| 盐分对黏性土的沉积特性与表面电位影响研究 |
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| 引用本文： | 张彤炜,邓永锋,邓婷婷,王冲.盐分对黏性土的沉积特性与表面电位影响研究[J].冰川冻土,2019,41(4):875-883. |
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| 作者姓名： | 张彤炜 邓永锋 邓婷婷 王冲 |
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| 作者单位： | 1. 兰州大学 土木工程与力学学院 西部灾害与环境力学教育部重点试验室, 甘肃 兰州 730000;2. 东南大学 交通学院岩土工程研究所, 江苏 南京 210096 |
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| 基金项目： | 国家自然科学基金青年项目（41807225）；国家自然科学基金面上项目（51378117；41572280）；中央高校基本科研业务费专项资金（lzujbky-2018-8）资助 |
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| 摘 要： | 为了明晰黏土矿物和盐分浓度在沉积过程中所起的作用及物理机制，选取高岭土、膨润土及两者组成的混合土进行粒径分析试验、沉积试验和Zeta电位测试。结果显示，盐分环境下高岭土和膨润土的平均粒径增大，部分黏粒组向粉粒组转化。高岭土在蒸馏水环境下和盐水环境下，最终都形成土-水的稳定分界面，但是絮凝稳定时间在盐分环境下更短。膨润土在蒸馏水环境下处于稳定的分散体系中，在盐水环境下迅速絮凝沉积。混合土在蒸馏水环境下，上部澄清层和下部沉淀层之间存在土颗粒的悬浮层，且该层的高度最终稳定；盐水环境下，混合土则迅速的发生土水分离。随着NaCl浓度增加，膨润土和高岭土的Zeta电位绝对值降低，因此胶粒组的絮凝行为对平均粒径产生影响，进而影响其沉积特性。
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| 关 键 词： | 高岭土 膨润土 沉积特性 Zeta电位 颗粒絮凝 |
| 收稿时间： | 2019-02-15 |
| 修稿时间： | 2019-06-05 |
The salinity effect on sedimentation behaviors and surface zeta potential of clay |
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| ZHANG Tongwei,DENG Yongfeng,DENG Tingting,WANG Chong.The salinity effect on sedimentation behaviors and surface zeta potential of clay[J].Journal of Glaciology and Geocryology,2019,41(4):875-883. |
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| Authors: | ZHANG Tongwei DENG Yongfeng DENG Tingting WANG Chong |
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| Institution: | 1. Key Laboratory of Mechanics on Disaster and Environment in Western China, School of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China;2. Institute of Geotechnical Engineering, Transportation College, Southeast University, Nanjing 210096, China |
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| Abstract: | The engineering properties of clay in cold regions are correlated to sedimentation environment and process,and its different sedimentation behaviors are possibly dependent on the clay minerals and water salinity. To clarify the water salinity impact on the sedimentation procedure of clayey soils,the particle size analysis,settling tests and zeta potential measurements were performed on kaolin,bentonite and their mixtures. The particle size distribution curves(>0.3 μm)show that the median particle diameter d50 of kaolin and bentonite in saline water were larger than that in distilled water. The proportions of particles smaller than 5 μm of kaolin and bentonite obtained in distilled water were higher than those in saline water,while the proportions of particles larger than 10 μm were lower in distilled water. The clear interfaces between kaolin and fluid formed in both distilled water and saline water. While,the formation of flocculation in distilled water was about 1×104 minutes,and 10 minutes in saline water. The bentonite dispersed in distilled water until 8 months,while the particles settled within 1 minute and a stable soil-water interface formed until 30 minutes in saline water. The dispersion layer between bentonite-kaolin mixtures and distilled water formed at the final settling stage,and the particles separated from saline water within 10 minutes. The absolute values of zeta potential of bentonite and kaolin decreased from 40 mV to 10 mV when the NaCl concentration increased from 0% to 5%. In view of the relationships between zeta potential and colloid stability,the increase of zeta potential and the compression of diffused double layer caused the clay particles flocculation and the median particle size increasing. |
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| Keywords: | kaolin bentonite sedimentation behavior zeta potential particle flocculation |
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