To cite this version:Solenn Le Pense, Chloé Arson, Ahmad Pouya.A fully coupled damage-plasticity model for unsaturated geomaterials accounting for the ductile-brittle transition in drying clayey soils.International AbstractThis paper presents a hydro-mechanical constitutive model for clayey soils accounting for damageplasticity couplings. Specific features of unsaturated clays such as confining pressure and suction effects on elastic domain and plastic strains are accounted for. A double effective stress incorporating both the effect of suction and damage is defined based on thermodynamical considerations, which results in a unique stress variable being thermodynamically conjugated to elastic strain.Coupling between damage and plasticity phenomena is achieved by following the principle of strain equivalence and incorporating the double effective stress into plasticity equations. Two distinct criteria are defined for damage and plasticity, which can be activated either independently or simultaneously. Their formulation in terms of effective stress and suction allows them to evolve in the total stress space with suction and damage changes. This leads to a direct coupling between damage and plasticity and allows the model to capture the ductile/brittle behaviour transition occurring when clays are drying. Model predictions are compared with experimental data on Boom Clay, and the flexibility of the model is illustrated by presenting results of simulations in which either damage or plasticity dominates the coupled behaviour.

No abstract

To cite this version:Behrouz Gatmiri, Solenn Le Pense, Pooneh Maghoul. A multi-scale seismic response of twodimensional sedimentary valleys due to the combined effects of topography and geology.. Journal of Multiscale Modeling, 2011, 3 (3), pp.133-149. <10.1142/S1756973711000455>. It is well-known that the response of a site to seismic excitation depends on the local topographical and geological conditions. The current building codes already take into account unidimensional site effects but ignore complex site effects due to two-dimensional irregular configurations. The aim of this work is to contribute to the establishment of a simple predictive method to estimate site effects. The horizontal ground movements at the surface of sedimentary valleys subjected to SV waves with vertical incidence are calculated by using the HYBRID program, combining finite elements in the near field and boundary elements in the far field (FEM/BEM). A parametric study is conducted to examine the combined effects of topography and geology on the amplification of the response spectrum at various points across the valley. The influence of different parameters is considered, such as filling ratios (from empty to full valleys), impedance contrasts between bedrock and sediments, and dimensions.