Abstract: The subsea tunnel of Xiamen crosses four geologically fractured rock mass zones. The rock mass at the fractured zones is predominantly weathered broken and granite with strong rheological effect. The rheological tests are performed on samples from the fractured zones. Then, rheological constitutive model is established specifically for the weathering pockets in the rock mass. Finite element analysis that considering the interactions between the rock mass with weathered pockets and the supporting system is also conducted. The results show that the time related rheological effect of tunnels in fractured zones is significant and has to be considered in the tunnel design and construction. The thickness of the second lining supporting system in the weathered zone is appropriate. After the initial supporting, the second lining system should be immediately followed in order to ensure the tunnel construction safety. This paper also gives a method to determine the deformation rate of the rock mass and a method for the deformation control during the construction.

Key words: Subsea Tunnel, Weathered Granite, Rock Mass and Supporting System, Creep test and Rheological Model, Finite Element Method, Deformation Rate