目前在颗粒材料的尺寸效应研究中，极少考虑颗粒的复杂形状和内部结构非均匀性。采用随机散粒体不连续变形分析方法（SGDD），引入无厚度界面单元和凝聚力模型模拟颗粒破碎，对5组不同粒径的堆石颗粒进行单颗粒压缩试验的数值模拟，分析了颗粒内界面单元强度对颗粒破碎的影响，并采用Weibull分布模型分析颗粒破碎强度的尺寸效应。通过与室内单颗粒压缩试验对比，试验的数值模拟能真实地再现单颗粒压缩下的破碎过程，不同颗粒的压缩曲线规律相似，达到峰值荷载前，承载力曲线急剧上升，随后颗粒发生致命破碎，承载能力骤降。不同粒径组的单颗粒破碎强度均服从Weibull分布，平均Weibull模数为2.48。不同粒径组的颗粒特征强度存在明显的尺寸效应，特征强度随着颗粒尺寸的增大而减小，与颗粒尺寸呈幂指数关系，但小于Weibull模型的预测值。

Currently many researchers studied size effect on the crushing strengths of rock particles, but they rarely considered the complex shapes and internal structures of heterogeneity. By the stochastic granular discontinuous deformation method (SGDD), numerical was employed to simulate the single particle compression tests for rock particles with five different sizes. Particle crushing is simulated by introducing zero-thickness interface element and cohesive zone in SGDD model. Then we studied the influence of interface strength on particle crushing, and analysed size effect on the crushing strengths of rock particles using Weibull model. Comparing with single grain compression test indoor, the SGDD method makes the crushing process of single particle compression very realistic. Every compressive curve shows the same trend, that is, the curves increase sharply before reaching the peak force and followed by a sharp drop at fatal breakage. The peak stress is the strength of particle crushing. Crushing strengths in every group of particles satisfy the Weibull distribution well with an average Weibull modulus of 2.48. In addition, the crushing strengths among different groups of particles shows that the characteristic strengths decrease with the increase of particle size. The characteristic strengths and particle sizes obey a power law with an exponent of -0.163, less than the prediction of Weibull model.