Structural Safety Analysis Of Operating Subway Shield Tunnel Based On Copula Dependency Modeling

Operating subway shield tunnel exists in a complex underground environment,and it’s structural safety is subject to long-term coupling effects of many dependent factors,which leads to the continuous deterioration of the tunnel structure’s service capacity over time.Under the condition of considering the dependence of various influencing factors,how to accurately and dynamically analyze the safety of the operating subway structure based on the limited data monitored on site,so as to provide effective information support for the safety management and control decision of the operating subway structure,which is an actual engineering problem that needs to be solved in the operation and maintenance management of the subway.Aiming at the above problems,based on Copula’s dependency modeling theory,a series of research work has been carried out on the safety analysis of operating subway shield tunnels.1.From the perspective of analysis of influencing factors of structural safety,introduced several common influencing factors and causes of structural safety of operating subway shield tunnels,summarized the characteristics of influencing factors,and from the theoretical level,it is confirmed that there are complex interdependencies among several common influencing factors.2.From the perspective of structural safety and reliability analysis,a method for analyzing the structural safety and reliability of operating subway shield tunnels based on Vine Copula model is proposed.Based on the Vine Copula dependency modeling theory,a joint probability distribution function of multi-dimensional influencing factor parameters is established.Under the condition of accurately characterizing the dependence of multiple influencing factors,the safety and reliability analysis of the operating subway shield tunnel structure is realized.3.From the perspective of dynamic analysis of structural safety,a method for dynamic analysis of structural safety of operating subway shield tunnels based on PCBN model is proposed.First,the key parameters of the PCBN model are obtained by fuzzy comprehensive evaluation method,and then based on the PCBN dependency modeling theory,the nonlinear mapping relationship between the dynamically changing dependency factors and the overall structural safety state of the tunnel is captured.,and finally the combination of Bayesian network inference and GM(1,1)time series prediction model and polynomial regression analysis technology to realize the dynamic analysis of the safety status of operating subway structures.In this paper,an empirical analysis is carried out by taking the operation of a shield tunnel in Wuhan Metro Line 3 as an example,and the analysis results show that the series of analysis methods for the structural safety of the subway shield tunnel proposed in this paper can not only capture the dependence of various influencing factors more sensitively,but also realize the accurate and dynamic analysis of the subway structure safety,which provide information support for the safety management and control decisions of operating subway shield tunnels.