Small strain shear modulus of anisotropically loaded sands

Abstract

This study aims to investigate the significant influence of stress anisotropy and different stress components on the small-strain shear modulus of sands using a comprehensive set of bender element tests on sand specimens undergoing anisotropic stress state along variable stress paths. Particular attention is given to the contribution of sand index properties, including grain size characteristics and particle shape. It is shown that there is a great difference between the contributions of the principal stresses along and perpendicular to the direction of wave propagation, especially for the well-graded sands having irregular in shape particles. Indeed, the contribution of the principal stress along the vertical direction, i.e. the direction of wave propagation, was observed to be more pronounced than that in the horizontal direction which coincides with the direction of particle perturbation. Using the experimental results obtained in the course of this study, a previously proposed equation is modified and presented in a new form in order to evaluate the small-strain shear modulus of sands subjected to anisotropic stress states in the major and minor principal stress plane.