Introduction to Tunnel Construction

Transcription

1 Introduction to Tunnel Construction David Chapman, Nicole Metje and Alfred Stark *< \ Spon Press an imprint of Taylor & Francis LONDON AND NEWYORK * V TECHNISCHE INFORMATION S8IBLIOTHEK UNIVERSITATSBIBUOTHEK HANNOVER J

2 Preface Acknowledgements and permissions Abbreviations Symbols xv xvii xxi xxiii Introduction Philosophy of tunnelling Scope of this book Historical context The nature of the ground Tunnel cross section terminology Content and layout of this book 7 Site investigation Introduction Site investigation during a project Introduction Desk study Site reconnaissance Ground investigation (overview) Ground investigation Introduction Field investigations Non-intrusive methods Intrusive exploration Laboratory tests Ground characteristics/parameters Influence of layering on Young's modulus Squeezing and swelling ground Typical ground parameters for tunnel design 46

3 2.4.4 Ground (rock mass) classification Rock Quality Designation Rock Mass Rating Rock Mass Quality Rating (Q-metbod) A few comments on the rock mass classification systems Site investigation reports Types of site investigation report Key information for tunnel design 61 Preliminary analyses for the tunnel 3.1 Introduction Preliminary stress pattern in the ground Stability of soft ground Stability of fine grained soils Stability of coarse grained soils The coefficient of lateral earth pressure (K0) Preliminary analytical methods J Introduction Bedded-beam spring method Continuum method Tunnel support resistance method Preliminary numerical modelling J Introduction Modelling the tunnel construction in 2-D Modelling the tunnel construction in 3-D Choice of ground and lining constitutive models 82 Ground improvement techniques and lining systems 4.1 Introduction Ground improvement and stabilization techniques Ground freezing Lowering of the groundwater table Grouting Ground reinforcement Forepoling Face dowels 100 umbrella Roof pipe Compensation grouting Pressurized tunnelling (compressed air) 105

4 ix 4.3 Tunnel lining systems Lining design requirements Sprayed concrete (shotcrete) Ribbed systems Segmental linings In situ concrete linings Fire resistance of concrete linings Tunnel construction techniques Introduction Open face construction without a shield Timber heading Open face tunnelling with alternative linings Partial face boring machine (roadheader) Tunnelling shields Tunnel boring machines J Introduction Tunnel boring machines in hard rock Gripper tunnel boring machine Shield tunnel boring machines General observations for hard rock tunnel boring machines Tunnel boring machines in soft ground Introduction Slurry tunnelling machines Earth pressure balance machines Multi-mode tunnel boring machines Choice of slurry or earth pressure balance tunnel boring machine Drill and blast tunnelling Introduction Drilling Charging Stemming Detonating Detonating effect Types of explosive Detonators Cut types Explosive material requirements Ventilation Mucking and support 182

5 x Contents 5.7 New Austrian Tunnelling Method and sprayed concrete lining New Austrian Tunnelling Method Sprayed concrete lining LaserSbell technique Cut-and-cover tunnels S.J Introduction Construction methods Design issues Excavation support methods (shoring systems) for the sides of the excavation Immersed tube tunnels Introduction Stages of construction for immersed tube tunnels Types of immersed tube tunnel Steel shell Concrete Immersed tube tunnel foundations and settlements Joints between tube elements Analysis and design Examples of immersed tube tunnels Jacked box tunnelling J O.J Introduction Outline of the method and description of key components Examples ofjacked box tunnels Vehicular under-bridge, Ml motorway, ]15A, Northamptonshire, UK Highway Extension, Boston, Massachusetts, USA Pipe jacking and microtunnelling Introduction The pipe jacking construction process Maximum drive length for pipe jacking and microtunnelling Horizontal directional drilling Health and safety, and risk management in tunnelling The health and safety hazards of tunnel construction J.J Introduction Hazards in tunnelling Techniques for risk management 245

6 xi Legislation, accidents and ill health statistics Role of the client, designer and contractors Ground risk Excavation and lining methods Tunnel boring machines Tunnel transport Tunnel atmosphere and ventilation Explosives Fire, flood rescue and escape Occupational health Welfare and first aid Work in compressed air Education, training and competence Concluding remarks Risk management in tunnelling projects Introduction Risk identification Analyzing risks Evaluating risks Risk monitoring and reviewing Ground movements and monitoring Ground deformation in soft ground Surface settlement profiles Estimating the trough width parameter, i Volume loss Horizontal displacements Long-term settlements Multiple tunnels Effects of tunnelling on surface and subsurface structures Effect of tunnelling on existing tunnels, buried utilities and piled foundations Design methodology Monitoring Challenges and purpose Trigger values Observational method In-tunnel monitoring during New Austrian Tunnelling Method tunnelling operations Measurements General development of displacements 287

7 its xii Contents Interpretation of the measurements: displacements Interpretation of the measurements: comparative observation Interpretation of the measurements: deformation Interpretation of the measurements: stress-intensity-index Measuring frequency and duration Contingency measures Instrumentation for in-tunnel and ground monitoring Instrumentation for monitoring existing structures Case studies Eggetunnel, Germany Project overview Invert failure of the total cross section in the Eggetunnel Sprayed concrete invert monitoring 314 purpose and 8.2 London Heathrow T5, UK: construction of the Piccadilly Line Extension Junction Project overview The 'Box' Construction of the sprayed concrete lining tunnels Ground conditions The LaserShell method TunnelBearner Monitoring Existing Piccadilly Tunnel Eastside Existing Piccadilly Tunnel Westside Lainzer Tunnel LT31, Vienna, Austria Project overview Geology Starting construction from the shafts Side wall drift section: excavation sequence and cross section Monitoring of the sprayed concrete lining of the side wall drift section Cracks in the sprayed concrete lining 339

8 xiii Appendix A: Further information on rock mass classification systems 345 A.l Rock Mass Rating 345 A.2 Rock Mass Quality Rating (Q) 350 A.2.1 Use of the Q-method for predicting TBM performance 354 Appendix B: Analytical calculation of a sprayed concrete lining using the continuum method 356 B. l Introduction 356 B.2 Analytical model using Ahrens et al. (1982) 357 B.3 Required equations and calculation process 358 B.4 Example for a tunnel at King's Cross Station, London 361 References and bibliography Index