Research On The Dynamic Evolution Of Urban Metro Network Vulnerability From The Perspective Of Multilayer Network Coupling

As an important part of urban public transportation,the subway is the main tool that residents rely on for their daily travel.With the rapid development of urban subway construction,the safety management of subways is also facing new challenges and requirements.Vehicle emergencies,sudden large passenger flows,natural disasters,terrorist activities and other emergencies will cause subway stations or lines to be paralyzed and trigger the subway network Vulnerability to disrupt the normal operation of the city's overall transportation network.In this context,the prevention and control of the vulnerability of the subway network is also more urgent and necessary.Based on a large amount of reading and combing the literature,this paper collected 90 cases of subway operation accidents at home and abroad based on the operation and development status of urban subways.The statistical analysis of the case data and the results of actual subway interviews obtained the currently main problems in the operation of the subway.Secondly,in order to determine the main factors that stimulate the vulnerability of the subway network,first of all,the 90 accident cases mentioned above are analyzed in more depth with the help of grounded theory,and the vulnerability of the subway network is established through the steps of open coding,main shaft coding and selective coding.Theoretical model,and identify the basic factors that affect the vulnerability of the subway network;use the DEMATEL method to screen all the basic factors,and finally get four first-level factors that affect the vulnerability of the subway network,including personnel,equipment,environment,and management,and It contains 9 second-level factors and 20 third-level factors.On this basis,to study the vulnerability evolution path of my country's urban subway network.Starting from the theory of multi-layer coupling network,construct a multi-layer factor network model of urban subways with influencing factors as nodes and logical interactions between the factors as sides.And use the accident chain analysis method to identify the interaction between various factors,at the same time,based on these relationships,the method and path of the interlayer coupling of the multi-layer network model are determined.Next,in order to further explore the dynamic evolution process of the urban subway network vulnerability,on the basis of the multi-layer factor network model of the urban subway,the SD structure model of the urban subway network vulnerability was established using the method of system dynamics analysis.The system boundary and the elements included in the system are determined,and the system causality diagram and system flow diagram are given.On the other hand,the difference equations of each variable in the system are obtained by means of fuzzy analytic hierarchy process,regression analysis method and expert scoring method.Finally,taking Xi'an subway as an example,the relevant data is input into the above model,and the trend of the vulnerability of Xi'an subway network is changed.First of all,the value of each variable in the model is adjusted to observe the dynamic evolution of the vulnerability of Xi'an subway network and its sensitivity to different influencing factors;then the simulation analysis of the coupling effect between different network layers is vulnerable to the subway network Sexual influence trend and influence degree.The study found that the vulnerability level of Xi'an subway network peaked,showing a trend of increasing first and then gradually decreasing;after analyzing the sensitivity of subway operation accidents to various factors,it was found that the subway equipment system,safety management level and employee comprehensive functions Factors such as level have the most significant impact on the vulnerability of Xi'an subway network.In addition,the coupling strength between network layers is proportional to the vulnerability level of the subway network.The smaller the coupling effect between the layers,the lower the vulnerability of the subway network.The strength of the coupling relationship between the personnel-equipment layer and the personnel-management layer has a high impact on the vulnerability of the subway network.Finally,based on the dynamic simulation results of the vulnerability of Xi'an subway network,a corresponding vulnerability prevention and control strategy is proposed.The research in this paper identifies the dynamic evolution of the vulnerability of my country's urban subway network,expands the application research of multi-layer coupled network theory in the field of subway vulnerability.At the same time,this article shows how to more effective prevent,controling and reduce the vulnerabilities in subway operation from the main influencing factors of subway network vulnerabilities,which has certain practical significance.