Abstract：Based on the geological conditions of Luan mining and a RFPA^-2Dnumerical simulation system,the formation mechanism of karst collapse column is studied and the developmental status of karst under the influence of different factors is analyzed. Then the influence of groundwater and geologic structure on karst collapse column development are simulated. The simulation results show that: if aquifer water pressure keeps constant,the stronger the karstification is,the bigger the fractures are; if the degree of development of cracks keeps constant,the bigger the karst,the larger the aquifer water pressure. According to the simulation results,the formation mechanism of karst collapse column is investigated. Firstly,the basis of karst collapse column formation contributes to that soluble stratum has larger thickness and area. Secondly,the dynamic condition is groundwater dissolution. Thirdly,geologic structure controls the distribution of karst collapse column in space.

Keyword：RFPA-2D;numerical simulation;karst collapse column;geologic structure;aquifer;