兴运煤矿河流下厚煤层开采安全性分析和防控技术

Safety analysis and prevention and control technology of thick coal seam mining under river in Xingyun coal mine

为掌握厚煤层开采覆岩破坏及导水裂隙发育规律,综合运用理论分析、数值模拟、地表钻孔冲洗液漏失量现场观测和钻孔电视相结合的研究方法,对某矿工作面煤层上方覆岩破坏及导水裂隙发育规律进行了研究。提出了河流下厚煤层开采覆岩导水裂隙带发育高度计算方法,揭示了厚煤层开采覆岩破坏形态及裂隙发育过程,分析了河流下采煤安全性,开展了河流下煤层开采地表河流综合防治技术研究并进行了实施。结果表明:研究区河流下厚煤层开采的导水裂隙带高度为118.5 m,裂采比为21.5;理论分析和数值模拟得到的导水裂隙带发育高度与现场实测结果一致,导水裂隙带高度呈阶梯形上升,每个阶段均有突增点,基本顶周期性破断后,基本顶上覆岩层易发生整体断裂下沉,最终表现为阶段稳定及突增现象;导水裂隙带在埋深较浅处(如河床)将直接发育到地表,没有防水安全煤岩柱;针对河流下厚煤层开采安全问题,提出了河流下采煤的安全技术措施,包括地面河流水体处理、河底内封堵导水通道、井下防治水等,彻底解除了河流下采煤的安全隐患,实现了河流下厚煤层安全开采。

A comprehensive method including theoretical analysis,numerical simulation,observations of surface borehole flushing fluid loss and borehole television was conducted to investigate the law of overlying strata failure and waterconducting fracture development above coal seam in working face of a mine.This paper proposed the method to predict the height of waterconducting fracture zone of overburden rock in thick coal seam mining under river,revealed the failure form and fracture development process of overburden in thick coal seam mining,analyzed the safety of coal mining under rivers,and carried out the research and implementation comprehensive prevention and control technology for surface rivers in coal mining under rivers.The results show that the height of waterconducting fracture zone is 118.5 m and the fracturemining ratio is 21.5 in thick coal seam mining under rivers.The height of waterconducting zone obtained by theoretical analysis and numerical simulation is consistent with the insitu measurement results.The height of the waterconducting fracture zone show a step change,and there is a sudden increase point at each stage.The overlying strata over main roof are prone to integral fracture and subsidence after the periodic fracture of the main roof stratum,which finally shows stage stability and sudden increase.In the place where the coal seam is buried at a shallow depth,such as in the riverbed area,the development height of the waterconducting fracture zone will directly reach the surface,without waterproof safe coal rock pillar.In view of the safety problems of thick coal seam mining under rivers,the safety technical measures of coal mining under rivers are put forward,including the treatment measures of surface water,the sealing of waterconducting channels in the riverbottom,underground water control measures and other measures,which have completely removed the safety hazards of coal mining under rivers and realized the safe mining of thick coal seam under rivers.