摘要
为揭示贵阳红黏土介-微观结构分形特征和准确预测其宏观物理力学特性,通过对组成贵阳红黏土的颗粒和孔隙分别进行粒度分析和吸附测试,研究其颗粒和孔隙分形特征,并采用岩土体多孔介质分形模型合理预测孔隙率等宏观物理力学特性.研究结果表明:贵阳红黏土颗粒和孔隙分布均具有分维性,通过对比分析贵阳红黏土颗粒质量分维和体积分维,并考虑介-微观结构的影响,取其颗粒分维数为2.83;基于N2吸附-脱附等温曲线,采用FHH模型和Pfeifer等理论求解出贵阳红黏土孔隙分维数为2.65,同时通过SEM图像定量计算出孔隙结构特征的量化参数与理论计算结果基本一致;采用Rieu和Sposito基于假想的团聚体模型和分形理论推导的土体孔隙率公式,结合贵阳红黏土基本物理力学试验,实现了对贵阳红黏土孔隙率的合理预测;结合不同干密度下贵阳红黏土三轴剪切试验结果,较好的分析了贵阳红黏土颗粒和孔隙分布分维特征及对初始干密度和宏观力学强度的影响.
In order to study the fractal characteristics of the meso-micro structure of Guiyang red clay and accurately predict it’s macroscopic physical and mechanical properties,the grain and pore fractal characteristics of Guiyang red clay are studied by conducting particle size analysis and adsorption test on them.The macroscopic physical and mechanical properties such as porosity is predicted by using porous media fractal model of rock and soil mass.The research results show that:the grain and pore distribution of Guiyang red clay have fractal dimension,and contrastive analysis is given on the particle fractal dimension and volume fractal dimension of Guiyang red clay,when the influence of the meso-microstructure is taken into consideration so that the particle fractal dimension is set as 2.83.Based on the adsorption-desorption isothermal curve of N2,by using FHH model and Pfeifer theory,the pore fractal dimension of Guiyang red clay is2.65,and the parameters of the pore structure got in the quantitative calculation by SEM image are consistent with the theoretical calculation results.Based on the hypothetical aggregate model and fractal theory,the soil porosity formula is deduced by Rieu and Sposito,according to the results of basic physical and mechanical tests on Guiyang red clay,reasonable prediction of Guiyang red clay porosity is presented.By analyzing the influence of the particle gradation and fractal dimension in pore distribution of Guiyang red clay on the initial dry density,considering the results of triaxial shear test on Guiyang red clay under different dry densities,the effect of fractal dimensions of Guiyang red clay particle and pore distribution on its macroscopic mechanical strength is analyzed.
作者
左双英
张彦召
赵蕊
张静
ZUO Shuangying;ZHANG Yanzhao;ZHAO Rui;ZHANG Jing(College of Resources and Environmental Engineering,Guiyang 550025,China;Weinan Vocational&Technical College,Weinan Shanxi 714000,China)
出处
《北京交通大学学报》
CAS
CSCD
北大核心
2019年第3期122-129,共8页
JOURNAL OF BEIJING JIAOTONG UNIVERSITY
基金
国家自然科学基金(51469007)
贵州省山地地质灾害防治工程技术研究中心([2017]5402)~~
关键词
地质工程
贵阳红黏土
介-微观结构
分形特征
粒度分析
吸附测试
geological engineering
Guiyang red clay
meso-microstructure
fractal feature
particle size analysis
adsorption test
