Desiccation-induced cracking and deformation characteristics in compacted loess: insights from electrical resistivity and microstructure analysis

IF 3.7 2区工程技术 Q3 ENGINEERING, ENVIRONMENTAL

Bulletin of Engineering Geology and the Environment Pub Date : 2024-11-21 DOI:10.1007/s10064-024-04012-1

Pengju Qin, Yao Geng, Yu Lu, Libo Mao, Jun Zhang

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引用次数: 0

Abstract

Compacted loess is widely used in construction and road engineering in the Loess Plateau region. It inevitably undergoes vertical deformation and desiccation-induced cracking due to environmental effects. This study investigates the deformation and cracking characteristics of compacted loess under vertical pressure during desiccation. Samples with initial water contents ranging from 5% to saturation are prepared for desiccation under vertical stresses of 0−100 kPa. Changes in resistivity are simultaneously monitored during desiccation. After desiccation, the microstructural characteristics of the soil are examined using X-ray computed tomography (CT), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM) techniques. The effects of initial water content and vertical pressure on vertical strain, drying cracks, and electrical resistivity of compacted loess are analyzed. The results indicated that high vertical pressure and water content lead to significant compressive and desiccated deformation of compacted loess, which is reflected in the microstructure by a smaller pore size distribution (PSD). Lower initial water content and higher vertical load are more effective in suppressing cracking during the desiccation of compacted loess. The surface crack ratio (R_sc) of compacted loess is reduced by 99.54% as pressure increases from 0 to 100 kPa and water content decreases from saturation to 5%. The directions of cracks in loess during desiccation and the microstructural changes caused by deformation are effectively characterized by resistivity measurements. This study explores the variations in mechanical properties during desiccation of compacted loess and provides a theoretical foundation to use resistivity for characterization.

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查看原文本刊更多论文

压实黄土中干燥诱发的开裂和变形特征：电阻率和微结构分析的启示

黄土高原地区的建筑和道路工程中广泛使用压实黄土。由于环境影响，黄土不可避免地会发生垂直变形和干燥引起的开裂。本研究探讨了干燥过程中压实黄土在垂直压力作用下的变形和开裂特征。在 0-100 kPa 的垂直压力下，初始含水量从 5%到饱和度不等的样品被准备用于干燥。在干燥过程中同时监测电阻率的变化。干燥后，使用 X 射线计算机断层扫描（CT）、汞侵入孔隙模拟（MIP）和扫描电子显微镜（SEM）技术检测土壤的微观结构特征。分析了初始含水量和垂直压力对压实黄土的垂直应变、干燥裂缝和电阻率的影响。结果表明，较高的垂直压力和含水量会导致压实黄土产生显著的压缩变形和干燥变形，并通过较小的孔径分布（PSD）反映在微观结构中。较低的初始含水量和较高的垂直荷载能更有效地抑制压实黄土干燥过程中的开裂。随着压力从 0 千帕增加到 100 千帕，含水量从饱和状态降低到 5%，压实黄土的表面裂缝率（Rsc）降低了 99.54%。干燥过程中黄土裂缝的走向以及变形引起的微观结构变化可以通过电阻率测量有效地表征出来。本研究探讨了压实黄土在干燥过程中机械性能的变化，为利用电阻率进行表征提供了理论基础。

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来源期刊

Bulletin of Engineering Geology and the Environment 工程技术-地球科学综合

CiteScore

7.10

自引率

11.90%

发文量

445

审稿时长

4.1 months

期刊介绍： Engineering geology is defined in the statutes of the IAEG as the science devoted to the investigation, study and solution of engineering and environmental problems which may arise as the result of the interaction between geology and the works or activities of man, as well as of the prediction of and development of measures for the prevention or remediation of geological hazards. Engineering geology embraces: • the applications/implications of the geomorphology, structural geology, and hydrogeological conditions of geological formations; • the characterisation of the mineralogical, physico-geomechanical, chemical and hydraulic properties of all earth materials involved in construction, resource recovery and environmental change; • the assessment of the mechanical and hydrological behaviour of soil and rock masses; • the prediction of changes to the above properties with time; • the determination of the parameters to be considered in the stability analysis of engineering works and earth masses.