Evaluation of Tunnel Elastic and Elasto-Plastic Deformations with Approximations Obtained from 3D-FEM Simulations

Abstract

Nowadays, there are computer tools designed to simulate engineering problems. Numerical simulations in three dimensions (3D) are the closest to reality, but they require a significant amount of time and experience. In this paper, the aim is to present formulae and graphs obtained from numerical simulations using the finite element method (FEM). Their application decreases the time required to obtain deformations in the periphery of different tunnel sections and further serves to evaluate them for different excavation lengths in the face of unexpected geotechnical changes during drilling. Using the RS2 and RS3 software, 3D analyses were carried out according to the Mohr-Coulomb (MC) model, considering elastic and elasto-plastic perfect behaviors as well as isotropic and anisotropic conditions. The graphs presented herein allow obtaining displacements from an axisymmetric model to infer the 3D displacements horseshoe tunnels, and the polynomial expressions aid in determining the displacements of an established excavation length. Finally, comparisons between the displacements reported by other authors and those obtained with the polynomial expressions are presented as a means of validation for this research.