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柴油污染高岭土柴油作用机制与孔隙特征微观结构分析

发表时间:2014-11-15  浏览量:1413  下载量:554
全部作者: 刘志彬,方伟,蔡奕
作者单位: 东南大学交通学院,岩土工程研究所;同济大学土木工程学院
摘 要: 为了解柴油污染物对高岭土宏观工程性质的影响机理及柴油污染高岭土的孔隙结构特征,在室内对人工制备的不同柴油含量的柴油污染高岭土进行试验研究。样品先养护90 d确保柴油在土中均匀分布,然后利用环境扫描电镜(environmental scanning electron microscope,ESEM)和常规扫描电镜(scanning electron microscopy,SEM)对土样进行微观结构分析,并采用压汞技术对其孔隙结构进行测试。试验结果表明:ESEM可以清晰地反映柴油在高岭土颗粒间的存在状态。柴油在高岭土中的作用机制可概括为3个方面:改变双电层结构的物理化学作用、附着于黏土颗粒表面的包裹效应和柴油高分子呈网状连接的链接效应。压汞分析(mercury intrusion porosimety,MIP)结果表明,随着柴油含量的增大,柴油污染高岭土中大孔隙总体积减小,但大孔隙尺寸有所增大,小孔隙尺寸减小。柴油含量存在一个阈值,超过该值后柴油污染土的工程性质由“水控”状态转变为“油控”状态。
关 键 词: 岩土力学;污染土;柴油;高岭土;微观结构;压汞分析
Title: Microstructural and the influence mechanism analysis of diesel oil and pore structure characteristics in contaminated kaolinite
Author: LIU Zhibin, FANG Wei, CAI Yi
Organization: Institute of Geotechnical Engineering, School of Transportation, Southeast University; School of Civil Engineering, Tongji University
Abstract: In order to learn the influence mechanism of diesel oil on the macro engineering property of oil-contaminated kaolinite and its pore structure characteristics, the manually made diesel oil-contaminated kaolinite specimens of different content of diesel oil are experimentally studied in laboratory. All the specimens are firstly cured for 90 d to ensure the oil equilibrium in soil, then they are observed with environmental scanning electron microscopy (ESEM) and traditional scanning electron microscopy(SEM). In addition, the pore structure characteristics of the contaminated specimens are also analyzed through mercury intrusion porosimety (MIP). Test results indicate that ESEM can clearly reflect the detailed existence state of the diesel oil between clay particles. The influence mechanisms of diesel oil in kaolinite can be classified into three aspects. The first is physical chemical effect which changes the electrical double layer structure of kaolinite. The second is a kind of wrapping effect which means that the diesel oil adheres to and wraps the clay particles. The third is a kind of interlinkage effect which means that the network of diesel oil chains connect to each other and link the particles together. MIP indicates that the diameter of large pores will become greater, and their total volume will decrease as the oil content increases. On the other hand, the diameter of small pores will become smaller as the oil content increases. If the oil content is larger than a threshold value, the engineering property of diesel oil-contaminated kaolinite will transfer from water-controlled state towards oil-controlled state.
Key words: rock and soil mechanics; contaminated soil; diesel oil; kaolinite; microstructure; mercury intrusion porosimetry
发表期数: 2014年11月第21期
引用格式: 刘志彬,方伟,蔡奕. 柴油污染高岭土柴油作用机制与孔隙特征微观结构分析[J]. 中国科技论文在线精品论文,2014,7(21):2142-2147.
 
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