软弱覆岩区重复采动煤层导水裂隙带高度研究

Height of water-conducting fracture zones during repeated mining coal seams in weak overlying rock areas

  • 摘要: 针对蒋庄煤矿软弱覆岩煤层重复采动覆岩裂隙演化特征,采用实验室测试、现场实测与数值模拟相结合的方法,分析了上覆岩层岩性及力学性能,探测了导水裂隙发育情况,建立了重复采动数值计算模型与相似试验模型,研究了重复采动覆岩移动变形特征。结果表明,顶板覆岩多为砂岩和泥岩,岩石质量中等,属典型软弱覆岩;覆岩导水裂隙带发育高度68~82 m,裂采比为17.0~20.5,则导水裂隙带高度约为20.5倍采高;重复采动后覆岩水平应力值和垂直应力值均增大,尤其是位于采空区上部的覆岩,其水平应力增加显著,原有的裂隙、离层再次发育导致导水裂隙带高度增加,为类似煤层赋存地质条件研究覆岩裂隙带发育高度提供借鉴。

     

    Abstract: In response to the evolution characteristics of overlying rock fractures caused by repeated mining in the weak overlying coal seam of Jiangzhuang Coal Mine, a combination of laboratory testing, on-site measurement, and numerical simulation was used to analyze the lithology and mechanical properties of the overlying rock layer.The development of water conducting fractures was explored, and a numerical calculation model and similar experimental model for repeated mining were established to study the movement and deformation characteristics of overlying rock caused by repeated mining.The results show that the overlying rock of the roof is mostly sandstone and mudstone, with moderate rock quality, belonging to typical weak overlying rock; The development height of the overlying rock water conducting fracture zone is 68~82 meters, and the fracture mining ratio is 17.0-20.5.The height of the water conducting fracture zone is about 20.5 times the mining height; After repeated mining, the horizontal and vertical stress values of the overlying rock increase, especially for the overlying rock located in the upper part of the goaf.The horizontal stress increases significantly, and the original fractures and separation layers develop again, leading to an increase in the height of the water conducting fracture zone.

     

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