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

作     者：Yongpeng Nie Wankui Ni Xiangfei Lü Wenxin Tuo 

作者机构：College of Geological Engineering and GeomaticsChang'an UniversityXi'an710054China Department of Civil EngineeringNagoya Institute of TechnologyNagoya466-8555Japan School of Water and EnvironmentChang'an UniversityXi'an710054China 

出 版 物：《Journal of Rock Mechanics and Geotechnical Engineering》 (岩石力学与岩土工程学报（英文版）)

年 卷 期：2024年第16卷第9期

页      面：3673-3695页

核心收录：

学科分类：070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 07[理学] 0818[工学-地质资源与地质工程] 

基　　金：supported by the Second Tibet Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0905) the Key Program of the National Natural Science Foundation of China(Grant No.41931285) the Key Research and Development Program of Shaanxi Province(Grant No.2019ZDLSF05-07) 

主　　题：Contaminated loess Dry-wet cycles Compressibility Shear strength Microstructural evolution 

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 *** the mechanical behavior and corresponding microstructural evolution of contaminated loess subjected to dry-wet cycles is essential to elucidate the soil degradation ***,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 *** mechanical response mechanisms were investigated using zeta potential,mineral chemical composition,and scanning electron microscopy(SEM)*** results indicate that the mechanical deterioration of sodium hydroxidecontaminated loess during dry-wet cycles decreases with increasing contaminant concentration,which is mainly attributed to the thickening of the electrical double layer(EDL)by Nat 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 *** 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 *** 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 ***,the salt expansion generated by the drying process of saline loess further intensifies the structural ***,the mechanical performance of compacted loess is sensitive to both pollutant type and concentration,exhibiting different response patterns in the dry-wet cycling condition.