As lamella and porous materials, the failure of clay soil is closely related to the microscale friction features between nano minerals sheets. This study delves into the microscale interface stick-slip friction behavior of clay minerals, with a particular focus on kaolinite and halloysite models, under varying hydrostatic pressure conditions. The research unveils several significant discoveries. Firstly, under hydrostatic pressure, the mechanical properties of clay minerals perpendicular to the mineral platelet weaken, accompanied by a gradual reduction in the space occupied by interlayer water molecules. As pressure increases, these molecules assemble into "water molecular clusters", resulting in the formation of two or three layers of water molecular films. At 6 GPa, interlayer water nearly reaches a state of stagnation. Secondly, both kaolinite and halloysite exhibit "stick-slip friction behavior" during shearing, with rising hydrostatic pressure intensifying interatomic interactions and augmenting shear stress fluctuations. Lastly, the calculated friction coefficients (μ) for the three systems (kaolinite –7 Å, halloysite –8.6 Å, and halloysite –10 Å) are 0.035, 0.048, and 0.033, respectively, while the friction angles (φ) are 2.270, 2.900, and 2.263. The cohesion values (C) for these systems, obtained through different methods, demonstrate consistency. These findings advance the understanding of clay mineral behavior under varying conditions and contribute valuable insights to the microscale failure mechanism of clay soil.

作为片状和多孔材料，粘土的破坏与纳米矿物片之间的微观摩擦特征密切相关。本研究深入研究了粘土矿物在不同静水压力条件下的微尺度界面粘滑摩擦行为，特别关注高岭石和埃洛石模型。该研究揭示了几项重大发现。首先，在静水压力下，垂直于矿物片层的粘土矿物的力学性能减弱，伴随着层间水分子占据的空间逐渐减少。随着压力的增加，这些分子聚集成“水分子簇”，从而形成两层或三层水分子膜。在6 GPa压力下，层间水几乎达到停滞状态。其次，高岭石和埃洛石在剪切过程中都表现出“粘滑摩擦行为”，随着静水压力的升高，原子间相互作用加剧，剪切应力波动增大。最后，计算出三个体系（高岭石 –7 Å、埃洛石 –8.6 Å 和埃洛石 –10 Å）的摩擦系数 ( μ ) 分别为 0.035、0.048 和 0.033，而摩擦角 ( φ )为2.270， 2.900 和 2.263。通过不同方法获得的这些系统的内聚值 ( C ) 表现出一致性。这些发现促进了对不同条件下粘土矿物行为的理解，并为粘土的微观破坏机制提供了宝贵的见解。