Research On Bus Bridging Network Plan Under Urban Rail Transit Disruption

The disruption of the operation of urban rail transit trains,especially at peak times,will result in mass passengers crowded in the station,which can cause some safety risks.Therefore,crowded passengers must be evacuated as soon as possible.However,the adjustment of the urban railway operation plan cannot meet the needs of passenger flow evacuation.In order to solve the above problems,some cities such as Beijing and Guangzhou have formulated some norms and plans about bus bridging under conditions of train operation disruption.However,the formulation of bus bridging plan is a complex combinatorial optimization problem,which is constrained by factors such as urban rail transit network topology,urban road network,interrupted operation station and available public transportation.In addition,the program also needs to meet the needs of passenger evacuation.This paper studies the generation of bus bridging plan under the disruption in order to alleviate the passenger flow pressure caused by the disruption of the train operation and meet the passenger travel demand.The abstract of the paper is as follows:1.The impact of the train operation disruption on passenger travelUnder the disruption of operation,the paper analyzes the influence of three conditions including different topological networks.the time-space factor of disruption event and bridging environment factor on passenger travel.The structure of disruption region includes non-transfer in the middle of line,transfer in the middle of line and the terminal of line.Based on the three region structures,five typical disruption emergency scenarios were constructed based on the partial or complete interruption caused by the adjustment of emergency operation plan.2.Influenced passenger flow division and redistribution under disruptionBased on the disruption emergency scenarios,this paper analyzes the travel chain time of passenger rail transit and uses Dijkstra algorithm and K-shortest path algorithm to get passenger travel route.In this study,a route selection model based on logit model is established to determine the travel route selection of passenger flow and calculate the bridging passenger demand.The stations in the three disruption regions are divided and the bus bridging path is planned for the purpose of resuming transport function of the disruption regions.Finally,the passenger loss elasticity coefficient is proposed to describe the behavior of other alternative modes of travel in the disruption regions.Then allocate the bridging passenger flow to the planned bus path once again.3.Bridging travel network construction and bridging plan generationBased on the three types of disruption regions,the paper takes bridging stations as nodes and bridging arcs between stations as edges to build emergency bridging travel network.Combining the impact of bridging paths which have different stop plans on the passenger flow,and considering the constraints including passenger conservation in the network,paths succession and ring formation,cluster site constraints and site capacity constraints,it takes the minimized total passenger flow time as the target and establishes the stop plan generation model for bus emergency bridging plan.In this paper,the number of vehicles in use is calculated by using the calculation model of the bridging vehicle.Combining the number of vehicles in use with stop plans,a bridging plan is formed.Finally,based on the use of branch and bound algorithm and design of the arc edge increase or decrease algorithm,the model is solved by programming on MATLAB software.Taking the case of Guangzhou subway as an example,the model and algorithm are used to generate the corresponding bus emergency bridging plan.The solved bridging plan with four bus paths in operation can save passenger bridging time up to 15088 minutes and save two buses.The results show that the optimization model and the arc edge increase or decrease algorithm proposed in the paper are feasible and effective.