A micro mechanical model for overconsolidated behaviour in soils

This paper presents a simple micro mechanical model for the behaviour of overconsolidated soils. We consider the simplest case of isotropic unloading and reloading of an isotropically normally compressed aggregate. The model is based on the definition of a unit cell which contains a rigid kernel representing a large grain, surrounded by a matrix of finer particles. On initial unloading, the model exhibits elastic behaviour followed by “kinematic yielding” which is the onset of sliding of grains. On reloading, kinematic yielding may not occur, but the inhomogeneous stresses may induce “clastic yielding” which is the onset of particle crushing. The model offers realistic hysteresis loops featuring shakedown on cyclic loading.