Study on numerical simulation and safety analysis of floor water inrush above confined water in deep mine

Mine water accident due to the mining above confined water is one of the main factors which affects and threatens safety in the coal production, especially for deep mine. Finding out the mine hydrogeological conditions, deepening the research of water inrush mechanism, and taking the effective safety measures of water bursting prevention, are all the key issues of mining under water pressure safely. Based on fractured rock mass equivalent continuum theory, according to drilling imaging method and water pressure test in borehole, in this paper we focus on discussing the water inrush of the floor rock, determining the floor rock permeability tensor with correction method and simulating the floor inrush problem by coupling stress field and seepage field theory and using anisotropic seepage model with FLAC(3D). The results show that, the depth of destroyed floor in normal area and fractured zone in fault are about 30m and 58m respectively. According to empirical equation and numerical simulation, we get the results that the effective protection layer thicknesses are 82m and 115m respectively, and it has presented dangers in fault fractured zone based on the water bursting coefficient method.