Tunnel lining design guide

The British Tunnelling Society and

The Institution of Civil Engineers

Published by Thomas Telford Publishing, Thomas Telford Ltd,

1 Heron Quay, London E14 4JD.

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First published 2004

Also available from Thomas Telford Books

Specification for Tunnelling. The British Tunnelling Society and The Institution of Civil

Engineers. ISBN 07277 2865 2

Building Response to Tunnelling. The Construction Industry Research and Information

Association and Imperial College, London. ISBN 07277 3117 7

A catalogue record for this book is available from the British Library

ISBN: 0 7277 2986 1

# The British Tunnelling Society, the Institution of Civil Engineers and Crown 2004

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Dedication

David Wallis1941–2000

Chairman of the British Tunnelling Society1999–2000

This publication is dedicated to the memory of David Wallis in thatthe Guide was one of several projects driven forward by him duringhis chairmanship of the British Tunnelling Society (BTS), cut shortby his untimely death in November 2000. The background to theconcept of the Guide is given in the Foreword, which was firstdrafted by David.

It was originally hoped that the Guide would be published at theend of his normal chairmanship period in October 2001. However,the work pressures placed on many members of the working groupduring a period of, fortunately, increasing tunnel design activity,but limited availability of experienced tunnel engineers, hasunavoidably delayed its appearance. A contributory factor wasthe determination of the working group to carry forward DavidWallis’ insistence on ‘getting it right’, as engineers are expected todo, and to provide practical recommendations and guidancerather than less focussed theory.

Contents

Foreword xAcknowledgements xii

1 Introduction 11.1 Scope 11.2 Background 1

1.3 Guide structure and objectives 1

1.3.1 Chapter 2 – Project definition 21.3.2 Chapter 3 – Geotechnical characterisation 21.3.3 Chapter 4 – Design life and durability 21.3.4 Chapter 5 – Design considerations 21.3.5 Chapter 6 – Theoretical methods of analysis 31.3.6 Chapter 7 – Settlement 31.3.7 Chapter 8 – Instrumentation and monitoring 31.3.8 Chapter 9 – Quality management 31.3.9 Chapter 10 – Case histories 3

1.4 Definitions 31.4.1 Support systems 4

1.5 Design process 51.6 References 7

2 Project definition 82.1 Introduction 8

2.1.1 Purposes 82.1.2 Construction 82.1.3 Functional requirements 82.1.4 Other factors 8

2.2 Operational requirements 82.2.1 Tunnel function 82.2.2 Function of the tunnel lining 92.2.3 Availability 112.2.4 Hazards 11

2.3 Serviceability and requirements 112.3.1 Durability and tunnel environment 112.3.2 Materials 112.3.3 Fire 122.3.4 Design life 122.3.5 Capital cost vs maintenance 13

2.4 Environmental considerations 132.4.1 Internal environment 132.4.2 External environment 13

2.5 Commercial framework 132.5.1 General 132.5.2 Funding and form of contract 142.5.3 Method of measurement and risk

apportionment 142.6 Management of risk 14

2.6.1 Risk Analysis and Management 152.6.2 1992 European Directive 16

2.6.3 UK Regulations of 1994 162.6.4 Joint Code of Practice for Risk

Management of Tunnel Works in theUnited Kingdom 17

2.6.5 Practicalities of what designers must do interms of strategy 18

2.7 References 19

3 Geotechnical characterisation 203.1 General 203.2 Ground investigation 20

3.2.1 Ground investigation process 203.2.2 Desk study and site reconnaissance 223.2.3 Field investigation and testing methods 223.2.4 Laboratory testing methods 243.2.5 Factors to consider in selecting

investigation methods and scope 253.3 Soil and rock description and classification 26

3.3.1 Soil 263.3.2 Rock 26

3.4 Groundwater identification in soils and rocks 273.5 Ground appreciation – link between investigation

and design 283.5.1 Interpretation process 283.5.2 Soft ground, hard ground and transition 293.5.3 Groundwater behaviour 293.5.4 Foreseeing the unforeseeable 30

3.6 Geotechnical parameters required for tunnel

lining design 313.6.1 Geotechnical design parameters and their

application 313.6.2 Range and certainty 31

3.7 Ground improvement and groundwater control 363.7.1 Changes in water table 363.7.2 Effects on ground parameters 363.7.3 Methods of ground improvement 363.7.4 Methods of groundwater control 37

3.8 Reference ground conditions 373.9 References 38

4 Design life and durability 404.1 Definition 404.2 Design life 404.3 Considerations of durability related to tunnel use 404.4 Considerations of durability related to lining type 40

