大面积巷式采空区覆岩破坏机理及上行开采可行性分析

为揭示大面积巷式采空区上覆岩层破坏失稳机理，建立了均布荷载下连续深梁力学结构模型，得出了巷式开采下顶板岩层应力分布规律。立足于顶板岩层结构的力学特性，提出了大面积巷式采空区上方煤层上行开采可行性判定理论及方法，理论计算得出虎龙沟煤矿8号煤层大面积巷式采空区影响高度为8.8 m。利用FLAC2D软件对5号煤层实施上行开采的可行性作进一步论证，研究结果表明：随着开挖条带个数的增多，应力弱化系数等值线的高度不断增加，然而当开挖条带个数大于4个时，应力弱化系数不再增高，得出虎龙沟煤矿8号煤层采空区影响高度为10 m。理论计算和数值模拟均表明8号煤层采空区影响高度小于煤层层间距25~30 m，因此，虎龙沟煤矿大面积巷式采空区上方煤层上行开采是可行的，对类似煤层进行上行开采具有一定的参考价值。

Breakage mechanism of roof strata above widespread mined-out area with roadway mining method and feasibility analysis of upward mining

In order to reveal the breakage mechanism of roof strata in roadway mining,a continuous deep beam model under uniformly distributed load is established and its stress distribution is analyzed.Based on the mechanical properties of roof strata structure,the determination theory and method of upward mining above widespread mined-out area of roadway mining is proposed,and the influence height of No.8 coal seam in Hulonggou colliery is 8.8 m by theoretical calculation.The feasibility of roadway mining of No.5 coal seam is further studied using FLAC2D software,the results show that the height of stress weakening factor contours increases as the number of strips increases,however,when the number of strips is greater than four,the stress weakening factor would not increase any more,and the influence height of 8# coal seam in Hulonggou colliery is 10 m.Theoretical calculations and numerical simulations show that the influence height of No.8 coal seam in Hulonggou colliery is less than 25-30 m,the coal layers spacing,so upward mining above widespread mined-out area is feasible.The study also has a certain reference value to feasibility analysis in roadway mining under similar conditions.