Resilience Assessment And Optimization For Urban Rail Transit Network

Urban rail transit has the characteristics of fast speed,large passenger flow,strong safety and security,so that it has become one of the most effective means to alleviate urban traffic congestion.The rail transportation system of large cities such as New York,Tokyo,Shanghai,Beijing,etc.,have entered the era of networked operation.The coupling between lines and stations of the urban rail transit network is extremely large.Therefore,complex and changing emergencies will have a great impact on the operational efficiency and transportation capacity of the networked urban rail transit system.Considering the transport service attributes of urban rail transit,it is of great significance to accurately assess the impact of disturbances on the system in the transportation network and the ability of the system to recover after disturbances.It has important reference value for the design,operation and optimization of rail transit.First of all,based on the theory of complex networks,this thesis analyzed the coupling relationship between passenger flow of urban rail transit and urban rail transit network structure;secondly,from the perspective of network resilience,this thesis quantitatively evaluates the performance and recovery characteristics of urban rail transit networks after system disturbances occur;finally,in this work,from the perspective of the response characteristics and recovery characteristics of the resilience model,comprehensively considering the characteristics of topological structure,engineering cost and recovery strategy,an optimized model of urban rail transit network is established.Specifically,the main research work of the thesis has the following aspects:(1)Based on the theory of complex network,the topological characteristics of rail transit networks were analyzed to understand the complexity and evolution of the rail transit network.This thesis constructs an L-space model and analyzed the six topological structure parameters of the rail transit network,including node degree,shortest path,clustering coefficient,betweenness,assortativity coefficient,and network efficiency.As well as their distribution rules,we also discussed the tightness,connectivity and compatibility of the rail transit network.Small-world and scale-free characteristics of the rail transit network have been proven.(2)A passenger flow assessment method based on GIS is proposed,the characteristics and distribution laws of passenger flow are studied and analyzed.The relationship between passenger flow and network topological parameters is explored,and the evolution mechanism of passenger flow and network structure is revealed.Based on the shortest path theory,a reasonable path evaluation index is proposed,and the diversity of passenger travel choices is modeled and analyzed.The above work has laid a foundation for the assessment of the resilience of urban rail transit networks.(3)In order to study the urban rail transit network performance and the impact of different attack strategies and attack schemes,this paper gives the definition of the urban rail transit network resilience,constructs its evaluation index,and proposes a resilience assessment model based on the passenger flow and topology attribute.According to the impact of station failure and section line failure on the network,the relationship between node degree,passenger flow and resilience was analyzed based on the diversified system disturbances.A list of station and section line importance for resilience was constructed,which provides reference for management operation department.(4)Based on the characteristics of the network topology,the resilience optimization model of the urban rail transit network is proposed from the perspective of the response characteristics of the resilience model.To reduce calculation,a dimensionality reduction mechanism is applied considering the characteristics of stations and lines.A method for generating resilience optimal strategies based on genetic algorithm under different conditions is given for urban rail transit planning.(5)Based on the engineering cost and recovery strategy,the resilience optimization model of the urban rail transit network was established from the perspective of the recovery characteristics of the resilience model.Urban rail transit operation emergencies were classified,and the impact of operation emergencies on the entire rail transit network system was analyzed.Then the optimal recovery strategy under typical disturbances was given.