Exploring the mechanical behavior and microstructure of compacted loess subjected to dry-wet cycles and chemical contamination

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外文摘要：Due to climatic factors and rapid urbanization,the soil in the Loess Plateau,China,experiences the coupled effects of dry-wet cycles and chemical contamination.Understanding the mechanical behavior and corresponding microstructural evolution of contaminated loess subjected to dry-wet cycles is essential to elucidate the soil degradation mechanism.Therefore,direct shear and consolidation tests were performed to investigate the variations in mechanical properties of compacted loess contaminated with acetic acid,sodium hydroxide,and sodium sulfate during dry-wet cycles.The mechanical response mechanisms were investigated using zeta potential,mineral chemical composition,and scanning elec-tron microscopy(SEM)tests.The results indicate that the mechanical deterioration of sodium hydroxide-contaminated loess during dry-wet cycles decreases with increasing contaminant concentration,which is mainly attributed to the thickening of the electrical double layer(EDL)by Na+and the precipitation of calcite,as well as the formation of colloidal flocs induced by OH-,thus inhibiting the development of large pores during the dry-wet process.In contrast,the attenuation of mechanical properties of both acetic acid-and sodium sulfate-contaminated loess becomes more severe with increasing contaminant concentration,with the latter being more particularly significant.This is primarily due to the reduction of the EDL thickness and the erosion of cement in the acidic environment,which facilitates the connectivity of pores during dry-wet cycles.Furthermore,the salt expansion generated by the drying process of saline loess further intensifies the structural disturbance.Consequently,the mechanical performance of com-pacted loess is sensitive to both pollutant type and concentration,exhibiting different response patterns in the dry-wet cycling condition.

外文关键词：

Contaminated loessDry-wet cyclesCompressibilityShear strengthMicrostructural evolution

作者：

Yongpeng Nie、Wankui Ni、Xiangfei Lü、Wenxin Tuo

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作者单位：

College of Geological Engineering and Geomatics,Chang'an University,Xi'an,710054,China

Department of Civil Engineering,Nagoya Institute of Technology,Nagoya,466-8555,Japan

School of Water and Environment,Chang'an University,Xi'an,710054,China

基金：

Second Tibet Plateau Scientific Expedition and Research ProgramKey Program of the National Natural Science Foundation of ChinaKey Research and Development Program of Shaanxi Province

项目编号：

2019QZKK0905419312852019ZDLSF05-07

出版年：

2024

DOI：

10.1016/j.jrmge.2024.05.012

岩石力学与岩土工程学报(英文版)

中国科学院武汉岩土力学所中国岩石力学与工程学会武汉大学

岩石力学与岩土工程学报(英文版)

CSTPCD

影响因子：0.404

ISSN：1674-7755

年,卷(期)：2024.16(9)