Crowd Evacuation Dynamic Model Considering The Effect Of Fire

When fire occurs in public place, there are two major factors that may lead to a large number of casualties. First, pedestrians can't escape from the fire in time. Second, the congestion at the exit may cause the panic stampede. Effective prevention and reduction of casualties in fires has been widely concerned for public safety both in China and abroad. The actual data of escaping in fire is hardly obtained, and the experiment is difficult to implement. Therefore, micro-simulation of the pedestrians'behavior is popularly used to reproduce the escape process. In the escape process in fire, the environment and its variation due to the fire have a great effect on the pedestrians' escape behavior. But the studies in this area are rare. In this paper, we extend the social force model to model escapers'behavior and simulate the escape process with consideration of the effect of fire.In this paper, the microscopic behavior characteristics and the macroscopic flow properties of crowds are firstly introduced, as well as the self-organization phenomena. The modeling method of the escape behavior and the existing results based on the social force model are presented in detail. Then, based on the extensive analysis of escapers' psychology, behavior features and the fire's impaction to the escapers, an improved social force model of escapers'behavior considering the effect of fire is proposed. In the improved model, the repulsive force of fire to the escapers is considered, and the self-driving force is modified with consideration of the fire's effect on the size and direction of the desired velocity. We extensively analyzed pedestrians'exit and route choice behaviors, and classified their behaviors into three categories:the shortest route choice behavior, the optional choice behavior and herding behavior. We also developed the corresponding exit choice models. For the optional choice behavior model, a novel method is proposed to estimate the escaping time which consists of the travel time to the exits, the queuing time at the exit and the waste time due to safety factor of the exit.Finally, we simulated the escape process in a small room using the above models, and verified the efficiency of the model. In a one-exit room, we simulated and analyzed the relationship between the expected velocity and the escaping time with different exit width and different number of escapers. We also simulated the escape process with various locations of the fire and people with different risk factor. In a multi-exit room, we simulated the escape process with different exit condition and different exit choice behavior. In the room with two doors in the same wall, we simulated and analyzed the escape process with different gap between the two doors.