4.4.1 Steel/cast-iron linings 404.4.2 Concrete linings 41

4.5 Design and specification for durability 424.5.1 Metal linings 424.5.2 Concrete linings 434.5.3 Protective systems 474.5.4 Detailing of precast concrete segments 484.5.5 Codes and standards 48

4.6. Fire resistance 494.6.1 Effects of tunnel type and shape 504.6.2 Types of fire 504.6.3 Lining material behaviour in fire 50

4.6.4 Codes and other standards 524.6.5 Design for fire 534.6.6 Fire protection 534.6.7 Fire repair 53

4.7 Waterproofing 544.7.1 Membranes 544.7.2 Gaskets 564.7.3 Injectable gaskets and seals 574.7.4 Grouting for leakage prevention 57

4.8 References 58

5 Design considerations 595.1 Introduction 59

5.1.1 Objectives 595.1.2 Tunnel design practice 595.1.3 Fundamental design concepts 60

5.2 Engineering design process 615.2.1 Design management 61

5.3 Design considerations 635.3.1 Ground/support interaction 635.3.2 Time-related behaviour 655.3.3 Groundwater 685.3.4 Ground improvement and pre-support 685.3.5 Effects of ground improvement or water

management on linings 695.3.6 Method of excavation and face support 715.3.7 Choice of lining systems 73

5.4 Segmental linings 755.4.1 Transport, handling and erection 755.4.2 Annulus grouting of segmental tunnels 78

5.5 Sprayed concrete linings 795.5.1 Potential weaknesses 805.5.2 Design issues 815.5.3 Detailing 825.5.4 Performance requirements 82

5.6 Cast in situ linings 835.6.1 Design requirements 835.6.2 Grouting 83

5.7 Special constructions 835.7.1 Shafts 835.7.2 Junctions and portals 865.7.3 Portals, launch chambers and reception

chambers 875.7.4 Tunnels in close proximity 885.7.5 Jacking pipes 885.7.6 Pressure tunnels 88

5.8 Design guidelines on performance requirements 895.8.1 Key Performance Indicators 905.8.2 Ground response 905.8.3 Lining flexibility 905.8.4 Lining distortion 925.8.5 Critical strains in the ground 92

5.9 References 95

6 Theoretical methods of analysis 986.1 Introduction 98

6.1.1 Purposes 98

6.2 Errors and approximations 986.2.1 Geometry 996.2.2 Construction method 996.2.3 Constitutive modelling 996.2.4 Theoretical basis 1006.2.5 Interpretation 1006.2.6 Human error 100

6.3 Design methods 1006.3.1 Empirical methods 1026.3.2 ‘Closed-form’ analytical methods 1046.3.3 Numerical modelling 1066.3.4 Modelling geometry 1086.3.5 Discretisation 1086.3.6 Modelling construction processes 1096.3.7 Constitutive modelling 1106.3.8 Validation 1116.3.9 Advances in numerical analyses 1116.3.10 Physical modelling 112

6.4 Recommendations on design methods 1136.5 References 113

7 Settlement 1157.1 Prediction of ground movements 115

7.1.1 Characterisation 1157.1.2 Models and methods 115

7.2 Effects of ground movements 1177.2.1 Buildings 1177.2.2 Pipelines 1187.2.3 Piled structures 118

7.3 Compensation grouting 1187.3.1 Effects on linings 1187.3.2 Controlling factors 119

7.4 References 120

8 Instrumentation and monitoring 1228.1 Introduction 1228.2 Value of instrumentation and monitoring 1228.3 Existing guidance 1238.4 Instrumentation and monitoring and lining design 123

8.4.1 General 1238.4.2 Observational Method 1288.4.3 Design checklist 129

8.5 Management of third-party issues 1318.6 Data acquisition and management 132

8.6.1 General 1328.6.2 Trigger values 133

8.7 Case histories 1348.8 References 135

9 Quality management 1379.1 Introduction 1379.2 Design stage 137

9.2.1 Quality Plan 1379.2.2 Design development statements 1399.2.3 Design outputs 139

9.3 Manufactured linings 1399.3.1 Quality Plan 139

9.3.2 Quality control 1409.3.3 Manufacture outputs 140

9.4 Cast in situ and sprayed concrete linings 1409.4.1 Site quality plan 1409.4.2 Site quality control 141

9.5 Monitoring 1419.5.1 Lining deformation 1419.5.2 Surface settlement 142

10 Case histories 14410.1 Heathrow Express – design and performance of

platform tunnels at Terminal 4 14410.1.1 Project background 14410.1.2 Geotechnical 14410.1.3 Design 14410.1.4 Lining details 14710.1.5 Instrumentation and monitoring 147

