Main insights from 2D/3D poroelastic analysis of tunnel excavation in low permeability anisotropic ground

Lina-María Guayacán-Carrillo (1) , Jean Sulem (1) , Siavash Ghabezloo (1)

1 NAVIER UMR 8205 - Laboratoire Navier

Pore pressure evolution induced by tunnel excavation in low permeability anisotropic ground is investigated by means of a fully coupled hydro-mechanical finite element simulation. The goal is to explore the main trends of the pore pressure evolution on the basis of a poroelastic analysis, taking into account: on the one hand, the influence of excavation and face advance; on the other hand, the inherent anisotropy of the material. It is shown that overpressures can be induced before the passage of the face, depending on: the consolidation time of the rock, the rate of excavation and the degree of anisotropy of both the material and the initial stress state. Finally, a discussion about pore pressure evolution at tunnel wall is presented. An analysis is performed in order to propose a pore pressure release rate at the tunnel wall for 2D models.

Mots clés: Poroelasticity; Hydro-mechanical coupling; Low-permeability ground; Tunnel excavation; Anisotropy; Overpressure

Domaines: Géotechnique

Lina-María Guayacán-Carrillo, Jean Sulem, Siavash Ghabezloo. Main insights from 2D/3D poroelastic analysis of tunnel excavation in low permeability anisotropic ground. Computers and Geotechnics, 2021, 130, pp.103935. ⟨10.1016/j.compgeo.2020.103935⟩. ⟨hal-03135154⟩