An Experimental Study of the Dynamic Shear Modulus and Damping Ratio of Calcareous Sand in the South China Sea

The marine deposits in the South China Sea are characterized by an abundance of calcareous sand. The dynamic characteristics and properties of this sand are important for potential engineering seismic analysis and infrastructure development in this oil- and gas-rich region. The present study aims to investigate the dynamic shear modulus and damping ratio of typical calcareous sand in the South China Sea. A series of dynamic triaxial tests under the strain control condition of cyclic loading were conducted, with a specific focus on the effects of relative density and confining pressure. The normalized dynamic shear modulus increases with the increase in confining pressure, and the shear modulus-shear strain relationship can be adequately described with the well-known Hardin-Drnevich model. However, the influence of confining pressure tends to decline in the sand samples of high initial relative density. Overall, the variations in the damping ratio as affected by confining pressure or relative density are not very significant. The experimental results were assessed and found to be reasonably consistent with some of the previously reported results in the literature.