ANALYSIS OF PEDESTRIANS SAFETY IN SUBWAY STATION PLATFORM BY INUNDATED FLOW

The increasing frequency of heavy rainfall due to climate change has heightened the risk of urban and underground space flooding, posing significant threats to pedestrian safety in subway stations. In August 2022, localized torrential rainfall caused severe flooding near subway stations in Seoul, Republic of Korea, highlighting the necessity of safe evacuation route planning. This study conducted laboratory-scale experiments to determine pedestrian stability conditions during subway platform inundation. A human body model was designed considering geometric and mass similitude to simulate toppling accidents caused by flood flow. By varying inundation conditions, the critical velocity-depth (U-H) relationship for pedestrian stability was derived, revealing a nonlinear decrease in critical depth as velocity increased. To validate the applicability of the U-H relationship, experimental data were compared with real-world inundation flow conditions. Compared to previous studies utilizing human body models, the U-H relationship derived in this study was found to be a more appropriate criterion for assessing pedestrian stability. Furthermore, this U-H relationship was applied to flood simulations of the August 2022 Isu subway station inundation to assess pedestrian safety. The results indicated that the primary evacuation route rapidly exceeded the critical velocity-depth threshold, emphasizing the need for swift decision-making when establishing evacuation routes during underground flooding events. This study is expected to provide fundamental insights for designing effective evacuation routes and minimizing casualties in future subway station flooding incidents.