10.2 Design of Channel Tunnel lining 14910.2.1 Project history 14910.2.2 Design background 14910.2.3 Geotechnical 15010.2.4 Summary of parameters 15010.2.5 Lining design 15310.2.6 Precast segmental lining design 15510.2.7 SGI lining design 156

10.3 Great Belt railway tunnels 15910.3.1 Plan, geotechnical longitudinal section and

cross-section 15910.3.2 Geology 15910.3.3 Summary of geotechnical and geophysical

properties 16010.3.4 Design of tunnel linings 161

10.4 Instrumentation of the CTRL North Downs Tunnel 16410.5 References 165

Appendix 1 Abbreviations and symbols 166

Appendix 2 Risk management 168A2.1 Introduction 168A2.2 Scope 168A2.3 Risk register 169

A2.3.1 When to use the risk register 169A2.3.2 What is it? 169A2.3.3 Assessment process 169A2.3.4 Key steps 169A2.3.5 Risk assessment, qualitative or

quantitative? 171A2.3.6 Managing risk 175

A2.4 References 175

Bibliography 177

Index 179

Foreword

The need for a single reference of recommendations and guidancefor tunnel lining design has been recognised for a number ofyears, as evidence by discussions in the pages of tunnelling industryjournals, at conferences and at the meetings of bodies such as theBritish Tunnelling Society. Hitherto, designers have adopted avariety of approaches based on practical experience of tunnelsbuilt in similar circumstances and on research carried out both onmathematical and scale physical models, either undertaken bythemselves or which have been presented in published papers. Com-bined with such existing knowledge, existing codes and standards,which have not been specifically written for, or appropriate to,tunnelling have been modified.The need for, perhaps more uniform, tunnel design guidance

was precipitated by some well-publicised tunnel collapses duringconstruction, and by the ever increasing demands on tunnellingengineers to increase the parameters within which secure under-ground excavations could be made, whilst maintaining a competi-tive stance against other possible solutions to problems intransport, utilities, storage and society’s similar needs.Tunnels are almost unique structures in that they are surrounded

by ground of many different types and this has a direct relationshipto the type and degree of tunnel supporting lining required. Theground may even be enlisted to aid support of the excavation. Inthis context, the development of tunnel lining design has includedspecial consideration of such issues as the interaction between thelining and ground, the relatively high compressive loading inrelation to bending, the application of loading to structuralelements before materials reach maturity, and many others whereexisting orthodox construction design recommendations areinappropriate.The British Tunnelling Society (BTS) considered that the valu-

able knowledge and experience of its members on tunnel liningdesign should be made available to the wider international under-ground construction community, and that a published guide wasan appropriate medium. A letter to the Editor of Tunnels & Tunnel-ling International in October 1998 finally prompted action by thethen Chairman of the Society. Funding for production of theGuide was sought and provided equally by the BTS and the Institu-tion of Civil Engineers Research and Development Fund.The Guide is drafted for particular use in conjunction with

relevant United Kingdom Standards, Codes of Practice, customsand practice (see Bibliography and section references). Such exist-ing Standards and Codes are usually not specific to tunnelling,and have no formal standing in tunnel lining design, so thisdocument carries new information and guidance. Best practicefrom elsewhere in the world is recognised and adopted whereappropriate, but no attempt has been made to comply with anyassociated norms.The authors trust that they have met most of the current needs of

tunnel designers with the following, but will welcome comments

and suggested improvements. These should be sent to the BTSSecretary at the Institution of Civil Engineers, One Great GeorgeStreet, London SW1P 3AA, England; telephone (+44) (0)207 6652233; fax (+44) (0)207 799 1325; E-mail: bts@ice.org.uk.

Acknowledgements

The production of the Tunnel Lining Design Guide (Guide) wasmade possible by equal funding from the financial resourcesof the British Tunnelling Society (BTS), and the Research andDevelopment Fund of the Institution of Civil Engineers.The BTS is grateful to all those, authors and reviewers, who have

given of their time freely despite, in most cases, great pressures ontheir time from other work. All work on the Guide, apart fromspecialist editing and publishing services, was unpaid.

Members of the working group

Chris Smith (Chairman)Maurice Jones (Editor and secretariat)

John AndersonMalcolm ChappellJohn CurtisPeter JewellSteve MacklinBarry NewDavid PowellSteve SmithAlun Thomas

Other major contributions byLesley ParkerPaul Trafford

Produced with additional funding from the Institution of CivilEngineers Research and Development Fund