Failure Analysis Of Urban Complex Metro Network Cascading Failure

As an important modern passenger flow carrier,urban subway has many advantages such as large carrying capacity,fast punctuality,low price and environmental protection.It has become an important choice for alleviating traffic problems in the world’s major cities.However,traffic accidents,natural disasters,and terrorist attacks may cause large-scale congestion in urban subway network systems.In particular,a large number of passenger transfer shunts caused by a small number of key transfer stations cause other stations to fail,and even cause large-scale cascading of networks.collapse.The complex network cascade failure theory has unique advantages in analyzing network structure characteristics.Therefore,taking the urban subway network as the research object,the complex network and cascade failure theory are applied to analyze the invulnerability of the subway network.The main research contents are as follows:(1)Applying complex network theory to construct the undirected network of metro and the weighted network topology model.The characteristic parameters are selected to analyze the structural characteristics of the subway network,which lays a foundation for the study of the subsequent subway network cascade failure problem.(2)Study and analyze the failure process of metro network cascade,and formulate the calculation formulas of relevant important concept parameters such as passenger flow allocation strategy and invulnerability evaluation index,so as to construct the subway network cascade failure model.(3)Taking the Beijing subway network as an example,construct a topology model of the Beijing subway network.The network topology map is drawn by using pajek,ucinet and MATLAB software to calculate the characteristic parameters of the complex network of Beijing subway network.The results show that the Beijing metro network has the characteristics of a scale-free network.There are a large number of nodes carrying a large number of passenger flow problems,which easily lead to traffic congestion and weak ability to withstand emergencies.(4)Construct a cascading failure model of the Beijing subway network.The simulation operation of cascade failure model is realized by MATLAB software,and the random attack strategy and selective attack strategy are used to compare and analyze the invulnerability of Beijing subway network.The research results show that the random attack strategy is relatively less destructive to the network than the other two attack strategies,and the subway network is more resistant to random emergencies.The two attack strategies based on the node value and the median will cause a sharp drop in network connectivity efficiency,and the subway network will be weaker in the face of deliberate targeted attacks.(5)According to the failure characteristics of Beijing metro network cascading,develop an active node immunization strategy to guide the load shunting situation,so as to prevent the subway network cascade failure problem.Comparing and analyzing the impact of application node immunization strategy on the failure of Beijing metro network cascade,the analysis shows that the node immunization strategy can effectively alleviate the cascade failure problem of subway network sites,enhance the invulnerability of metro network,and ensure the stable and reliable operation of metro network.