Types of Shearing and Anisotropy in Undrained CPTu

Abstract

Most natural clays acquire an anisotropic fabric upon deposition. This anisotropic fabric induces differences in the soil mechanical responses, for instance in the undrained shear strength observed in the laboratory. It is unclear how much of that anisotropy is reflected on the responses measured by the cone penetration test. In this work, we use GPFEM to numerically simulate cone penetration tests (CPTu) in undrained, anisotropic clays. The constitutive response is represented by S-CLAY1, a critical state, anisotropic model. Full details of the representative stress path during CPTu insertion are provided. Preliminary numerical results suggest that even a large amount of anisotropy, as described by the model, will have a very small effect on the cone responses. The numerical simulation results also show that the prevailing stress path has strong similitudes with that found during anisotropically-consolidated undrained compression triaxial test.