School of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi, 710055, People's Republic of China.
Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering, Xi'an, Shaanxi, 710055, People's Republic of China.
Environ Sci Pollut Res Int. 2021 Jun;28(23):29845-29858. doi: 10.1007/s11356-021-12749-5. Epub 2021 Feb 11.
Even though soil acidification can cause significant destabilizing effects on various geotechnical issues, studies have rarely been conducted to determine the influence of soil structure on the impact of acid-contaminated soil. The current work aims to understand the effect of acid fluids on engineering behavior of undisturbed loess through laboratory tests. The sampling site is in a typical region of Loess Plateau, China. The variations in particle size distribution, Atterberg limits, uniaxial compression strength, and permeability were investigated with the help of microstructure for a better understanding of the governing mechanism of undisturbed loess subjected to acid fluids. It was found that exposure to acid fluids can improve the particle size distribution of loess. In contrast, the experimental results indicated that acid fluids can decrease Atterberg limits and strength and permeability of loess, although Atterberg limits and strength of loess are considerably increased in a highly sulfuric acid environment. Then, analyzing the engineering response in the light of microstructure revealed that the face-to-face contacts primarily exist in loess prepared with hydrochloric acid and nitric acid, respectively, whereas the mosaic structure is indeed active in sulfur-contaminated loess. Furthermore, a micro-conceptual structure was proposed based on the experiment led to the conclusion that the cementitious salt and structural characteristics play a dominant role in governing the engineering behavior of loess under acidic conditions.
尽管土壤酸化会对各种岩土工程问题产生显著的不稳定影响，但很少有研究来确定土壤结构对受酸污染土壤影响的作用。本工作旨在通过实验室试验了解酸液对原状黄土工程特性的影响。采样地点位于中国典型的黄土高原地区。借助微观结构研究了颗粒大小分布、界限含水量、单轴抗压强度和渗透性的变化，以便更好地了解原状黄土在酸液作用下的控制机制。结果表明，酸液的作用可以改善黄土的颗粒大小分布。相比之下，实验结果表明酸液会降低黄土的界限含水量和强度以及渗透性，尽管在高硫酸环境中黄土的界限含水量和强度会显著增加。然后，根据微观结构分析工程响应，发现盐酸和硝酸制备的黄土中主要存在面-面接触，而受硫污染的黄土中则存在镶嵌结构。此外，基于实验提出了一种微观概念结构，得出的结论是胶结盐和结构特征在控制酸性条件下黄土的工程特性方面起主导作用。
