Constitutive Modeling of Dilatancy for Overconsolidated Clay

The dilatancy of clay has long been considered as a function of the current stress state independent of the loading history. Experimental evidence, however, indicates the dilatancy behavior of over-consolidated (OC) clay bears close correlation with the overconsolidation ratio (OCR) of the soil. This paper presents a simple dilatancy relation for OC clays based on the modified Cam-clay (MCC) model. The dilatancy relation is integrated into a bounding surface model to predict the behavior of OC clays. With only three extra parameters added to the MCC model which can be easily calibrated by triaxial compression tests, the new model is shown to offer good predictions for the experimental data