远距离下保护层开采对上覆煤层卸压保护效果研究

Research on upper seam pressure-relief effect of long distance lower protective seam mining

以平顶山煤田十矿为工程背景,针对远距离煤层群开采条件下,下保护层开采对上覆岩层卸压保护技术研究,应用离散元数值模拟技术,对被保护煤层卸压情况进行监测和分析,同时对下保护煤层跨越相距248m的被保护煤层顶板大巷和保护煤柱开采过程的巷道变形进行计算和分析。结果表明,下保护层采煤工作面虽然距上部岩层巷道248m,但采动的影响仍很显著,使远距离覆岩大巷产生大变形和沉降,丧失使用功能,数值模拟结果与现场观测到的情况一致,验证了数值试验对卸压保护效果的可靠性;通过数值模拟分析,下保护层开采后,上覆相距180m的被保护煤层最大主应力降低了20%,卸压保护角约为80°,卸压膨胀稳定区的膨胀变化率为2.25%-2.5%。这表明首先开采下保护煤层,对上覆被保护层煤层的卸压效果明显,具有一定的保护作用。

Based on the engineering background of No. 10 mine of Pingdingshan coalfield,under the condition of long distance coal seam group mining,the upper seam pressure-relief effect with long distance lower protective seam mining is studied. Discrete element numerical analysis is applied to monitor and analyze the coal seam pressure- relief effect,and calculate the roadway deformation of the protected coal seam roof roadway and coal pillar mining 248 m apart from lower protective seam. The result showed that,the distance between the lower seam mining face and upper rock roadway is248 m,but the mining influence is still significant, leading to the large deformation and subsidence of long distance overburden rock roadway and functional failure. This is consistent with the field observation. The reliability of pressure-relief effect numerical experiments is verified; according to the simulation,after the lower protective seam mining,the vertical stress of the protective seam 180 m apart reduces by 20%,the pressure-relief protection angle is about 80° and the inflation rate of pressure- relief expansion region is 2. 25% - 2. 5%. The protective coal seam mining achieves obvious pressure-relief effect and favorable protection effect of upper coal seam.