An elastoplastic model with inherent and induced anisotropy for soil behaviour under rotational loads

摘要

The paper presents an elastoplastic constitutive model for soil behaviour subjected tosolicitations where the principal directions are continuously rotated as encountered in earthquakeengineering. The model employs a formulation where phenomenological and microstructural approachesare combined by introducing the geometrical anisotropy tensor defined as a measure ofboth inherent and induced anisotropy. An orthotropic elasticity depending on hardening variables isdefined using an approach quite similar to the one used in damage theory. A non associative flowrule is adopted. A more physical meaning of the hardening variables of the phenomenological formulationis obtained by making them dependant explicitly on the orientation of the stress tensorwith respect to the material. The model is used to simulate the response of a two dimensionalSchnebelli material along paths where the principal strain directions are continuously rotated. Themodel is shown to be capable of satisfactorily predicting the liquefaction of the specimen duringrotation cycles. The effects of inherent anisotropy on liquefaction potential are also shown.