罗浩, 伍法权, 常金源, 等. 2021.马兰黄土孔隙结构特征———以赵家岸地区黄土为例[J].工程地质学报, 29(5): 1366-1372. doi: 10.13544/j.cnki.jeg.2014-0392.
    引用本文: 罗浩, 伍法权, 常金源, 等. 2021.马兰黄土孔隙结构特征———以赵家岸地区黄土为例[J].工程地质学报, 29(5): 1366-1372. doi: 10.13544/j.cnki.jeg.2014-0392.
    Luo Hao, Wu Faquan, Chang Jinyuan, et al. 2021. Pore characteristics of Malan loess—A case study at Zhaojia an landslide[J]. Journal of Engineering Geology, 29(5): 1366-1372. doi: 10.13544/j.cnki.jeg.2014-0392.
    Citation: Luo Hao, Wu Faquan, Chang Jinyuan, et al. 2021. Pore characteristics of Malan loess—A case study at Zhaojia an landslide[J]. Journal of Engineering Geology, 29(5): 1366-1372. doi: 10.13544/j.cnki.jeg.2014-0392.

    马兰黄土孔隙结构特征——以赵家岸地区黄土为例

    PORE CHARACTERISTICS OF MALAN LOESS—A CASE STUDY AT ZHAOJIA'AN LANDSLIDE

    • 摘要: 颗粒间的孔隙分布特征从本质上控制着马兰黄土的宏观结构,影响马兰黄土的强度特性。马兰黄土的微观结果分析已逐渐成为研究黄土基本特性的一个新方向。本文通过固结实验、扫描电镜和ImageJ图像分析软件对赵家岸滑坡地区马兰黄土的孔隙分布和变形特性进行分析。首先确定了适合ImageJ图像分析的扫描电镜二维照片的阈值和图像拍摄最佳倍数;获取了原状马兰黄土在不同含水量固结试验前后的孔隙数量和孔隙面积的分布特征;揭示了大、中架空孔隙为黄土固结过程中的主要变形区;建立了马兰黄土孔隙中大架空孔隙、中架空孔隙和小架空孔隙的逐步破坏模式;明确了水对孔隙破坏的促进作用,当含水量增加到液限范围时,大、中型架空孔隙会出现加速的破坏现象。

       

      Abstract: Loess is present in many parts of the world, especially in arid and semi-arid climate zones. The loess in China covers approximately 631 000 km2. Many slopes consisting of Malan loess collapsed or slid during past several decades. Macrostructure characteristics and strength properties of the Malan loess are essentially controlled by intergranular pore distribution, which has gradually become a new focus to study loess basic characteristics. Undisturbed Malan loess samples were collected from excavated profiles on the northern side of Zhaojiaan landslide. Depth of the sample was 5 m below ground surface. Pore distribution and pore deformation behavior of the Malan loess in Zhaojiaan area were analyzed based on consolidation test, scanning electron microscope and ImageJ image analysis software. The samples were humidified by deionized water to predetermined water contents of 9%, 12%, 15%, 18% and 21% and subjected to uni-axial compression experiments. The pore structures of the undisturbed loess samples before and after uni-axial compression experiments were determined using scanning electron microscopy. The Ostu method was used as part of the ImageJ analysis to determine the threshold of binary images. The pore area distribution characteristics and the number of the pore of undisturbed samples were calculated under the different water content condition, which supports loess collapse caused by the large and medium trellis pores to a great extent. A pore destroy mode was proposed that large, medium and small trellis pores destroyed gradually in consolidation or wetting condition. The experiments also show that water must promote the failure of the loess pore structure. Large and medium trellis pores maybe accelerate collapse of the Malan loess when the water content increases to the liquid limit.

       

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