ABSTRACT
Tunnelling inside city limits is often troubled by the non-availability of appropriate working space. To minimize restrictions on neighbouring traffic, compromises have to be made. Consequently time consuming and cost intensive construction sequences might arise, which demand the selection of innovative methods of equipment setup and which make construction procedures a real challenge.
MRT Contract 201A, located in downtown Taipei, involved the construction of twin tunnels, each 360 m long, utilizing an Earth-Pressure-Balanced Shield Machine. The Tunnel Works for Project CP264, located in Pan Chiao, a densly populated suburb of Taipei, consisted of the construction of 1,000 m long twin tunnels by the same method.
For both cases the paper will focus on the effects and difficulties of limited initial setup area and the therefore required arrangements, especially with regard to the assembly of the TBM and to other technical and operational aspects and the impacts on construction time and costs.
The paper will further detail the prevailing ground conditions and the thus resulting TBM operating parameters and the achieved and achievable advance rates in similiar soft ground conditions. In addition the TBM and its components, the tunnel lining, the works involved in the planned abandoning of the shield and the arrival procedure of the TBM into a reception shaft will be described.
