Research On Safety Risk Assessment Of Shield Tunnel Close-up Overlapping Construction In Wuxi Metro Section X

In recent years,in the process of metro construction in big cities,the shield tunnel overlapping construction in close distance appears.In the previous research on subway risk management,few scholars have studied its construction risk.Considering that the risk of shield construction is much higher than that of previous shield construction,it is of great significance to carry out risk management research on shield construction from the perspective of reducing construction risk and economic and property loss.This paper mainly conducts construction safety risk assessment based on the actual situation of Wuxi Metro Section X,and conducts construction safety risk management research on the close-up and overlapping construction of shield tunnels in the project interval.The method of evidence theory is adopted to deal with the uncertain information,so as to improve the subjectivity and uncertainty caused by the quantitative indicators of influencing factors scored by experts involved in the construction risk assessment process.Firstly,through field visits,literature review,brainstorming and other methods,from the "human,machine,material,method,environment" five aspects of the project construction risk identification.The 21 indexes,such as the experience of site management personnel,the selection of shield machine and supporting equipment,and ground reinforcement,are screened out.On this basis,the index system of the near-distance overlapping construction risk evaluation of shield tunnel in X section of Wuxi metro is established,and then the risk evaluation model is established.COWA operator is used to weighted distribution of indicators and Gaussian membership function to construct the Mass function.Finally,matrix calculation is used to obtain the overall risk evaluation value of the project.Through the study,it is concluded that the construction risk grade of shield tunneling near the upper and lower overlapping construction in X section of Wuxi metro is medium,in which the construction risk evaluation value of the first-level index is environmental factor,construction material factor,construction technology factor,mechanical equipment factor and personnel factor from large to small.According to the conclusions drawn,targeted improvement suggestions were made for the followup shield construction,which provided a favorable reference for the safe and smooth completion of the project.