Drainage feasibility of water from coal roof based on dewatering test of multi-aquifer

ZHAO Bao-feng; MA Lian-jing

doi:10.11799/ce201803019

Abstract：In order to formulate water disaster prevention and control project for roadway drivage and worLing face mining, through the dewatering test of Ⅱ aquifer and Ⅲ aquifer on the roof, the hydrogeology parameters of each aquifer are calculated based on analytical method. Combined with observation data of dewatering test, the hydraulic connection between Ⅱ aquifer and Ⅲ aquifer is ascertain, and the drainage feasibility of each aquifer is evaluated. The results show that permeability and water-bearing of Ⅲ aquifer were good, and there is a close hydraulic connection betweenⅡaquifer and Ⅲ aquifer. The drainage fesibility of Ⅲ aquifer is poor during roadway 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 ofⅡaquifer 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 worLing 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 worLing face, then, drainage feasibility is evaluated, and corresponding water disaster prevention method is formulated.