Analysis of the interaction between the lining of a TBM tunnel and the ground using the convergence-Confinement method

Abstract

The support used when a tunnel is excavated by a shielded TBMis complex because it consists of two different materials: A concrete segmentallining and a filler annulus between the lining and the tunnel wall. A detailedanalysis of the behavior of such a support system requires a three-dimensionalnumerical modeling and should also consider the presence of the TBM machine.This article presents an analytical calculation procedure that allows to assessthe interaction between the support system and the tunnel using theconvergence-confinement method and Vlachopoulos-Diederichs method. Furthermore,it is defined the overall stiffness of the support system starting from thedetailed analysis of the stresses and strains developed in the two constituentmaterials. From the analysis of the evolution of the radial displacements inthe longitudinal section, it was then possible to evaluate another fundamentalparameter: The radial displacement of the tunnel wall at the point ofinstallation of the support system. The computational procedure was thenapplied to a specific case, showing the influence of the stiffness of the fillingmaterial on the final loads acting on the segmental lining.