Preface Acknowledgements: International Society for Rock Mechanics About the authors 1 Introduction and background 1.1 The previous book "Rock Engineering Design" and this book "Rock Engineering Risk" 1.2 Rock engineering risk 1.3 Governing flowchart for the book 1.4 Structure and content of the book 1.5 Chapter summary 2 Uncertainty and risk 2.1 Introduction 2.2 Approaches to risk management 2.3 Epistemic and aleatory uncertainties 2.3.1 Explanation of the terms `epistemic' and `aleatory' 2.3.2 Procedures for dealing with epistemic/aleatory uncertainties and Eurocode 2.4 Chapter summary 3 Rock Engineering Systems (RES), auditing and Protocol Sheets 3.1 Introduction to the systems approach and auditing concepts 3.2 Reducing epistemic uncertainty using the rock engineering systems approach 3.3 A review and explanation of the Rock Engineering Systems (RES) methodology 3.3.1 The interaction matrix 3.3.2 Coding the interaction matrix, and the Cause-Effect plot 3.3.3 Mechanism pathways 3.3.4 Step-by-step evolution of the interaction matrix 3.4 Examples of Rock Engineering Systems (RES) applied to rock mechanics and rock engineering design 3.4.1 Natural and artificial surface rock slopes 220.127.116.11 Surface blasting 18.104.22.168 Natural slopes 22.214.171.124 Instability of artificial rock slopes 3.4.2 Underground rock engineering 126.96.36.199 Underground blasting 188.8.131.52 Tunnel Boring Machines (TBMs) 184.108.40.206 Tunnel stability 3.4.3 Underground radioactive waste disposal 3.4.4 Use of the RES interaction matrix in other subject areas 3.5 Further development of the RES methodology 3.6 Auditing and Protocol Sheets 3.6.1 `Soft', `semi-hard' and `hard' technical audits and the audit evaluation 3.7 Chapter summary 4 Rock fractures and in situ rock stress 4.1 Introduction 4.2 Rock fractures 4.2.1 The spectrum of brittle and ductile rock deformation 4.2.2 Multiple deformational sequences 4.2.3 The risks associated with different types of rock mass 4.3 In situ rock stress 4.3.1 The stress state in a rock mass 220.127.116.11 In situ rock stress scales 4.3.2 Stress perturbation factors 18.104.22.168 Rock inhomogeneity 22.214.171.124 Rock anisotropy 126.96.36.199 Rock fractures 188.8.131.52 The influence of a free surface 4.3.3 Evidence of in situ stress variability 184.108.40.206 Stress vs. depth compilations 220.127.116.11 The ways ahead for improving the understanding of rock stress variability 4.3.4 A case study of modelling in situ rock stress at the Olkiluoto site, western Finland 4.4 Chapter summary 5 Radioactive waste disposal: overcoming complexity and reducing risk 5.1 The disposal objective 5.1.1 An example of radioactive waste repository statistics 5.2 Features, Events and Processes 5.3 Thermo-Hydro-Mechanical (THM+) processes 5.3.1 The THM+ issues in context 5.3.2 The excavation, operational and post-closure stages 18.104.22.168 The excavation stage 22.214.171.124 Operational stage 126.96.36.199 Post-closure stage 188.8.131.52 Heterogeneity and multiple stage data needs 184.108.40.206 Modelling phases and scaling 5.3.3 The use of numerical computer codes 220.127.116.11 The nature of numerical codes 18.104.22.168 Uncoupled and coupled codes 22.214.171.124 Technical auditing of numerical codes 126.96.36.199 Capturing the essence of the problem 188.8.131.52 The overall Technical Auditing (TA) procedure and risk 184.108.40.206 Validation 220.127.116.11 The future of numerical codes 5.4 The DECOVALEX programme 5.4.1 The development of the DECOVALEX programme 5.4.2 Research work in the current DECOVALEX phase: D-2015 18.104.22.168 Task A: The Sealex in situ experiment, Tournemire site, France 22.214.171.124 Task B1: The HE-E in situ heater test, Mont Terri Underground Research Laboratory, Switzerland 126.96.36.199 Task B2: The EBS experiment at Horonobe, Japan 188.8.131.52 Task C1: THMC modelling of rock fractures 184.108.40.206 Task C2: Modelling water flow into the Bedrichov Tunnel, Czech Republic 5.5 Underground Research Laboratories (URLs) 5.5.1 The purpose of URLs 5.5.2 The Swedish AEspoe URL 5.6 Chapter summary 6 Risks associated with long deep tunnels 6.1 Introduction 6.1.1 Development of long deep tunnels 6.1.2 Flowchart to develop risk management for long, deep tunnels 6.2 Epistemic uncertainty