Instrumenting Uniaxial Compressive Strength Tests to Assess the Anisotropic Deformability of a One-Dimensionally Consolidated Kaolinite

The concept of the axial shear was developed to catch several aspects of the anisotropic behaviour of soils. It was inspired by the end shear forces and moments which develop when specimens are cut at an angle to the material axes of symmetry and subjected to triaxial testing between rough platens. In routine triaxial and uniaxial compressive strength tests, these horizontal forces are unknown. In the laboratory work presented in this paper, they were measured. Tests were performed on specimens of one-dimensionally consolidated kaolinite. The testing program highlighted the difficulty of producing in the laboratory a material exhibiting a strong stiffness anisotropy. Despite this, the horizontal forces which developed along the base of inclined specimens and are at the base of the concept of the axial shear apparatus could be picked up. They were found to be low (less than 10N) but higher than those measured in vertical and horizontal specimens.