李同录, 范江文, 习羽, 谢潇, 侯晓坤. 2019: 击实黄土孔隙结构对土水特征的影响分析. 工程地质学报, 27(5): 1019-1026. DOI: 10.13544/j.cnki.jeg.2019045
    引用本文: 李同录, 范江文, 习羽, 谢潇, 侯晓坤. 2019: 击实黄土孔隙结构对土水特征的影响分析. 工程地质学报, 27(5): 1019-1026. DOI: 10.13544/j.cnki.jeg.2019045
    LI Tonglu, FAN Jiangwen, XI Yu, XIE Xiao, HOU Xiaokun. 2019: ANALYSIS FOR EFFECT OF MICROSTRUCTURE ON SWCC OF COMPACTED LOESS. JOURNAL OF ENGINEERING GEOLOGY, 27(5): 1019-1026. DOI: 10.13544/j.cnki.jeg.2019045
    Citation: LI Tonglu, FAN Jiangwen, XI Yu, XIE Xiao, HOU Xiaokun. 2019: ANALYSIS FOR EFFECT OF MICROSTRUCTURE ON SWCC OF COMPACTED LOESS. JOURNAL OF ENGINEERING GEOLOGY, 27(5): 1019-1026. DOI: 10.13544/j.cnki.jeg.2019045

    击实黄土孔隙结构对土水特征的影响分析

    ANALYSIS FOR EFFECT OF MICROSTRUCTURE ON SWCC OF COMPACTED LOESS

    • 摘要: 土水特征曲线是非饱和土的基本土物理-力学关系,即将含水率这一物理参数转化为土粒间力的作用,土水特征曲线受土的结构控制。为了探讨击实黄土孔隙结构对土水特征曲线的影响,本文在3种不同的初始含水率(小于最优含水率8%、最优含水率17%和大于最优含水率19%)下制备不同结构的击实黄土试样,分别用压汞试验测其孔隙分布曲线,用滤纸法测其土水特征曲线,并用扫面电镜获得其微观结构图像。对以上测试结果的分析表明,3种击实土样的孔隙分布曲线在相应的大孔径范围内相差较大,在小孔径范围内趋于一致;土水特征曲线在低吸力区差异较大,小于最优含水率的击实黄土土水特征曲线最陡;在高吸力区,3种击实土样的土水特征曲线趋于一致,这与孔隙分布特征一致。对比孔隙密度分布曲线与土水特征区曲线发现,土的土水特征受孔隙分布的控制,孔隙密度越大,土水特征曲线的斜率越陡。SEM图像也显示出3种击实土样的结构特点,小于最优含水率的土样有较多架空孔隙,优势孔径最大;高于最优含水率的土样,大孔隙减少,小孔隙增多,优势孔径最小。而最优含水率的击实黄土的孔隙分布较均匀,优势孔径覆盖范围大。

       

      Abstract: Soil water characteristic curve(SWCC) is a basic physical-mechanical relation of unsaturated soils and changes the physical index of water content to the mechanical index of forces among soil particles. Soil water characteristic curve is controlled by soil structures. To investigate the effect of soil structure on the SWCC, the compacted loess samples are made with three different moisture contents in the study. They are less than the optimum 8%, at the optimum 17%, and more than the optimum 19%. Mercury intrusion poroimetry(MIP) and scanning electronic method(SEM)as well as filter paper method are respectively used to explore the pore size distribution(PSD), the soil water characteristics(SWCC) and the microstructure of the compacted loess at difference water contents. It can be observed from the SWCCs and PSds that compacted loess at different moisture contents have a significant impact on the microstructure and soil water characteristics. In low suction zone, the SWCCs of three compacted loess are significantly different. The SWCC of dry of optimum is the steepest. It tends to be the same in the high suction region. The PSD varies greatly in the macro-pores and is almost the same in the micro-pores, which is similar to the SWCC. By comparing the SWCC and PSD, it is found that the pore distribution of loess compacted with different moisture content is tightly related to SWCC. The larger the pore size density, the steeper slope of SWCC. SEM imagines also show the typical characters of the three compacted soils as follows:(1)the specimen with the less optimum moisture content is dominated with large inter-particle pores; (2)the specimen with more than the optimum moisture content is dominated with smaller inter-particle pores; and (3)the specimen at the optimum has a wide range of pore distribution.

       

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