Abstract:It is difficult to calculate the accurate displacement of each point in rock mass because of the complexity of the problem. Instead,various approximate methods have been used for this calculation. In fact,the movement of each point at a level of overburden can be regarded as a fuzzy event. In other words,this displacement will take place at a fuzzy probability,and so the theory of fuzzy probability measures can be applied to describe the displacements and deformations of rock mass. In this paper,the application of the fuzzy probability measures to the analysis of the rock mass displacements due to underground mining under the mountain areas in Xiangyu phosphorus mine is described. Available and safe mining scheme is proposed based on the study result.