An Elasto-Plastic Model for Unsaturated Soils with Evolving Anisotropy
Résumé
A new elasto-plastic model for unsaturated soils incorporating the effect of evolving fabric anisotropy is presented. The model is formulated in terms of mean net stress, deviator stress and suction and reduces to the Barcelona Basic Model for an isotropic material. Model simulations are performed and compared against experimentally observed behaviour from constant suction triaxial tests on isotropically and anisotropically compacted kaolin samples along a variety of stress paths. Simulations indicate an improvement in the prediction of the size and shape of the yield surface compared to the Barcelona Basic Model. In addition, the deformation generated during shearing are better predicted than in the Barcelona Basic Model, even though experimentally observed strains are still grossly over-estimated. Further refinement to model assumptions are required to improve predictions of experimental data and the reformulation of the model in terms of average skeleton stresses, instead of net stresses, might help in this respect as outlined in Al-Sharrad (2013). \textcopyright 2014 Taylor & Francis Group, London.