巨厚古近系含水层下工作面导水裂隙带高度探查

Height detection of water conduction fracture zone in working face under thick Paleogene aquifer

为了确定巨厚古近系含水层下工作面的开采上限、预测涌水量及制定防治水方案,需要针对工作面的导水裂隙带进行现场实测。以红四煤矿HI0503工作面为研究对象,采用经验公式初步确定导水裂隙带发育高度,设计井下探查钻孔的参数。分别用0.5、1.0和1.5 MPa的水压进行压水试验,同时采用钻孔窥视对工作面覆岩中的裂隙发育程度进行观测,最后利用数值模拟对现场实测的结果进行验证。结果表明,压水试验得到HI0503工作面导水裂隙带高度为65.6~67.4 m,采用钻孔窥视法确定导水裂隙带高度为66.5~68.1 m,导水裂隙带高度数值模拟结果为65.29 m,利用3种方法综合确定HI0503工作面导水裂隙带高度为65.29~68.1 m,大于经验公式计算值59.79 m。5-2煤与巨厚古近系含水层的平均距离为95 m,工作面开采后的导水裂隙带不会波及至古近系含水层。通过现场验证,利用井下压水试验、钻孔窥视和数值模拟,综合确定的导水裂隙带高度与实际情况较为吻合,可以作为防治水工作的依据。

In order to determine the mining upper limit of the working face under the thick Paleogene aquifer,predict the water inflow and formulate the water prevention and control scheme,it is necessary to carry out field measurement on water conduction fracture zone of the working face.Taking the No.HI0503 face of Hongsi Mine as the research object,the development height of water conduction fracture zone was preliminarily determined by empirical formula,and then the parameters of underground exploration borehole were designed.The water pressure test was carried out with 0.5 MPa,1.0 MPa and 1.5 MPa water pressure respectively.At the same time,the fracture development degree in the overlying rock of the working face was observed by drilling peeping.Finally,the results of field measurement were verified by numerical simulation.The results showed that the height of water conduction fracture zone in No.HI0503 face was 65.6-67.4 m by water pressure test.The height of water conduction fracture zone was determined to be 66.5-68.1 m by drilling peeping method.The height of water conduction fracture zone was 65.29 m by numerical simulation.The height of water conduction fracture zone in No.HI0503 face was determined to be 65.29-68.1 m by three methods,which was 59.79 m higher than the calculated value of empirical formula.The average distance between the No.5-2 coal seam and the thick Paleogene aquifer was 95 m,and the water conduction fracture zone after mining of the working face would not affect the Paleogene aquifer Through field verification,the height of water conduction fracture zone determined by underground water pressure test,drilling peeping and numerical simulation was in good agreement with the actual situation,which could be used as the basis for water prevention and control.