煤层自燃对高陡露天矿边坡稳定性的影响与防治对策

Influence of coal spontaneous combustion on slope stability of high and steep open-pit mine and countermeasures

为了探究煤层自燃过程对边坡稳定性的影响,以河曲露天煤矿为工程背景,借助于有限差分数值软件FLAC^(3D)模拟再现了煤层不同自燃深度下边坡片帮滑移过程,分析了传统灭火方法在河曲露天矿应用的不足之处,提出了挂网锚喷这一更加适用于河曲露天矿工程特点的边坡防灭火方法。结果表明:露天矿两非工作帮现状边坡安全系数均高于设计规范要求的安全储备系数,满足安全生产的要求;露天矿边坡位移值随着煤层自燃范围的扩大逐渐增加,而安全系数随着煤层自燃范围的扩大而逐渐减小,且均呈二次函数规律;边坡体中应变集中带范围随着煤层自燃程度的增加而逐渐增大,煤层自燃引起的边坡失稳是煤层上部岩体"悬臂梁"损伤渐进累积破断引起的边坡整体滑坡过程。

In order to explore the influence of coal seam spontaneous combustion process on slope stability,the slope slip process under different coal seam spontaneous combustion depths was simulated by using FLAC^(3D) based on the engineering background of Hequ Open-pit Coal Mine.The shortcomings of the traditional fire extinguishing methods in Hequ Open-pit Mine was analyzed,and the method of slope fire prevention and control,which is more suitable for Hequ Open-pit Mine,is proposed.The results show that:the safety coefficient of the current slope of the two non-working sides in the open pit mine is higher than the safety reserve coefficient required by the design code,which meets the requirements of safety production.The slope displacement of open-pit mine increases gradually with the expansion of spontaneous combustion range of coal seam,while the safety factor decreases gradually with the expansion of spontaneous combustion range of coal seam,and both of them show quadratic function law.The range of strain concentration zone in slope increases with the increase of spontaneous combustion degree of coal seam.The slope instability caused by spontaneous combustion of coal seam is the whole slope landslide process caused by the gradual accumulation of damage of cantilever beam in upper coal seam.