Abstract：Along with the construction of underground caverns in depths，the stability of deep underground cavern excavation is a hot issue. According to the special mechanical behaviors of rock in deep tunnel，the strain-softening model is more suitable for numerical analysis. First，the mechanical properties of surrounding rock in deep tunnel and rock strain-softening model are simply analyzed；and through a simple numerical loading example of rock，the stress-strain computation results of Mohr-Coulomb elastoplastic model and strain-softening model are analyzed. Then，a simple circle deep tunnel numerical analysis is carried out；and the comparative analysis of computation results of Mohr-Coulomb elastoplastic model and strain-softening are analyzed；mainly for the analysis of the surrounding deformation，plastic zone and factor of safety. Finally，the strain-softening model is used to the deep underground caverns of Liangjiaren Hydropower Station；and the stability of underground caverns is evaluated. The results show that the deformations of both sides of main cavern and the junction cavern are larger，more dangerous than other places. The support of the both sides of main cavern and junction cavern should be considered.
