Based on the practical situation that the opening of outburst mouth is man-made controlled in experiments of coal and gas outbursts, the simulation device of outburst is designed and developed which can change axial pressure, confining pressure and pore pressure. The outburst mouth can open by itself. Sunjiawan coal mine in Fuxin is a typical high gassy mine as example, the whole processes of outburst induced are simulated by experiments on conditions of joint action of stress and gas pressure near working face when mining depth is respectively 900 m, 1 100 m and 1 300 m. In experiments, axial pressure and confining pressure are used to simulate ground stress. And pore pressure is used to simulate gas pressure. According to similarity theory, axial pressure and confining pressure are determined in advance on condition of 900 m, 1 100 m and 1 300 m. With the step-by-step increment of pore pressure, the gas pressure of outburst is obtained. The relationship curves are presented. The results show that the relationship curves are all power exponent among mining depth, axial pressure, confining pressure, gas pressure and outburst distance, outburst intensity. With depths increasing, the influences of stress and gas pressure on the intensity increment of gas outburst are gradually decreased. The effect of the gas pressure on outburst presents three stages characteristics, dramatic stage, steady stage and slow stage of impact increasing. The gas pressure of 0.75 MPa is the threshold influenced on maximum rate of outburst. That is also cut-off point of gas pressure between abnormal and steady region, corresponding mining depth of 350 m, which is consistent with previous theoretical results. On the basis of analysis above, it can be presented that with deep mining, the frequency of coal and gas outbursts will increase on the joint action of stress and gas pressure. But the increment of impact strength and damage will decrease. The conclusions will have reference significance to mechanism, forecasting and prevention of gas outburst for Sunjiawan coal mine.
