双出口房间人群疏散的出口选择行为

采用基于背景场的元胞自动机模型研究双出口房间的人群疏散. 为了刻画行人的出口选择行为, 引入了衰减背景场, 其中考虑了出口处拥堵的影响. 出口区域内人数的变化导致衰减背景场随之动态改变. 在疏散过程中, 行人根据变化的背景场来选择出口. 数值模拟结果显示, 在衰减背景场的作用下, 多数行人选择大出口, 少数行人选择小出口. 从两个出口离开的人群几乎同时完成疏散, 因此疏散时间明显缩短, 两个出口都得到了有效利用. 背景场衰减系数可以作为衡量行人对出口拥堵状况变化敏感程度的标志, 但衰减系数并非越大越好. 当衰减系数较大时, 会出现振荡流并导致疏散时间变长. 确定了临界衰减系数, 当衰减系数取临界值时, 疏散时间最短, 出口利用率最大. 模拟结果表明, 采用衰减背景场可以很好地描述多出口人群疏散的出口选择行为.

Exit choice behavior of pedestrians evacuating from a two-exit room

Pedestrian evacuation from a two-exit room was investigated using a cellular automaton model based on the floor field. To depict the exit choice behavior, a decaying floor field was introduced, taking into account the degree of congestion near exits. Since the number of pedestrians in the exit areas varied over time, the decaying floor field was dynamical. In evacuation, a pedestrian might turn to another exit according to the varying floor field. The decay factor might be regarded as a measure of the pedestrians’ sensitivity to the exit congestion. Numerical results showed that more pedestrians left the room from the large exit and fewer from the small exit. Two groups of pedestrians almost completed their evacuation from the two exits simultaneously. However, large decay factors led to undulation of the pedestrian flow and a prolonged evacuation time. The optimal decay factor was then determined, which minimized the evacuation time and maximized the usage of exits. It was shown that the decaying floor field played a vital role in capturing the essential features of exit choice behavior during evacuation.