Research On Emergency Evacuation Simulation Of Subway Station Fire Based On Improved Social Force Model

As an important node of passenger flow distribution in rail transit network,subway station has complex structure,limited and relatively closed internal activity space,which is prone to all kinds of safety accidents.At present,the station emergency evacuation problem is mainly studied from the aspects of pedestrian individual micro model optimization and evacuation path calculation and evaluation.Among the classic micro models,the social force model focuses more on the model construction,parameter values,and the psychological impact of people,while the research on space evacuation is less.In addition,the evacuation path from the overall point of view is not considered enough.For the formulation of the subway station fire emergency plan,it is more based on experience and less theoretical support,which is quite different from the actual situation.Therefore,this paper considers both pedestrian evacuation and fire development,constructs pedestrian evacuation path based on harmony search algorithm,and realizes the visualization of simulation process and results by using Anylogic.The main research contents are as follows:Firstly,the influencing factors of pedestrian emergency evacuation in subway station are analyzed,and the evacuation characteristics and behavior characteristics of pedestrian are summarized;Based on FDS and Pyrosim simulation software,the fire source is located in the middle of the platform,the end of the platform and the middle of the station hall.The model output is visualized.The distribution of smoke,temperature and CO₂concentration in the station under each condition is analyzed and summarized,and the corresponding evacuation suggestions are put forward.Secondly,the basic idea of social force model is elaborated and compared with other classic pedestrian evacuation models.Based on the social force model,the range of human elastic coefficient is improved to avoid the rigid collision in the classical social force model.The results show that when the range of human elastic coefficient is 400-1000N/m,it is more consistent with the individual evacuation situation of adult pedestrians in China;Combined with the stress characteristics of pedestrians in the vertical direction,this paper introduces the psychological force of rising speed,establishes the social force model of stair evacuation in three-dimensional space,and obtains that the psychological coefficient of rising speed ranges from 0.1 to 0.5.Thirdly,in order to minimize the evacuation time of all pedestrians in the station to the safe area,the subway station pedestrian path selection model is established,and the representative fire scenes are set up.Based on the harmony search algorithm,the MATLAB program is written to preliminarily calculate the corresponding optimal evacuation path of each carriage;According to the principle of maximizing the utilization rate of station evacuation facilities,the sub optimal path of each carriage is calculated again,and finally the pedestrian evacuation path scheme of subway station is determined comprehensively.Finally,the case of Jintai Lu Station in Beijing is analyzed.The emergency evacuation simulation model of Jintai Lu Station is constructed by using Anylogic software,and the relevant parameters and function codes are set.The improved social force model and harmony search algorithm are applied to the simulation model.The results show that the total evacuation time of the improved simulation model is 325s,which meets the evacuation requirements and improves the efficiency of pedestrian emergency evacuation.On this basis,the improvement measures of station emergency evacuation scheme are put forward,which provides theoretical reference for subway station emergency plan.For example,passengers in the west part of station hall of Line 6preferentially choose Exit B to exit the station to reduce the density of passenger flow in the passageway of Exit A and the congestion at the escalators.