Abstract：Considering rock as porous media，the relation between rock porosity and volumetric strain is established. Then the rock permeability coefficient，damage，saturation¢s evolution equations are defined；and the unsaturated elastoplastic damage coupling model is proposed based on the effective stress law of porous media. The proposed model is implemented with user subroutines into the nonlinear FE software ABAQUS；then the stability evaluation of rock mass for the diversion tunnel of Jinping Hydropower Station is conducted. The numerical results show that the proposed model is reasonable and it can explain the rock mass¢s saturated- unsaturated-resaturated process.