analysis of design and construction for long deep tunnels 6.2.1 Geological settings 220.127.116.11 Geological factors relating to rockbursts in deep tunnels 18.104.22.168 Geological conditions exhibiting squeezing or large deformation behaviour 6.2.2 Rock stress 6.2.3 Hydrogeology 6.2.4 Properties of the rock mass 6.2.5 Project location 6.2.6 Excavation and support methods 6.3 Aleatory uncertainty analysis of design and construction for long deep tunnels 6.3.1 Detailed geology variations 6.3.2 Rock stress variations 6.3.3 Local water variations 6.3.4 Mechanical behaviour of the rock mass after excavation and in the long term 6.4 Methods to assess and mitigate risk for long deep tunnels 6.4.1 Rockbursts 22.214.171.124 Rockburst risk assessment 126.96.36.199 Risk mitigation concepts in rockburst prone tunnels 188.8.131.52 New approaches and optimisation of the risk-reduced construction procedures 6.4.2 Water inrush 184.108.40.206 Procedures for water inflow assessment 220.127.116.11 Assessment of water inrush potential 18.104.22.168 Assessment of tunnel water inflow 22.214.171.124 Treatment technologies for tunnel water inrush 6.4.3 Large deformations of weak rock in deep tunnels 126.96.36.199 Large deformation assessment 188.8.131.52 Treatment technologies for large deformations 6.4.4 Long term stability 184.108.40.206 Long term stability assessment in deep tunnels 220.127.116.11 Treatment technologies to ensure long term stability in deep and long tunnels 6.5 Illustrative example: Assessment and mitigation of risk for deep tunnels at the Jinping II Hydropower Station, China 6.5.1 Epistemic uncertainty analysis of headrace long deep tunnels 18.104.22.168 Geological setting 22.214.171.124 Rock stress 126.96.36.199 Hydrology 188.8.131.52 Properties of the rock mass 184.108.40.206 Specific project location 220.127.116.11 Excavation and support method 18.104.22.168 Water inrush 22.214.171.124 Rockbursts 126.96.36.199 Large deformations 188.8.131.52 Long term stability 6.5.2 Aleatory uncertainty analysis of the headrace tunnels 184.108.40.206 Geological variations at different chainage intervals 220.127.116.11 Rock stress variations affecting the threedimensional stress field 18.104.22.168 Local water variations based on prediction in advance 22.214.171.124 Mechanical behaviour of the rock mass after excavation and in the long term 6.5.3 Assessment and mitigation of local risk during the construction of the headrace tunnels 126.96.36.199 Water inrush 188.8.131.52 Rockburst: monitoring, in situ tests, warning and mitigation 184.108.40.206 Large deformation: monitoring and treatment 220.127.116.11 Long term stability 6.6 Chapter summary 7 Risks associated with hydropower cavern groups 7.1 Introduction 7.1.1 Development of large hydropower cavern groups 7.1.2 Current status of design and risk management for large rock caverns 7.1.3 Why is a new method of risk management required? 7.1.4 Outline flowchart for risk management for large hydropower cavern groups 7.1.5 Initial and final risk management for assessing and mitigating the risks for a large hydropower cavern group 7.2 Database of 60 large hydropower cavern groups in China 7.2.1 Principles for establishing a database 7.2.2 Content of the database 7.2.3 Statistical analysis of key issues 18.104.22.168 Lithological character and rock mass quality 22.214.171.124 Structure and strength of the rock mass 126.96.36.199 Stress conditions 188.8.131.52 Arrangement of cavern group by size 184.108.40.206 Excavation scheme and parameters 220.127.116.11 Support parameters 18.104.22.168 Monitoring 22.214.171.124 Rockbolt stresses 126.96.36.199 Stress in cable anchors 188.8.131.52 Relaxation depth of the surrounding rock 184.108.40.206 Fractures in the surrounding rock mass 220.127.116.11 Typical failure modes 18.104.22.168 Effect of loss of cable anchors and rockbolts 22.214.171.124 Measures used to reduce local risks 7.3 Epistemic uncertainty analysis 7.3.1 Geological setting 7.3.2 In situ rock stress 7.3.3 Hydrogeology 7.3.4 Properties of the rock mass 7.3.5 Specific project location 7.3.6 Excavation and support method 7.4 Aleatory uncertainty analysis 7.4.1 Detailed geology variations 7.4.2 Rock stress variations 7.4.3 Local water variations 7.4.4 Mechanical behaviour