巨厚煤层综放工作面断层活化导水规律研究

Study on water conducting law of activated fault in fully mechanized top-coal caving face in extremely thick coal seam

采煤工作面存在断层时,采动影响可能会造成断层活化形成新的导水通道,造成突水灾害。鉴于此,龙王沟煤矿在现有断层活化数值模拟成果的基础上,以巨厚煤层综放工作面过断层为工程背景,通过微震监测、水量监测和电阻率监测等技术方法,动态监测断层活化状态及垂向导水裂隙的发育情况,对断层活化导水的规律进行研究。研究表明:微震监测发现采面距离断层400 m时断层即进入准静态阶段,距离断层157 m时断层进入活化阶段,通过断层与巷道交叉点后应力释放恢复至原岩状态;断层进入活化状态后微震能量增大,使导水裂缝带导通部分含水层至采空区,出水量增大;电阻率监测到断层底板区域存在横向发育的低阻异常区,采动影响未发育新的垂向导水通道至奥陶系灰岩含水层,工作面安全回采通过异常区。根据工作面过断层期间断层活化导水的规律,提出了相应的监测防治技术,保障工作面的安全开采。

Mining influence may cause fault activation in coal mining face to form new water channel,resulting in water inrush disaster.On the basis of the existing fault activation numerical simulation results,taking the fault crossing of fully mechanized top-coal caving face in extremely thick coal seam as the engineering background,the fault activation state and vertical water-conducting fracture development condition were monitored dynamically by the micro-seismic monitoring,water monitoring method and resistivity monitoring technology,and the water conducting law in activation fault was studied.The micro-seismic monitoring results show that the fault enters the quasi-static stage when the mining face is 400 m away from the fault,and enters the activation stage when the mining face is 157 m away from the fault,and the stress releases and recovers to the original rock state after the mining face passing the intersection of the fault and the roadway.After the fault entering the activated state,the micro-seismic energy increases,the water conducting fracture zone leads part of the aquifer to the goaf,and the water yield increases.The resistivity monitoring results show that there is a low resistivity anomaly area with transverse development in the fault floor area,and no new vertical water conducting channel is developed to the Ordovician limestone aquifer due to the influence of mining,so the working face can safely advance through the anomaly area.According to the law of fault activation and water conducting during the working face crossing the fault,the corresponding monitoring and control technology is proposed to ensure the safe mining of the working face.