Numerical analysis of twin tunnels including long-term effects considering the creep and shrinkage of concrete

Resumo

This paper aims to show, through three-dimensional numerical analysis on finite element method, the
effect that the twin tunnel causes on the convergence profile considering several constitutive models of rockmass:
elastic, elastoplastic and viscoplastic. The elastic and viscoelastic constitutive models for the lining are considered.
For the viscoelastic constitutive model of the lining, the concrete creep and shrinkage are considered. For the case
studied in this paper a difference in the magnitude of the convergence profile of up to 9% for the twin tunnel was
observed, considering the rockmass and the lining with elastic behavior. For the other models, plastic rockmass
with elastic lining, viscoplastic rockmass with elastic lining and viscoplastic rockmass with viscoelastic lining,
minor differences were observed. Considering the viscoplastic rockmass, the presence of the viscoelastic lining
increased the deformations by about 20% (at the end of tunnel construction) and by about 40% in the long-term
behavior, in relation to the elastic lining.