Simulation of the Unsaturated Excavation Damage Zone around a Tunnel Using a Fully Coupled Damage-Plasticity Model

Solenn Le Pense (1) , Chloé Arson (2, 3) , Behrouz Gatmiri (4) , Ahmad Pouya (3)

1 navier umr 8205 - Laboratoire Navier
2 Geosystems engineering department
3 cermes - Géotechnique
4 Departement of Civil Engineering

During tunnel excavation, stress redistribution produces plastic deformation and damage around the opening. Moreover, the surrounding soil can be either saturated or unsaturated. Suction has a significant influence on the mechanical behaviour of geomaterials. Depending on their stress state and on their moisture content, clay-based materials can exhibit either a ductile or a brittle behaviour. Plasticity leads to permanent strains and damage causes the deterioration of the soil elastic and hydraulic properties. The damage-plasticity model proposed in this work is formulated in terms of a damaged constitutive stress, defined from the principle of Bishop's hydro-mechanical stress (for unsaturated conditions), and from the principle of damaged effective stress used in Continuum Damage Mechanics. The evolution laws are obtained by using the principle of strain equivalence. This hydro-mechanical damage-plasticity model was implemented in a Finite Element code. The excavation of a tunnel is simulated at different constant suctions. The results obtained illustrate the influence of suction on the development of plastic and damaged zones.

Domains: Mechanics of materials [physics.class-ph]; Mechanics of materials [physics.class-ph]

Solenn Le Pense, Chloé Arson, Behrouz Gatmiri, Ahmad Pouya. Simulation of the Unsaturated Excavation Damage Zone around a Tunnel Using a Fully Coupled Damage-Plasticity Model. Fifth Biot Conference on Poromechanics, Jul 2013, Vienna, Austria. pp.2556-2565, ⟨10.1061/9780784412992.297⟩. ⟨hal-00838367⟩