Table Of ContentSoft Ground
Tunnel Design
Soft Ground
Tunnel Design
Benoît Jones
First edition published 2022
by CRC Press
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Library of Congress Cataloging‑in‑Publication Data
Names: Jones, Benoît, author.
Title: Soft ground tunnel design / Benoît Jones.
Description: First edition. | Boca Raton, FL : CRC Press, [2022] | Includes index.
Identifiers: LCCN 2021013258 (print) | LCCN 2021013259 (ebook) | ISBN
9780367419592 (hbk) | ISBN 9781482254679 (pbk) | ISBN 9780429470387 (ebk)
Subjects: LCSH: Tunnels--Design and construction. | Tunneling. | Soil stabilization.
Classification: LCC TA815 .J66 2022 (print) | LCC TA815 (ebook) | DDC
624.1/93--dc23
LC record available at https://lccn.loc.gov/2021013258
LC ebook record available at https://lccn.loc.gov/2021013259
ISBN: 978-0-367-41959-2 (hbk)
ISBN: 978-1-4822-5467-9( pbk)
ISBN: 978-0-429-47038-7 (ebk)
DOI: 10.1201/9780429470387
Typeset in Sabon
by KnowledgeWorks Global Ltd.
Contents
Preface xv
Books on tunnel construction methods xvii
Acknowledgements xix
Author xxi
1 Real tunnel behaviour 1
1.1 In situ stress states 2
1.2 Overview of tunnel behaviour 3
1.2.1 Undrained soil behaviour 7
1.2.2 Drained soil behaviour 8
1.3 Movements of the ground surface 8
1.3.1 Transverse vertical settlements 9
1.3.2 Transient settlements 10
1.3.3 Horizontal surface movements 13
1.3.4 Long-term settlements 15
1.4 Subsurface ground movements 19
1.5 Stability 19
1.5.1 The consequences of instability 20
1.5.2 The causes of instability 22
1.6 Tunnel lining movements 24
1.6.1 Case studies of tunnel lining
movements 25
1.7 Tunnel lining stresses 28
1.7.1 How do tunnel lining stresses develop
over time? 28
1.7.2 Design based on precedent practice 33
1.7.3 Heathrow Express Terminal 4 Station
concourse tunnel case study 34
1.8 Summary 41
References 41
v
vi Contents
2 Undrained stability 45
2.1 Overview of stability theory 46
2.2 Undrained stability 47
2.2.1 Heading stability in homogeneous clay 49
2.2.2 Heading stability in clay with undrained
shear strength increasing with depth 59
2.2.3 Heading stability in clay with
overlying coarse-grained soils 61
2.2.4 Numerical modelling of heading stability
in clay 63
2.2.5 Summary of undrained stability 65
2.3 Blow-out failure in clay 66
2.3.1 Softening and erosion 66
2.3.2 Hydraulic fracturing in clay 67
2.3.3 Passive failure in clay 69
2.3.4 Uplift failure of a tunnel heading invert
in clay 76
2.3.5 Summary of undrained blow-out failure 76
2.4 Problems 77
References 80
3 Drained stability 83
3.1 Drained stability without seepage 83
3.1.1 Dry cohesionless soils 84
3.1.2 Dry drained soils with cohesion 85
3.1.3 Comparison of analytical methods with
centrifuge tests and finite element models 90
3.1.4 Summary of drained stability theory 92
3.2 Application of drained stability to closed-face TBMs 93
3.2.1 Application to slurry TBMs 93
3.2.2 Slurry infiltration during TBM standstills 96
3.2.3 Slurry infiltration during excavation 98
3.2.4 Application to earth pressure balance
TBMs 100
3.3 Blow-out failure in drained soils 103
3.3.1 Passive failure in drained soils 103
3.3.2 Blow-outs caused by hydraulic fracturing 111
3.3.3 Summary of blow-outs in drained soils 113
3.4 Piping 114
3.1 Problems 115
References 120
Contents vii
4 Stability of shafts 123
4.1 Hydraulic failure in a shaft during excavation 123
4.2 Base heave failure of a shaft in clay 131
4.3 Uplift failure in a shaft during excavation 134
4.3.1 Verification of the uplift ultimate
