Variations in strength and deformation of compacted loess exposed to wetting-drying and freeze-thaw cycles
Variations in strength and deformation of compacted loess exposed to wetting-drying and freeze-thaw cycles
复制标题
干湿和冻融循环下压实黄土的强度和变形变化
DOI：
10.1016/j.coldregions.2018.03.021
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发表时间：
2018-07-01
影响因子：
4.1
通讯作者：
Hou, Xin
中科院分区：
文献类型：
--
作者：
Li, Guoyu;Wang, Fei;Hou, Xin
密实黄土是许多人工基础设施的基础，经常暴露在强烈的风化过程中，如反复干湿(WD)和冻融(FT)循环。干旱和季节性冻土区的这些风化作用导致了黄土的松散结构和强度劣化，导致了严重的工程问题和昂贵的基础设施维护费用。在受控的实验室环境下，将密实黄土试件暴露于不同强度的风化过程中，以定量评估其对岩土性质的恶化影响。室内试验结果表明，湿干风化比冻融风化对密实黄土的岩土性质影响更大。黄土试件的无侧限抗压强度、弹性模量和粘聚力随WD和FT循环次数的增加而减小，竖向压缩应变和湿陷变形增加。密实非湿陷性黄土试件在经过5次WD循环后又表现出湿陷性(次生湿陷)。阐述了湿干和冻融风化作用引起的密实黄土的劣化机理，并建议在密实黄土上修建人工基础设施的长期稳定性和使用性能预测中应考虑这两个因素。
Densely compacted loess on which many man-made infrastructures are built are often exposed to strong weathering processes such as repeated wetting-drying (WD) and freeze-thaw (FT) cycles. These weathering processes in arid and seasonally frozen ground regions result in loose structure and strength deterioration of loess soils, and they cause serious engineering problems and expensive maintenance costs of infrastructures built on densely compacted loess. In this study, specimens of densely compacted loess were exposed to different intensities of weathering processes under controlled laboratory environment to quantitatively assess their deterioration effects on geotechnical properties. According to the laboratory results, the wetting-drying weathering has a stronger impact on the geotechnical properties of densely compacted loess than the freezing-thawing weathering. The unconfined compressive strength, elastic modulus, and cohesion of the loess specimens decrease with increasing number of WD and FT cycles while the vertical compression strain and collapse deformation increase. The densely compacted and non-collapsible loess specimens exhibited collapsible again (secondary collapse) after 5 WD cycles. The deterioration mechanisms of densely compacted loess induced by wetting-drying and freezing-thawing weathering processes have been presented and were strongly recommended to be taken into account for the prediction of long-term stability and serviceability of man-made infrastructures built on densely compacted loess.