Abstract:In response to the characteristic of rock masses and initial geostresses in Xiaowan Hydropower Station,elastic-brittle-plastic (EBP) constitutive model is employed to analyze the deformation and plastic zone of the rock mass surrounding the underground structures after the completion of excavation. Meanwhile,elastic-plastic (EP) model is also applied to analyse the problems. The results obtained by the two models are compared and the difference between them is obvious. Considering that several faults intersect the underground caverns,the effects of the faults on both deformation and the damage zone by the replacement of the infillings of them are presented. Numerical results show that faults exert much influence on the stabilities of the caverns when the faults are near the surfaces of the caverns.