of the rock mass after excavation and in the long term 7.5 Risk assessment method for a large hydropower cavern group 7.5.1 Principles 7.5.2 Method for assessment and mitigation of overall risk for a large hydropower cavern group before construction 126.96.36.199 Method to determine the membership degree of the assessment index 188.8.131.52 Weight vector determining method 184.108.40.206 Determining the overall risk frequency 220.127.116.11 Determining overall risk consequence 18.104.22.168 Overall risk control analysis 7.5.3 Method for assessment and mitigation of local risk for a large hydropower cavern group before construction 22.214.171.124 Large deformation local risk assessment model before construction 126.96.36.199 Index membership degree determining method 7.5.4 Method for assessment and mitigation of local risk for a large hydropower cavern group during construction 7.6 Illustrative example: Assessment and mitigation of risk for the underground powerhouse at Jinping II Hydropower Station, China 7.6.1 Epistemic uncertainty analysis 188.8.131.52 Geological setting 184.108.40.206 Rock stress 220.127.116.11 Hydrology 18.104.22.168 Specific project location 22.214.171.124 Excavation and support method 7.6.2 Assessment and mitigation of overall risk before construction 126.96.36.199 Assessment 188.8.131.52 Risk mitigation measures 7.6.3 Assessment and mitigation of local risk before the construction 184.108.40.206 Assessment 220.127.116.11 Risk mitigation measures 7.6.4 Aleatory uncertainty analysis 18.104.22.168 Estimation of geological conditions at different layers 22.214.171.124 Estimation of three dimensional stress field 126.96.36.199 Local water variations 188.8.131.52 Mechanical behaviour of the rock mass after excavation and in the long term 7.6.5 Assessment and mitigation of local risk during construction 184.108.40.206 Construction of the main powerhouse layer I 220.127.116.11 Construction of main powerhouse layer II and transformer chamber layer I 18.104.22.168 Construction of main powerhouse layer III and transformer chamber layer II 22.214.171.124 Construction of main powerhouse layer IV and transformer chamber layer III 126.96.36.199 Construction of layer V of the main powerhouse 188.8.131.52 Construction of layers VI, VIII and IX of the main powerhouse 184.108.40.206 Construction of layer VII of the main powerhouse 220.127.116.11 Construction of different types of tunnel 18.104.22.168 Overall evaluation of the complete construction and final design 7.6.6 Important points 22.214.171.124 Optimisation of bench height of layers II and III, and the excavation procedure for layers IV-IX 126.96.36.199 More than ten local warnings and reinforcement improved the main powerhouse and transformer chamber 188.8.131.52 Support reinforcement for different types of tunnel 184.108.40.206 Overall evaluation of the complete construction process and final design 7.7 Chapter summary 8 Concluding remarks Appendix A: Cavern risk events during construction Appendix B: The Chinese `Basic Quality' (BQ) system for rock mass classification B1 Introduction B2 Terminology and symbols B2.1 Terminology B2.2 Symbols B3 Classification parameters for the rock mass basic quality B3.1 Classification parameters and the method of their determination B3.2 Qualitative classification of rock mass solidity B3.3 Qualitative classification of rock mass integrity B3.4 Determination and classification of quantitative indices B4 Classification of rock mass basic quality B4.1 Determination of the rock mass basic quality class B4.2 Qualitative characteristics of the basic quality and the basic quality index B5 Engineering classification for a rock mass B5.1 General rules B5.2 Engineering rock mass classification B6 Establishing the KV and Jv indices B6.1 The KV index B6.2 The Jv index B7 Preliminary assessment of the rock stress field B8 Physical and mechanical parameters of the rock mass and discontinuities B8.1 Rock mass parameters B8.2 Discontinuity parameters B9 Corrected value of the rock mass basic quality index B10 Stand-up time for an underground rock mass B11 Acknowledgements
