A unified characterization of small-strain shear modulus of sands under triaxial compression stress states

Abstract

In slopes and embankments, soil elements are often anisotropically loaded and the sustained stress ratio SR may vary a lot. The understanding of the influence of SR on the small-strain shear modulus G₀ of sands prior to failure is a practical concern that remains inadequately understood in the existing literature. This study aims to address this knowledge gap through a meticulously designed experimental program. The testing program encompasses three quartz sands with differing particle shapes and a diverse set of principal stress ratios produced via drained triaxial compression. By employing bender elements embedded within the apparatus, elastic shear waves are generated, enabling the measurement of G₀ from isotropic stress states to anisotropic stress states. A careful evaluation and comparison of existing anisotropic G₀ models in the literature is also conducted, and the potential limitations when subjected to elevated SR levels are noted. A new, unified model is proposed to effectively characterize G₀ of different sands subjected to a wide range of triaxial compression states and it is validated using literature data.