高压奥灰水大型逆断层下盘煤层安全开采研究

 在底板高压岩溶含水层上且靠近较大断裂构造弱面采矿时，隔水层段的残余厚度和断裂的采动活化程度是能否突水的关键因素。为探索这类问题，以徐州矿区柳新煤矿在大型逆断层下盘带高压奥灰岩溶水开采深部煤层为实验现场，根据奥陶系顶部存在隔水层的观点，对该逆断层进行数值模拟、力学及演化的地质历史分析、探测和现场渗透性实验后，完成工作面的安全保水试采。试采结果表明：该矿井田内的奥陶系顶部存在厚约118 m碳酸盐岩隔水层，该隔水层由充填带和岩溶不发育带构成；逆断层天然状态下不导水，工作面开采造成了下盘煤层至上盘奥陶系顶板逆断层面(约60 m)的局部活化，而处于奥陶系顶部隔水层段内的断层面未被活化。若上盘奥陶系顶板就是岩溶含水层顶板，则在高水压的驱动下岩溶水将沿逆断层活化段向工作面渗透而造成突水。奥陶系顶部碳酸盐岩隔水层和断层天然不导水是工作面贴近断层开采而不发生突水的主要原因。

RESEARCH ON WATER-RESERVED MINING WITH HIGH WATER PRESSURE UNDER LARGE-SCALE THRUST-FAULT IN ORDOVICIAN KARST

The residual thicknesses of aquifuge and mining reactivations of the fault are the key factors to control the water inrush when mining is near the large-scale fault with karst aquifer under the floor. Taking the mining working face of deep coal seam under large-scale thrush-fault with high water pressure of Ordovician karst at Liuxin mine in Xuzhou mining area as a case，the numerical simulation，the mechanical analysis and the geological evolution process have been performed based on the viewpoint that aquifuges exist in Ordovician top and can be considered as key aquifuges，which can guarantee the safe mining of the working face. The research results show that in the experimental area，there are carbonatite aquifuge about 118 m in thickness，in which the karst cave is refilled and undeveloped. The fault in natural state is not water-conducting one；and the part of thrush-fault between coal seam in drop side and the Ordovician roof(about 60 m) in upthrust side is reactivated by mining，but the part of thrush-fault in top Ordovician aquifuge is not reactivated. If the Ordovician top is saturated with karst water，the water driven by high water pressure may infiltrate to the working face along the reactivation part of fault，which means the water inrush will occur. The aquifuge existing in Ordovician top is the primary reason for the mining safely around the fault.