Civil Excavations and Tunnelling

Contents

Preface ix

Acknowledgements xiii

1 Introduction and site investigations 1

1.0 Introduction 1

1.1 Brief history – growth and development of civil excavations 1

1.2 Site investigations – ground and rock characterization 5

1.3 Core drilling 7

1.4 Tomography 8

1.5 Lugeon test 8

1.6 Laboratory testing 9

1.7 Rock composition and ground types 11

1.8 Rock mass classification 12

1.9 Projection of geological model 14

References 18

2 Ground and rock fragmentation – drilling and blasting 21

2.0 Introduction 21

2.1 Drilling 21

2.2 Chipping hammers/pneumatic breakers 32

2.3 Explosives 34

2.4 Blasting 42

2.5 Blasting accessories 51

2.6 Properties of explosives 56

2.7 Blasting cost 59

2.8 Safety 59

2.9 Terminology 60

References 63

Civil exemptions and tunnelling

3 Earth movers, excavators and open-cut excavations 65

3.0 Introduction 65

3.1 Classification – earth excavation, loading and casting units 66

3.2 Equipment details 66

3.3 Haulage system 86

3.4 Some developments 88

3.5 Equipment selection 89

3.6 Benching 94

3.7 Channelling/canal construction 100

3.8 Uprooting or blasting stumps 101

3.9 Excavation for foundations 101

3.10 Smooth blasting 102

3.11 Road construction and laying sewage lines 102

3.12 Landfill 103

References 103

4 Tunnelling by conventional methods 105

4.0 Introduction – function of drives and tunnels 105

4.1 Pre-cursor or prior to driving civil tunnels 105

4.2 Tunnelling techniques 107

4.3 Drilling – drivage techniques with the aid of explosives 109

4.4 Blasting – charging and firing rounds 120

4.5 Muck handling and disposal at the subsurface locale 123

4.6 Ventilation 131

4.7 Driving large-sized drives/tunnels in tough rocks 133

4.8 Tunnelling through soft ground and rocks – conventional methods 136

4.9 Supports for tunnels 137

4.10 Past, present and future of tunnelling technology 140

4.11 Over-break and scaling – some innovations 142

References 143

5 Mechanized tunnelling 145

5.0 Introduction 145

5.1 Classification 147

5.2 Partial-face heading machines 148

5.3 Full-face boring machines 156

5.4 Backup system 167

5.5 Boring system 168

5.6 Rock cutting tools and their types 172

5.7 Cutting head configuration 173

Contents

5.8 Some developments 173

References 174

6 Shield tunnelling in soft ground 177

6.0 Introduction 177

6.1 Function of the shield 178

6.2 Shield tunnelling – classification 178

6.3 Open shield 179

6.4 Partial-face extraction units 181

6.5 Compressed air shields 182

6.6 Slurry shield 184

6.7 Slurry and mix-shield 187

6.8 Earth-pressure-balance (EPB) shield 189

6.9 Combined shield 191

6.10 Excavation tools 192

6.11 Excavation procedure 192

6.12 Excavation and transportation techniques 193

6.13 Supports/linings 194

6.14 Health, safety and environment (HSE) 194

6.15 Selection of the shield 195

6.16 Ground settlement/displacement 197

6.17 Terminology 199

References 200

7 Special methods 201

7.0 New Austrian tunnelling method (NATM) 201

7.1 NATM case studies 207

7.2 Lee’s Tunnelling Method (LTM) 209

7.3 Semi-mechanized methods 212

7.4 Barrel vault method 214

7.5 Ground improvement 215

7.6 Use of shotcrete during tunnelling 216

7.7 Cut and cover tunnelling 217

7.8 Submerged (immersed) tubes/tunnels 217

References 218

8 Microtunnelling 221

8.0 Introduction 221

8.1 Pipe jacking 222

8.2 Pilot method 223

8.3 Thrust boring 223

8.4 Slurry microtunnelling machines 225

Civil excavations and tunnelling

8.5 Iseki (Unclemole) 226

8.6 Herrenknecht microtunnelling system 226

8.7 Developments and challenges in microtunnelling 228

8.8 Some experience of microtunnelling in North America 232

8.9 The future 233

8.10 Terminology 233

References 234

9 Raising, sinking and large subsurface excavations 237

9.0 Introduction 237

9.1 Raising 238

9.2 Shaft sinking 247

9.3 Subsurface excavations 254

9.4 Equipment and services selection 265

References 271

10 Hazards, safety and the environment 273

10.0 Introduction 273

10.1 Hazards 274

10.2 Potential hazards 274

10.3 Mechanization and automation 281

10.4 Fires, rescue and escape 285

10.5 Occupational hazards (health and physique) 286

10.6 Legislation, guidance and norms 287

10.7 Safety and accidents 288

10.8 Conceptual planning, detailed design and evaluation 293

10.9 Risk analysis 294

10.10 Environment 295

10.11 Environment management 301

10.12 Sustainable development 301

10.13 Emergency measures/preparedness 305

References 305

11 Conversion tables 307

Index 311