Study On Optimal Recovery Strategy Of Urban Subway Network From The Perspective Of Resilience

With the acceleration of urbanization,the urban population has gradually increased.The emergence of urban subway has alleviated the urban pressure and become the preferred mode of transportation for people’s daily travel.However,urban subway is located in an underground closed space,so it is faced with a variety of uncertain risk factors,and it is difficult to implement the restoration project after damage.Therefore,it is of great significance to improve the emergency level of the subway network and maintain the normal operation of the subway by analyzing the vulnerable stations and intervals in the subway network and determining the optimal recovery strategy based on the damage situation of the subway.Firstly,based on the complex network theory,this paper introduces the actual distance between stations,takes the subway running time as the edge weight,and constructs the weighted network of urban subway by using Space L method according to the accessibility relationship between stations.The degree and degree distribution,average path length,clustering coefficient and other network characteristic parameters of the network were calculated by using Matlab according to the network topology structure diagram,and the network performance was analyzed.On this basis,the key stations and intervals in the metro network are identified by simulating the changes of network efficiency when a single station and interval are damaged.Secondly,based on the theory of resilience to select "Three Stage" method to calculate resilience,taking the efficiency of network as the quantitative indicators of network resilience,the interval running time and station degree are respectively used to represent the recovery project duration of the interval and station.The restoration model of urban subway network was constructed with taking the maximum network resilience as objective function and the number of recovery resources as constraints.Finally,the genetic algorithm was used to solve the optimal recovery time sequence combination of station and interval under three failure modes:station failure,interval failure,and simultaneous failure of both station and interval.The conclusions are as follows: The factor of edge weight does not change the vulnerability degree of the stations;Vulnerability stations and intervals in the network are located at the intersection of central line and branch line.The priority recovery of stations and intervals is related to their location in the network and the duration of the restoration project.Under the same failure mode,weighted networks are more resilient than nonweighted networks;Under different failure modes,subway network is more resilient when interval failure occurs.An increase in the number of recovery resources does not change the priority recovery of a station or interval.