Numerical Analysis of Tunnel Face Stability in Non-Cohesive Materials with an Innovative Constitutive Model

Tunnel face stability is generally of great concern in tunnel excavation with both traditional methods and with modern tunnel boring machines (TBMs). Several methods have been proposed in the literature for the analysis of face stability, which are generally based on the limit equilibrium method and on different assumptions of the failure mechanisms. The major uncertainties typically concern the purely frictional materials. The aim of this work is to analyse the tunnel face stability in non-cohesive soil by employing the finite element method (FEM) with the constitutive model recently proposed by Argani & Gajo, and to compare the computed failure mechanisms and support forces with the results proposed in literature.