Abstract:

There are many difficulties in the design, construction and shield type selection of shieldbored Metro tunnels in hardsoft heterogeneous ground. In the paper, countermeasures and technologies are proposed in terms of design, shield type selection, cutter head configuration and construction technology, on basis of construction and experiences of actual projects in China. Conclusions drawn are as follows: 1) The hardsoft heterogeneous ground should be avoided rationally in the route design, and countermeasures and cost budget should be prepared; 2) The shield type and cutter head configuration adopted should meet the requirements of boring in hard rock and pressurekeeping in soft ground; 3) A series of comprehensive and practicable construction technologies and contingency plan should be provided.

Key words: Metro, shieldbored tunnel, hardsoft heterogeneous ground, design and construction, shield type selection