John A. Hudson graduated from the Heriot-Watt University, UK, and obtained his PhD at the University of Minnesota, USA. He has spent his professional career in consulting, research, teaching and publishing in engineering rock mechanics, and was awarded the DSc. degree by the Heriot-Watt University for his contributions to the subject. He has authored many scientific papers and books, and was the editor of the 1993 five-volume "Comprehensive Rock Engineering" compendium, and from 1983-2006 editor of the International Journal of Rock Mechanics and Mining Sciences. Since 1983, he has been affiliated with Imperial College London as Reader, Professor and now Emeritus Professor. In 1998, he became a Fellow of the UK Royal Academy of Engineering and was President of the International Society for Rock Mechanics (ISRM) for the period 2007-2011. In 2015, the 7th ISRM Muller Award was conferred on Professor Hudson in recognition of "an outstanding career that combines theoretical and applied rock engineering with a profound understanding of the basic sciences of geology and mechanics". Xia-Ting Feng graduated in 1986 from the Northeast University of Technology and obtained his PhD in 1992 at the Northeastern University, China. He was then appointed and acted as Lecturer, Associate Professor and Professor at the same university. In 1998, he was admitted by the Hundred Talents Programme to the Chinese Academy of Sciences (CAS). Subsequently, he permanently joined CAS's Institute of Rock and Soil Mechanics at Wuhan, China. In 2003, he obtained the support of the China National Funds for Distinguished Young Scientists; in 2010, he became a Chair Professor of the Cheung Kong Scholars' Programme, Ministry of Education, China; and, in 2009, he was elected as President of the International Society for Rock Mechanics for the period 2011-2015. He is currently Director of the State Key Laboratory of Geomechanics and Geotechnical Engineering in Wuhan. Additionally, in 2012, Professor Feng became the Co-President of the Chinese Society for Rock Mechanics and Engineering. He has made original contributions to the subject of `intelligent rock mechanics' and his methods have been applied to large rock engineering projects in China and other countries.
This invaluable book reports the outcome of the work of the Commission on Design Methodology of the International Society for Rock Mechanics (ISRM) in the ISRM's 2011-2015 term of office during which Professor John Hudson acted as Commission President while Professor Xia-Ting Feng served as ISRM President. It provides a sequel to the authors' previous book, Rock Engineering Design (Feng and Hudson, 2011), which reported the work of the Commission in the ISRM's 2007-2011 term of office when Professor Feng acted as Commission President and Professor Hudson served as ISRM President. [...] This book is extremely well written, easy to follow and well-presented on high quality paper. [...] The publication of this book reinforces and adds to the already high reputation of the ISRM Commission on Design Methodology. It brings great credit to its authors, Professors John Hudson and Xia-Ting Feng; to the other members of the Commission on Design Methodology in the 2011-2015 period (their names are listed in the book's Acknowledgements); to the staff of the Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, China; to the ISRM itself; and to the publishers. The subject of the book is highly topical and is central to all modern rock engineering undertakings. The writer is pleased to be able to recommend this outstanding book unreservedly to all advanced students, researchers, teachers and practitioners in rock mechanics and rock engineering, particularly, but far from exclusively, those having an interest in underground excavations in rock. He believes that they will find the study this book to be as rewarding as he did. E.T. Brown, Senior Consultant, Golder Associates Pty Ltd, Milton, QLD, Australia, quoted from the Journal of Rock Mechanics and Geotechnical Engineering 2012a; 4(1): III-IV (June 2015). This book will apeal to rock engineers world-wide as it addresses generic rather than specific topics. The book covers the topic fully. John Hudson is one of the most highly regarded people in his field. I cannot think of two people in a better position to write this book. John Cosgrove, Professor of Structural Geology, Imperial College, London.