Research On Pedestrian Turning Behavior And Luggage-carrying Evacuation Characteristics At Exit Bottleneck

The"Bottleneck"structures are commonly found in large crowded places(such as exits,staircases,narrow passageways,etc.),and have gradually attracted more and more researchers’attention.The"Bottleneck"structures in these buildings play a role in connecting the building space,but in the event of an emergency disaster,they will become an obstacle to evacuation.A large number of pedestrians congestion in front of the bottleneck may reduce the efficiency of evacuation,causing injuries such as collisions,falls,and trampling.Therefore,this paper explores the effect of pedestrian turning behavior and luggage on the pedestrian flow characteristics and evacuation efficiency at the narrow bottleneck from two aspects of simulation and controllable experiment,and focuses on the pedestrian movement behavior in the"bottleneck"structure of the room exit.First,considering the heterogeneity,anisotropy,time correlation and turning behavior at the bottleneck of pedestrian movement,a finely discretized field cellular automata model is proposed.Compared with the traditional field cellular automata model,the proposed model has better discrete accuracy from the two dimensions of space and time,and uses the export turning rule to solve the"bottleneck"deadlock caused by spatial refinement problem.By controlling the two variables of the pedestrian exit turning probability parameter P_rTand the lateral backward velocity ratioa,the evacuation of the simulator through the"bottleneck"is simulated.The simulation results show that the introduction of pedestrian turning behavior at the bottleneck can effectively solve the"deadlock"problem at the bottleneck.The evacuation time first decreased sharply with the increase of the exit turning probability P_rT and the lateral backward velocity ratioa,but the evacuation efficiency remained almost stable when P_rT>0.5 α>0.6.The increase in the lateral velocity ratio α will cause more frequent conflicts between pedestrians.In order to explore the impact of pedestrian luggage on the pedestrian flow at the exit bottleneck,this paper conducted a series of room evacuation experiments.In the experiment,different evacuation conditions were set,such as the proportion of pedestrians carrying luggage,the width of exit bottleneck and the degree of evacuation emergency.Experimental results show that luggage-carrying pedestrian has a significant impact on the movement characteristics of narrow bottleneck pedestrians.The evacuation time increases as the proportion of luggage-carrying pedestrianqincreases.The average flowq=0%is higher than that ofq=100%.Under the normal situation and emergency,they increase by 76%and 94%respectively.The complementary cumulative distribution function CCDF of the time interval satisfies the power-law“tail”distribution,and the power-law indexβincreases with the rise in the proportion of pedestrian luggage.Consistent with previous studies,the pedestrian flow in this study also increases linearly with the width of the bottleneck.The simulation results can improve pedestrian traffic management,and ensure the safety of crowded evacuation.The simulation results of the model can improve pedestrian traffic management and ensure the safety of the evacuation of dense crowds.The results of the evacuation experiment can verify the model,reveal the movement characteristics and evacuation rules of the"bottleneck"structure downstream pedestrian flow,and provide an important theoretical basis for the planning and design of pedestrian facilities.