Optimization of advance drainage borehole layout based on Visual Modflow

Abstract It is an effective measure to prevent water damage in coal mine to construct drainage borehole in water-filled aquifer of working face roof. The hydrogeological parameters of the roof water-filled aquifer and the parameters of the drainage borehole are closely related to the underground drainage effect. Taking the 3085 working face of Donghuantuo Mine in Kailuan as an example, the influence degree of hydrogeological parameters and hydrophobic borehole parameters on the amount of drainage water was analyzed through the generalized grey correlation degree. Based on Visual Modflow, the 3D groundwater visualization model is established, and the dredging borehole is generalized into pumping borehole. By changing the main influencing factors, the design optimization of advanced hydrophobic borehole is discussed. The results show that the aquifer thickness has a great influence on the amount of water discharged, and the influence degree of the sharp angle between the formation and the direction of drilling, the depth of the final hole, the azimuth angle of drilling, the dip angle of drilling, the elevation of the final hole and the elevation of the borehole on the amount of water discharged decreases successively. Based on the simulation calculation, it can be observed that the hydrophobic borehole should be placed in the position with larger accumulated thickness of aquifer to have a better effect of hydrophobic depressurization.