In order to effectively prevent and control floor water inrush accident occurred by the mining operation,a plastic theory and empirical formula were applied to analyze andi summarize the factors affected to the floor failure and the deposition factor and the mining design factors were divided.Based on No.15 seam in shangkong coal mine as a study background,an aquiclude thickness,water pressure of the seam floor,seam thickness and inclined length of the coal mining face were selected as the main control factors,a "deposition-mining" multi factor combined model was established and a FLAC3D software was applied to simulate the fioor vertical stress and plastic zone distribution law under the combination of different factors.The results showed that the depth of the mining failure zone would be very sensitive to the width variation of the coal mining face,the aquiclude thickness and the water pressure of the seam floor would play a control role to the scope of the confined water pressurized zone and the aquiclude thickness woull have higher influences.A fluctuation of the mining thickness woull have a weak influence to the floor failure.An idea of the equivalent failure depth was firstly provided and would be applied to the water inrush coefficient method.The water inrush danger of the pressurized mining in No.15 seam was predicted.The proposals were make to reduce the width of the coal mining face and to enhance the water detection and discharging at the coal mining wall,the front location of the coal mining face and other mining boundary in order to prevent and control the water inrush.%为有效防治采动影响导致的底板突水事故,采用塑性理论及经验公式分析总结了底板破坏的影响因素,并将其分为赋存因素与开采设计因素.以上孔煤业15号煤层为研究背景,选取隔水层厚度、底板水压、煤厚及工作面斜长作为主控因素,建立了“赋存-采动”多因素组合模型,利用FLAC3D模拟了不同因素组合下底板垂直应力及塑性区分布规律.结果表明:采动破坏带深度对工作面宽度的变化十分敏感;隔水层厚度及底板水压则对承压水导升带范围起控制作用,且隔水层厚度影响更大;采厚的波动对底板破坏影响微弱.首次提出了等效破坏深度的概念,并将其应用于突水系数法中,预测了15号煤层带压开采突水危险,并建议降低工作面宽度、在煤壁及工作面前方等采场边缘处加强探放水以预防突水.
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