Conventional plasticity models of soils, established based upon triaxial experiments, have exhibited, less or more , drastic deficiencies under loading patterns with principal stress axes rotation, especially , under stress paths in which non-coincidence of plastic flow and principal stress directions, so-called non-coaxiality , ocurs. Herein development of a non-coaxial plasticity sand model has been outlined. Various comparison between results of simulations by the new-developed model and the same model, which neglects the effect of non-coaxiality on deformation , with experimental results of real tests on sand have showed that the non-coaxial model able to provide more realistic predictions compared to a similar model which does not account for non-coaxiality.

كلمات كليدي:

Plasticity , Non -coaxiality , Fabric , Ansiotropy State Parameter