Abstract：Based on engineering characters and stability controlling factors of layered rocky slope，the distribu- tion characters of ground water in layered rocky slope are shown. The simulation method is proposed to simplify the effect of fissure water in aeration zone to slope stability as planar pressure discounted by hydrostatic discount rate. Then，the hydrostatic discount rate is taken as back-analysis parameter. 3D nonlinear FEM and the flexible tolerance optimization method are introduced to establish the forecast model for layered rocky slope based on observed shear displacement of potential slippage surface. This model has displayed satisfying results in Jiangyin Yangtze Bridge Project.
