Tunnelling and Tunnel Mechanics (eBook)

Preface 6
Contents 8
Part I Design 15
1 Introduction 16
1.1 Benefits from tunnelling 16
1.2 Statistical review 16
1.4 Cross sections 20
1.4.1 Road tunnels 28
1.4.2 Rail tunnels 30
1.5 Alignment 31
1.6 Underground water conduits 33
1.7 Standards and Recommendations 35
1.8 Costs 37
1.9 Planning and contracting 38
1.9.1 Cost and time management 41
1.9.2 Experts 42
2 Installations in tunnels 44
2.1 Installations for traffic control 44
2.2 Installations for telecommunication 45
2.3 Ventilation 45
2.3.1 Ventilation during construction 45
2.3.2 Design of construction ventilation 48
2.3.4 Control of ventilation 54
2.4 Fire protection 55
2.4.1 Fire-resistant concrete 58
2.4.2 Fire detectors and extinguishers 59
2.4.3 Example: Refurbishment of the Montblanc tunnel 61
2.5 Illumination of road tunnels 62
2.6 Drainage 65
2.7 Examples for the equipment of modern road tunnels 66
2.8 Rating of safety in road tunnels 68
3 Investigation and description of the ground 70
3.1 Geotechnical investigations 70
3.1.1 Preliminary investigation 71
3.1.2 Main site investigation 72
3.1.3 Investigation during and after construction 72
3.2 Site investigation 73
3.2.1 Exploration drilling 75
3.3 Geophysical exploration 77
3.4 Joints 77
3.5 Weathering 82
3.6 Rock rating and classification 82
3.6.1 RMR-System 83
3.6.2 Q-system 84
3.7 Reports 85
4 Heading 88
4.1 Full face and partial face excavation 88
4.2 Excavation 93
4.3 Drill & blast
4.3.1 Drilling of blastholes 98
4.3.2 Charging 99
4.3.3 Tamping 99
4.3.4 Ignition 99
4.3.5 Distribution of charges and consecution of ignition 100
4.3.6 Explosives 101
4.3.7 Explosive consumption 102
4.3.8 Safety provisions 102
4.3.9 Ventilation 103
4.3.10 Backup 103
4.3.11 Shocks and Vibrations 103
4.4 Shield heading 105
4.4.1 Shield heading in groundwater 116
4.4.2 Tunnelling with box- or pipe-jacking 122
4.4.3 Microtunnels 123
4.4.5 Drive-in and drive-out operations 125
4.4.6 Problems with shield heading 125
4.5 Comparison of TBM with conventional heading 127
4.6 Rock excavation 128
4.6.1 Drilling of boreholes 129
4.6.2 Rock excavation with disc cutters 131
4.6.3 Abrasion 137
4.6.4 Drilling: history review 138
4.7 Profiling 139
4.8 Mucking 140
5 Support 143
5.1 Basic idea of support 143
5.2 Shotcrete 144
5.2.1 Steel fibre reinforced shotcrete (SFRS) 148
5.2.2 Quality assessment of shotcrete 149
5.3 Steel meshes 149
5.4 Rock reinforcement 149
5.4.1 Connection with the adjacent rock 150
5.4.2 Tensioning 154
5.4.3 Testing 155
5.4.4 Application 155
5.5 Timbering 156
5.6 Support arches 158
5.7 Forepoling 159
5.8 Face support 161
5.9 Sealing 161
5.10 Recommendations for support 162
5.11 Temporary and permanent linings 164
5.12 Permanent lining 165
5.12.1 Reinforcement of the permanent lining 166
5.12.2 Quality assessment of the lining 167
5.13 Single-shell (monocoque) lining 168
6 Grouting and freezing 170
6.1 Low pressure grouting 170
6.2 Soil fracturing, compensation grouting 172
6.3 Jet grouting 174
6.4 Grouts 174
6.5 Rock grouting 177
6.6 Advance grouting 179
6.7 Soil freezing 179
6.7.1 Frost heaves 180
6.8 Propagation of frost 181
7 The New Austrian Tunnelling Method 182
7.1 HSE Review 184
8 Management of groundwater 187
8.1 Flow within rock 187
8.1.1 Porosity of rock 187
8.1.2 Pore pressure 188
8.1.3 Permeability of rock 189
8.2 Inflow in the construction phase 191
8.3 To drain or to seal? 193
8.4 Drainage 193
8.5 Water ingress into a drained circular tunnel 197
8.5.1 Seepage force 199
8.6 Influence of drainage 200
8.7 Sealing (waterproofing) 201
8.8 Geosynthetics in tunnelling 205
9 Application of compressed air 206
9.1 Health problems 208
9.2 Influence on shotcrete 210
9.3 Blow-outs 210
10 Subaqueous tunnels 211
10.1 Towing and lowering method 212
10.2 Caissons 214
11 Shafts 218
11.1 Driving of shafts 218
11.2 Earth pressure on shafts 221
12 Safety during construction 223
12.1 Health hazards 223
12.2 Electrical installations in tunnelling 227
12.2.1 Hazards due to failure of vital installations 227
12.2.2 Special provisions 227
