Research on Back Analysis of Shield Tunnel Structure Based on Damped Least Square Method

In the construction and operation of shield tunnel, it is often difficult to obtain the strength and external load of shield tunnel segment structure quickly and accurately by measurement. In order to quickly and accurately obtain the mechanical parameters for shield tunnel during construction and operation period, the parameter inversion using accurate measurement data is widely and extensively researched and applied. Based on the Damped Least Square (DLS) method, the structural strength parameters and external load parameters in the load structure model of shield tunnel are inverted. Based on the Tongji Shuguang three-dimensional finite element method platform, the corresponding software for such back analysis has been developed. Three algorithms including the Genetic Algorithm (GA), the Simplex Method (SM) and the Damped Least Square method are implanted, and the multi-value problem in multi-parameter inversion is discussed. Finally, combined with practical engineering cases, which stably yielded the values of local loads and ground spring coefficient. The results show that the parameter inversion for the shield tunnel structure based on the DLS method are relatively stable and reliable, which provides a quantitative way to obtain mechanical parameters during the construction and operation period of the shield tunnel.