AI 中文总结
本研究提出融合长程Buckingham势与Hertzian颗粒接触力学的混合CGMD框架，揭示颗粒间摩擦力对黏土力学行为的关键作用，为黏土多尺度模拟提供指导。
AI 中文摘要
鉴于颗粒间物理化学力在调控黏土行为中起主导作用，研究人员越来越多地采用粗粒化分子动力学（CGMD）模拟。然而，由于方法学限制，颗粒间摩擦力在历史上被忽视，且该遗漏对模拟精度的影响程度仍是未解决的问题。本研究提出一种新型混合CGMD框架，明确将长程Buckingham势与Hertzian颗粒接触力学耦合。基线模型通过各向同性压缩验证，所得可压缩性及推导的压缩指数（Cc）与宏观岩土观测结果一致。参数分析显示，颗粒接触的黏弹性阻尼控制结构演化；升高的阻尼会抑制致密化，使黏土片滞留于无序、高孔隙率构型中。此外，评估与热波动的相互作用强调，需精确控制温度以防止此类非物理的动力学滞留。最后，单轴压缩试验证明颗粒间摩擦力的关键重要性：明确的摩擦力锁定滑动界面，与无摩擦模型相比承受显著更高的载荷；无摩擦模型仅依赖几何互锁，最终表现出非物理的类流体屈服行为。通过连接原子势与接触力学，该框架凸显了颗粒间摩擦力的基础作用，并为黏土集合体的未来多尺度模拟提供重要指导。
英文摘要
Given the predominant role of inter-particle physicochemical forces in governing clay behavior, researchers have increasingly utilized coarse-grained molecular dynamics (CGMD) simulations. However, inter-particle friction has been historically overlooked due to methodological limitations, and the extent to which this omission influences simulation accuracy remains an unresolved question. This study proposes a novel hybrid CGMD framework explicitly coupling long-range Buckingham potential with Hertzian granular contact mechanics. A baseline model was validated via isotropic compression, where the resulting compressibility and derived compression index (Cc) aligned with macroscopic geotechnical observations. Parametric analyses revealed that viscoelastic damping of particle contacts governs structural evolution. Elevated damping suppresses densification, trapping platelets in disorganized, high-void-ratio configurations. Furthermore, evaluating the interplay with thermal fluctuations underscores the necessity of precise temperature control to prevent such unphysical kinetic trapping. Finally, uniaxial compression tests demonstrate the critical importance of inter-particle friction. Explicit friction locks sliding interfaces and sustains significantly higher loads compared to frictionless models; the latter rely solely on geometric interlocking and ultimately exhibit unphysical fluid-like yielding. By bridging atomistic potentials with contact mechanics, this framework highlights the fundamental role of the inter-particle friction and offers essential guidelines for future multi-scale simulations of clay assemblies.
Comments25 pages in total, 11 figures, 2 tables
