Abstract The importance and quality of particle orientation on the performance of clay has been well-documented experimentally. This paper aims to quantitatively evaluate clayey mineral reorientation during swelling/sedimentation according to the balance of mechanical contacts and electrochemical forces. A DEM code has been developed and the behavior of montmorillonite, kaolinite and illite, each having different pore fluid characteristics, has been simulated as for platy-shaped particles. Nonlinear contact law was considered for the induced net force as it relates to the mechanical contacts, Van der Waals attractive force, and diffuse double-layer (DDL) repulsive force. Good compatibility was observed between the DEM simulation and DDL theory. The results showed that the particle weight, magnitude of the repulsive force, and number of DDL contacts were effective parameters controlling particle reorientation. At a low swelling pressure, the particles rotated easily such that an edge-to-face fabric was created and the potential for overlap between particles as well as the mechanical contacts increased. The number of the mechanical contacts versus the time of sedimentation was not linear, but bell-shaped. Kaolinite ranked higher on the DDL repulsive contact list; however, it had a higher deposition rate due to its higher particle weight and lower repulsion force.

中文翻译：

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膨胀和沉降过程中机械和电化学接触对粘土矿物颗粒取向的影响：DEM 模拟

摘要 颗粒取向对粘土性能的重要性和质量已得到充分的实验证明。本文旨在根据机械接触和电化学力的平衡，定量评估膨胀/沉积过程中粘土矿物的重新定向。已经开发了 DEM 代码，并模拟了具有不同孔隙流体特征的蒙脱石、高岭石和伊利石的行为，就像片状颗粒一样。非线性接触定律被认为是诱导净力，因为它与机械接触、范德华引力和扩散双层 (DDL) 排斥力有关。在 DEM 模拟和 DDL 理论之间观察到良好的兼容性。结果表明，粒子的重量、排斥力的大小、和 DDL 接触的数量是控制粒子重新定向的有效参数。在低膨胀压力下，颗粒很容易旋转，从而形成边缘对面的织物，颗粒之间重叠的可能性以及机械接触增加。机械接触的数量与沉降时间的关系不是线性的，而是钟形的。高岭石在 DDL 排斥接触列表中排名更高；然而，由于其较高的颗粒重量和较低的排斥力，它具有较高的沉积速率。机械接触的数量与沉降时间的关系不是线性的，而是钟形的。高岭石在 DDL 排斥接触列表中排名更高；然而，由于其较高的颗粒重量和较低的排斥力，它具有较高的沉积速率。机械接触的数量与沉降时间的关系不是线性的，而是钟形的。高岭石在 DDL 排斥接触列表中排名更高；然而，由于其较高的颗粒重量和较低的排斥力，它具有较高的沉积速率。