Study On Safety Risk Assessment And Application Of Xi’an Shield Tunnel Interval Construction

With the development of my country’s infrastructure,subway construction will usher in a new peak.For the Xi’an area: a large number of highways or high-speed railways have been built around the city,the municipal pipe network is densely covered,and many buildings around it have been gradually established;important ancient buildings and tomb groups can be seen everywhere.This makes the urban subway in Xi’an inevitably have spatial conflicts with some existing bridges,buildings,pipelines and underground tombs during its construction.Therefore,systematically discussing the safety risk control technology of Xi’an subway construction has important practical significance for the development of subway construction in the northwestern region of the contemporary era.On the basis of the above background,this article combines the internship work experience of related subway projects,takes Xi’an Metro Line 14 as a research case,systematically uses risk theory research analysis methods and local unique regional construction standards as research basis,and collects 2003-2019 Metro accident data,using research methods that combine expert investigation,numerical simulation,and on-site practical investigation,were used to analyze the risk factors,risk identification,risk assessment,risk management and control technical measures,and emergency measures during the construction of the line between Shangxian Road and Xuefu Road Quantitative and qualitative research on management technical measures,etc.The research shows that the risk level of this line passing through the Daxi Expressway Viaduct is generally higher,and on the basis of this discussion,this paper mainly achieved the following research results:First,through statistical analysis of the 192 accidents that occurred during the construction of the subway,this article has drawn 11 common types of accidents and analyzed the causes of the accidents,mainly reflected in adverse geological effects and pipelines There are four aspects of damage,formation damage and deformation,and insufficient construction management;second,this paper studies the influence of bad geological conditions on shield construction,and analyzes the supporting factors and geological factors in the process ofshield construction with the accident data,Groundwater control factors and other risk factors and their consequences;third,the investigation of the surrounding environment of the line shows that the types of environmental risks along the line pass through important buildings(structures),such as underground pipelines,high-speed,high-speed railway bridges,Bahe,etc.,take the Shangxue interval as an example of the project to conduct a risk assessment;fourth,establish a calculation model for the piers,piles and tunnels under the Daxi Expressway under the shield,which can settle the pile foundation,the stratum within the affected area and the tunnel arch.Numerical calculation of deformation;Fifth,according to the scope of influence of the shield method on the surrounding environment and the criteria for dividing the degree of influence,the importance of the surrounding environment,the safety requirements,and the spatial location of the project under construction and the surrounding environment,combined with fuzzy network analysis The law gives the environmental risk level of the Daxi Expressway viaduct under the shield as the first level.In order to better reduce the risk level of the subway viaduct,further ensure the smooth construction of the Xi’an subway,and promote the development of transportation construction in the western region,this article puts forward relevant reference suggestions for the above conclusions.First,starting from three aspects: strengthening the building,strengthening and isolating the surrounding stratum,and reducing the disturbance of the construction to the soil layer,to carry out risk control;gives the monitoring process in the risk control program of the high-speed railway viaduct;second In view of the emergencies and their risk characteristics during the shield construction process,corresponding pre-control and emergency treatment methods are given.