8.8 m超大采高综采工作面顶板水害动态监测技术研究

Study on dynamic monitoring technology of roof water disaster in 8.8 multra-high fully mechanized working face

针对上湾煤矿8.8 m超大采高综采工作面回采过程中顶板可能存在的水害隐患,采用视电阻率监测系统对工作面回采至石灰沟段顶板裂隙导通上覆含水层的情况进行了分段动态监测,结合地面水文观测孔及工作面涌水量对监测结果进行验证,并划分顶板水害预警级别。结果显示:在采空区内有明显的高阻异常发育,分析为煤层采空后顶板冒落导致上覆岩体裂隙增大所致。随着工作面的推进,在距离切眼1576~1766 m、1842~2260 m范围内存在低阻异常区,分析认为导水裂隙带导通了上覆含水层;通过查看井下采空区涌水和地面水文孔观测数据,验证了视电阻率监测结果。根据视电阻率监测情况对12401工作面顶板水害预警级别进行了评估,该工作面水害风险预警级别为二级预警,水害风险一般。

In view of the hidden water disaster in the roof of 8.8 m ultra-high fully mechanized working face in Shangwan Coal Mine,the apparent resistivity monitoring system was used to monitor the situation of roof crack connecting the overlying aquifer when mining into the Shihuigou section.The monitoring results were verified by combining the surface hydrological observation holes and the working face water inflow,and the warning level of roof water disaster was divided.The results showed that there was obvious abnormal development of high resistivity in the gob,which was caused by the increase of overlying rock fracture caused by roof caving after mining out.With the advance of the working face,there were low resistivity abnormal areas in the range of 1576~1766 m and 1842~2260 m away from the cut-off.It was considered that the water flowing fracture zone could conduct the overlying aquifer.The monitoring results of apparent resistivity were verified by checking the water inflow in the gob and the observation data of surface hydrological holes.According to the monitoring situation of apparent resistivity,the early-warning level of roof water disaster in 12401 working face was evaluated as grade II,and the risk of water disaster was general.