A Resilience Evaluation And Optimization Framework For Metro Networks Considering Emergency Resource Allocation

The subway plays an important role in the daily travel of urban residents.In recent years,with the expansion of metro construction and the increase of lines in major cities in China,the characteristics of network have become more and more obvious in the operation of the metro.Under this circumstance,the links between sites and lines are getting closer and closer,making it easier for the impact of emergencies to spread across the metro network.It is necessary to study the metro system’s ability to respond to emergencies under the characteristics of networked operation.Resilience is used to assess the system’s ability to absorb disasters and recover from disasters.Compared with indicators such as robustness and vulnerability,it emphasizes the ability of the metro system to maintain stability,resist interruption,and recover performance after an emergency.This study evaluates the disaster resistance of the subway network from the perspective of resilience and proposes effective measures to improve resilience.First,based on the theory of complex network and resilience,a resilience metric and a resilience accessment method of the metro system are proposed.The performance of the metro system during the operation period is measured by the global efficiency index of the metro network considering the weight of passenger flow,and the calculation formula of the annual expected resilience of the metro network is determined.Secondly,a resilience evaluation model is built by the method of network based simulation.After analyzing the factors that affect the resilience of the subway network and its action path,the whole process of the metro system from the destruction of the emergency to the completion of the recovery is simulated to obtain the performance change curve and the resilience value of the metro system under disasters.Among them,considering that the allocation of emergency resources has an important impact on the resilience of the recovery phase,a multi-objective optimization model is proposed to determine the layout of emergency resources in the metro network,which improves the applicability of the proposed model on resilience assessment.Finally,the constructed model was used to evaluate the annual expected resilience of the metro network in Wuhan against heavy rain disasters,and based on this case,the effect of various preventive measures on the resilience of the metro network was discussed.The resilience evaluation model proposed by this research can quantify the expected loss of the metro network under emergency attacks,and evaluate the effect of various prevention and control measures on resilience improvement.After determining the benefits of resilience improvement brought by risk prevention and control measures and their input costs,based on the principle of cost-benefit balance,it can be used for managers to formulate a safe investment plan that maximizes expected benefits.