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倾斜特厚煤层上分层开采时下分层煤体载荷及渗透率演化规律研究

Load and permeability evolution law of lower layering in upper slicing of inclined extra-thick coal seam

  • 摘要: 为了得到倾斜特厚煤层上分层开采时下分层煤体载荷及渗透率演化规律,以新疆硫磺沟煤矿9-15(06)工作面为研究对象,构建了采空区底板应力传递模型,模拟了随着上分层推进时下分层煤体载荷演化过程,并以此为下分层采集煤样应力路径,开展了下分层含瓦斯煤应力加卸载实验,得到了下分层煤体渗透率演化规律。结果表明:随着上分层推进,下分层煤体垂直应力经历了原岩应力、应力增加至支承应力峰值、支承应力峰值后卸压、应力升高恢复稳定;沿煤层倾向,下分层煤体进入采空区后,由倾斜上部至下部,煤体应力最大恢复程度逐渐增加;下分层煤体渗透率经历了初始渗透率、渗透率下降、渗透率上升、渗透率突增、渗透率降低恢复稳定;不同位置煤体进入采空区后,渗透率最大恢复程度随应力最大恢复程度的升高而增加。研究结果为揭示下分层煤体瓦斯涌出时空演化规律奠定了基础。

     

    Abstract: In order to obtain the load and permeability evolution law of lower layering in upper slicing of inclined extra-thick coal seam, taking the 9-15 (06) working face of Xinjiang Liuhuanggou Coal Mine as the research object, the stress transfer model of the floor in goaf was constructed. The development of coal load in lower layer were simulated during the advancing process of the upper layering, then taking this as the stress path of lower layering coal samples. The stress loading and unloading experiments of lower layering gas-bearing coal were carried out, and the permeability evolution law of lower layering coal was obtained. The results show that, with the advancement of the upper layering, the vertical stress of the coal in the lower layering has experienced original rock stress, stress increase to the peak value of supporting stress, pressure relief after the peak value of the support stress, stress increases to stability. Along the coal seam inclined direction, after the coal of lower laying enters the goaf, the stress recovery degree of the coal gradually increases tilt from the upper part to the lower part of the goaf. The permeability of lower layering coal has experienced initial permeability, permeability decreases, permeability increases, permeability increases sharply, permeability decreases and restores stability. After the coal at different positions enters the goaf, the maximum recovery degree of permeability increases with the expanded of the maximum recovery degree of stress. The research results lay a foundation for revealing the spatio-temporal evolution law of gas emission of lower laying coal.

     

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