The Research On Gas Fracturing Technology For Outburst Prevention In The Coal Roadway Tunneling In Xin Yuan Mine

Gas fracturing technology belongs to the new technology of non-explosive crack,belong to the intrinsically safe technology,which has many advantages than explosive,and it is very practical in the process of the management of coal and gas outburst,a large number of engineering application test has proved its reliability and validity.Carbon dioxide gas fracturing technology is through the liquid carbon dioxide converted into gas and instantaneous expanding power in coal,which can transfer the ground stress,increasing the coal cracks,improve the amount of gas extraction,reduce the gas pressure,reach the purpose of outburst elimination,Manufacturing crack and pressure reliving of the gas fracturing is the key technology for the management of coal and gas outburst.The gas fracturing test is carried out in 31004 assisted ventilation airway and return airway of Xin yuan mine in Yang quan mining area,the test adopts three projects,during the process of test,research the effect of different projects:gas extraction,dynamical phenomenon of power-released hole's construction,the test of K1,driving speed and the influenced radius of gas fracturing,which has achieved good results,explore suitable method of gas fracturing for outburst mines in Yang quan mine area.The results of test as follows:1.In the process of excavating in coal roadway,the effect of 60 m double-drill's is best,80 m double-drill's gas fracturing if want to ensure the optimal effect,the number of fracturing pipe should be above 25.2.Through the implementation of the gas fracturing,the dynamical phenomenon of power-released hole's construction is reduced and the amount of power-released hole is reduced,the speed of construction becomes faster.3.The exception of K1 slashed mostly,tunneling speed increased,compared with the same geological condition of tunneling faces,the speed increased to 1.8~2.25 times,realized the purpose of safely and fast drive.4.Through the theoretical calculation and micro-seismic test,it is concluded that the influence of gas fracturing radius is about 15 m.Through analysising the effect of gas fracturing in tunneling face,summarizes gas fracturing mechanism of outburst prevention.Manufacturing crack and pressure reliving is the key technology for gas fracturing,Cracks is made by high pressure gas jet and eventually quasi static gas successively,pressure reliving can reduce the stress gradient and eliminate the stress concentration,After the pressure reliving of coal can make the permeability increase and this will prompt the gas desorption,So gas fracturing has the double-effect of pressure reliving and permeability increasing.Put forward the concept of scope of pressure reliving and protrusion-dispelling,indicate that scope of pressure reliving and protrusion-dispelling can effectively prevent the outburst.