近距离煤层开采巷道布置合理性分析

Analysis on Rationality of Roadway Layout in Close Coal Seam Mining

以界沟煤矿8220工作面机巷为研究对象,针对7220工作面回采造成8220机巷顶板不稳定的情况,运用极限平衡理论和弹性力学理论对煤柱一侧塑性区宽度和上位煤层底板应力分布规律进行研究。结果表明,7#煤煤柱一侧塑性区宽度x0为21.1 m,上位煤层开采后,原岩应力平衡状态被打破,在煤壁附近区域出现了应力集中区和卸压区。底板最大破坏深度hmax为15.91m,由塑性区宽度得出煤层底板最大破坏深度与煤壁的水平距离为7.41 m,采空区底板破坏区沿水平方向的最大距离为84.3 m。根据7#煤层采空区左侧煤壁与8#煤层回采巷道顶板中心线的相对位置不同,提出4套布置方案,通过综合分析,当煤壁与回采巷道顶板中心线距离为22 m时,回采巷道受力较小且均匀,塑性区分布不大,围岩变形量也很小,为最佳布置方案。

Aiming at the unstable roof of 8220 machine roadway in 7220 face of Jiegou Coal Mine,the width of plastic zone on one side of coal pillar and the stress distribution law of upper coal seam floor are studied by using limit equilibrium theory and elasticity mechanics theory.The results show that the width of plastic zone on one side of 7#coal pillar is 21.1 m.After mining of the upper coal seam,the stress balance state of the original rock is broken,and the stress concentration area and pressure relief area appear near the coal wall.The maximum damage depth hmaxof floor is 15.91 m,the maximum damage depth of floor is 7.41m from the horizontal distance of coal wall and 84.3 m from the horizontal direction of floor damage area of goaf.According to the relative position of the left coal wall of the goaf in 7#coal seam and the central line of the roof of the mining roadway in 8#coal seam,four sets of layout schemes are proposed.Through comprehensive analysis,when the distance between the coal wall and the central line of the roof of the mining roadway is 22 m,the stress of the mining roadway is small and even,the distribution of the plastic zone is small,and the deformation of the surrounding rock is also small.