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.