Evaluation And Optimization Of Transportation Plan For Urban Rail Transit Network Based On Node Importance

In recent years,with the rapid development of the scale of urban rail transit network,the number of stations has continued to expand,and the relationship between lines has become more and more closely.Under the conditions of networked operation,the complexity of the network structure,the unbalanced distribution of passenger flow demand and the diversity of train operation organization have all put forward higher requirements for urban rail transit planning.Based on this,this paper takes the network operation of urban rail transit as the research background,and based on the time-varying passenger flow demand,constructs a network transportation plan evaluation and optimization model that considers the difference in the importance of network sites,sections and lines,and focuses on the network transportation capacity.The matching of supply and demand and the optimization of the connection between the operation lines are explored.The main work is as follows:1.The related concepts and contents of the urban rail transit line network transportation plan are expounded,and the research focus of the line network transportation plan is clarified.On the basis of analyzing the connotation,performance and passenger flow characteristics of urban rail transit network operation,the line network The evaluation and optimization of the transportation plan carried out a demand analysis,and determined the goals and principles of the evaluation and optimization.2.Construct a three-dimensional space-time travel network according to the line network topology,network train operation schedule and passenger travel characteristics,and calculate the generalized travel cost of the route based on the travel choice behavior of passengers,and establish a passenger flow distribution model based on the space-time travel network.On this basis,fully considering the difference of passengers’ familiarity with the line network under different route choices,a logit flow distribution method based on the familiarity of the line network is proposed to solve the problem to restore the travel process of passengers to the greatest extent.3.According to the factors that affect the importance of urban rail transit nodes,a node importance evaluation system is constructed for the functional characteristics of passenger flow operations and complex network structure characteristics.To measure the importance contribution of network nodes in three aspects,a method for identifying key nodes of urban rail transit based on information transmission efficiency matrix is proposed,and a calculation method for the importance of each interval and line in the network is constructed.4.Based on the difference of each node,interval and line in the line network,an evaluation and optimization model of the line network transportation plan considering the order of importance is proposed.Firstly,based on the dynamic interaction model of train operation status and time-varying passenger flow,the matching values are output from the three micro-levels of station,interval and line,and fuzzy evaluation is applied to comprehensively measure the matching degree of supply and demand at the macro level based on the importance of each element.Secondly,considering the constraints of train operation,line connection and coordination time period,with the goal of minimizing the transfer waiting time of all passengers during the study period,a network transfer coordination model based on key transfer stations and key lines is constructed to evaluate the trains on each line in the line network.The departure time and departure interval are coordinated,and the importance weight ratio of key routes and transfer stations is introduced into the model to improve the coordination priority of key transfer stations.5.Select the local network of Chengdu Metro for example verification,and evaluate and optimize the network transportation plan based on the passenger flow data within 14:00-15:00and the operation data of the line network during the period.On the basis of considering the importance ranking of each station,interval and line in the line network,the matching degree values of network capacity supply and passenger flow demand at the station,interval and line level are 64.63%,48.04% and 25.48% respectively;The order of importance of each level is used to optimize the connection and optimization of the running lines of each line.The proposed coordination optimization model improves the matching degree of the three levels of stations,sections and lines in the network by 34.58% in total,which effectively improves the operation efficiency of the line network transportation plan.