上保护层开采遗留煤柱对保护效果的影响

为研究上保护层开采遗留区段煤柱对被保护层保护效果的影响,以平煤四矿己;-23160联络巷下帮遗留的4 m煤柱及己_(15)-23140、己_(15)-23160、己_(16.17)-23140工作面为研究对象,采用数值模拟和现场实测相结合的方法进行了研究。研究结果表明:煤柱沿z轴负方向被压实,累计最大位移为0.289 m;煤柱两侧煤壁沿x轴移动方向不同,上壁沿x轴负方向,下壁沿x轴正方向,累计位移量分别为0.055 m和0.156 m,己;-23160工作面采掘活动对煤柱位移影响最为显著;遗留煤柱最大残余高度为0.59 m,相比原始煤柱高度降低1.01 m;深部煤体残余瓦斯含量和钻屑量变化趋势一致,最大残余煤层瓦斯含量2.63 m^(3)/t,煤层瓦斯释放率保持在50%以上,最大钻屑量为3.7 kg/m。残余煤柱影响区内煤层瓦斯得到很好地释放且无明显应力集中,保护层开采遗留4 m煤柱能够达到连续的保护效果。

Influence of residual coal pillar from upper protective layer mining on protection effect

In order to study the influence of the coal pillar left in the upper protection layer on the protection effect of the protected layer,the 4 m coal pillar left at the lower side ofⅥ₁₅-23160 connecting roadway andⅥ₁₅-23140,Ⅵ₁₅-23160 andⅥ_16.17-23140 working faces in Pingmei No.4 Mine are taken as the research objects.The research is carried out by combining numerical simulation and field measurement.The research results are as follows:the coal pillar is compacted along the negative direction of the z axis,with a cumulative maximum displacement of 0.289 m;the coal walls on both sides of the coal pillar move in different directions along the x axis,the upper wall is along the negative direction of the x axis,the lower wall is along the positive direction of the x axis,and the cumulative displacement is 0.055 m and 0.156 m,respectively;the mining activities ofⅥ₁₅-23160 working face have the most significant impact on the displacement of the coal pillar,and the largest remaining coal pillar is 0.59 m,which is 1.01 m lower than the original coal pillar height;the residual gas content of deep coal has the same change trend as the amount of drill cuttings.The maximum residual coal seam gas content is 2.63 m³/t,and the coal seam gas release rate remains above 50%,and the maximum amount of cuts is 3.7 kg/m.The coal seam gas in the area affected by the residual coal pillars is well released without obvious stress concentration.The 4 m coal pillar left by protective layer mining can achieve continuous protection.