慈林山矿煤层群下部采场覆岩运移规律

    Overburden Migration Law of Lower Stope in Cilinshan Mine Coal Seam Group

    • 摘要: 煤层群下部煤层开采,上部工作面与下部工作面双重扰动作用会加剧覆岩运移,覆岩原、次生裂隙发育演化形成导水裂隙,顶板、采空区水会极大地制约下部工作面安全、高效开采。为解决此类工作面开采难题,采用相似材料实验、理论分析法,对慈林山矿煤层群下部煤体开采时覆岩运移规律等进行研究。研究结果表明:慈林山矿煤层群下部工作面初次来压步距为55 m,平均周期来压步距18.7 m,岩体垮落角在煤壁侧大于切眼处,下部煤体开采会扰动上部工作面煤柱,破断裂隙会贯通上部工作面采空区,且在上部壁式工作面一侧不易闭合,进而演变为导水裂隙,使下部工作面遭受岩体冲击、采空区水威胁,覆岩运移量由下至上具有降低—升高—降低演变特性,上部工作面覆岩沉降量整体较下部工作面大。

       

      Abstract: Double-action of upper and lower faces will aggravate the overburden migration, primary and secondary fractures develop into water flowing fractures during lower coal seam mining coal seam group, the water in roof and gob will greatly restrict the safe and efficient mining of the lower working face. In order to solve the mining problem of such face, the similar material experiment and theoretical analysis method are adopted to study overburden migration and the laws of overburden migration of coal seam in the lower working face of Cilinshan Mine is studied. Results show that the first and average periodic weighting distance of Cilinshan Mine lower mining face is 55 m and 18.7 m, the collapse angle of the rock mass is greater than the cut hole in the side of the coal wall, lower face mining will disturb the coal pillar in the upper face, broken fracture will penetrate the gob in upper face and be not closed easily on the side of the upper wall face, and then evolve into water flowing fracture, the lower face will suffer from rock impact and water threat in goaf, overburden migration has reducing-increasing-reducing evolution characteristics, upper face overburden settlement is larger than the lower face.

       

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