榆神府矿区采煤地表裂缝发育规律及特征

Development law and characteristics of surface cracks caused by coal mining in Yushenfu mining area

  • 摘要: 榆神府矿区是陕北一个重要的原煤产地,煤炭开发利用规模大、强度高,但区内生态环境脆弱,采煤诱发的矿山地质环境问题尤为显著。为全面掌握榆神府矿区采煤地表裂缝“静”、“动”态发育规律、揭示其形成机理,以榆神府矿区的安山煤矿、柠条塔煤矿和小保当一号井的典型工作面为对象开展研究。研究结果表明:① 地表裂缝分为台阶型、挤压隆起型、滑动型和拉张型4种类型以及“塌陷槽”、“平行并列”2种组合方式;② 榆神府矿区地表裂缝平面展布规律具有相对统一性,而地表裂缝表现特征具有差异性,且与采深采厚比呈负相关关系;③ 极浅埋煤层开采、浅埋煤层开采以及中深埋煤层开采地表裂缝分别具有滞后回采位置1.0 m、超前回采位置8.5 m和滞后回采位置30.14 m的动态展布规律,且地表裂缝滞后距与采深采厚比之间存在多项式的函数关系;④ 边界裂缝和面内正向坡裂缝具有“只开不合”的活动特征,面内逆向坡裂缝具有“先开后合”的活动特征,面内平坦区裂缝则具有“先开后合再开”和“先开后合”两种裂缝活动特征,平均活动时间3.7~7.0 d;裂缝“先开后合再开”的活动受覆岩运移控制,“只开不合”和“先开后合”的裂缝活动受地表移动变形控制,而斜坡裂缝活动机理则与坡体滑移密切相关。研究成果可为榆神府矿区地表裂缝治理和生态修复提供指导。

     

    Abstract: Yushenfu mining area, with large scale and high intensity, is an important raw coal-producing area in northern Shaanxi, but the fragile ecological environment makes the mine geological environment problems caused by coal mining particularly relevant. To grasp the development law of surface cracks and reveal the formation mechanism caused by coal mining in the Yushenfu mining area, the typical working faces of Anshan Coal Mine, Caragana Tower Coal Mine, and No. 1 Coal Mine of Xiaobaodang in the Yushenfu Mining area were chosen as the research object to conduct the study. The results show that the surface cracks can be divided into four types: step type, extrusion uplift type, sliding type, and tension type, as well as two combination modes of collapse, trough and parallel. In the Yushenfu mining area, the spatial distribution law of surface cracks is relatively unified. The performance characteristics of surface cracks are different and negatively correlated with the ratio of mining depth to mining thickness. The surface cracks induced by very shallow coal seam mining, shallow coal seam mining, and medium-deep coal seam mining have the dynamic law of lagging mining position 1.0 m, advanced mining position 8.5 m, and lagging mining position 30.14 m, respectively, and the relationship between the lag distance of surface cracks and the ratio of mining depth to mining thickness is a polynomial function. The characteristic of the width of boundary cracks and forward slope cracks in the working face was increased until stable. In contrast to the boundary cracks, the characteristic of the width of the reverse slope fractures increases and then decreases, and the width of the cracks in the flat area in the working face increases first, then declines, and then increases. The average activity time was 3.7–7.0 days. The crack with the activity of “opening first and then closing” is controlled by the dynamic evolution of overlying rock structure, and the fracture with the activity of “only opening and then closing” and “opening first and then closing” was controlled by surface dynamic evolution. However, the activation mechanism of slope fracture is closely related to slope slip. The findings of this study can provide theoretical guidance for surface crack control and ecological restoration in the Yushenfu mining area.

     

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