A molecular dynamics study on the softening of kaolinite in water: Weakening of tensile property during stretching and disintegration of structure during soaking

M Lu and YY Zheng and ZY Yin, COMPUTERS AND GEOTECHNICS, 173, 106562 (2024).

DOI: 10.1016/j.compgeo.2024.106562

The softening and collapse of soft rocks have been a persistent problem in infrastructure construction. The mechanism by which clay minerals are softened by water can be divided into two ways: the interparticle water film weakens the tensile properties, and the external water can cause the disintegration of clay aggregates. This study explained the two softening phenomena through two simulations. Moreover, the effect of wettability was investigated by establishing three models. In the stretching simulation, the liquid bridge was observed in the pore when the interparticle water content was high. The tensile strength was dominated by the interaction of claywater. In the soaking simulation, the kaolinite stack with a tensile crack was prone to slip and tilt when immersed in external water. The resist disintegration property was determined by the interaction of clay-clay. Additionally, the three models have advantages and disadvantages in resisting failure due to the wettability. Wherein the hydrophilic (001)-(001) model has the highest tensile strength in the three models. The liquid bridge phenomenon of the hydrophobic (001)-(001) model was the most significant. The (001)-(001) model was the most stable during the soaking process. These findings contribute insights into clay mineral failure behavior under varying water environments.

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