A Study On The Identification And Simulation Of Bottleneck Of Evacuat Ion Capacity In Urban Rail Transit Stations

The urban rail transit, as a kind of public transit with the characteristics of large traffic volume, high speed and convenience, has become the main means to resolve urban traffic jam. However, the growing number of passengers has caused potential safety problems to the rail transit, in which subway stations are the nodes whose evacuation capability is closely connected with passengers’life security. Therefore, it is necessary to know how to identify bottlenecks of evacuation capacity, which is helpful for staff in the station to promptly work out proper and effective evacuation plans so that they can organize stranded passengers to disperse into secure places within a short period of time. Thus the identification of bottlenecks of evacuation capacity has become a key issue to guarantee safe operation of the urban rail transit.First, this thesis classifies facilities in the station of the urban rail transit according to their evacuation function, describes stations as a network in an abstract way, and designs the K-shortest algorithm directed towards the generation of paths in emergency so as to form alternate routes for the evacuation of passengers.Then, a large number of data concerning the macro characteristics of passengers are obtained through observation and analysis of videos recorded during rush hours in typical stations. And equations concerning the relationship between passenger flow speed and density are generated through curve fitting of flow speed and density in main service facilities the passengers pass by when being evacuated. Next, the calculated maximum through capacity per unit width is compared with the values in Railway Design Standards so as to prove reliability of the data.Third, based on equations concerning the relationship between passenger flow speed and density in various kinds of facilities, the thesis presents the algorithm for calculating evacuation capacity of facilities. The thesis also designs a method to identify static bottleneck grounded on backward search by taking into consideration the alternate routes for passenger evacuation. And the ranks of dynamic bottleneck are classified according to flow fluency. Then the method to identify dynamic bottleneck is worked out with the ranks as the universe and speed and density as fuzzy sets.Finally, Fuxingmen station in Beijing is selected as a case. According to alternate routes and evacuation capacity of facilities, the static bottleneck of evacuation capacity of the station is calculated. And according to the speed and density of facilities acquired by VISSIM simulation, the ranks of dynamic bottleneck of evacuation capacity are judged so as to offer suggestions to plan-making of passenger evacuation. At last, the method to identify dynamic bottleneck is proved to be practical and reliable by comparing and analyzing the results of the original and the new evacuation pattern.