Abstract:With finite element software ABAQUS,a three-dimensional viscoelasto-plastic finite element analysis was performed for the excavation of rock mass of a natural gas underground storage. The stress variation and deformation during the excavation process were calculated and analyzed. The deformation of the casing with which water is pumped in and out was calculated. The main researchs include:(1) the stress field and displacement distribution of rockmass caused by solution mining were presented,as well as a curve of rock mass displacement versus z-direction for the rock around casing;(2) a practical curve of viscoplastic constitutive model of rock mass with reference to the form requirements of software ABAQUS was given out;(3) the possible plastic area was predicted,and the estimation of the stability of the storage rock mass structure was given out. The numerical results indicate that the self-bearing system which is characterized by “compressive arch” has been formed around the storage space after 3 years solution mining construction. The design of the underground storage is reasonable and practical. However,it is necessary to adopt reasonable measure to enhance the lower section of casing as well as to reduce the pulling effect of rock mass acting on the casing.