CO_2 controllable phase transition fracturing and outburst prevention technology of gateway driving face in outburst seam

According to the poor seam permea ilt chficult sean gas drainage high geostess and other features of the seam gateway driving face in the trial mine,in ordertorealize a raid and safetydrving in the outbust seam.with the theoretical analysis and indutraltra method. a CO 2 controlable phase ranstion frcturingand cuburst prevention tfechnology suitable for the seam gateway driving facein the tial mine was provided.The efiectiveness suitability and satetyof the Co_2 contolable phase trn stion fracturing and outburst prevention technology was systematically evauated. The study resuis showed that,the energy power occured from thec0_ liuid and gas phase ransition vas used to cut cuting piece in CO 2 contrllable hase trnstion frcturing.and generate stress waves and high pressure gas, which would improve the seam permeatilly so as to reach the coal and gas outbust prevention target.The rall of the 500 m drving gateway showed that afer fracturingwith the C_2 conrllable phase transiiton frcturing and outburst prevention technology in the seam drving face.the gas desorption index of the driling cuttings wouldbe 50% lower than using the outburst prevention technology with conventional intensive discharging borehole,the gas drain age volumne vould beincreased about to tmes and the safety driving speed of the gateway would be increased by over 1.5times.