Determination of shear modulus and damping ratio from small to large strains is essential to understand the non-linear stress–strain and damping behaviour of sand. The shear modulus and damping ratio with shear strain relationships of sand are dependent on a number of parameters: mean effective stress, void ratio, coefficient of uniformity, mean grain size and particle shape. The most common parameters investigated are mean effective stress and void ratio. This paper investigates the effect of the mean grain size on the normalised shear moduli and damping ratios of sands. Strain-dependent dynamic properties of sands are determined using bender element tests and cyclic triaxial tests at different mean effective stresses, void ratios and mean grain sizes. It was observed that normalised shear modulus and damping ratio increase as mean grain size decreases at a given strain amplitude. The effect of mean grain size was not considered in past empirical equations for the normalised shear modulus degradation and damping ratio curves. Hence, empirical equations were established for sand to incorporate the effect of mean grain size. The newly proposed empirical equations are shown to perform better than other empirical equations using data from the literature.

中文翻译：

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平均粒径对砂土剪切模量退化和阻尼比曲线的影响

确定从小应变到大应变的剪切模量和阻尼比对于理解砂土的非线性应力应变和阻尼特性至关重要。砂的剪切模量和阻尼比与剪切应变的关系取决于许多参数：平均有效应力，空隙率，均匀系数，平均晶粒度和颗粒形状。研究的最常见参数是平均有效应力和空隙率。本文研究了平均粒径对砂的归一化剪切模量和阻尼比的影响。在不同的平均有效应力，孔隙率和平均晶粒度下，使用弯曲元件试验和循环三轴试验确定与应变有关的砂土动力特性。观察到，在给定的应变幅度下，随着平均晶粒尺寸的减小，归一化的剪切模量和阻尼比增加。过去的经验方程式中未考虑平均晶粒尺寸对归一化剪切模量退化和阻尼比曲线的影响。因此，建立了沙的经验方程，以结合平均粒度的影响。使用来自文献的数据，新提出的经验公式表现出比其他经验公式更好的性能。