关键词: 多含水层, 放水试验, 渗透系数, 水力联系, 可疏降性

Abstract: In order to formulate water disaster prevention and control project for tunnel drivage and workingface mining, through the dewatering test of Ⅱ aquifer and Ⅲ aquifer on the roof, the hydrogeology parameters of each aquifer were calculated based on analytical method. Combined with observation data of dewatering test, the hydraulic connection between Ⅱ aquifer and Ⅲ aquifer was ascertain, and the drainage feasibility of each aquifer was evaluated. The results show that permeability and water-bearing of Ⅲ aquifer were good, and there is a close hydraulic connection between Ⅱ aquifer and Ⅲ aquifer . The drainage fesibility of Ⅲ aquifer is poor during tunnel drivage, the grouting transformation of roof aquifer and local drainage groundwater can be used to prevent and control water disaster. Compared with the pumping test, the permeability coefficient of Ⅱaquifer is bigger based on dewatering test, this result is mainly due to the drilling process, the influence of hydraulic jump and well loss. Long time dispersing drainage and short time concentrated drainage can be used before working face mining. In the case of multi-aquifer on the roof of coal seam, dewatering test can be used to explorate the condition of water disaster of working face, then, drainage feasibility was evaluated, and corresponding water disaster prevention method was formulated.