The Study On Hydraulic Wetting Technology For Outburst Prevention In High-gas And Outburst Coal Seam

Coal and gas outburst is one of the most serious natural disasters and seriously threatening the safety production in coal mine.Hydraulic wetting is one of the most important production technical measures for outburst prevetion. In this paper, the combined methods of theoretical analysis, laboratory research and field trials are used. The impact of the wetting of the coal on the gas adsorption characteristics, mechanical properties of coal as well as the index of outburst is studied in lab. The effect of water moist on the mine face IV315 of Mengzhuang mine is studied by field test.The protection against outburst mechanism of hydraulic wettingin is analyzed by using the theory of coal and gas outburst at the end.Studies have shown that:the content of gas adsorption reduce with the increase of water content in coal seam as well as the gas adsorption capacity of coal fall down. The strength and elastic modulus of coal fall down, plasticity enhance, brittleness diminish and the indicators of outburst are cut down with the wetting of coal seam, with which the risk of coal and gas outburst is reduced. Water expel part of the gas in coal, and it comes into the pore and fracture of coal, plugging the channel of gas release, and that reduce the speed of gas desorption, so that the gas concentration exceeding limits problem can be set up effectively. With water wetting, the stress concentration fall significantly, and it distribute more evenly with a widened pressure relief, and the stress concentrated zone transfer to the deep coal seam. The largest coal powder quantity of bore and index of drilling chip are all decreased with hydraulic wetting measure. Hydraulic wetting have a certain degree of influence on the gas and stress distribution status, and the physical and mechanical properties of coal, with a wide range of combined function the outburst risk of gas and coal is reduced. Though theoretical analysis, laboratory studies and field test, it is proved that hydraulic wetting have broad applicability and effectiveness for the outburst prevention in high gas outburst coal seam.