Abstract: The permeability test on complete stress-strain of the rock sample in the floor of Tao Yuan Coalseam 10 was conducted by using MTS815.2 Rock Mechanics System.Studied the seepage properties of rock sample on different unconfined state，including the characteristics of fracture closure，initiation and extension，some important parameters were provided for the research of water isolating in mining floor.The simulation results showed that the floor had been in a state of compression-expansion-compression in the process of face advance.In the transition zone of deformation between compression and expansion state ，failure occurred easily when the floor had a shear plastic deformation.The evaluation of water isolating and the prevention practice were based on the research.The study had certain significance to water-inrush prevention while mining.

Key words: Fractured rock mass, Permeability, Coupling, Discrete element method, Water isolating