【作者】 冯磊；

【导师】 赵光明；

【作者基本信息】 安徽理工大学 ， 采矿工程， 2012， 硕士

【摘要】 我国大部分煤层赋存的水文地质条件较为复杂,受不同程度的承压水威胁,因而预防底板突水成为采矿过程中所面临的一类重要问题。承压水体上采煤时,底板在采动影响和水压的共同作用下使得隔水层上下两方都可能发生破坏,当采动裂隙贯通至含水层时承压水会沿着通道涌入工作面发生突水事故。本文以孙疃煤矿1028工作面煤层实际的水文赋存特点,以理论计算为基础,结合数值模拟对影响底板破坏的因素(煤层埋深、倾角等)进行了系统的研究,与孙疃煤矿1028工作面的现场观测结合,总结出如下研究成果：(1)依据煤层开采过程中顶板不同的运动阶段,把工作面开采过程分为初次来压阶段和周期来压阶段,并结合承压水水压的作用,建立两阶段底板在采动和承压水共同作用下的弹性力学模型,分别求解两个力学模型中底板岩层内任意一点的应力,以此得到底板岩层的应力分布并结合Mohr-Coulomb强度准则计算出破坏区域。(2)利用FLAC3D数值模拟软件分别对埋深、工作面推进速度及推进距离、煤层倾角和底板岩性各因素建立三维数值模拟计算模型,模拟分析了各个因素单独变化在采动过程中对底板岩体应力及破坏情况的影响。煤层开采过程中：底板的破坏深度随着埋深的增大而增大；一定程度上推进速度越快,底板的破坏相对较小；随着倾角的增大,底板的应力及破坏与水平煤层有显著的区别,上端头剪应力对下端头剪应力影响随角度的增大不断增加；隔水层不同的岩性受采动影响而破坏的情况也不同,从力学角度说：硬岩的承载能力(即抗破坏能力)要强于软岩。(3)通过直流电阻率CT技术对孙疃煤矿1028工作面底板岩体随采动的破坏情况进行了连续、动态的监测。通过对观测资料的对比分析得出孙疃煤矿1028工作面底板的破坏深度为17m,远小于煤层至含水层的距离。对所述研究内容,实地观测结果与理论计算和数值模拟结果相符合,与此同时理论计算和数值模拟的结果为煤层开采前的事故预测提供参考。更多还原

【Abstract】 Many coal mines in China suffer from the water in limestone aquifers, so water inrush is one of the serious mine disasters. The floor damaged on both sides under abutment pressure and hydraulic pressure. The condition of water inrush is that both sides of the failure under mining are breakover.Based on the practical coal mining and practical geological conditions of1028workface in Suntuan mine of Huaibei mining group, the paper study on the factor which can affect the destruction of the floor, such as burial depth and dip, by using numerical simulation. And then combine the actual conditions of1028workface, obtained some achievements as follows:(1) According to two movement of roof beam (before first roof pressure and motion by roof beam law) and hydraulic pressure, an elastic mechanical model was established which calculated to any point stress of floor. Then it can be used to judge whether the soleplate damage combined with Mohr-Coulomb.(2) On the basis of the occurrence features of an inclined coal seam, using the software FLAC3D, the paper established a three-dimensional numerical calculation model of a seam workface with longwall mining, simulated and analyzed the distribution laws of stress and failure depth of floor along both directions of coal seam at different advancing speed, dip and rock assembles.The results show that:in the process of mining, the depth of destroyed floor increases as mining depth, the destroy depth and range of floor at a higher speed is smaller than slower to some extent. As the slope grows, the stress field and failure features of floor is markedly different from the nearly flat seam, the shear stresses affected zone on the upper part of workface grow closer and closer to the bottom part. The different lithologic association has different affection to the coal seam floor’s failure, it concluded that the anti-destructive of hard rock is higher than the anti-destructive power of soft rock, from the mechanics point of view.(3) It can be continuous and dynamical observation to the ground damage conditions of working face1028in Sun Tuan. Huaibei mining group in the process of mining, using resistivity method CT. The result shows that the depth of destroyed floor is away from aquifuge thickness, water inrush canift occur. According the above analysis, field test result accord with the correctness of the theoretical calculation and the numerical simulation, and the theoretical analysis result and the numerical simulation result can provide theoretical references before coal seam mining. Figure [61] table [3] reference [76]更多还原