Abstract：The deformation of surrounding rock and the seepage field of pore water with a fully-water karstic collapse column in the process of coal mining are numerically simulated by finite element method，in which elastoplastic constitutive model for the coal layer and the surrounding rock and Darcys seepage model for pore water are adopted. The body force is introduced to describe the coupling influence of pore water pressure on the deformation of surrounding rock. The varying characteristics of stress，plastic deformation and seepage velocity with the mining process are probed. The damage areas in the surrounding rock and the coal layer with the decrease of the distance between the mining face and the karstic collapse columns are computed，and the distance from the mining face to the karstic collapse columns needed as the reserved coal column for prevention of water inrush is also quantitatively given. Besides，the results for two cases，one with the existence of the body force and another without the existence of the body force ，are compared to show the effect of solid-liquid coupling. The result is helpful for coal mining design under complicated geological structure. It is also useful for further analysis of fluid-solid coupling，and study of the mechanism of water inrush from coal floor，as well as proper design of coal pillar to prevent water inrush in coal layer.
