西部矿区特大采高工作面覆岩破断运移全周期动态演化特征

The whole-cycle dynamic evolution characteristics of overburden fracture and movement in extremely high mining longwall face in western mining area

  • 摘要: 为探索西部矿区特大采高工作面覆岩的损伤破断结构特征及运动规律,以上湾煤矿8.8 m特大采高工作面为背景,采用现场实测、物理模拟等方法研究中等埋深、厚覆岩地质特征和固有采动损伤条件下覆岩破断垮落过程及其时空演化规律。结果表明:覆岩破坏高度随工作面推进呈现“台阶式”上升的演化过程,揭示特殊地质条件下特大采高工作面覆岩的“三带”破断模式以及主控岩层上方组合厚软岩层缓冲层对采动损伤的抑制作用;基本顶以“切落体”形式垮落于采空区,而主关键层则形成“砌体梁”结构;覆岩以“协同下沉组”形式破断沉降,且不同层位岩层沉降量随埋深减小而减小,地表随厚软岩层的弯曲下沉形成均匀沉降,下沉系数达0.58。

     

    Abstract: In order to explore the structural characteristics and movement laws of overburden damage and fracture in the extremely high mining longwall face in the western mining area, the 8.8 m extremely high mining longwall face of Shangwan Coal Mine was used as the research background. Based on the field measurement results, physical modeling and other methods, the geological characteristics of medium burial depth, thick bedrock and inherent mining damage conditions of overlying rock damage and its spatiotemporal evolution process were studied. The results show that: the damage height of overlying rock shows a "stepwise" development and evolution process. It reveals the "three-zone" fracture mode of overlying rock in extremely high mining longwall face under special geological conditions and the restraining effect of the combination of thick and soft rock layers above the primary key strata on mining damage. The main roof collapsed in the goaf in the form of a "caved rock block", while the primary key strata formed a "masonry beam" structure. The "non-uniform" characteristics of overlying rock subsidence were formed in the form of "collaborative subsidence groups" when the overlying rock broke and settled. The subsidence of overlying rock showed the non-linear decrease with the decrease of burial depth, and the surface movement was uniform with the bending of thick and soft rock layers, with the subsidence coefficient of 0.58.

     

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