The Study On Hydraulic Flushing Technology For Outburst Prevention In Low-gas-permeability And High-gas Coal Seam

In this paper, the hydraulic flushing technology in high-stress and low gas permeability coal seam of Mengzhuang Mine is studied, using the combined methods of theory analysis, computer simulation and filed test. The mechanism of outburst prevention with hydraulic flushing measure was put forward and analyzed, based on the theory of gas flow and storage in coal seams and the theory of water-jet. The mathematical model of hydraulic flushing measure used in floor pump drainage Lane was established, simulated by the numerical simulation software of ANSYS, which take coal seam 3 of Menzhuang coalmine as the research object. Simulation results show that coal body stress around drilling hole is reduced under the effect of the high pressure fluid, and generate continuous displacement in the drilling direction, enlarging the range of pressure relief of the drilling holes and improving the permeability of the coal. Through experimentation of hydraulic flushing technology on floor pump drainage lane of faceⅣ315 in Mengzhuang Mine, the application effect of hydraulic flushing measure is analyzed and the technology system and equipment selection of hydraulic flushing are introduced. The result shows that the amount of extracted gas increase from 0.10m3/min to 0.45m3/min with the implementation of the hydraulic punching measures, and gas drainage rate increased 4.5-fold, so that indicators of outburst is not overrun in the process of roadway excavating, eliminating the risk of coal and gas outburst effectively. With this measures the speed of roadway excavating was increased 2 times or more, making excavating in the outburst coal seam safely and effectively.Figure [35] Table [23] Reference [55]...