中文摘要：

为了探究南京地区砂砾卵石土的压实特性，基于离散元数值分析软件PFC2D，模拟了砂砾卵石土的击实试验及加州承载比（CBR）试验的试验过程，分析了砂砾卵石土含石量及颗粒粒径对其压实特性的影响。通过与室内试验的对比验证了离散元法分析砂砾卵石土压实特性的可行性，并根据模拟结果提出了工程中建议采用的土石比例区间。结果表明：砂砾卵石土的孔隙率随着含石量的增加先减小后增大，随着颗粒粒径的增大而不断减小；砂砾卵石土CBR值随着含石量的增加先增大后减小，随着颗粒粒径的增大而不断增大；砂砾卵石土含石率在70％～80％时，能达到最佳压实效果。

英文摘要：

In order to explore the compaction characteristics of sand-gravel-cobble （S-G-C） mixture in Nanjing area, based on DEM software PFC2D, the processes of compaction tests and CBR （California bearing ratio） tests were simulated, and the influences of gravel content and particle size on compaction characteristics of S-G-C were analyzed. The comparison with laboratory tests validated the feasibility of DEM in analyzing compaction characteristics of S-G-C mixture, and the ratio interval of soil to gravel used in practical project was proposed based on the Simulated results. The results show that the void ratio of S-G-C mixture first decreases and then increases with the increase of gravel content, while it decreases continuously with the increase of particle size. The CBR of S-G-C mixture first increases and then decreases with the increase of gravel content, while increases continuously with the increase of particle size. When the gravel content is of 70% to 80%, the S-G-C mixture has the best compaction effect.