Vulnerability Analysis And Cascading Failure Model Study Of Urban Rail Transit Network

With the development of urban rail transit in China,the scale of the line network has been continuously expanded,the passenger traffic has increased significantly,and the characteristics of networked operations are increasingly prominent.Although the networked operation of urban rail transit provides convenient,fast and on-time services,frequent emergencies also expose its vulnerability during operation.Therefore,in order to improve the safety level of urban rail transit network operation,it is necessary to clarify the causes of vulnerability,determine the mechanism of the factors affecting vulnerability,and grasp the law of network vulnerability change after an emergency,and give corresponding control measures to reduce the vulnerability of the network.To study the vulnerability of the urban rail transit network,the specific research contents are as follows:(1)Research on the mechanism of factors affecting the vulnerability of urban rail transit network.Collect and arrange domestic and international urban rail transit operation accidents,summarize and analyze the types,time and space of accidents.On this basis,the influencing factors of the vulnerability of the urban rail transit network are determined from six aspects.According to the relationship between the influencing factors,the improved Interpretative Structural Modeling is used to clarify the structural hierarchy among the influencing factors,and the Cross Impact Matrix Multiplication Applied to Classification,to classify the vulnerability factors.From the influencing factors of the vulnerability of the urban rail transit network and its complex factor chain,the direct,indirect,and fundamental influencing factors of the vulnerability of the urban rail transit network are revealed.(2)Research on cascading failure model of urban rail transit network.Considering the impact on the network vulnerability after the accident,a cascading failure model of urban rail transit network is constructed.In the model,the node state is defined,the node state transition process is clarified,the passenger flow redistribution method of the failed node is improved,and the simulation process is determined according to the cascading failure process.On this basis,three attack methods are clarified,and the evaluation index of network cascading failure vulnerability is selected and used as the basis for evaluating the dynamic importance of nodes.(3)The model of Beijing rail transit network is built for empirical study.First ofall,this paper selects Space L method to construct Beijing rail transit network model,and calculates and analyzes the network's characteristic parameters.Then simulated the cascading failure process of the Beijing rail transit network under three attack strategies,and analyzed the vulnerability of the network.Finally,the individual attacks of each node were simulated to determine the importance of the nodes in the network and rank them.On the basis of the proposed optimization recommendations to improve network vulnerability.Based on the theory of complex network,this paper studies the vulnerability of urban rail transit network.On the one hand,through the analysis of the influencing factors of the vulnerability of the urban rail transit network,it reveals its mechanism of action on the vulnerability of the urban rail transit network,and provides a decision basis for the management department to prevent the occurrence of operational accidents and reduce the network vulnerability.On the other hand,combined with the characteristics of urban rail transit network,a cascading failure model of urban rail transit network was constructed,and the vulnerability of network cascading failure after an accident was analyzed,which has an important reference for reducing the impact of the accident and ensuring the safety of urban rail transit network operation.