远距离下保护层开采卸压效果数值模拟研究

Numerical simulation study on stress release effect of remote underside protective seam mining

以芦岭煤矿远距离下保护层（即Ⅲ11软岩工作面）开采作为工程背景,采用FLAC3D数值模拟技术,通过对虚拟监测点数据的统计分析,研究了下保护层开采过程中被保护8~#煤层的应力变化规律、膨胀变形程度及瓦斯压力变化规律。模拟结果显示：随保护层开采范围的不断增大,8~#煤层垂直应力、最大主应力及最小主应力变化量均超过10%;厚度变形量超过3‰;且在保护层开采中后期8~#煤层瓦斯压力低于国家防突规定的临界值0.74 MPa,表明下保护层开采对被保护的8~#煤层起到卸压保护作用。

Taking remote underside protective seam（Ⅲ11 soft rock face） mining in Luling Coal Mine as engineering background,using FLAG 3D numerical simulation technique and through statistical analysis of virtual monitoring points,the stresses change law,swelling deformation degree and gas pressure change law of the protected No.8 coal seam in the process of remote underside protective seam mining were studied.Simulation results showed that with the increasing of protective seam mining areas,the variation of vertical stress,maximum principal stress and minimum principal stress of the No.8 coal seam were all more than 10%,the thickness deformation was more than 3‰,and in the middle and later periods of protective seam mining,the gas pressure of the No.8 coal seam was lower than the critical value of state burst prevention regulation 0.74 MPa,which indicated that the underside protective layer mining played a important role in pressure releasing and protection of the protected No.8 coal seam.