上保护层开采对下部特厚煤层移动变形规律及保护效果考察研究

Study on movement deformation laws and protection effect of lower ultra-thick coal seam affected by upper protective layer mining

选取海石湾煤矿特厚煤层6124工作面为研究对象,为了确定上保护层开采对下部特厚煤层6124工作面的影响,运用FLAC 3D 软件对上保护层开采后被保护层应力和位移变化规律进行了数值模拟研究。研究结果表明:被保护层被保护区域位移沿垂直方向呈“拱形”分布,被保护层最大位移变化量为354 mm,变化范围在160~354 mm之间;被保护层被保护区域的应力变化呈“V”形分布,被保护层最大拉应力变化量为0.489 MPa,变化范围在0.314~0.489 MPa之间,最大压应力变化量为31.3 MPa,变化范围在25.8~31.3 MPa之间;实施上保护层开采后,煤层瓦斯抽采率提高了39.5%,残余瓦斯含量降到7.16 m^3 /t,残余瓦斯压力降到0.58 MPa,该参数的确定为海石湾煤矿特厚高瓦斯煤层的合理开采提供了一定的理论指导。

Taking 6124 working face in ultra-thick coal seam of Haishiwan coal mine as the research object, in order to determine the influence of upper protective layer mining on 6124 working face in lower ultra-thick coal seam, the numerical simulation study on the change laws of stress and displacement of the protected layer after the upper protective layer mining was carried out by using FLAC 3D software. The results showed that the displacement of the protected area in the protected layer presented the arch-shape distribution in the vertical direction, the change of the maximum displacement of the protective layer was 354 mm, and the change range was between 160-354 mm. The stress change of the protected area in the protected layer presented the V-shape distribution, the change of the maximum tensile stress of the protective layer was 0.489 MPa, and the change range was between 0.314-0.489 MPa. The change of the maximum pressure stress was 31.3 MPa, and the change range was between 25.8-31.3 MPa. After the implementation of upper protective layer mining, the gas extraction rate of coal seam increased by 39.5%, the residual gas content reduced to 7.16 m^3/t, and the residual gas pressure reduced to 0.58 MPa. The determination of this parameter provides certain theoretical guidance for the rational exploitation of the ultra-thick coal seam containing high gas in Haishiwan coal mine.