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浅埋深厚煤层高强度开采地表沉陷规律研究

Research on surface subsidence law in high-intensity mining of shallow buried with thick coal seam

  • 摘要: 以西部神东矿区大柳塔煤矿为工程背景,选取典型的浅埋深高强度开采工作面52307工作面为研究对象,设立地表岩移观测站,并结合RTK观测技术与三维激光扫描技术进行实时监测,基于关键层理论和CISPM综合地表沉陷预计模型软件,综合分析在浅埋深高强度开采条件影响下,地表移动变形特征、地表岩移角值参数变化以及地裂缝发育等问题。研究结果表明:在工作面从开切眼向前推进过程中,地表下沉值在开切眼位置较小,之后突然迅速增大,下沉曲线急剧变陡,当达到最大下沉值时,下沉速度开始变缓;地表移动变形主要集中在工作面中部,工作面四周下沉变形较小,地表移动影响范围较小;大柳塔矿区地表岩移角值参数偏大,基岩移动角和边界角分别达到了87.7°和84.1°。开采引起的地裂缝整体呈“C”字型主要分布在工作面中部;随着工作面的不断推进,地裂缝从开切眼位置开始继续向回风巷一侧缓慢延伸、发育并逐渐闭合,最终形成连续包围“漏斗”型形状;地裂缝总是滞后于工作面出现,地裂缝滞后距与工作面推进速度呈线性增大的关系。根据地表沉陷规律及地裂缝发育分析结果得出,在浅埋深厚煤层高强度开采条件下,由于工作面开采强度大、推进速度快、关键层结构单一且赋存层位低,引起顶板活动剧烈、易滑落失稳,从而造成地表下沉盆地四周收敛快、中部破坏严重,地裂缝发育密集。

     

    Abstract: Taking Daliuta Coal Mine in Western Shendong mining area as the engineering background, this paper selected typical shallow buried high-intensity mining panel 52307 to establish the observation station for surface movement. Combined RTK technology and 3D laser scanning technology for real-time monitoring, based on key layer theory and CISPM comprehensive surface subsidence prediction model software, the characteristics of surface movement and deformation, surface movement angular parameters and surface cracks in high-intensity mining of shallow buried was studied. The results showed that with the advance of the panel from the set-up room, the surface subsidence was small at the set-up room position and then increased suddenly and rapidly. Simultaneously, the subsidence curve became steep sharply. When the maximum subsidence value was reached, the subsidence velocity tended to slow down. The surface movement deformation was mainly concentrated in the middle of the panel, while the subsidence deformation around the panel and the influence range of surface movement was small. The surface movement angular parameters were quite larger in the Daliuta coal mine area, while the bedrock movement angle and boundary angle reached 87.7 ° and 84.1 ° respectively. The surface cracks caused by mining were in an overall “C” shape, mainly distributed in the middle of the panel. Then, As the working face continued to advance, the ground fissures continue to slowly extend, develop, and gradually close from the set-up room to the tailgate side, eventually forming a continuous surrounding "funnel" shape. Ground fissures always lagged behind the working face position and the lag distance of surface cracks increases linearly with the mining speed. According to the analysis of surface subsidence law and surface cracks development, it was concluded that under the condition of high-intensity mining of shallow buried with thick coal seam, due to the high mining intensity of the working face, fast advancing speed, single key layer structure and low occurrence horizon, the roof activity was intense and easy to slide and lose stability. As a result, it was appeared resulting in rapid convergence around the surface movement basin, serious damage in the middle, and intensive development of ground fissures.

     

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