Research On Bus Dispatching In Case Of A Sudden Disruption Of Urban Rail Transit

With the rapid development of China’s urbanization process,the population of many large and medium-sized cities has grown rapidly,which has brought great challenges to the daily passengers transportation system in cities.In recent years,urban rail transit has developed rapidly in many large and medium-sized cities in our country,and an urban public transport passengers transportation network system with urban rail transit as the main public transport modes and routine public transport assistance has been gradually formed.Urban rail transit has the characteristics of high intelligence,high level of informatization,large passenger traffic,dense crowd flow within the system,and high degree of system closure,which is the main artery of urban passenger transportation.However,due to the interference of some uncontrollable factors inside or outside the system,sudden disruptions at one or several stations or sections of the urban rail transit network occur from time to time during normal operation of rail transit trains,which leads to passenger travel delays,and large numbers of passengers are stranded inside the system,posing potential security risks.Therefore,calling ground buses to evacuate stranded passengers and using ground buses to continue the evacuation of interrupted sections is an efficient and feasible measure,which is also of great significance to reduce passengers travel delays and economic losses when an accident occurs.Therefore,the thesis will take the urban rail transit sudden operation interruption event as the research object to analyze some relevant issues such as emergency bus connection evacuation and passengers diversion when the interruption event occurs,and the main research contents are summarized as follows:（1）A systematic summary is made by combining the related theories of rail transit sudden interruptions in emergency at home and abroad.Besides,it introduces the definition and classification of emergencies,and analyzes the impact of different interruption positions on passenger travel.Then,this thesis systematically inducts rail transit operation adjustment plans and the bus emergency response in sudden interruptions,which lays a solid foundation for the following research.（2）Taking the affected passenger as the research object,it defines the scale of the affected passengers,and analyzes the influencing factors during passengers redistribution,construction of impedance function based on passenger travel time chain,and builds the passengers redistribution models.Using the improved Frank-Wolfe algorithm,through Matlab programming to redistribute the affected passenger flow into the newly constructed bus connection network,provides detailed data support for the subsequent development of specific connection plans.（3）Based on the relevant design specifications and the actual situation,the thesis analyzes the feasibility of operating temporary emergency crossings when the rail transit is suddenly interrupted.Then combined with the research results of the identification of key nodes in the urban rail transit network based on the loading of passengers,by minimizing the travel time cost of passengers and the operating time cost of emergency bus connections,and comprehensively considers the constraints of the number of emergency buses,line length,line occupancy rate,builds an optimization model,formulates operating schemes of the bus emergency response to the emergent passengers transportation.（4）Case analysis.With a network of six rail transit lines in a city as a background,assuming that the two-way operation of Line 1 station section v₁₃-v₁₅ is interrupted for one hour,and meets the conditions for starting an emergency bus.Through solving and analyzing models,the final emergency bus connection combination scheme is formulated.Compared with the traditional connection scheme,it is found that the combined connection plan formulated in this thesis optimizes the total travel time cost of passengers,bus operation costs and the emergency bus vehicles called,and effectiveness of the model proposed in this thesis is also verified as well.