Análise elastoplástica de túneis pelo método dos elementos de contorno

Abstract

In this dissertation a two-dimensional elastoplastic tunnellig analysis, using the Direct Boundary Element Method, is presented. Mikhlin's concept for the derivative of the singular integral of the inelastic term, in the expressions for the stresses at internal points, is employed. A review of the theory of plasticity and a description of several construction procedures for underground openings are also done. Tresca, Von Mises, Mohr-Coulomb and Brucker-Prager yield criteria in a unified form are used in association with the initial stress process in a non-linear algorithm which does not include the assumption of incompressibility of the inelastic strains. With this process, plane stress problems can be solved by the plane strain expressions simply changing Poisson's ratio. Lined tunnels are analysed using the sub-regions technique. Kelvin's fundamental solution for 2D infinite domain is employed in the analysis of deep tunnels and the half-plane fundamental solution for shallow tunnels and the half-plane fundamental solution for shallow tunnels. Four example problems are discussed to demonstrate the accuracy and versatility of the method comparing results for elastic and elastoplastic analysis.