12.2.3 Energy supply of excavation machines 228
12.2.4 Illumination during construction 229
12.3 Controls 229
12.4 Risk management 230
12.5 Emergency plan and rescue concept 231
12.6 Quanti.cation of safety 232
12.7 Collapses 233
12.7.1 Heathrow collapse 235
Part II Tunnelling Mechanics 238
13 Behaviour of soil and rock 239
13.1 Soil and rock 239
13.2 General notes on material behaviour 239
13.3 Elasticity 241
13.4 Plasticity 243
13.5 Strength 244
13.5.1 Strength of soil 244
13.5.2 Strength of rock 247
13.5.3 Brittle and ductile behaviour 250
13.6 Post-peak deformation 252
13.6.1 Point load test 253
13.6.2 Griffith’s theory 254
13.6.3 Acoustic emission 255
13.6.4 Friction of joints 255
13.7 Anisotropy 256
13.8 Rate dependence and viscosity of soil and rock 257
13.9 Size effect 260
13.9.1 Size effect in rock 260
13.9.2 Size effect in soil 262
13.9.3 Rodionov’s theory 263
13.10 Discrete models 264
13.11 Rock mass strength 265
13.12 Swelling 269
13.13 Field tests 272
14 Stress and deformation fields around a deep circular tunnel 276
14.1 Rationale of analytical solutions 276
14.2 Some fundamentals 276
14.3 Geostatic primary stress 281
14.4 Hydrostatic primary stress 284
14.5 Plastification 286
14.5.1 Consideration of cohesion 289
14.6 Ground reaction line 290
14.7 Pressuremeter, theoretical background 293
14.8 Support reaction line 294
14.9 Rigid block deformation mechanism for tunnels and shafts 295
14.10 Squeezing 298
14.10.1 Squeezing as a time-dependent phenomenon 298
14.10.2 Neglecting time-dependence 300
14.10.3 Interaction with support 302
14.11 Softening of the ground 306
15 Supporting action of anchors/bolts 310
15.1 Impact of pattern bolting 311
15.1.1 Ground stiffening by pre-stressed anchors 312
15.1.2 Pre-stressed anchors in cohesive soils 314
15.1.3 Stiffening effect of pattern bolting 316
16 Some approximate solutions for shallow tunnels 318
16.1 Janssen’s silo equation 318
16.2 Trapdoor 321
16.3 Support pressures at crown and invert 324
16.4 Forces acting upon and within the lining 330
16.5 Estimations based on the bound theorems 332
16.5.1 Lower bound of the support pressure 332
16.5.2 Upper bound of the support pressure 333
17 Stability of the excavation face 334
17.1 Approximate solution for ground with own weight 334
17.2 Numerical results 335
17.3 Stability of the excavation face according to the bound theorems 335
17.4 Stand-up time of the excavation face 338
18 Earthquake effects on tunnels 340
18.1 General remarks 340
18.2 Imposed deformation 341
19 Settlement of the surface 343
19.1 Estimation of settlement 343
19.2 Reversal of settlements with grouting 348
19.3 Risk of building damage due to tunnelling 348
20 Stability problems in tunnelling 352
20.1 Rockburst 352
20.2 Buckling of buried pipes 352
20.2.1 Buckling of pipes loaded by fluid 353
20.2.2 Buckling of elastically embedded pipes 355
21 Monitoring 356
21.1 Levelling 357
21.2 Monitoring of displacements and convergence 357
21.3 Extensometers and inclinometers 358
21.4 Monitoring stresses within the lining 360
21.5 Measurement of primary stress 363
21.5.1 Hydraulic fracturing 363
21.5.2 Unloading and compensation methods 365
21.6 Cross sections for monitoring 366
22 Numerical analysis of tunnels 368
22.1 General remarks 368
22.1.1 Initial and boundary conditions 369
22.1.2 Coping with non-linearity 371
22.1.3 Constitutive equation 373
22.2 Method of subgrade reaction 374
22.3 Diffculties related to the design of shotcrete lining 376
Part III Appendices 379
A Physics of detonation 380
A.1 Detonation 380
A.2 Underground explosions 382
A.3 Interaction of charges 383
B Support of soil with a pressurised fluid 386
C A simple analytical approximation for frost propagation 387
D Rigorous solution for the steady water inflow to a circular tunnel 392
E Aerodynamic pressure rise in tunnels 395
F Multiphase model of reinforced ground 397
G Deformation of a tunnel due to seismic waves 400
H A rational approach to swelling 402
9 Glossary 405
9.1 English - German 406
9.2 German - English 415
Index 425