The progressive failure of geotechnical engineering field is an important research subject.Based on the particle discrete element method

the particle connected damage model is deduced.This paper establishes the rock mesoscopic discrete model and studies the uniaxial compression numerical simulation under different particle parameter conditions.The results show that the bonding force is the main factor of bond failure.Friction coefficient among particles is a sensitive parameter influencing the macroscopic strength.Uniaxial compression test forms a shear zone close to 45°.The results of numerical simulation match the experimental results well

and this proves the model is reasonable.This paper establishes the excavation mesoscopic discrete model

simulates different formation conditions of the excavation process and analyses the settlement difference between the excavations with supporting and without supporting.The study finds that the unsupported deep excavation under a shallow excavation testing point has obvious settlement.Supported rock can effectively reduce the surrounding rock deformation and prevent stress increasing.This paper reveals the rock progressive failure mechanism under excavation and provides a theoretical and technical support for further study of geotechnical engineering mechanic characteristics

rock fracture and progressive failure process.