基于分子动力学的缓冲/回填材料膨胀性能研究进展  

Advances on molecular dynamics study of buffer and backfill materials swelling

作　　者：戴文杰 陈永贵[1,2] 叶为民[1,2] 王琼[1,2] 陈宝[1,2] Dai Wenjie;Chen Yonggui;Ye Weimin;Wang Qiong;Chen Bao(College of Civil Engineering,Tongji University,Shanghai 200092,China;Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《土木工程学报》2023年第11期91-102,共12页China Civil Engineering Journal

基　　金：国家杰出青年科学基金(42125701);国家自然科学基金(41977232,42030714);中央高校基本科研业务费。

摘　　要：缓冲/回填材料的矿物特性是决定其优良工程性质的本质因素,传统试验手段难以为纳米级矿物行为研究提供足够的微观结构与动力学信息,借助分子动力学技术可在分子尺度定性观察、定量分析膨润土矿物水化的动力学特性,在辅助解释试验现象、改进现有理论模型、修正经验参数等方面具有独特的优势。文章在详细阐述膨润土矿物建模基本原理的基础上,总结膨润土层间膨胀的产生机制与主控因素,以及晶体膨胀行为的环境效应。结果表明,在层间阳离子的强烈吸引作用下,水分子进入层间,致使层间距增大;膨胀过程主要受控于晶体结构与层间阳离子种类等因素。然而,当前研究在蒙脱石模型参数以及力场的选择上并未有统一认识;仅对单一晶层进行模拟忽略了相邻晶层之间的相互影响;缺乏对复杂耦合场长时效性问题以及周期性变化问题的研究。因此,在提高膨润土矿物模型准确性、实现多晶层组合模型计算与复杂多场耦合作用模拟等方面需要展开进一步深入研究。Mineral characteristic of buffer and backfill material is the essential factor affecting its engineering properties.It is difficult,however,for traditional test method to provide sufficient dynamic and microstructure information for nanoscale mineral characteristics research.Molecular dynamics(MD)provides such an alternative method to analyze the dynamic characteristics of clay minerals at the molecular scale,and it has significant potential in explaining the experimental phenomena,improving theoretical models and modifying empirical parameters.In this study,the montmorillonite modeling principles and the mechanism and environmental effects of montmorillonite swelling are summarized.The results show that water molecules are attracted into interlayer by the strong attraction of interlayer cations,resulting in the increase of layer spacing.The swelling process is mainly controlled by crystal structure and interlayer cations species.Nowadays,there is no unified understanding on the parameters of montmorillonite model and the choice of force field,and existing MD simulations of montmorillonite ignored the interaction of adjacent crystal layers.Besides,there is a lack of studies on the long⁃term effectiveness and periodic variation of complex coupling field.Hence,further studies sahll be carried out on the accuracy improvement of clay mineral model,calculation of the polycrystalline layer hydration,and simulation of complex multi⁃field coupling.

关 键 词：深地质处置 膨润土 膨胀性能 分子动力学 研究进展 

分 类 号：TU41[建筑科学—岩土工程]