Mechanized Tunnelling in Urban Areas: Design methodology and construction control

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(Last Updated On: January 10, 2018)
Internationally, the mechanized excavation of tunnels has intensified in the last two decades, as the number of tunnels being constructed for subways and railway underpasses increases. The subject of mechanized tunnelling in urban areas has not previously received the attention that it deserves, despite there being specific hazards associated with the construction of tunnels in metropolitan areas, including poor ground conditions, water tables higher than the level of tunnels, and subsidence leading to damage to the existing structures on the surface. The application of technologies for achieving the stability of the tunnel and for minimizing surface settlement is described in this book. Accurate characterization of the ground; rigorous assessment and management of risk from design to maintenance; the correct choice of a tunnel boring machine and a plan for the advancement of the tunnel; specific excavation procedures and real-time monitoring of excavation parameters are all discussed in this thorough work. 

Table of Contents

Introduction: tunnels in urban areas and the related challenges
The opportunities
The particular challenges of urban tunnelling
The correct approach to success
A brief history of mechanized tunnelling
The scope of this book

Initial risks: definition, analysis and management
Basic definitions
Sources of initial risk in mechanized urban tunneling
Analysis and management of risks: the risk management plan
Designing for the identified risk scenario
Quantifying the risk of time and cost overruns at the design stage with the use of DAT
Use of Plan for Advance of Tunnel (PAT) for controlling the residual risks 

Selection of tunnel alignment with low-level risks
Introduction

The general layout of an urban tunnel
Alignment constraints and specific functional requirements
Constraints and peculiar characteristics of the urban environment relevant to the selection of a tunnel route
Starting and arrival points, shield launching and receiving shafts, logistic work sites
The relationship between the excavation of running tunnel by TBM and the construction of the stations
Conclusions

The primary responses to the initial risks: a "city machine" and its essential characteristics
Principles for making the macro choices
The common solution: a "city machine"
Essential components of a "city machine"
Slurry and earth pressure balance shields: functioning principles and review of the state of the art
Some considerations for the choice between HS and EPBS

Tunnel design
Prediction and control of tunnelling-induced settlements and assessment of their impacts

The design of face-support pressure
The design of precast concrete segmental lining
Backfilling of the tail void

The control of tunnel construction
Updating and implementation of PAT
Excavation control: the case of slurry/hydro shield (SS/HS)
Excavation control: the case of earth pressure balance shield (EPBS)
Integrated real-time monitoring system

Health and safety
General considerations
TBM working environment
Critical processes
Additional critical elements
Emergencies

Case histories
EOLE project - Paris
St. Petersburg metro
Porto light metro
Turin metro line 1
SMART solution of Kuala Lumpur (Malaysia)
High speed railway line of Nodo di Bologna

References

Appendices
Appendix 1 Type and characteristics of TBMs
Appendix 2 TBM manufacturers from the new millennium
Appendix 3 Geotechnical investigations for tunnelling in urban areas
Appendix 4 Description of the principal elements of the 12 analytical methods for defining face-support pressure
Appendix 5 An example of risk management plan for a job using slurry shield
Appendix 6 Typical excavation procedures for EPB shield
Appendix 7 The Italian experiences

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Mechanized Tunnelling in Urban Areas: Design methodology and construction control
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