Time and space effect of water gushing from drainage borehole in coal mine and controlling drainage to prevent roof water disaster in coal seam

Considering the lack of scientific basis for extensive drainage treatment of coal mine roof water disaster, this paper firstly analyzed the time-varying effect of drainage borehole water inrush process, and taken the borehole water inrush quasi stable period as the drainage control period to control the roof water disaster. secondly, according to the characteristics of water gushing in the coal seam roof water filled aquifer, that was the superposition of static water storage and dynamic recharge, the paper proposed that the maximum pre-drainage (dry) of underground water static reserves in the area affected by water flowing fractures was a reasonable method to reduce the roof concentrated water gushing in the process of peak shaving and valley leveling. Thirdly, based on the spatial development law of mining induced water flowing fractures, the upper limit of mining induced water flowing fracture zone was taken as the final hole position of drainage borehole and the predicted fracture angle of mining induced fracture zone was taken as the elevation angle of drainage borehole, that reduced the static reserves of water filling aquifer to the maximum extent. The fourth was the comprehensive drilling engineering economy and drainage efficiency. It proposed an optimization mode of the hole layout construction mode that had less than 3 boreholes in the single drilling field and the 60° of included angle According to the water inflow characteristics of coal seam roof in different successive mining faces, the drilling construction mode of first mining type two lane drainage and adjacent mining type single lane drainage was determined. Finally, according to the space-time effect of water inrush from drainage boreholes in coal mines, this paper put forward the drainage mode of roof water disaster control in coal mining face from two aspects of drainage boreholes spatial layout and drainage cycle identification. The research results had guiding significance for the practice of roof water disaster scientific drilling in western mining areas in China. © 2023 China University of Mining and Technology. All rights reserved.