ISSN 1000-3665 CN 11-2202/P
    冯笑瑞,朱兴华,孙恒飞,等. 泾阳浅层黄土细微观孔隙结构试验[J]. 水文地质工程地质,2024,51(0): 1-11. DOI: 10.16030/j.cnki.issn.1000-3665.202305008
    引用本文: 冯笑瑞,朱兴华,孙恒飞,等. 泾阳浅层黄土细微观孔隙结构试验[J]. 水文地质工程地质,2024,51(0): 1-11. DOI: 10.16030/j.cnki.issn.1000-3665.202305008
    FENG Xiaorui, ZHU Xinghua, SUN Hengfei, et al. Meso and micro pore structure test of Jingyang shallow loess[J]. Hydrogeology & Engineering Geology, 2024, 51(0): 1-11. DOI: 10.16030/j.cnki.issn.1000-3665.202305008
    Citation: FENG Xiaorui, ZHU Xinghua, SUN Hengfei, et al. Meso and micro pore structure test of Jingyang shallow loess[J]. Hydrogeology & Engineering Geology, 2024, 51(0): 1-11. DOI: 10.16030/j.cnki.issn.1000-3665.202305008

    泾阳浅层黄土细微观孔隙结构试验

    Meso and micro pore structure test of Jingyang shallow loess

    • 摘要: 降雨与灌溉是黄土地区最常见的地灾驱动力,通常情况下入渗深度较浅且主要受细微观通道的控制,孔隙结构对渗流特性的影响十分显著。为了研究浅层黄土孔隙结构分布规律,本文以泾阳南塬黄土为研究对象,采用CT断层扫描法和压汞法分析黄土结构试样,观察并讨论了细微观孔隙结构特性随黄土埋深的变化规律。研究表明:泾阳浅层黄土根据其孔隙结构特征可划分为3层,1~2 m为第一层,3~4 m为第二层,5 m为第三层;孔径小于1.0 mm的孔隙占总孔隙数量的95%以上,以类球状和柱状的封闭孔隙为主。孔径大于0.8 mm的孔隙占总孔隙体积的65%以上,多为枝杈状和柱状的连通孔隙;随着埋深的增加,连通性逐渐降低,大孔隙的变形破坏对黄土结构的稳定起着关键作用;根据压汞试验可知,集粒内孔隙以0.2 μm为界,随着埋深的增加左侧孔隙占比无明显变化,右侧随之增大。本文的相关成果,为后续进一步探索浅表层黄土细微观孔隙渗流机制提供了研究基础。

       

      Abstract: Rainfall and irrigation are the most common driving forces of geological disasters in loess areas. Generally, the infiltration depth is shallow and mainly controlled by microchannels. The pore structure has a significant influence on the seepage characteristics. Aiming to study the distribution of pore structure in shallow loess, this study analyzes the structural samples of loess using CT tomography and mercury intrusion methods in the southern plateau of Jingyang, Shaanxi Province. The changes in meso and micro pore structure characteristics with the burial depth of loess are observed and revealed. The results show that Jingyang shallow loess can be divided into three layers according to its pore structure characteristics: 1−2 m as the first layer, 3−4 m as the second layer, and 5 m as the third layer. The diameter of more than 95% of the total pores are less than 1.0 mm, which mainly are spherical and columnar closed pores; while more than 65% of the total pore are larger than 0.8 mm, and most of them are branched and columnar connected pores. With depth increasing, the pore connectivity gradually decreases, and the deformation and failure of macropores play a key role in the stability of loess structure. In the mercury intrusion test, intragranular pores are bounded by 0.2 μm. The proportion of pores on the left side shows insignificant change with depth, while on the right side, it increases with depth. This study provides a basis for further exploring the micro pore seepage mechanism of shallow loess in the future.

       

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