General strength criterion for geomaterials

This note presents the results of a study on the variation of the strength of geomaterials. A general isotropic strength criterion is proposed which unifies the peak strength and critical state (or steady state) strength into one strength criterion. The proposed criterion describes the strength of a geomaterial in terms of its current stress state, its current voids ratio, and the bonding of its constituents. The proposed criterion has been applied to sand, clay, cemented sand and rocks. Based on comparisons presented between theoretical simulations and experimental data, it is seen that the proposed criterion describes successfully the isotropic strength of all these materials for general stress conditions.