Analysis on Mechanism of Drilling Induced Outburst and Prevention Measures

In order to analyze the coal and gas outburst mechanism occurred from the gas drainage borehole drilling and the gas outburst prevention borehole drili ng processing at the working face in the underground mine, the outburst processing occurred from the borehole drilling was analyzed.From the strength and hardness 0 f the coal and rock in the working face, the three zone distribution law of the working face, the stress and strain full process conditions of the seam, the ground stress re leased the borehole, the plasticity zone radius of the coal and rock around the borehole, rheology mechanism of the coal and rock and others, a theoretical analysis wa s conducted on the outburst. The study results and the engineering practices showed that the boreholes in the coal mining face could effectively drain the seam gas in t he coal mining face, reduce the seam gas pressure, enhance the length of the pressure releasing zone in the coal mining face, enhance the thickness of the outburst pr evention curtain in the coal mining face and have the outburst prevention effect. But the intensive boreholes drilled in the coal mining face would destroy the previous str ucture of the coal and rock, reduce the previous hardness and strength of the coal and rock and reduce the strength of the outburst prevention curtain in the coal minin g face.Meanwhile the disturbances occurred during the borehole drilling process could increase the danger of the outburst and thus the borehole drilling in the coal mini ng face would have double roles of the outburst prevention and the outburst induced.