(1. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China；2. Second Highway Consultants Co.，Ltd.，China Communications Construction Corporation，Wuhan，Hubei 430056，China)
Abstract：The underwater section of the Xiamen subsea tunnel will encounter many weathered strata，and the main rock of the weathered strata is fully or strongly weathered granite. The main mechanical characteristics of this kind of rock is low strength，high compressibility；its self-stability，and its bearing capacity is low；and it brings many unexpected problems to the liner design and the tunnel construction technology. A series of laboratory tests for the strongly weathered granite have been performed to study the hydro-mechanical coupled behavior；and a new mechanical model has been suggested；and corresponding parameters have been identified by back analysis. The results obtained from the research work are useful for soft rock engineering especially for weathered granite engineering；it has guiding effect on the tunnels¢ design and construction in this kind of rocks.
