Workshop Manual

Mechanised Tunnelling for Asia
  • Realising The Benefits
  • Avoiding the Pitfalls

Ian McFeat-Smith

IMS Tunnel Consultancy Ltd.
with contributions from
Jim Broomfield, Director, Herrenknecht International Ltd
and
The Robbins Company

MECHANISED TUNNELLING

ABSTRACT

This manual answers the question why are bored tunnels, particularly those excavated by microtunnelling and TBMs (tunnelling boring machines), in such high demand in Asia at this time?  Issues relating to the application of these techniques are discussed frankly for the full range of geological conditions encountered in Asias key cities.  This is presented with the steps necessary to help ensure their successful application - to realise the benefits and avoid the pitfalls.   Aspects of good site investigation practice are given and the advantages and disadvantages of machine options in comparison with the use of traditional methods are outlined.

A collection of twenty five case histories are presented illustrating different aspects of TBM performance with respect to the specific geological conditions encountered on site. In many cases the delays encountered have been quantified and key aspects of TBM design and the Contractors performance are critically reviewed.  These cases include microtunnelling, hard rock TBMs, machines for soft ground and the new range of hybrid multi-mode TBMs for mixed fax condition.  Methods of predicting machine utilization rates, cutting rates and rates of progress are given.

A section on water inflow issues affecting TBM performance in rock tunnels is included.  A new empirical method of predicting inflows is presented together with means of controlling water inflows by pre-grouting techniques.

 

Finally contractual issues arising from the use of so called fixed price contracts, a risk sharing option for rock tunnelling contracts, and an outline of the Partnering value added approach are discussed.

 

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