Research On Network Vulnerability And Operation Strategies Of Urban Metro

The increasing congestion of urban traffic stimulates the rapid development of urban metro.Urban metro system is favored by majority of travelers due to its fast,punctual and efficient characteristics.However,the frequent occurrence of train operation failure has caught serious impact on urban travelers' normal life and work.This study is based on the practical problems of frequent occurrence of train operation failure,aiming at better understanding the urban metro network performance and ensuring its safe and orderly operation.This thesis mainly focuses on the following study:(1)First of all,this thesis abstracts the urban metro into a complex network based on graph and complex theory.Then the passenger flow data was introduced as weights for redefining the topological index of complex network.From the perspective of metro line operation,four factors,namely probability of line operation failure,network service passenger volume,network weighted average shortest path and network weighted global efficiency,were comprehensively considering for establishing an evaluation model of metro network vulnerability.An empirical research on the urban metro network vulnerability was made by taking Shanghai Metro as a case study.(2)Then,this thesis focused on the metro line operation strategy.Considering that the characteristics of cumulative passenger flow at different stations was largely different,short tuning operation mode was introduced.Congestion degree of the train was limited by passenger load factor.The train operation model was established with the objective of minimizing the cost of passengers' travel time aiming at relieving congestion degree of some links during AM peak hour.Results shown that the Line carrying the largest passenger flow has the greatest influence on metro network performance.The Line with special topology,like circular line,which can offer alternative travel routes for passengers,also has significant influence on metro network performance.Train congestion can be effectively alleviated during peak hour and operation can be guaranteed by applying full length and short turning operation mode.Results of this thesis could provide a good perspective for understanding the urban metro network vulnerability performance comprehensively and accurately,and an efficient method for optimizing urban metro operation mode.It is of great significance for reducing disruption and ensuring safe and efficient operation of urban metro.