考虑采空区压实效应的煤矿单一保护层开采数值模拟研究

Numerical simulation of coal mine single protective layer mining considering goaf compaction

  • 摘要: 【目的】为研究近距离煤层群保护层开采覆岩移动规律及卸压效应,【方法】采用PHASE 2D有限元软件建立了考虑采空区压实效应的单一保护层开采数值模型,获得了工作面前后方支承应力演化规律、煤壁塑性区变化特征、采场围岩及覆岩移动规律。【结果及结论】研究结果表明,采空区内支承压力系数呈现先增长、后稳定,而工作面煤壁前方4 m处出现了支承压力峰值系数1.73;由于保护层开采的卸压作用,主采煤层采空区支承压力并未恢复至原岩应力水平;主采煤层工作面塑性区宽度先增大后稳定,塑性区最大宽度为2.50 m;采场顶板向煤壁方向挤压,而工作面煤壁具有向采空区运动的趋势,煤壁上方最大位移约为0.24 m;覆岩位移呈左右对称,保护层顶板最大位移为0.90 m,主采煤层顶板最大位移为0.40 m,均发生在模型中部。

     

    Abstract: In order to investigate the overburden displacement and pressure relief effect of near-distance coal seam group, the PHASE 2D finite element software was used to develop a numerical model for single protective layer with a consideration of the goaf compaction.The overburden stress evolution ahead and behind the working face, the development of plastic zone of coal wall, and the displacement of surrounding rocks in the face area and overburden were obtained.The results show that: The support pressure coefficient grew first and then stabilized in the goaf.The largest abutment pressure coefficient of 1.73 occurred at 4 m ahead of the face.The recover pressure in the gob area was not restored due to the pressure relief of the protective layer mining.The width of plastic zone of working face at the main coal seam increased first and then stabilized with the maximum width of 2.50 m.The roof in the face area squeezed the coal wall, which showed a tendency of movement to the gob direction.The maximum displacement of the coal wall was 0.24 m at the top position.The overburden displacement was symmetrical.The maximum displacement of the roof were 0.90 and 0.40 m for the protective layer and the main coal seam, respectively.

     

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