摘要
红黏土水化膨胀和强度劣化对公路、建筑物、桥梁、大坝等至关重要,常常引发严重的工程问题。然而作为红黏土的主要矿物成分,伊利石理化性质研究较少受到关注。作者借助分子动力学方法研究了不同温压和层间水饱和度下伊利石的理化特性,分析了层间水饱和度递增过程中伊利石结构的基本层间距、体系相互作用能、热力学参数和晶体力学性能的变化规律。结果表明:含水饱和度增加、温度升高与压力降低,使伊利石基本层间距均增大,但含水饱和度影响最为显著;随着伊利石层间水饱和度增加,体系压力和键结相互作用小幅度增大,但非键相互作用大幅减小,导致结构总能量和变形模量减小,引起黏土材料强度劣化的内在机理;温度升高压力降低加快了水分子与钾离子的扩散,是导致结构变形模量减小的重要影响因素。在不同温压和层间水饱和度下研究伊利石理化性质对工程实践具有重要意义,可为实现黏土矿物资源化应用以及黏土强度改良提供理论依据。
Swelling and strength deterioration of red clay during the processes of hydration and dehydration will cause serious engineering problems in the construction of highways,buildings,bridges,dams,and so on.Unfortunately,as the main mineral composition of red clay,few studies have focused on the hydration properties of illite.The physical and chemical properties of illite under different temperatures,pressures,and interlayer water saturations are studied by molecular dynamics.The variations of basic layer spacing,interaction energy,thermodynamic parameters and crystal mechanical properties are simulated and analyzed during hydration of illite.The results showed that the basic layer spacing of illite increased with the increase of water saturation and temperature,and the decrease of pressure.However,the water saturation has a more significant influence on the basic layer spacing comparing with other factors.With the increase of water saturation,the pressure and bond interaction of the system increase slightly,while the non-bond interaction decreases significantly,leading to a considerable decrease in total energy and deformation modulus of the structure,which is the internal mechanism of strength degradation in clay materials caused by hydration.Additionally,it is found that the increase of temperature and the decrease of pressure accelerates the diffusion of water molecules and potassium ions,which is an essential factor causing to the deformation modulus reduction.It is of great significance to study the hydration properties of illite under different temperatures,pressures and water saturations for engineering practice,which provides a theoretical basis for the application of clay minerals and the improvement of clay strength.
作者
任愉
吴道勇
贾继巍
REN Yu;WU Daoyong;JIA Jiwei(Key Laboratory of Karst Geological Resources and Environment,Ministry of Education,Guizhou University,Guiyang 550025,China;College of Resource and Environment Engineering,Guizhou University,Guiyang 550025,China)
出处
《材料科学与工程学报》
CAS
CSCD
北大核心
2023年第1期98-106,146,共10页
Journal of Materials Science and Engineering
基金
国家自然科学基金资助项目(42002280)
贵州省科技计划资助项目(黔科合基础[2019]1056号)。
关键词
黏土矿物
伊利石
水化特征
分子模拟
含水饱和度
Clay minerals
Illite
Hydration characteristics
Molecular simulation
Water saturation
