承压水上充填开采底板破坏特征研究

Failure characteristics of floor above aquifer using backfilling mining method

为探索充填开采对底板破坏深度的影响及对突水灾害的控制效果,结合理论计算、数值分析和煤矿现场观测等方法对某矿A工作面承压水上充填开采底板破坏特征进行了综合研究;通过理论计算推导出了充填开采工作面底板最大破坏深度计算公式;通过数值模拟对充填开采和非充填开采时底板破坏情况进行了对比研究,通过现场实测分析了充填开采时底板岩层的实际变形破坏特征。结果表明:充填开采时,采场围岩的采动卸压范围、顶底板移近量明显减小,围岩应力集中程度降低,底板破坏深度并未随着推进距离的增加而持续纵向发展;由于充填体的应力传递和支撑作用,A工作面开采对底板的损坏影响得到减缓,破坏深度未连通下部含水层,可实现安全回采。

In order to explore the influence of backfilling mining on the damage depth of floor and the control effect of water inrush disaster,combined with the methods of theoretical calculation,numerical analysis and field observation in coal mine,the failure characteristics of the floor in backfilling mining above confined water in A working face of a mine are comprehensively studied.Theoretical calculation formula for determining maximum damage depth of the floor in backfilling workface is proposed.Through numerical simulation,a comparative study is carried out on the floor failure of backfilling mining and non backfilling mining,and the actual deformation and failure characteristics of floor rock during filling mining are analyzed through field measurement.The results show that surrounding rock stress concentration and roof-to-floor convergence is decreasing because of the existence of the filling body;floor damage depth remain stable,no longer development in the vertical direction with advancing of the workface,mining influence of A workface to the floor is eased for stress transfer function of the filling body,the damage depth of the floor does not reach the limestone aquifer,and the coal seam can be safely mined.