Abstract: In order to further understand the mechanism to cause shock hazard of coal-gas outburst gas-solid two-phase flow and the propagation law of the two-phase flow, a self-developed large-scale multi-field coupling coal mine dynamic disaster simulation testing system is used to study the impact force and movement characteristics of the outburst gas-solid two-phase flow under different gas pressure conditions. The results show that during the process of outburst coal-gas two-phase flow, the peak impact force at the front end of the roadway fluctuates within a small range from 20 kPa to 50 kPa, and the impact force has no obvious linear relationship with the gas pressure. The peak impact force sharply increases in the range from 3 944 mm to 4 944 mm in the roadway. After 4 944 mm, the peak impact force shows a trend of oscillating attenuation along the roadway, and its average attenuation coefficient gradually decreases with the increase of gas pressure. The flow patterns of the outburst two-phase flow can be divided into suspended flow, stratified flow, dune flow and slug flow, and the higher the coal seam gas pressure is, the more obvious each flow pattern is reflected. The process of pulverized coal flow movement can be divided into three stages: initial acceleration, medium-term attenuation and late secondary acceleration. The gas pressure mainly affects the migration rate of pulverized coal flow and the migration distance into the second acceleration stage. The higher the gas pressure, the faster the migration rate of pulverized coal flow, and the shorter distance to reach the second acceleration stage.

Key words: coal and gas outburst, outburst two-phase flow, impact force, morphological characteristics, pulverized coal speed