AND ROTATIONAL SHEAR 183 Plane Shear 183 Rotational Shear 196 CHAPTER 7 KINETIC SLOPE STABILITY: ANALYSIS OF TOPPLING FAILURE 221 General Model for Toppling Failure 222 Limiting Equilibrium Analysis of Toppling on a Stepped Base 223 Example: Toppling Failure 231 CHAPTER 8 KINETIC SLOPE STABILITY: ANALYSIS OF WEDGE FAILURE 237 Wedge Geometry 241 Factor-of-Safety Determination 246 Other Considerations 252 CHAPTER 9 ROCK SLOPE STABILIZATION TECHNIQUES 259 Grading 260 Controlled Blasting (Overbreak Control) 271 Mechanical Stabilization 283 Structural Stabilization 286 Vegetative Stabilization 294 Water Control 294 CHAPTER 10 GEOTECHNICAL INSTRUMENTATION AND MONITORING 301 Instrumentation to Measure Rock Deformation 303 Monitoring 325 GLOSSARY 345 INDEX 357 Copyright © 2018 Society of Mining, Metallurgy & Exploration. All rights reserved. Preface The process of assessing a rock slope for stability involves the application of many branches of engineering and natural science. The determination of rock or soil strength parameters requires a working knowledge of rock mechanics and/or soil mechanics. Knowledge of basic hydrological concepts is essential for interpreting the effects of water on a rock slope. An understanding of geology—especially structural geology, mineralogy, petrology, and the geological processes—is extremely important for the rock slope engineer. These areas of knowledge—geology, rock and soil mechanics, and hydrology—along with other basic areas such as statics, engineering mechanics, statistics, and structural engineering are all important elements of rock slope engineering and design. The computer has become an invaluable tool for the engineer and scientist. With its aide, the geotechnical engineer can make numerous computations or consider many design alternatives in a short period of time. Additionally, modern rock slope instrumentation and monitoring systems use computerized data acquisition and state-of-the-art data trans- mission. The rock slope engineer must be familiar with computer analysis techniques and some of the current three-dimensional visualization techniques. The danger, however, with computerized analysis techniques is that engineers who do not have the proper background will not know for certain whether the results are realistic—in other words, “garbage in, garbage out.” Therefore, it is imperative that rock slope stability engineers have a solid understanding of the many methodologies in common use for the analysis of the stability of rock slopes. On the basis of experience and a solid engineer- ing background, they should be able to provide and verify the data used in the analysis, verify the results of the investigation, and then make proper recommendations for reme- dial actions. The emphasis of this book is on rock slope stability, with sections on geological data col- lection, geotechnical data collection and analysis, surface water and groundwater effects, kinematic and kinetic stability analysis, rock slope stabilization techniques, and rock slope instrumentation and monitoring. Numerous examples of solutions to typical rock slope engineering problems are given. Additionally, many figures and photographs are included to aid the reader in understanding the various concepts. v Copyright © 2018 Society of Mining, Metallurgy & Exploration. All rights reserved. vi ROCK SLOPE STABILITY During development of the manuscript, the scope was intentionally broadened to include not only mining engineering and geological engineering applications but also civil engi- neering. Therefore, the text is intended to be a reference and guide for mining and con- struction engineers responsible for rock slope stability. Work began on this second edition in 2014. It was envisioned for this edition that, in addi- tion to correcting any errata discovered in the first edition, sections within the book would be expanded to include the following: ■ Within Chapter 2, a discussion of three-dimensional imaging techniques for map- ping discontinuities and a section on engineering rock mass classification schemes. ■ Significantly more on the rotational shear mode of failure. Consequently, Chapter 6 on Kinetic Slope Stability Analysis of Shear Failure was expanded to include exam- ples, and some of the more common techniques for analysis, of rotational shear. ■ An expanded section on catch bench design in Chapter 9, Rock Slope Stabilization Techniques. As the work developed, much was added to, or replaced in, the original chapters to mod- ernize the book as much as possible. The overall goal, however, remained: to provide fun- damental knowledge in the field of rock slope stability to those interested in or responsible for rock slope engineering in both construction and mining applications. Copyright © 2018 Society of Mining, Metallurgy & Exploration. All rights reserved. Acknowledgments In the acknowledgments to the first edition, I thanked and acknowledged certain individ- uals and companies, including the late Richard L. Klimpel, Tad Szwedzicki, Don Berger, Doug Hoy, Mark Keenihan, Russ Kliche, Dave Pierce, Hai-Tien Yu, Jim Bachmann, Howard Grant, Frank Olivieri, Phil Murray, and my loving wife Donna Kliche, Homestake Mining Company, Wharf Resources, Barrick Goldstrike, Newmont Mining, BHP, Modular Mining Systems, and Slope Indicator Company. I thank you again. To the preceding list I add Scott Durgin, Nichole King, Ekrem Tamkan, Bob McClure, Tamara Wiseman, Brian Wenig, Alvis Lisenbee, F.W. Breithaupt and Sohn, Peabody Energy Company, Cloud Peak Energy, Freeport-McMoRan New Mexico Operations, and RAM Inc. The first edition was published in 1999. In 1997 our daughter, Alexandra Veturia, to whom the first edition was dedicated, was born. A very substantial portion of the work on the first edition was done by me during the daytime periods and late hours while Alex slept. Alex is now a junior in engineering at my alma mater. How time flies! The work for the second edition was completed over a period of about the last five years. I started, then stopped, started again, then stopped. It was very difficult staying motivated. However, with the encouragement of family and very special friends, I managed to plod along until this point. I also thank Jane Olivier, SME manager of book publishing, and Diane Serafin, my editor, for bearing with me. A very special thank you is extended to the following people: Arden Davis, who reviewed and suggested changes to Chapter 3, Groundwater; my old friend, S.A. Gauger, who always provided that extra little bit of encouragement; and the wonderful people I worked with for so very long in the mining engineering program at the South Dakota School of Mines and Technology: Duff Erickson; S.N. Shashikanth; the late Ziggy Hladysz, who is sorely missed by all; and Cindy Hise, the mining program’s secretary extraordinaire. vii Copyright © 2018 Society of Mining, Metallurgy & Exploration. All rights reserved. Copyright © 2018 Society of Mining, Metallurgy & Exploration. All rights reserved. About the Author Charles A. Kliche is professor emeritus of Mining Engineering and Management at the South Dakota School of Mines and Technology (SDSMT). He has more than 45 years of varied mining experience in industrial minerals (bentonite mining), taconite mining, gold mining, consulting, and mining education. Kliche holds B.S. and M.S. degrees in mining engineering from the SDSMT and a Ph.D. degree in mining engineering from the University of Arizona. Kliche has worked extensively as an independent mining consul- tant in the fields of rock slope stability, explosives engineering, and the environmental effects of mining. He has written numerous papers on those subjects as well as this second edition of Rock Slope Stability and Chapter 8.3, Slope Stability, in the third edition of the SME Mining Engineering Handbook, both published by SME. Kliche is a registered professional engineer in the states of Minnesota and South Dakota. He is also a member of the National Society of Professional Engineers and the South Dakota Engineering Society. Kliche is active in SME and the International Society of Explosives Engineers (ISEE), both on the local and national level. He was a founder and first chairman of the Black Hills chapter of the ISEE and also served on its board of directors for many years. Kliche served as chairman of the Black Hills section of SME in 1986, 1999, and, for the third time, from 2006 to 2016. He has served in various capacities for the SME and ISEE national meetings. ix Copyright © 2018 Society of Mining, Metallurgy & Exploration. All rights reserved.