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.

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

    • 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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