Evacuation Optimization of a Typical Multi-exit Subway Station: Overall partition and local railing

In the process in which high-density passengers need to be evacuated from a multi-exit subway station, not all the exits can be effectively utilized, and the bottlenecks near the exits are often crowded. Therefore, the utilization of different exits and the optimization of congestion at bottlenecks were investigated in this study. To alleviate the congestion of the evacuation in a large-scale and multifunctional subway station, the first underground floor of the station was divided into four regions, referring to the idea of fire compartment division, in which passengers were evacuated from local exits. The results reveal that the evacuation time increases as the initial passenger density increases. The railings have a positive effect on balancing the proportion of different exits for the region with fewer exits in the early evacuation stage. For regions with several exits well-distributed, the symmetrical structure is beneficial to the evacuation and the effective use of different exits. What's more, setting railings can reduce crowding at bottlenecks to a certain extent. The results of the study can guide passenger evacuation in typical multi-exit subway stations.