Shear Modulus and Damping Ratio of Sand–Gravel Mixtures Over a Wide Strain Range

A total of 153 cyclic triaxial tests were performed on 19 sand–gravel mixtures over the strain range of 10–5–10–2, which shows that the particle characteristics have significant influence on the small-strain shear-modulus G0, shear modulus reduction G/G0, and damping ratio λ. An improved Hardin’s equation for the G0 was proposed to consider the effects of particle characteristics and consolidation state. Furthermore, the KZM model correlation was improved to characterize the G/G0 curve. A four-parameter equation of λ with parent rock type, particle gradation, and consolidation condition was also introduced to characterize the λ curve.