纳米膨润土改良红黏土力学特性机理分析  

Mechanical properties and mechanisms of modified red clay by nanometer bentonite

作　　者：李佳明 陈学军[1,2] 黄翔 宋宇[1,2] 陈李洁 LI Jia-ming;CHEN Xue-jun;HUANG Xiang;SONG Yu;CHEN Li-jie(College of Civil and Architecture Engineering,Guilin University of Technology,Guilin 541004,China;Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin 541004,China)

机构地区：[1]桂林理工大学土木与建筑工程学院,广西桂林541004 [2]广西岩土力学与工程重点实验室,广西桂林541004

出　　处：《广西大学学报（自然科学版）》2020年第1期147-154,共8页Journal of Guangxi University（Natural Science Edition）

基　　金：国家自然科学基金资助项目(41762022,41262011);广西中青年教师基础能力提升项目(2018KY0239);桂林市科技开发项目(20170222);广西矿产资源开发与环境保护国合项目(桂科能15104002-3-6)

摘　　要：为研究纳米膨润土对桂林红黏土的改良效果,通过三轴试验、X射线衍射试验、X射线荧光光谱分析试验和扫描电镜试验,分析不同掺量的纳米膨润土对红黏土力学性质的影响,并探索改良土的作用机理。结果表明,红黏土的抗剪强度、粘聚力、内摩擦角随着纳米膨润土掺量的增加呈先增大后减小的趋势,最优掺量分别为2.23%、2.87%、1.76%,当纳米膨润土掺量相同时,抗剪强度与围压成正比例关系;纳米膨润土使红黏土中高岭石、赤铁矿的半定量增加,石英的半定量减少,并且使化学成分中Al2O3、Fe2O3分别提高了5.67%、1.93%;加入纳米膨润土后,红黏土的结构从粒团结构变化至絮状结构,颗粒间由点点接触转变为面面接触,颗粒的边缘轮廓变得模糊,孔隙率、分型维数降低,结构致密性增强。In order to study the improvement effect of nano-bentonite on the red clay of Guilin,a series of experiments were carried out to investigate the influence of nano-bentonite of different dosages on mechanical properties of red clay and to explore the mechanism of improved soil,including triaxial test,X-ray diffraction test,X-fluorescence spectrographic analysis and SEM test.The results indicate that the shearing strength,cohesion and internal friction angle will increase and then decrease as the dosage of nanometer bentonite increases.The optimal dosages are 2.23%,2.87%and 1.76%,respectively.As the dosage of the nanometer bentonite is not changed,the shearing strength and the confining pressure will present a proportional relationship;The nanometer bentonite can increase the semi-quantitative result of kaolinite and hematite in red clay while decrease that of quartz.Besides,it increases Al2 O3 and Fe2 O3 components by 5.67%and 1.93%,respectively;with nanometer bentonite,the red clay is structured in flocculent form converted from original granular structure.Compared with original point-to-point contact,pore structure modified between granules becomes surface-to-surface contact,and becomes more compact and mixed.And nanometer bentonite also declines the porosity and fractal dimensionality and improves the structure compactness.

关 键 词：红黏土 纳米膨润土 力学特性 改良机理 

分 类 号：TU411[建筑科学—岩土工程]