Reasearch On Risk Identification And Evaluation Of Subway Shield Construction

As the urban population becomes more and more dense,traffic pressures increase sharply,the subway is more and more widely used in large cities in order to alleviate the traffic pressure.The common construction method for subway construction is shield construction.However,due to the complexity,concealment and uncertainty of the subway construction environment and the complexity of the construction process,the risk of the subway construction is relatively high,and security incidents often occur and the consequences are severe.Therefore,it is of practical significance and applicable value to study the safety risk of subway construction.In order to effectively reduce engineering risks and enhance risk response capabilities,it is necessary to identify and evaluate risks in the subway construction process to improve the safety of the subway construction process.Through a large number of investigations,this paper carries out the identification and assessment of construction safety risk of subway shield construction.The main work includes:In this paper,according to the principle of subway shield construction,the operation process of subway shield construction is decomposed,and it is divided into construction preparation,construction of initial well,shield machine assembly,shield origination,shield tunneling and shield tunneling.Each stage is identified from the possible structural and personnel safety risks,and the source code of the subway shield construction safety risk is established to provide the follow-up shield construction risk researchers and risk managers.Then,according to the risk source of each stage established in the previous stage,the LEC method is used to identify the major risk sources in the construction process of the subway shield method,and the construction of the underground excavation method,the construction of the freezing method,the launching of the starting frame,and the assembly of the shield machine are identified.Construction procedures such as construction and tunnel door excavation construction are major sources of risk,which are important preventive and attention process in construction.Secondly,for the identified major sources of risk,it is necessary to analyze the specific factors affecting these sources of risk,and further analyze the impact of the specific factors of these sources,in order to provide a basis for managers to more clearly focus on risks.This paper analyzes the specific factors of the construction process of major risk sources from five aspects:"human,machine,material,law,and ring",and uses AHP to evaluate these influencing factors.Finally,taking the Nanning Rail Transit Line 3 as an example,the identification of the risks and the identification and evaluation of the major risk sources and the influencing factors have proved that the research is applicable.