Subway Fire And Evacuation Simulation Based On Multi-agent

Subway system is an important part of urban rail transportation,and its fire evacuation research is of great significance for safeguarding passengers’ lives,maintaining social stability and promoting economic development.In recent years,the direction of subway fire evacuation research has become more and more comprehensive,while the research method has risen from empirical validation research to quantitative theoretical modeling research.Subway fires occur in reality,and the data generated in reality is the verification and guidance of the theoretical research results.However,experiments on the realism of fires in subway stations are costly and have the risk of causing harm to lives.Therefore simulation research has become the mainstream direction of the current subway fire and evacuation research.Thanks to the development of computer hardware level and simulation software,the simulation research of subway fire and evacuation has already had a good foundation.Based on the theory of fire and evacuation,the paper integrates the simulation results of Pyrosim,Pathfinder and Vensim to study the fire and evacuation of subway station.The main contents of the thesis include:(1)Principles of fire injury and evacuation and methods of simulation study.The main factors of fire injury,the basic theory of safety evacuation and the calculation method of evacuation time are the basis of the dissertation research,and the characteristics and shortcomings of the three simulation software for fire simulation and evacuation are analyzed on the basis of combing and summarizing the existing classical theories.(2)Fire evolution simulation research in different building structure situations.Apply FDS software Pyrosim to simulate the fire scenarios under different subway building structures,and modify the scenarios through the software to simulate the fire scenarios again,and simulate and compare the fire situations under different scenarios by setting up smoke,temperature and visibility slices.(3)Simulation study of crowd evacuation under different building structures.Apply multi-intelligence body software Pathfinder to simulate the scenarios of crowd evacuation under different subway building structures,modify the evacuation environment through the software,simulate the evacuation of crowds after the fire under different scenarios,and compare the results of evacuation by observing the evacuation paths,heat maps of crowd density,and evacuation time.(4)Integration of evacuation time control and evacuation process.Based on the method of applying system dynamics to simulate the evacuation time control and evacuation process,by proposing a simulation modeling method for crowd flow in different building structure situations,a system dynamics model containing evacuation time control and evacuation path is established,and the evacuation time control and evacuation process are integrated in the same model.(5)Case study.Taking Xizhimen subway station as an example,three simulation software are systematically applied to establish Xizhimen subway fire dynamics simulation model,multi-intelligence body evacuation simulation model and system dynamics model.The three simulation methods are combined through the fire evolution law and evacuation theory to simulate the objective environment,crowd evacuation and evacuation system control when fire occurs in the subway station.And the conclusion of the simulation study is given in the ending part of the paper.The innovations may include the following three aspects:(1)A geographic orientation-based system dynamics modeling approach is proposed.Previous system dynamics modeling has been in the absence of a representation of orientation.The introduction of orientation-based system dynamics modeling is an initial exploration in this direction.The introduction of the Vensim model of orientation indicates the direction of the path of transportation(evacuation)as well as the spatial positional relationship of the simulation objects,and there is a representation method for the simulation objects in different layers(Z-axis).It makes the orientation-based simulation have the idea and path to realize,and more realistically simulate the spatial environment of the subway.(2)A retrograde evacuation model based on Pathfinder is proposed.The retrograde model can be used to simulate the route of firefighters,and can also be used to simulate the return of the evacuation crowd.Pathfinder software focuses on multi-intelligent body path judgment and search,and the logic of its software algorithm is based on the search for the path-accessible exit.In the actual fire evacuation,the behavior of the crowd is diverse,the retrograde model can not only simulate the retrograde traveler to reach the target location time,but also for the retrograde traveler speed and the crowd evacuation speed of the interactions can be simulated.(3)A multi-method fusion subway fire and evacuation simulation system is proposed.The mainstream idea of the current simulation software is to categorize and simulate the segmented topics related to fire occurrence.The thesis innovatively combines the use of three types of simulation methods and conducts a comprehensive simulation based on the actual topography of Xizhimen subway station,avoiding the shortcomings of a single simulation,especially in the system dynamics simulation model,combining the crowd evacuation with the safe evacuation time,so that the whole evacuation process and the final effect of evacuation can be grasped and controlled as a whole.The combination of FDS simulation,pedestrian dynamics and system dynamics provides an effective theory and research method for exploring the environmental changes,pedestrian flow characteristics and evacuation problems in the subway after a fire.This study has certain theoretical contributions to the hazards caused by fire in the subway,the objective law of pedestrian flow,the possibility of risk avoidance and damage reduction,and is of great practical significance to the optimization of the structural layout of the subway station and the reduction of the prevention of injuries and deaths caused by unexpected accidents in the subway station.