DDARF numerical simulation technique was used for theoretical analysis and numerical simulation of specimens of rock mass with parallel joints.The degree of influence of physical parameters

such as different pressure states and original crack angle on shear failure was researched.It is pointed out that the lateral pressure and crack angle are the primary reasons for shear faiture of rock mass.Analysis of surrounding rock structure for excavation of underground cavern in rock mass with two sets of parallel joints shows that under different terrestrial stress conditions

the influence of parallel joint of rock mass on stability of rock mass surrounding cavern is on the different levels.