【摘要】 天然裂缝在外力作用下扩展导致堆石颗粒破碎，而裂缝长度及其空间分布的随机性使颗粒强度表现出显著的尺寸效应和离散性.为定量评价颗粒强度分布特征，基于裂缝遵循修正幂律空间不均匀分布和最弱链理论，构建了一种Log-Logistic强度分布统计模型.通过不同粒组石灰岩单颗粒压缩试验验证表明，Log-Logistic分布模型在定量评价上优于Weibull分布模型，尤其在处理颗粒强度分布的极端值时，具有更好的拟合能力.研究进一步分析了外部环境因素对裂缝长度分布的影响，揭示了裂缝长度分布的差异是导致现场堆石颗粒强度离散性普遍大于室内试验条件的主要原因.研究成果为颗粒强度的细观建模提供了新的思路，并为工程设计中堆石材料强度的准确评估和风险控制提供了理论支持.更多还原

【Abstract】 Natural crack expansion under external forces leads to the crushing of rockfill particles, while the randomness of crack lengths and their spatial distribution results in significant size effect and dispersion of particle strength. To quantitatively evaluate the particle strength distribution characteristics, a Log-Logistic strength distribution statistical model was established based on the spatially inhomogeneous distribution of the modified power law and the weakest-link theory followed by the cracks. Validation through single-particle compression tests on limestone with different particle size fractions demonstrates that the Log-Logistic distribution model outperforms the Weibull distribution model in quantitative evaluation, particularly in handling extreme values within particle strength distribution where it has superior fitting capability. Additionally, the influence of external environmental factors on crack length distribution is further analyzed, revealing that the greater dispersion of rockfill particle strength in the field compared to that in laboratory tests is primarily attributed to the differences in crack length distribution. New insights into mesoscopic modeling of particle strength are offered, and theoretical support for the precise assessment and risk control of rockfill material strength in engineering design is provided.更多还原