中文摘要：

通过颗粒流软件PFC2D中的clump命令,生成4种不同外轮廓特征的颗粒组,并结合颗粒材料变形机制,定义构建基于颗粒圆度与凹凸度的形状系数。用形状系数与粒间摩擦因数分别反映颗粒的外轮廓特征和表面粗糙度。用PFC2D模拟颗粒堆积试验、双轴试验和直剪试验,探讨颗粒形状对类砂土材料宏观力学特性的影响。试验结果表明：在颗粒堆积试验中,颗粒外轮廓的不规则以及颗粒间摩擦因数的增大会导致自然休止角和天然孔隙率增大;在双轴试验中,材料的峰值强度与形状系数的变化规律可用线性函数很好地进行拟合,内摩擦角随形状系数的减小而增大;在直剪试验中,材料的抗剪强度有随形状系数的减小而增大的趋势,颗粒形状的不规则还导致强力传递链数目的减少和速度场分布的不均匀。

英文摘要：

Four particle groups with different outlines are generated by the command of clump in PFC2D.Combining with deformation mechanism of granular materials,a shape coefficient is defined based on roundness and unevenness.The shape coefficient and friction coefficient are used to reflect the characteristics of particle outline and surface roughness respectively.The particle stacking test,biaxial test and direct shear test have been simulated with PFC2D,and how the shape of the particles affect the macro-mechanical properties of granular materials has been discussed.The results show that particle shape plays an important role in the macro-mechanical properties of these tests.In the particle stacking test,the natural angle of repose and natural porosity increases with the irregular outline of particles and the friction coefficient between particles.In the biaxial test,peak strength and shape coefficient can be fitted with linear functions well,and the internal friction angle increases with the decrease of shape coefficient.In the direct shear test,the shear strength of materials increases with the decrease of shape coefficient;the irregularity of particle shape also results in the decrease of strong force chain and the inhomogeneity of velocity field.