It is believed that the relative density (Dr) can affect the internal stability of the gap-graded soils and hence the erosion of their fine particles (i.e. susceptibility to suffusion). This paper investigates the influence of Dr on the contribution of fine particles to soil fabric. A new procedure is proposed to produce samples with target Dr using the discrete element method (DEM). DEM simulations were carried out using spherical particles. Particulate scale analysis of variation of stress reduction factor (αDEM), the evolution of contact type and fine particle coordination number (Zfine) with Dr reveals how Dr affects packing stability. The results show that packings with a fine content of 35% and the gap ratio in a range of 4–7 are in the transitional zone in which they are unstable initially and become internally stable as Dr increases. The behaviour of gap-graded soil in the transitional zone is governed by fine-coarse contacts, but fine-fine contacts dominate the behaviour when soil becomes internally stable. Both αDEM and Zfine are reliable parameters in determining internal stability of gap-graded soils. Finally, the correlation between the results and macro-scale matrix phase diagrams confirms the validity of micro-scale information to describe the underlying phenomenon.

中文翻译：

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DEM 建模以评估在各种相对密度、细粒含量和间隙比下球形颗粒间隙分级组件的内部稳定性

据信，相对密度 (Dr) 会影响间隙级配土壤的内部稳定性，从而影响其细颗粒的侵蚀（即对扩散的敏感性）。本文研究了 Dr 对细颗粒对土壤结构贡献的影响。提出了一种使用离散元方法 (DEM) 生成具有目标 Dr 的样本的新程序。DEM 模拟是使用球形颗粒进行的。应力折减因子 (αDEM) 变化的微粒尺度分析、接触类型和细颗粒配位数 (Zfine) 的演变与 Dr 揭示了 Dr 如何影响填充稳定性。结果表明，细粒含量为 35% 且间隙比在 4-7 范围内的填料处于过渡区，在该过渡区中，它们最初不稳定，随着 Dr 的增加而内部稳定。过渡带中间隙级配土的行为受细粗接触控制，但当土壤内部稳定时，细细接触主导行为。αDEM 和 Zfine 都是确定间隙级配土内部稳定性的可靠参数。最后，结果与宏观矩阵相图之间的相关性证实了微观信息描述潜在现象的有效性。