Analysis And Intervention In Pedestrian Evacuation Via A Modified Social Force Model

In recent years,with the accelerated process of urbanization,the scale and density of urban population have increased sharply.Large-scale public facilities or activities attract a large number of people,which leads to high local crowd density and place great pressure on security.The probability of accidents increases accordingly with the increase of pedestrian flow.The stampede accidents which have something to do with crowd panic or congestion,in particular,always result in serious consequences.So,it's of great significance to investigate crowd evacuation.The social force model is a common evacuation model.We propose some simple but efficient modifications of the social force model allowing for its high complexity.The improved model has good robustness.Based on the improved model,a mass of simulation researches are performed.The relationship between crowd evacuation time and the degree of pedestrians' nervousness is investigated through a simulation of crowd evacuation from a single-exit room.The faster-is-slower phenomenon is reproduced when there are enough pedestrians.Crowd evacuations from a double-exit hall where pedestrian vision is limited are studied from the point of pedestrian traffic psychology,exit locations and information source deployments.It's found that herd mentality has different effects on crowd evacuation when the crowd size differs,that following the wall is always a better strategy,that placing exits on opposite walls is better for evacuation than placing them on a same wall and that information sources do good to crowd evacuation but no best deployment of information sources is found.We also study the emergency evacuation from a scenario and find that it's not necessarily better to provide pedestrians with information earlier or precisely.Giving more information is not necessarily better,neither.Furthermore,we perform simulations on evacuation from East Nanjing Road Station of Shanghai Metro Line 2.Based on the improved social force model,the effects of game behaviors between individuals on crowd evacuation are studied.By inflicting punishment on impatient individuals,the effects of intervenor's position on crowd evacuation from bottlenecks are investigated.It is found that it's better for the intervenor to stand directly in front of the bottleneck to make crowd evacuation faster.