Research On Merging Pedestrian Walking Mechanism In Subway Station Y-shaped Passage

Crowding has become the most common phenomenon in subway systems.Based on plentiful researches and statistical analyses,congestions usually occur at the bottleneck facilities and propagate to passage in subway stations.Y-shaped passage is the most junction of walking facility.When the density exceeds certain extent,the passenger flow will interfere with each other,which will decrease passengers walking efficiency.One of the important characteristics of pedestrian walking is the merging behavior observed at Y-shaped passage.Congestion usually occurs in merging area,where pedestrians from multiple directions converge into a single stream by turning and intertwining.Therefore,studying the walking mechanism of merging pedestrians will help to improve the traversal efficiency and optimize the design of walking facilities.The difference of layout and dimension of Y-shaped passages will lead to different pedestrian walking behaviors.To obtain the dimension of facilities and walking behavior parameters of passengers,this paper made field survey in representative Y-shaped passages in several Beijing Subway stations.Based on the survey,characteristics of merging pedestrians’ behaviors in Y-shaped passage were analyzed.This study improves the basic social force model(BSFM)in order to simulate three different walking behaviors,such as conering,passing through stairs,and turning.Doing a series of simulation experiments can reveal the coupling relationship of the pedestrians walking parameters and traversal time with passage layout,merging mode,and geometric dimension.We compare the the simulation results with the actual walking parameters to validate the feasibility of the improved social force model(ISFM).The main contents of the paper are as follows:(1)We collected walking behavior parameters at Y-shaped passages in 57 transfer stations of the Beijing Subway.The field survey includes layout structure,geometric dimension and direction of pedestrian flow in Y-shaped passage.We select the Y-shaped passage with typical characteristics to obtain the speed,walking trajectory,density,flow,turning and stopping behavior.The pedestrian walking characteristics in vertical and horizon Y-shaped passage are statistically analyzed to obtain the microscopic characteristic parameters in merging area.(2)This paper improves the BSFM to model the behaviors of cornering,passing through stairs and turning.Based on the BSFM(consisting of desired force,the interaction force between pedestrians,and the interaction force between pedestrians and the walls),we will add attraction to describe the conering behavior of pedestrians in the merging area of the horizon Y-shaped passage.We add vertical social force to describe the walking behaviors of pedestrians through the stairs in vertical Y-shaped passage,also add the descending speed control force to describe the descending behavior,and add centripetal force to describe the turning behavior of the pedestrian when entering the merging area from down-stairs.(3)Based on pedestrian’s behaviors and walking parameters,we define the walking rules in merging area and write the simulation program with object-oriented programming in MATLAB.This program includes the following modules: loading customizable Yshaped passage config,invoking ISFM,setting and managing parameters,saving and outputing simulation results,etc.We construct the simulation scenarios of pedestrian flow based on the field survey.Simulation analysis is carried out on the horizon Y-shaped passage and the vertical Y-shaped passage to verify the validity of the model.(4)The simulation scenarios with various Y-shaped passages based on ISFM are established,which has different topology,merging mode,merging angle,and passage dimension.Then we simulate the characteristics of pedestrians’ flow distribution by setting walking parameters in different areas.The simulation results suggests pedestrian trajectories,traversal time,speed,and density.By analyzing simulation results to study the effect of influencing factors,we quantify the functional relationship between traversal time and geometric dimension in Y-shaped passage.(5)This chapter simulates with the Fuxingmen station as the scenario.According to the blockage probability and traversal time,the merging area in Y-shaped passage is identified as bottleneck.Referring to the coupling relationship of the types of Y-shaped passages and geometric dimension with pedestrians walking mechanism,we have proposed optimization methods for pedestrian movements in merging area and recommendations for Y-shaped passage.