Numerical simulation of evolution of potential water inrush area in coal seam floor on the top of high-confined aquifer

Modeled for the study on No.10 coal seam of Luling Coal in Huaibei, whose seam floor is threatened by high-confined aquifer of Carboniferous Taiyuan Formation limestone, the finite element software Plaxis 8.2 is adopted to establish numerical simulation which can simulate the dynamic mining of No.10 coal seam on the top of confined acquifer, considering the roof falling rock density, the change of deformation parameters and strength parameters with time.The spatial and temporal distribution and affected factors of floor failure zone and potential water inrush area are analyzed. The results show that the rupture depth of floor will increase with the addition of advancing distance of working face in the normal mining, then it will reach a maximum value when working face reach a certain distance; and that water conducted crack of collapsed zone closes ahead with the increase of coal seam dip because of the filling effect of roof falling rock, and potential water inrush area becomes small, and gradually focuses on the recent goaf; and that the greater the pressure of high-confined aquifer is, the greater the likelihood of crack propagation and ultimate connection with each other is, and when the pressure of confined aquifer is in the high value, water inrush may occur at any time.