Fabric: A Missing Link Between Critical State and Critical State Theory

Abstract

The Critical State Theory of Roscoe et al. [1] and Schofield and Wroth [2], proposed two analytical conditions as necessary and sufficient for soil to reach and maintain Critical State. In this work the sufficiency of these two conditions is challenged by the results of a virtual experiment performed by means of the Discrete Element Method, where stress principal axes rotation is imposed at Critical State of a granular sample. The fabric emerges as the important entity that can explain the lack of sufficiency of the two conditions and serve as a link between Critical State Theory and Critical State as a physical event. The recently developed Anisotropic Critical State Theory includes an additional condition on fabric, that combined with the classical two provide a triplet of necessary and sufficient conditions for reaching and maintaining Critical State.