Based on the geological investigation

the deformation and damage characteristics of hard rock mass with thick weak interlayer of a typical tunnel is simulated using FLAC3D.Two models with and without weak interlayer are adopted to analyze the characteristics of ground stress

plastic zone

deformation of the rock mass and the displacement and pressure of underlying rock mass.The results show that stress distribution of the two models are almost the same which are 30%～50% of normal rock mass

but the plastic zone

the strain

the interface normal stress and the displacement of underlying rock mass are quite different.So it can be concluded that the joint and the weak interlayer both contribute to the deformation and damage of rock mass.At the same time

the construction and deformation process of a tunnel are si-mulated using a 3d model.The result shows that the deformation and damage have the characteristics of concealment and temporal uncertainty.This study can provide reference to other tunnels with similar geological conditions.