薄煤层开采顶板三带可视化探测方法研究

    Research on visualization detection method of overlying strata three zones in thin coal seam mining

    • 摘要: 薄煤层资源开采受上覆煤层瓦斯影响严重,采空区覆岩“三带”范围的探测对安全生产具有重要意义。基于此,开展了煤岩加载电阻率测试实验,分析了煤岩受载破坏过程中电阻率变化和分布规律,并根据现场实际进行了覆岩“三带”埋深规律理论分析及数值模拟,然后开展现场测试。应用直流电法进行的工作面电法测试正演“三带”视电阻率分布规律主要结论如下:煤样裂隙的扩展导致电阻率的变化,其电阻率突增点与煤岩破坏点具有良好的对应性;煤岩受载破坏过程中,电阻率等值线图在载荷作用下存在异常区域,且随煤岩受载产生的不均匀变形产生迁移;煤层开采中采空区受到割顶后集体下沉,将会在采空区上部的裂隙区形成较大的割裂区域,这部分割裂区域内部存在着较大的裂隙,并且会扩展到回风巷顶板岩层中,导致岩层中裂隙增加。电法探测结果表明:实践矿井工作面到垮落带水平距离约为20 m左右,断裂带影响阻值变大,其高度为17 m,该结果与理论计算及数值模拟结果一致。

       

      Abstract: The mining of thin coal seam resources is seriously affected by the overlying coal seam gas. The detection of three zones of goaf roof is of great significance to the safety production. In this paper, we carried out loading coal and rock resistivity testing experiment, analyzed the loading damage in the process of coal and rock resistivity change and distribution, and carried on the theoretical analysis and numerical simulation of overlying strata three zones according to the actual embedded depth, and then carried out field test. Direct current method has been used to test the forward three-zone apparent resistivity distribution. The main conclusions are as follows: the resistivity changes due to the crack propagation of coal samples, and the resistivity surge point corresponds well with the failure point of coal and rock; in the process of coal and rock failure under load, there are abnormal areas in the resistivity cloud diagram under load, and it migrates with the uneven deformation of coal and rock under load; the collective subsidence of the goaf after the roof is cut in the coal seam mining will form a large sectioned area in thefracture area of the upper part of the goaf. There are large cracks in this part of the sectioned area, and it will extend to the roof rock of the return air roadway, resulting in the increase of cracks in the rock; the electrical detection results show that the horizontal distance from the working face to the caving zone is about 20 m, and the influence resistance value of the fracture zone becomes larger and its height is 17 m, which is consistent with the theoretical calculation and numerical simulation results.

       

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