河流下综放工作面覆岩破坏特征和陷落柱防水煤柱留设研究

Study on overburden failure characteristics and collapse column waterproof coal pillar design in fully-mechanized top coal caving face under river

目的长平矿Ⅲ2317工作面在开切巷处揭露陷落柱,地表丹河流向与工作面推进方向一致,受采动影响,陷落柱内部水体及河水可能通过开采裂隙导入回采空间,从而造成工作面突水。针对以上问题,方法本文采用理论分析、数值模拟和现场观测等方法,对回采工作面覆岩“两带”高度、覆岩破坏特征和陷落柱煤柱留设宽度进行研究。结果结果表明:工作面顶板垮落带与导水裂隙带最大发育高度分别为18.38,93.85 m,河水对工作面不构成突水威胁;无煤柱开采时,陷落柱一侧顶板裂隙沿陷落柱胶结面向上高度发育;结合理论计算和数值模拟分析,确定煤柱宽度为35 m。工作面在留设35 m煤柱条件下安全完成回采,地表变形特征符合预期,最大下沉量达到4000 mm,回采过程中工作面未发生突水事故。结论研究结果可为类似条件下的煤层安全开采提供理论和经验支撑。

Objectives TheⅢ2317 working face of Changping Cole Mine exposed the SX20 collapse column at the open-off cut.The surface Dan River flows in the same direction as the advancement of the working face.Affected by mining,the water in the collapse column and the river may flow into the working space through the mining fissures,potentially causing water inrushes in the working face.Methods This study in‐vestigated the“two-zone”height of the overburden,overburden failure characteristics,and the width of the collapse column coal pillar using theoretical analysis,numerical simulation,and field observation.Results The results showed that the maximum development heights of the roof caving zone and the water-conducting fissure zone were 18.38,93.85 m,respectively.The Dan River water did not pose a water inrush threat to the working face.When mining without coal pillars,roof damage on the collapse column side developed upwards along the cemented face of the collapse column.Combining theoretical calculations and numerical simulations,the coal pillar width was determined to be 35 m.The working face was safely mined with a 35 m coal pillar left in place.Surface deformation characteristics met expectations,with a maximum subsidence of 4000 mm.No water inrush incidents occurred during the recovery process.Conclusions The research results could provide theoretical and empirical support for the safe mining of coal seams under similar conditions.