Resilience Oriented Design Of Emergency Feeder Bus Lines For Urban Rail Transit

As a large capacity transport carrier,urban rail transit has many advantages,such as fast,punctual,environmental protection and so on.It has become the backbone of public transport network in large cities.Due to the openness of urban rail transit system,it is often disturbed and damaged by various emergencies such as natural disasters,equipment failures and human destruction.These emergencies will cause the delay of train operation or the interruption of line operation,and affect the travel of passengers in the rail transit system.When the operation interruption lasts long,the structure of the rail transit network is damaged,the original optimal travel path of some passengers is damaged,and the travel time is increased due to the inaccessible of the destination or the need to detour to other lines.The local and overall passenger flow transport capacity of the urban rail transit network is affected.In order to maintain the connectivity and accessibility of the network and restore certain network transport functions,it is necessary to use the ground emergency feeder bus lines to cover the rail transit section and complete the transport of passenger flow.The emergency disposal of urban rail transit emergency is the key content of urban emergency management.In recent years,the concept and index of resilience have been introduced into urban emergency management and control and the evaluation and optimization design of traffic network to study resistance and recovery ability of the system.In this paper,resilience theory is applied to urban rail transit network.Firstly,the characteristics of urban rail transit system in terms of network structure,transportation capacity and passenger flow.are analyzed.Based on the summary and analysis of the concept of resilience in various fields,this paper puts forward the connotation and evaluation method of urban rail transit system resilience,comprehensively considering the impact of network passenger demand,network topology and capacity supply on passenger travel time,the overall passenger travel efficiency of the network is established as the resilience measurement index of urban rail transit system.Secondly,types of emergency events and emergency management measures of urban rail transit system are described,and the impacts of interval operation interruption of urban rail transit system on network structure and passenger flow in the case are analyzed.Next,the stage division,station setting and type of bus emergency connection of emergency feeder bus strategy is described in detail when long-term operation interruption occurs in urban rail line section.Then,a mathematical model is established,which aims at maximize the resilience index of urban rail transit system,under the situation of local operation interruption of urban rail transit network,with the help of ground buses capacity,the emergency network topology composed of uninterrupted rail transit lines and emergency feeder bus lines is reconstructed,and passenger flow re-assignment within the network is processed,an optimal scheme of emergency feeder bus lines design and vehicle resources allocation is then generated.Finally,based on the topological structure of Nanjing metro line network and the data of AFC system,a case scenario of urban rail transit line operation interruption is constructed.According to the scheme results of the proposed resilience oriented design model of emergency feeder bus lines,resilience of urban rail transit network before and after the recovery measures of reconstruct the emergency connecting line network is analyzed,which verifies the validity of the proposed model.