高承压水体上开采煤层底板潜在突水区动态演化数值模拟
Numerical simulation of evolution of potential water inrush area in coal seam floor on the top of high-confined aquifer
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摘要: 以底板受石炭系太原组灰岩高承压含水层威胁的淮北芦岭煤矿10煤为研究示范,利用有限元软件Plaxis 8.2建立能模拟承压水压力的10煤动态开采的数值模型,并考虑冒落矸石密度、变形参数与强度参数随时间的变化,分析底板采动破坏带与潜在突水区域的时空分布及其影响因素。研究结果表明:正常开采条件下,底板破坏深度随工作面推进距离的加大而增加,推进到一定距离后将达到极大值;随着煤层倾角的增大,由于冒落岩体的充填效应,开采冒落区导水裂隙提前闭合,潜在突水区域变小,并逐步集中于新近采空区;承压水压力越大,底板裂隙扩展并最终相互沟通的可能性越大,当承压水压力处于高值时,突水随时可能发生。Abstract: 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.
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