Risk Assessment Of Urabn Rail Transit System Considering The Impact Of Passenger Flow

With the rapid economic and social development,the process of urbanization in China is accelerating,a large number of people are pouring into cities,the urban transportation system is overwhelmed,and traffic congestion is becoming more and more serious.The urban rail transit system has the advantages of rapidity,punctuality,and large transportation capacity,which can effectively alleviate the problem of urban traffic congestion.However,due to the large passenger volume and relatively closed operating environment of the urban rail transit system,the occurrence of serious accidents will lead to heavy casualties and property losses,and cause adverse social impacts.Therefore,scientific research on the risk assessment method of urban rail transit system is of great significance for realizing the safe operation of urban rail transit system and ensuring the safety of life and property of passengers.First of all,based on the analysis of risk assessment research at home and abroad,this paper gives the definition of risk,clarifies the basic attributes and components of risk,and points out that risk assessment should be closely related to the two basic attributes of "uncertainty" and "impact",further measuring the risk impact on the basis of paying attention to the probability of risk occurrence.The characteristics of urban rail transit system and its risk are analyzed.Based on the basic attributes of risk and the risk characteristics of the urban rail transit system,the research ideas of the risk assessment method proposed in this paper are introduced.The manifestations of the risk uncertainty of the urban rail transit system are analyzed,and the concrete manifestation of the risk impact of urban rail transit system is analyzed.The fundamentality and intuitiveness of the impact of passenger flow is pointed out.Then,the risk probability of urban rail transit system is analyzed.Combined with the actual operation,the risk factors of the urban rail transit system are identified,and the definitions of five types of basic risk events that are common in the actual operation process are given.Based on this,the urban rail transit system risk probability model is established.Thereafter,the risk impact of urban rail transit system is analyzed.The impact of basic risk events is defined from the perspective of network,an urban rail transit system risk impact model based on the improved Logit passenger flow distribution model is established,and the risk event impact degree index and the comprehensive risk level index of urban rail transit are proposed.Finally,the effectiveness of the model is verified by taking the Chengdu Metro as an example.The probability of occurrence of various basic risk events is calculated by using the risk probability model and the statistical data of Chengdu Metro accidents.The impact degree of various basic risk events is calculated by using the risk impact model and actual operation data.Based on the above results,the comprehensive risk level of Chengdu Metro is obtained,and the sensitivity analysis is carried out on the key parameters of the model.And risk management and control measures considering the impact of passenger flow are put forward.