Research on Fire Smoke Spread Law and Evacuation Path Optimization of Coal Mine Joint Construction Building Based on PyroSim and Dijkstra

Aiming at the problems of dense personnel, staggered space and easy congestion in static evacuation during sudden fire in a coal mine joint building, a joint building of a mine in Inner Mongolia was taken as the research object, and PyroSim and Pathfinder software were used to carry out research on fire smoke spread law and evacuation path optimization. The simulation results of the high-risk scenario of the locker room fire showed that the fire was affected by the chimney effected and showed the diffusion characteristics of “vertical priority and stairs leading.” The visibility, temperature and CO concentration of the main channel (No. 3 stair) in the southwest direction reached the critical value quickly – within 3.9 s, 10.4 s and 16.2 s, respectively – which seriously affected the safe evacuation in the early stage of the fire. To this end, this study constructed a Dijkstra dynamic emergency evacuation optimization model with personnel density and exit utilization rate as weights. The verification results showed that the optimization scheme can scientifically guide and effectively alleviate congestion in high-density areas, reduce the maximum congestion density in the building from 2.82 people / m2 to 2.36 people/m2, and reduce the total evacuation time from 116 s to 97 s. The research results realized the organic combination of fire evolution characteristics and dynamic diversion algorithm, and significantly improved the evacuation efficiency, providing scientific technical guidance for fire protection optimization and emergency plan preparation of complex industrial buildings.