急倾斜煤层开采地表塌陷坑形成机理与安全矿柱尺寸研究

Discussion on mechanism of surface collapse pit and dimensions of obstructive ridge for steep inclined coal seam mining

地表塌陷坑和台阶状塌陷盆地是急倾斜煤层开采地表移动的主要形式。本文从力学原理出发 ,对急倾斜煤层开采地表出现塌陷坑的机理、决定因素进行了研究 ,当煤层倾角大于 5 5°时 ,冒落岩石下滑形成上部自由空间 ,这是产生地表塌陷坑的先决条件。利用极限平衡条件 ,获得了避免地表出现塌陷坑的矿柱安全留设尺寸及其稳定性系数表达式。当落入塌陷坑中的岩石和表土不足以支撑其它岩层时 ,地表塌陷坑的渐近破坏将可能导致地面出现台阶状塌陷盆地。研究结果表明 ,该方法可以用于指导生产实践中相关问题的解决。

Surface sinkhole and steps are the most prevalent subsidence features over steep inclined coal seam. On the basis of mechanical principles, the mechanism of surface sollapse pit and its decisive factors for the mining of steep pitch coal is investigated It is the caved rock blocks slide downwards and the upper free space formed when the dip angle of coal seam is larger than 55°. It is precondition of ground collapse pit that the expressions of obstructive ridge dimensions and the stability coefficient are obtained using the limit equilibrium conditions. When the caved rock blocks and top soil are not strong enough to support the other rock strata, the progressive damage of sinkhole may lead to surface steps. This new method is very useful in practice to solve certain related problems.