WHICH EVER WAY YOU SLICE IT

摘要

Traditionally, tbms for tunnelling projects are procured by the successful contractor. Occasionally projects are procured with a TBM and precast segments already readily available and contractors are left with no other option than to accept whatever the client has ordered for them to work with. When clients develop projects where tunnels are involved, usually extensive evaluations are taking place by client organisations, and/or by consultants to select the appropriate tunnelling methods. Upon many other factors, i.e. surface structures, settlement restrictions, site access and length of tunnel, the right selection is also and importantly dependent on the geo-hydrological conditions along the tunnel alignment. Using the principle of the geotechnical baseline report (GBR) is one good and fair approach for clients and contractors, which when applied appropriately, clearly defines parameters and risk allocation.