远距离下保护层开采遗留煤柱对被保护层回采的影响研究

Study on the influence of coal pillar left by long-distance mining of protected layer on the mining of protected layer

为探究远距离下保护层开采遗留煤柱对被保护层回采效果的影响,以平顶山六矿戊_(8)煤层的戊_(8)-22310机巷和戊_(8)-32010风巷之间遗留宽度为4 m的区段煤柱和丁_(5-6)-22190工作面为研究对象,采用理论分析、数值模拟和现场实测结合的方法,研究了煤柱影响范围、煤柱区域垂直应力分布及影响区相关参数变化规律。结果表明:宽4 m遗留煤柱的影响范围为27.3 m,极限强度为25.9 MPa,塑性区宽度为2.26 m,弹性区宽度为2.68 m;煤柱两侧工作面均回采后,其承载的最大垂直应力87.9 MPa,远超煤柱本身的承载极限;在煤柱影响范围内测得的残余瓦斯含量、压力与卸压保护区无明显差异,并均小于突出危险临界值,煤柱影响区内瓦斯得到较好释放;煤柱影响范围内未产生明显应力集中现象,遗留小煤柱对被保护效果影响较小,保护效果在倾向上有连续性,对被保护层工作面回采影响小。

In order to study the influence of the coal pillar left over from the mining of the protective layer over a long distance on the mining effect of the protected layer,the coal pillar andⅣ_(5-6)-22190 working face of the section with a remaining width of 4 m betweenⅤ_(8)-22310 machine lane andⅤ_(8)-32010 air lane ofⅤ_(8)coal seam in Pingdingshan No.6 mine are taken as the research object,by means of theoretical analysis,numerical simulation and field measurement,the influence range of coal pillar,the distribution of vertical stress in coal pillar region and the variation law of related parameters in the influence region are studied.The results show that the influence range of 4 m wide residual coal pillar is 27.3 m,the ultimate strength is 25.9 MPa,the plastic zone width is 2.26 m,and the elastic zone width is 2.68 m.When the working faces on both sides of the coal pillar are mined,the maximum vertical stress of the coal pillar is 87.9MPa,which far exceeds the load limit of the coal pillar itself;there is no obvious difference between the residual gas content and pressure measured in the coal pillar influence area and the pressure relief protection area,and they are all less than the critical value of outburst danger,and the gas is released well in the coal pillar influence area;there is no obvious stress concentration phenomenon in the influence range of the coal pillar,the small coal pillar left behind has little influence on the protected effect,the protection effect has continuity in trend,and the influence on the working face of the protected layer is little.