缓倾斜薄煤层群相向同采围岩稳定性数值模拟

Numerical simulation of surrounding rock stability of gently inclined coal seam group in opposing mining

为了保证缓倾斜煤层群的安全开采以及了解相向开采时围岩的破坏规律,基于木城涧煤矿+250水平西一采区二、三槽煤层赋存条件,采用相似材料实验观测采空区顶板产生裂隙、断裂、冒落和离层情况,运用FLAC3D软件建立模型,分析煤层工作面推进距离与围岩应力变化的关系以及得到采空区影响下煤层的纵向位移的变化情况。研究结果表明:随着上覆煤层工作面推进,下覆煤层顶板大部冒落,使下覆煤采空区上部岩层和上覆煤层及上部岩层整体下沉,压密上覆煤层和上部岩层,提高顶板岩体整体性,上覆煤层和直接顶岩层没有受到破坏有利于上覆煤层开采;上覆煤层的开采,对下覆煤层顶板有明显的卸压作用,降低顶板积压的危险,有利于下覆煤层的开采。

In order to ensure the safe mining of gently inclined coal seam group and learn the failure law of the surrounding rock when opposing minging,based on occurrence condition of Muchengjian coal mine ＋ 250 m level,No. 2 and 3 spout,West No. 1 winning district,observed the variation of gob roof crack generation,fracture,fall and separation layer through simulation experiment. Taken FLAC3 Dto build model and numerical simulation to analyze the relations between the advance distance of coal seam and the change of surrounding rock stress and get the changes of the longitudinal displacement of overlying coal seam under the influence of goaf. The results indicate that： with the advance of the overlying coal seam the roof weights over great extent make the overlying coal and strata on the top of the underlie coal mined-out area have a integral settlement,compressing overlying coal and top rock stratum,enhancing the integrality of roof rock. It benefits mining overlying coal that overlying coal and its roof rock are not damaged. Mining overlying coal has pressure-relief effect on roof of underlie coal seam,lowering the risk of roof extruded,benefiting mining underlie coal seam.