温度和压强对花岗岩中矿物微观物理力学特性的影响

发布时间：2018-05-09 22:36

本文选题：花岗岩 + 矿物　；参考：《工程地质学报》2017年06期

【摘要】：岩石工程性质取决于岩石中不同矿物的微观特征,本次研究将从微观角度计算北山花岗岩中主要矿物(石英、黑云母和钠长石)的物理性质和力学性质。矿物的微观物理性质使用体积和密度来表征,矿物的微观力学性质使用杨氏模量和泊松比来表征;矿物的初始晶体结构、初始晶胞参数、单晶胞模型和超晶胞模型使用公开数据库获得;矿物晶胞的稳定构象由几何优化方法来实现;使用分子力学模拟,得到了不同矿物稳定构象的微观物理性质参数和微观力学性质参数;使用分子动力学模拟,分析了温度和压强对这些微观物理力学性质参数的影响。结果表明,花岗岩的3种主要矿物中,晶胞体积大小顺序是钠长石、黑云母、石英,晶胞密度大小顺序是黑云母、石英、钠长石;石英的杨氏模量为161.70~168.78GPa、泊松比为0.25,黑云母的杨氏模量为164.85~579.93GPa、泊松比为0.16~0.31,钠长石的杨氏模量为110.72~112.49GPa、泊松比为0.27;压强为0.0001GPa、温度从300K变化到500K时,石英晶胞体积增大0.17%、密度减小0.15%、杨氏模量和泊松比没有明显变化,黑云母晶胞体积增大0.24%、密度减小0.26%、杨氏模量增大140.55%、泊松比减小26.92%,钠长石晶胞体积减小3.76%、密度增大3.91%、杨氏模量增大319.71%、泊松比减小7.41%;温度为298K、压强从0.010GPa变化到0.020GPa时,石英晶胞体积、密度、杨氏模量和泊松比没有明显变化,黑云母晶胞体积和密度没有明显变化、杨氏模量增大53.79%、泊松比减小23.81%,钠长石晶胞体积和密度没有明显变化、杨氏模量减小36.24%、泊松比增大29.41%。研究结果对分析岩石宏观物理力学特性的微观机制具有一定的参考价值。
[Abstract]:The engineering properties of rocks depend on the microscopic characteristics of different minerals in rocks. In this study, the physical and mechanical properties of the main minerals (quartz, biotite and albite) in the Beishan granite will be calculated from the microscopic point of view. The microphysical properties of minerals are characterized by volume and density, the micromechanical properties of minerals are characterized by Young's modulus and Poisson's ratio, the initial crystal structure, initial unit cell parameters, The unit cell model and supercell model are obtained by using open database; the stable conformation of mineral unit cell is realized by geometric optimization method; and the molecular mechanics simulation is used. The parameters of microphysical properties and micromechanical properties of different mineral stable conformations are obtained, and the effects of temperature and pressure on these parameters are analyzed by molecular dynamics simulation. The results show that among the three main minerals of granite, the order of unit cell volume is albite, biotite, quartz, and the order of cell density is biotite, quartz and albite. The Young's modulus, Poisson's ratio, biotite's Young's modulus and Poisson's ratio of quartz and biotite are 161.70, 168.78, 0.25, 164.85 and 0.16, 0.31, 110.72 and 0.27, respectively, and the pressure is 0.0001GPa. the temperature changes from 300K to 500K. The volume of quartz cell increased by 0.17 and the density decreased by 0.15.The Young's modulus and Poisson's ratio did not change obviously. The volume of the crystal cell of biotite increases by 0.24, the density decreases by 0.26, the Young's modulus increases by 140.55, the Poisson's ratio decreases by 26.92, the volume of the albite cell decreases by 3.76, the density increases by 3.91, the Young's modulus increases by 319.71, the Poisson's ratio decreases by 7.41, the temperature is 298K, and the volume of quartz cell changes from 0.010GPa to 0.020GPa. The density, Young's modulus and Poisson's ratio did not change obviously, but the volume and density of biotite cell did not change obviously, the Young's modulus increased 53.79, Poisson's ratio decreased 23.81, and the volume and density of albite cell did not change obviously. The Young's modulus decreases 36.24 and the Poisson's ratio increases 29.41. The results have some reference value for analyzing the microscopic mechanism of macroscopic physical and mechanical properties of rock.
【作者单位】：上海大学土木工程系;
【基金】：国家自然科学基金项目(41472254)资助
【分类号】：TU45

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