Abstract: In order to further explore the dynamic behaviors of outburst coal-gas two-phase flow under different roadway layouts, the self-developed multi-field coupled coal mine dynamic disaster large-scale simulation test system was used to carry out coal and gas outburst tests under the T-shaped roadway layout. The tests obtained the evolution law of impact force and static pressure during the migration of outburst coal-gas two-phase flow in the roadway. The results show that the impact force in the straight main roadway shows a trend of multi-peak oscillation and attenuation over time, reflecting the pulse characteristics of the outburst process. The closer to the outburst hole, the more impact force oscillation times. The impact force in the branch roads on both sides of the bifurcation has two evolutionary trends in the early stage. One is that it increases rapidly to the peak and then decreases slowly, and the other is that it increases slowly and then decreases slowly. Larger impact force values appear at 1 500 mm from the left side of the bifurcation structure and at 500 and 1 900 mm from the right side, indicating that these areas are severely dangerous. The whole process is divided into two stages of single-phase flow and two-phase flow by using the outburst motion image. In the single-phase flow stage, the impact force after the bifurcation structure firstly rises rapidly to the peak value. The impact force before the bifurcation structure rises to a peak point in the two-phase flow stage. There is a phenomenon that the peak value of the impact force after the bifurcation is higher than that before the bifurcation. During the outburst process, the static pressure value on the wall of the roadway is generally low. The static pressure fluctuates intermittently with time, and the peak value from near the coal seam to far first increases and then decreases. The time when the static pressure in the straight main roadway reaches the peak value is delayed with the increase of the distance from the outburst hole. The evolution of the static pressure on the left and right sides of the branch roadway is similar. As time progresses, the static pressure attenuation before and after the bifurcation structure gradually increases.

Key words: coal and gas outburst, T-shaped roadway, impact force, static pressure