Experimental investigation of shear modulus and damping ratio of saturated marine coral sand: Effects of frequency

The dynamic deformation characteristics of saturated sands are considerably influenced by the loading frequency (f). Nevertheless, the effect of f on the deformation behavior of saturated coral sand (CS) has not been comprehensively investigated. This study aims to investigate how frequency (0.01‒4Hz) affects the shear modulus (G) and damping ratio (λ) characteristics of CS through a series of cyclic shear tests. The experimental results demonstrate that, under consistent initial conditions, both the strain-dependent G and λ increase as f increases. Moreover, there is a linear relationship between the maximum shear modulus (G0) and small strain damping ratio (λmin) with ln(f). Specifically, the regularized G of CS remains unaffected by variations in f. To facilitate the prediction of G in CS at different f, we propose a prediction equation that integrates the revised Hardin’s model and Davidenkov skeleton curve. Besides, a power function expression is suggested for λ−λmin versus G/G0 to predict λ in CS at different f. The revised equations for G and λ are validated using experimental data from natural sands in the literature, confirming their suitability for evaluating strain-dependent G and λ values of natural sandy soils over a wide strain range.