Anisotropy of Undrained Shear Strength of Clays under Axi-Symmetric Loading Conditions

Abstract

ABSTRACT Experimental investigations indicate that an anisotropically consolidated clay changes its undrained shear strength depending on the experimental procedures and/or direction of shear. It is needed to formulate the anisotropy of undrained shear strength of clays for use in reliable analyses of shear failures of foundations, embankments, retaining walls etc. In this paper, the anisotropy of undrained shear strength is formulated assuming the anisotropy induced by the initial anisotropic stress state. Theoretical considerations on the undrained behaviour of normally and overconsolidated clays are made on the basis of a constitutive equation. Two equations describing the undrained state and the failure state are derived and, applying these equations to axv-symmetric stress state, derived are some equations which give the theoretical values of the undrained shear strength to be obtained from the triaxial tests on normally and/or overconsolidated clays. The validity of the equations are examined by the comparison of the calculated strengths and the experimental strengths reported in the past.