limit state using Eurocode 7 134
4.3.2 Geometry of uplift failure during
excavation 138
4.4 Uplift failure of a shaft after base
slab construction 139
4.5 Long-term heave under a shaft base slab 145
4.6 Summary of shaft stability 146
4.7 Problems 146
References 148
5 Stability and Eurocode 7 151
5.1 Size of the zone of ground governing
the occurrence of the limit state 152
5.2 Correcting for confidence in the site
investigation 153
5.3 Modelling spatial variability of soil
parameters explicitly 155
5.4 Applying partial factors 157
References 158
6 Global design using analytical solutions 159
6.1 Simple wished-in-place equilibrium 160
6.2 Empirical methods 166
6.3 Soil-structure interaction using the
Curtis-Muir Wood solution 166
6.3.1 Notation used in the Curtis-Muir
Wood solution 167
6.3.2 Boundary conditions and ground
stresses 167
6.3.3 Elliptical deformation of a circular
opening 171
6.3.4 Elliptical deformation of a thin
inextensible lining 175
6.3.5 ‘Full slip’ - no shear between
lining and ground 177
viii Contents
6.3.6 ‘No slip’ - full shear interaction
between lining and ground 178
6.3.7 Direct compression of the lining
due to uniform load 178
6.4 Global design of shafts 183
6.5 Bedded beam models 184
6.6 Summary 186
6.7 Problems 187
References 189
7 Global design using numerical modelling 191
7.1 Boundary conditions at the tunnel perimeter 193
7.1.1 Wished-in-place tunnel lining 194
7.1.2 The convergence-confinement method 195
7.1.2.1 The β-factor method 198
7.1.2.2 The target volume loss
method 199
7.1.3 Gap method 202
7.1.4 The grout pressure method 202
7.1.5 Surface contraction 204
7.1.6 Core softening 204
7.1.7 Summary 204
7.2 Boundary conditions at the edges of the model 205
7.3 Boundary distances 208
7.4 Element types for the lining and the ground 209
7.5 Mesh density and refinement 210
7.6 Modelling groundwater 211
7.6.1 Undrained behaviour 212
7.6.2 Long-term effects 215
7.7 Validation and error checking 216
7.7.1 Comparison with an analytical
solution 217
7.7.2 Validation by comparison with a
laboratory test or experiment 219
7.7.3 Validation by comparison with
a case history 222
7.8 Constitutive models 223
7.9 Interpretation and presentation of results 224
7.10 3D numerical analysis 224
7.10.1 Modelling an advancing tunnel in 3D 224
7.10.2 Modelling the tunnel lining 228
Contents ix
7.10.3 Modelling junctions 231
7.10.3.1 Kirsch solution 231
7.10.3.2 Wished-in-place 3D numerical
model 235
7.10.3.3 3D numerical model with
sequential construction 236
7.11 Summary 240
7.12 Problems 241
References 244
8 Lining materials 247
8.1 Reinforced concrete 248
8.2 Steel fibre-reinforced concrete 248
8.2.1 Codes of practice and sources of design
guidance 249
8.2.2 Material behaviour 250
8.2.3 Design assisted by testing 252
8.2.4 Determination of characteristic strength
values 254
8.2.5 Determination of the characteristic
mean strength values 257
8.2.6 Durability 258
8.2.7 Watertightness 259
8.2.8 Fire resistance 261
8.3 Concrete reinforced with other fibres 262
8.4 Plain concrete 262
8.5 Cast iron 263
8.6 Summary 265
References 265
9 Segmental lining design 269
9.1 Taking account of the effect of joints
in 2D plane strain analyses 270
9.2 Rotational rigidity - flat joints 272
9.2.1 Linear elastic packers 274
9.2.2 Nonlinear packers 281
9.2.3 Comparison of different packer types 283
9.3 Estimating local forces due to joint rotation 286
9.3.1 Calculating joint rotation from
a specified ovalisation 286
