Abstract:

Solid or slightlyweathered rocks are often encountered in the central sections of running tunnels, while heavilyweathered rocks or residual soils exist on both ends of the running tunnels. Therefore, such running tunnels can not be constructed only by shield machines. In such cases, the composite method of “mining method + shield method” is often adopted. The application scope, construction process and advantages of “mining method + shield method” are presented, the key technical problems to be solved are listed, the mechanical status and deformation behavior of the composite reinforcement structure of the tunnels are analyzed, with a running tunnel of Shenzhen Metro as an example. The paper can be served as engineering practical guidance and theoretical basis for the promotion and application of the new construction method.

Key words: mixed stratum, shielddriven tunnel, mined tunnel, composite reinforcement structure