Abstract: Physical model tests usually could only monitor several key points in the tunnel excavation. The threedimensional numerical analysis can effectively simulate the entire stress and strain change in the surrounding rock mass, the seepage field in the karst rock solution channels. The groundwater and mud rush through the fill media of karstic bedrock during the tunnel excavation are analyzed in this paper.

Key words: Groundwater and Mud Rush in Tunnel Excavation, Finite Difference by FLAC3D, Stress Change