近距离下部煤层应力分布规律研究

Study on stress distribution of low coal seam with short distance

针对近距离煤层中上部煤层开采容易引起下部煤层应力环境复杂化而导致巷道难以维护的问题,采用数值计算的方式分析了近距离煤层的煤柱宽度、埋深、层间距等因素对下部煤层应力分布的影响。研究得出:随着煤柱宽度增加,上部煤柱底板附近应力呈降低趋势,但应力衰减速度和下部煤层应力增高区范围呈增加趋势;随着埋深增加,上部煤柱底板岩层应力和传递深度呈现增加态势,但下部煤层应力增高区扩散范围逐渐减小;层间距的变化对于上部煤柱底板岩层的应力传递影响较小,但下部煤层应力增高区扩散范围增大,且增加幅度高;当采空区顶板能够及时垮落时,工作面长度变化对于上部煤柱底板附近岩层应力分布影响并不明显,但使得采空区下方低应力区范围扩大,有利于下部煤层巷道布置位置选择。

Stress environment of the lower coal seam will be complicated after the mining of the upper seam of short distance coal,and it will lead the roadway difficult to maintain.The effect of coal pillar width,depth,spacing of layer to stress distribution of the lower seam was analyzed with the method of numerical analysis,following that：with the coal pillar width increasing,stress near the pillar tends to decrease,but the stress relaxation rate and the range of in lower seam show an increasing trend;with depth increasing,and transfer depth show an increasing trend,but the range of stress increased zone in lower seam decreases;the stress under the upper pillar floor is less affected by variable layer spacing,but the range of stress increased zone of the lower seam increases,and the rate of increase is high;When the gob roof caving in time,stress distribution near upper pillar to is not obvious when working face length changes,but low stress areas expand under the mined-out area which is conducive to lower seam roadway layout options.