Intersecting Pedestrian Flows Characteristics Analysis And Evacuation In Stations Based On Social Force

Urban rail transit plays an important role in solving traffic problems and promoting economic and social development due to its advantages of large capacity,high efficiency and environmental protection.With the rapid development of urban rail transit in China,the passenger flow volume is growing rapidly,which easily leads to congestion in stations and affects passengers5 passage and comfort.Due to the characteristics of closed space and complex structure of urban rail station,the safety of passengers’ lives and property will be seriously endangered if passengers cannot be evacuated effectively in time in case of emergency.The traffic efficiency and safety of pedestrians in urban rail stations have attracted wide attention of scholars around the world.It is of great theoretical and practical significance to develop the control and optimization methods of pedestrian flows and the emergency evacuation strategies by studying the characteristics of pedestrians’ movements under normal and emergency conditions.This paper focuses on the dynamic characteristics analysis and optimization of intersecting pedestrian flows and the emergency evacuation under the view-limited condition in urban rail stations.The main contents are as follows:Firstly,the modeling of intersecting pedestrian flows,the evolution mechanisms of self-organized phenomenon and analysis of the dynamic characteristics in stations are investigated.Considering the heterogeneities of desired speed,relaxation time and other characteristics of pedestrians,a motion model of intersecting pedestrian flows is established based on the concept of social force,and the validity of the model is verified by comparing with the fundamental diagrams of pedestrian flows.By analyzing the microscopic motion process of pedestrians at the intersection,the formation mechanisms and evolution laws of macroscopic self-organized stripe phenomenon are revealed.And the effects of cross angle and inflow on the dynamic characteristics such as average speed and speed fluctuation are further studied.Secondly,the identification of traffic bottlenecks in stations and the optimization of intersecting pedestrian flows are studied.Based on the survey data of station structure,facility layout,streamlines and passenger flow volume,the model of urban rail station which can realize pedestrian-train-environment interactive simulation is established,and traffic bottlenecks of the station are identified based on the grading indicators of level of service.Aiming at the clogging phenomenon in the intersecting bottleneck area,a pedestrian motion optimization method based on inflow control is proposed and a quantitative index for evaluating the optimization effect is given.In the scenarios of intersecting corridors and station hall,the proposed method can effectively reduce the congestion and improve traffic efficiency.Finally,the problems of pedestrian motion modeling and evacuation characteristics analysis under the view-limited condition are studied.Considering the changes of pedestrians’ perception abilities and psychological states in case of emergencies such as smoke and power failure,the exit-seeking strategy and movement rules based on the visual field and herding behavior are proposed,and an evacuation model under the view-limited condition is established.Furthermore,the relationships among the visibility distance,the degree of herding behavior,the initial density and the evacuation characteristics such as average evacuation time in the scenario of station hall are studied.The group formation during the evacuation process and the dual effects of pedestrian density are found.