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针对高突低透矿井上、下保护层开采具体方案选择缺乏理论支撑的难题,基于二维颗粒流软件PFC2D建立了上、下保护层及被保护层卸压增透模型,对比分析研究了上、下保护层开采后被保护层全过程卸压趋势及孔隙率变化规律。结果表明,下保护层开采模式下煤层卸压效果更明显,裂隙网络更为发育,防突效果更佳,同一水平位置不同埋深处竖直方向下保护层开采最大卸压值约为上保护层开采的2倍、最大孔隙率约为上保护层开采的1.26倍。该研究成果有助于为保护层开采方式的合理选择。
In view of the lack of theoretical support for the selection of the specific schemes of the upper and lower overburden mining in the high outburst low permeability mine, the upper and lower protective layers and the pressure relief and penetration enhancement model of the protected layer are established based on the two-dimensional particle flow software PFC2D. , The lower protective layer after the mining process by the protection of the entire process of pressure relief trends and changes in porosity. The results show that the coal seam is more effective in pressure relief under lower protective layer mining mode, the fracture network is more developed and the outburst prevention effect is better. The maximum pressure relief value of protective layer in vertical direction at the same horizontal position is about upper protective Layer mining 2 times the maximum porosity of about 1.26 times the upper protective layer mining. The results of this research contribute to the rational choice of the mode of protective layer mining.