Pedestrian stability assessment and applicability analysis based on human model experiments in inundated flows

Frequent occurrences of heavy rainfall caused by climate change have increased the risk of urban and underground space flooding, posing significant threats to pedestrian safety in subway stations. This study conducted lab-scale experiments to derive pedestrian stability conditions on subway platforms under flooding events. To demonstrate the toppling accident of a human body due to inundation flow, a human body model was designed considering mass similitude. By varying the inundation flow conditions, the flow conditions causing a toppling accident were determined, and based on these results, the relationship between walking threshold velocity and water depth (U-H relationship) was derived. The U-H relationship demonstrated a nonlinear decrease in inundation depth with increasing flow velocity. These findings can be utilized to quantitatively assess the threshold conditions by which toppling accidents occur as flow velocity increases. The applicability of the U-H relationship derived from laboratory-scale experiments to real-world inundation flow conditions was evaluated by comparing it with prototype experiments. Compared to previous experiments using human body models, this study presented more appropriate U-H relationship for pedestrian stability.