摘要
分散土遇水分散的特性是造成分散土地区堤坝、渠道边坡、道路边坡被冲蚀和管涌破坏等的重要原因,开展土体分散性判别工作是分散土地区进行工程建设的重要前提。首先通过针孔试验、碎块试验等对分散土进行判别,随后基于扫描电镜、X衍射等试验,研究分散土的分散机制及微观结构,分析土体分散的主次要影响因素。针对标准吸湿含水率与土体矿物成分蒙脱石含量具有较强线性关系的情况,大数据总结典型分散性黏土的蒙脱石含量与pH值分布特点,提出基于标准吸湿含水率+p H值测试的土体分散性的综合判别法,并给出相应的判别指标及判别程序,最后采用工程实例进行了验证。结果表明:具有一定的蒙脱石含量以及较高的p H值赋存环境是土体具备分散性的物质基础和环境保障;若土体中的蒙脱石含量≥10%且pH≥8.5,则可判断为分散土;不在此区间的土料仍需采用土的分散性判别方法及野外调查结果来综合判断土的分散性。
The dispersity of dispersive clay in water is essential for the erosion and piping damage of dikes,channel slopes,and road slopes in dispersed land areas,and the discrimination of soil dispersion is prerequisite for engineering construction in dispersed land areas.In this paper,the tests such as pinhole test and crumb test are conducted to determine the dispersity of soil samples,then scanning electron microscope and X-ray diffraction are carried out to study the dispersion mechanism and microstructure of dispersive clay,and the primary and secondary influencing factors of soil dispersion are analyzed.Because of the strong linear relationship between the standard hygroscopic moisture content and the montmorillonite content of soil mineral composition,the distribution characteristics of montmorillonite content and p H value of typical dispersive clay are summarized by big data,a comprehensive discrimination method of soil dispersion based on the standard hygroscopic moisture content+pH value test is proposed,and the corresponding discrimination indices and discrimination procedures are given.Finally,it is verified with an engineering example.The results show that the existing environment with certain montmorillonite content and high pH value is the material basis and environmental guarantee for the dispersity of soil mass.If the requirements of montmorillonite content≥10%and pH≥8.5,the soil can be judged as dispersive clay;for soils out of this range,soil dispersity should be comprehensively judged in combination with the determination of dispersity of soil and field investigation results.
作者
刘杰
崔瑜瑜
卢正
姚海林
LIU Jie;CUI Yu-yu;LU Zheng;YAO Hai-lin(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;Hubei Key Laboratory of Geo-Environmental Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2022年第S01期237-244,共8页
Rock and Soil Mechanics
基金
国家自然科学基金(No.42077261,No.42077262,No.41672312).
关键词
分散土
分散机制
蒙脱石
标准吸湿含水率
PH值
dispersive clay
dispersion mechanism
montmorillonite
standard hygroscopic moisture content
pH value
作者简介
第一作者:刘杰,女,1983年生,博士,副研究员,主要从事特殊土长期性能衰变机制及处治技术方面的研究。E-mail:liuj@whrsm.ac.cn
