【摘要】 为了揭示不同类型的蒙脱石晶体表面水化差异的机制，通过分子动力学模拟了钠、钾和钙蒙脱石的水化过程。模拟结果表明，随着水分子数量的增加，蒙脱石的层间距逐步扩大，同时伴随着体积膨胀、密度降低以及水分子和阳离子的自扩散系数增加。此外，随着水分子层的积累，Na⁺/K⁺/Ca²⁺离子与水分子中的氧和氢原子之间的径向分布函数的峰值逐渐降低。水的聚合度在增加之前逐渐增强，而弹性模量和声速则逐渐降低。值得注意的是Na⁺离子的水化倾向最强，其次是Ca²⁺，然后是K⁺。在所研究的阳离子中，Ca²⁺离子的水化配位数、水化数和水化半径最高。因此，钙蒙脱石具有最宽的强度范围和最大的声速。这些发现可为石油和天然气勘探、隧道挖掘、边坡稳定以及深地质处置等工程实践提供参考依据。更多还原

【Abstract】 In order to reveal the mechanism of surface hydration differences for different types of montmorillonite crystals, the hydration processes of sodium, potassium, and calcium montmorillonite were simulated by molecular dynamics. These simulation results show that with the increase of the number of water molecules, the interlayer spacing of montmorillonite expands in a step-by-step manner, accompanied by volume expansion, decrease in density, and increase in self-diffusion coefficients of water molecules and cations. In addition, as the water molecular layer accumulates, the peak values of the radial distribution function between Na⁺/K⁺/Ca²⁺ ions and Ow/Hw（oxygen or hydrogen atoms in water molecules） gradually decrease. The degree of polymerization of water intensifies before decreasing, while the elastic modulus and acoustic velocity are gradually decreasing. It is worth noting that Na⁺ ion shows the highest tendency to hydrate, followed by Ca²⁺, and then K⁺. Among the cations studied, Ca²⁺ ion has the highest hydration coordination number, hydration number and hydration radius. As a result, calcium montmorillonite exhibits the widest intensity range and the largest acoustic velocity. These findings can provide references for engineering practices such as oil and gas exploration, tunnel excavation, slope stabilization, and deep geological disposal.更多还原