| With the rapid development of China’s economy and the improvement of people’s quality of life,people’s demand for convenient travel is getting higher and higher,and along with the increased awareness of environmental protection,new requirements for green travel have been put forward.As an urban public transportation mode,subway has become the main way to relieve traffic pressure.With the increase of subway passenger flow,the task of subway personnel gathering and dispersing has become more and more heavy,and how to guide people to evacuate safely,orderly and efficiently in case of emergency has become the focus of attention from all walks of life.Due to the high density of passenger flow and uneven distribution of crowd gathering areas,it is easy to cause crowding,thus affecting the efficiency of passenger passage in the whole station.Therefore,the problem of emergency evacuation of people under complex environmental conditions needs to be solved.The key point to solve the emergency evacuation problem lies in the research of scientific and reasonable evacuation methods in the process of evacuation organization,and it is taken as the basic link of evacuation organization.In this paper,the pedestrian evacuation in subway platform scenario is studied with computer simulation as the main research method,taking into account the characteristics of people’s movement behavior,in order to provide theoretical and technical support for the formulation of effective and optimal evacuation methods.The heterogeneity of pedestrians includes the difference in speed due to physiological factors and the difference in decision making due to psychological factors.Based on the research results at home and abroad,this study develops two aspects of speed differences and decision differences: for the speed differences caused by physiological factors,a multi-velocity level pedestrian evacuation model is constructed to overcome the limitations of the meta-cellular automata model in achieving speed differences;for the decision differences caused by psychological factors,the representation of panic psychology is introduced,including the representation of the causation and evolution of panic psychology and the representation of the representation of the behavioral decisions triggered by panic is introduced.Through the representation of heterogeneity in both speed differences and decision differences,a pedestrian behavior micro model is constructed to overcome the limitations of the homogeneous behavioral sparse model.Based on the heterogeneous pedestrian micro-model,a Net Logo-based simulation environment is constructed to study the change pattern of crowd panic in multiple speed levels under different evacuation states and speed distributions and its impact on evacuation efficiency.The research of this paper includes the following aspects.(i)The role and expression of speed differences in pedestrian evacuationConsidering the variability in the movement ability of people due to physiological and psychological influences,this paper investigates the problem of expressing the movement of pedestrians with multiple speed classes in the field metacellular automata modeling.The multi-velocity class representation can reflect the expected velocity differences due to the natural properties of pedestrians,and can reflect the differences of deceleration and stagnation due to the limited space in the evacuation process by the actual walking speed,so as to reproduce the walking behavior and group movement efficiency of pedestrians in the evacuation process more realistically.(2)Expression and update of panic level in pedestrian evacuationIn the actual evacuation process,panic is a common emotion when pedestrians are in danger.In case of emergency,pedestrians facing different evacuation scenarios will have different levels of panic.However,panic is an abstract concept,and its complex mechanism is so far difficult to be fully explained.In this paper,we improve the expression of panic degree in existing studies by considering the difference between the actual walking speed and the desired speed,as well as the distance of pedestrians from the evacuation exit,and propose an individual-level expression and update method of pedestrian panic degree in evacuation scenarios.When the pedestrian evacuation process is obstructed and the actual walking speed is much lower than the desired speed,the panic level will gradually increase;while when the actual walking speed is close to the desired speed and the evacuation process is smooth,the panic level will be effectively relieved.(3)Heterogeneous pedestrian evacuation behavior modelingBased on the widely used field metacellular automata model,a heterogeneous pedestrian evacuation behavior model considering multiple speed levels and panic degree is constructed to simulate the pedestrian evacuation process.A synchronous update strategy is used to represent the movement process of pedestrians with multiple speed levels in real scenes,and the conflict expression problem under synchronous update is solved by using the role of two types of heterogeneous features,namely speed and panic,on pedestrian decision making and competitiveness.In expressing speed differences,the indirect algorithm is used to avoid the pre-determination of pedestrian trajectory intersection and overlap and the complexity of the direct algorithm,which improves the computational efficiency;the calculation of actual walking speed is realized by rolling statistics of individual pedestrians’ real-time running trajectories in a fixed period,so as to realize the update of panic degree changes,and then reproduce and analyze the phenomenon of panic-triggered desired speed increase.(4)Simulation test and evacuation efficiency analysis by scenarioWith speed distribution,panic degree and evacuation status as the key factors,we design experimental scenarios covering different evacuation scenarios to obtain quantitative relationships between heterogeneous pedestrian behavioral decisions and group evacuation efficiency,and provide technical support for the optimization of evacuation plans.Firstly,two square room scenarios are selected based on the existing research,which are used to calibrate the parameters in the panic equation and verify the accuracy of the heterogeneous pedestrian evacuation behavior model,respectively.Secondly,the Xizhimen Line 2 subway platform is used as a case study to simulate the pedestrian evacuation behavior of the platform based on the validated model.Finally,by analyzing the simulation results and taking the evacuation scenario in the disorderly state as the benchmark,the following conclusions were obtained: 1)The evacuation efficiency of the evacuation scenario in the cooperative state and the orderly state was improved compared with that in the disorderly state,so it was necessary for the station to intervene to guide the pedestrians to evacuate in case of emergency.2)The evacuation time of the scenario without considering the effect of panic emotion is shortened by 8.62% compared with the scenario under panic emotion,so panic emotion has some negative effect on evacuation.3)The evacuation efficiency decreases instead when pedestrians with high expected speed account for a large proportion of the evacuation process in an emergency.There are 53 figures,9 tables,and 65 references. |
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