摘要
以红黏土为研究对象,探究NaCl溶液引起界限含水率变化的机理,为判断岩土工程中土体力学特性变化规律提供参考。然后通过电泳和热分析试验,分析NaCl溶液造成桂林红黏土界限含水率改变的原因,并提出一种判断黏土颗粒表面结合水含量变化的思路。研究结果表明:随NaCl溶液浓度不断增大,红黏土的界限含水率呈减小趋势,且当浓度增大到一定值时,曲线趋于平缓;随Na+浓度增大,黏土颗粒表面电势逐渐减小,扩散层厚度随之变小,这主要是黏土颗粒表面带有的负电荷与孔隙溶液中的Na+相互吸引导致的;随盐浓度增大,红黏土中的自由水、弱结合水、强结合水的温度界限均有上升趋势,这主要是孔隙溶液中Na+浓度升高,使土粒表面对水分子吸附能力加强,结合水含量降低引起的。
The red clay was taken as a research object to explore the mechanism of the change of critical water content caused by NaCl solution,which could provide reference for judging the change law of soil mechanical properties in geotechnical engineering.Then through electrophoresis and thermal analysis,the reason of the change of the critical moisture content of Guilin red clay caused by NaCl solution was analyzed.In addition,an idea to judge the change of bound water content on the surface of clay particles was proposed.The results show that the limit moisture content of red clay decreases with the increase of NaCl solution concentration,and the curve tends to be gentle when the concentration increases to a certain value.With the increase of Na+concentration,the surface potential of clay particles decreases gradually,and the thickness of diffusion layer becomes thinner.This is mainly due to the mutual attraction between the negative charge on the surface of clay particles and Na+in pore solution.Moreover,with the increase of salt concentration,the temperature limits of free water,weak bound water and strong bound water in red clay increase,this is mainly due to the increase of Na+concentration in pore solution,which makes the adsorption capacity of water molecules on the surface of soil particles increase and the content of bound water decrease.
作者
肖桂元
朱杰茹
徐光黎
安冉
刘芠君
刘闯
XIAO Guiyuan;ZHU Jieru;XU Guangli;AN Ran;LIU Wenjun;LIU Chuang(School of Engineering,China University of Geosciences,Wuhan 430000,China;Guangxi Key Laboratory of Geomechnics and Geotechnical Engineering,Guilin University of Technology,Guilin 541004,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2021年第9期3314-3321,共8页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(52169022,41772314)
广西科技基地和人才专项(AD19110085)。
关键词
界限含水率
红黏土
NACL
扩散双电层
结合水
limit moisture content
red clay
NaCl
diffusion double layer
bound water
