Abstract:

Muzhailing tunnel on LanzhouChongqing railway passes through carbonaceous slate ground, where large deformation occurs. In order to establish the methods to control the large deformation, advance largediameter boreholes and pilot heading are installed in No. 7 inclined shaft of Muzhailing tunnel so as to perform stress control tests. Comparison is made between the monitoring data in the test section and those in the original section. The test indicates that advance largediameter boreholes and pilot heading are helpful to the control of the deformation, but further study is needed to improve the feasibility of the deformation control method.

Key words: tunnel, carbonaceous slate, large deformation, stress control, pilot heading, large diameter borehole