Research On The Vulnerability Evaluation Of Urban Rail Transit System

In recent years,urban rail transit system has become an effective means to delay the ground traffic problems in cities with the advantages of large passenger capacity,safety,speed and punctuality,which plays an important role in the transportation system.Rail transit brings great convenience for people to travel,but the occasional operation accidents also show that the system has certain vulnerability.In order to improve the safety and reliability of urban rail transit system,we should grasp the formation mechanism of rail transit vulnerability,determine its influencing factors,and build the corresponding vulnerability evaluation index system.Four models such as normal cloud model are proposed to calculate the vulnerability level of urban rail transit,and the sensitivity of evaluation index is analyzed.According to the evaluation results,some suggestions are put forward to reduce the vulnerability level of urban rail transit system.This will promote the research method and scope of urban rail transit vulnerability;It is also helpful for traffic managers to take targeted measures when making management decisions,so as to improve the traffic operation performance,reduce the occurrence of accidents and make the system operate more safely.Taking the vulnerability of urban rail transit system as the research object,the following researches are carried out:Firstly,based on the Swiss cheese model,the process and principle of vulnerability formation were proposed.Combined with the characteristics of rail transit system and the data of rail transit accidents at home and abroad,the influencing factors of urban rail transit vulnerability were analyzed from the perspectives of personnel,equipment,environment and management,and 31 vulnerability evaluation indicators were selected.The grey correlation analysis method was used to sort the correlation degree of the indicators successively,and the dominant influence factors with higher correlation degree were screened out,namely,a total of 22 vulnerability evaluation indicators,which were used to construct the vulnerability evaluation index system of urban rail transit system.Secondly,based on many uncertain issues in the vulnerability assessment of urban rail transit,a normal cloud model is proposed to construct a rail transit vulnerability model.First determine the basic characteristic parameters of each indicator of the model,use MATLAB software combined with forward cloud generator programming simulation to obtain the membership degree of the vulnerability index,make fuzzy transformations of the index weight set and membership degree,and then calculate the vulnerability of urban rail transit The degree of membership belonging to the five evaluation levels is combined with the level feature value and the set confidence criterion to determine the urban rail transit vulnerability evaluation level.Then,considering the applicability of each model comprehensively,the matter element theory,set pair analysis-variable fuzzy set method,and improved TOPSIS method are proposed to build the urban rail transit vulnerability evaluation model respectively.The evaluation results obtained from the three models are compared with the normal cloud model.To verify whether the vulnerability evaluation index system and the evaluation model of urban rail transit based on personnel,equipment,environment and management are reasonable and effective.This study aims at provide a variety of scientific and reliable quantitative evaluation systems and methods for vulnerability assessment of urban rail transit system,so as to enrich the vulnerability research of rail transit system.Finally,the single factor rotation method is used to analyze the sensitivity of the weight of vulnerability evaluation indicators,which is also one of the innovation points of this paper.The absolute average change rate of vulnerability of four levels of rail transit in Chongqing was calculated,and the more sensitive evaluation indexes were obtained by ranking the sensitivity indexes,and then the measures to improve the vulnerability of rail transit were put forward directionally.