By analyzing the stress characteristics and simulating numerically the law of the stress distribution on the roadway face in coal mine, the mathematical model is established and calculated to determine the stress relaxation zone and the forming process and evolution rules of the stress relaxation zone were discussed. The stress distribution on the roadway face was measured with the electromagnetic emission (EME) technology. The testing results are in good agreement with the theoretical calculation results on the whole. The research results show that stress relaxation zone of the roadway face is related with the height of roof-floor and the inner frictional angle of the coal and the calculating model is accurate.
Coal and gas outburst is a kind of very complicated dynamic disaster of coal or rock containing gas in which the coal-rock containing gas in coal mines, in broken state, abruptly moves from the coal-rock stratum to mining space and a large amount of gas erupts (ZHAI et al, 2007, HE 1995). At present, the synthetic hypothesis about coal and gas outburst is widely recognized: outburst is the result from the comprehensive effects of crustal stress and the physical and mechanical properties of gas and coal. According to the statistics of the job sites where outburst occurred, most of outbursts took place on the roadway face and accounted for 66.2% of the outbursts, of which average outburst intensity was 66.9 t/times. Frequent outburst occurring during the mining of roadway constitutes a major threat to the life safety of coal mine workers. Effective prevention and control of coal and gas outburst is not only the safeguarding of safe production, but also the prerequisite to quicken roadway tunneling speed, eliminate outburst hazard for stoping face and extend space and time.