中文摘要：

为了探索砂土颗粒级配对其剪切特性的影响,以标准砂为基本材料,制备4种不同人工级配砂进行室内直接剪切试验;同时建立了和4种人工制备砂土相同级配的离散元数值试样进行数值剪切试验。直剪试验结果表明,颗粒级配对砂土内摩擦角影响比较明显,总体表现为内摩擦角随不均匀系数的增大而增大,随曲率系数的增大而减小。离散元数值模拟表明,砂土初始级配对孔隙率、颗粒配位数以及颗粒滑动率的影响都比较显著;砂土试样的破坏是与颗粒级配有关的渐进破坏过程;剪胀系数均随d（10）,d（30）和d（60）的增大而先减小后增大。

英文摘要：

In order to investigate the effect of sandy soil gradation on its shear properties, direct shear tests were conducted for four types of different artificial gradation of sandy soil samples made of the standard sand. The numerical shear tests were conduc-ted for DEM samples that have the same gradation with the four artificial sand samples. The test results show that the influence of particle gradation on the internal friction angle is significant; generally, the internal friction angle increases with the non - uni-formity coefficient, and decreases with the curvature coefficient. The DEM tests show that the initial sandy soil gradation has sig-nificant effect on the porosity ratio, particle coordination number and the particle slide fraction ; in ad d ition , the failure of sandy soil is a progressive process that depends on the particle gradation ; the dilatancy coefficient decreases at the beginning and in-creased later with increase of the parameters of d 10 , d20 and d 60 .