Modeling and simulation of crowd dynamics at evacuation bottlenecks during flood disasters

Investigating and simulating the impact of floods on crowd dynamics at evacuation bottlenecks is essential, given the increment of the intensity of these disasters due to climate change. Previous studies have primarily focused on flood risk assessment for crowd evacuation during flooding. The complex interactions between pedestrians and water flow near evacuation bottlenecks have been rarely investigated. In this work, we developed a pedestrian-water flow coupling evacuation model by incorporating the social force model with a hydraulic model. The optimal parameter combination for the coupled evacuation model was identified through a sensitivity analysis. The final parameter tuning was conducted through a model calibration based on controlled evacuation experiments under various inflow depths. The proposed model is employed to examine how exit width, exit position, and inflow volume affect the evacuation efficiency of crowds in a flooded environment. The findings indicate that the distribution of exit positions has a prominent impact on evacuation efficiency in an exit width of 1.0 m for different inflow depths, while this impact manifests uncertainty for other exit widths. The coupling evacuation model proposed in this work will offer valuable insights for formulating scientific evacuation plans or emergency response strategies in flood-prone areas.