Based on the framework of damage mechanics for geological materials

a constitutive model is proposed for anisotropic structured sandy soils considering the micromechanism of the destructuring. The Lade-Duncan failure criterion is adopted to consider the effect of intermediate principal stress on the shear strength. An anisotropic state variable A considering the fabric of particle arrangement is employed to reflect the influence of the anisotropy on the mechanical behavior of structured soil. The influence of soil structure on the mechanical behaviors is considered by enlarging the structural yielding surface for reconstituted soils in geometry. The non-associated flow rule is applied to describe a reasonable plastic strain for the anisotropic structured soil. A damage law based on the debonding effect on microscale is used to model the soil destructuring in the hardening law for structured soils. The effect of both plastic volumetric strain and shear strain is considered in the hardening law. Thus

this model can properly describe the mechanical behaviors of soils from intact state to reconstituted state. The proposed model is preliminarily verified by predicting the mechanical behaviors of natural and artificially cemented sands in the triaxial tests.