Drainage Radius after High Pressure Water Jet Slotting Based on Methane Flow Field

Considering that the methane drainage radius cannot speedily and accurately be confirmed after high pressure water jet slotting, a model for slotting the radius of high pressure water jet slotting is established based on the theory of round turbulent jet and Loland damage model. Combining the linear seepage theory and nonlinear seepage theory, this paper proposes the seepage model for various seepage statuses around the slot. The methane drainage radius after using a high pressure water jet consists of three parts: slotting radius, linear seepage area and nonlinear seepage area. Taking Zhongliangshan Mine as an example, the calculated results show that the slotting radius is 1.57m. The linear seepage areas range from 1.57m to 4.81m, and the nonlinear seepage areas range from 4.81m to 9.36m from the center of borehole, respectively. Field experimentation shows that the radius of slotting reaches 1.5m. The effective drainage radius is 5m and the radius of influence is 9m. It is relatively consistent with the theoretical calculations.