Zhou Cuiying, Cui Guangjun, Yin Hao, Yu Lei, Xu Gankai, Liu Zhen, Zhang Lihai
School of Civil Engineering, Sun Yat-sen University, Guangzhou, Guangdong, China.
Guangdong Engineering Research Center for Major Infrastructures Safety, Sun Yat-sen University, Guangzhou, Guangdong, China.
PLoS One. 2021 Jan 28;16(1):e0246214. doi: 10.1371/journal.pone.0246214. eCollection 2021.
The main cause of rainfall-induced red-bed shallow landslides is the tendency of red-bed weathered soil to expand when it meets water. However, studies on the expansion mechanism of expansive soil have not considered the effects of hydration and particle orientation. In this study, the hydration force of soil was determined according to the electric double-layer theory, the particle direction of soil was determined by analyzing images of soil obtained by scanning electron microscopy, and, finally, a microscopic model of the electrical double layer of red-bed weathered expansive soil was established in which the hydration force and soil-particle orientation were taken into account. The results showed that the expansion of red-bed weathered expansive soil is the result of hydration forces and repulsive forces in the electric double layer. The grain orientation of the soil strongly influenced the microscopic model. The unloading expansion rate of red-bed weathered expansive soil decreased with an increase in cation concentration and a decrease in pH value. It increased with an increase in the hydration cation radius. These experiments indicate the reliability of the microscopic model and provide a theoretical basis for the prevention and control of rainfall-induced red-bed shallow landslides.
降雨诱发红层浅表层滑坡的主要原因是红层风化土遇水膨胀的特性。然而，关于膨胀土膨胀机制的研究尚未考虑水化作用和颗粒取向的影响。本研究依据电双层理论确定了土壤的水化力，通过分析扫描电子显微镜获取的土壤图像确定了土壤颗粒方向，最终建立了考虑水化力和土壤颗粒取向的红层风化膨胀土电双层微观模型。结果表明，红层风化膨胀土的膨胀是电双层中水化力和排斥力共同作用的结果。土壤颗粒取向对微观模型有显著影响。红层风化膨胀土的卸载膨胀率随阳离子浓度的增加和pH值的降低而减小，随水化阳离子半径的增大而增大。这些实验证明了微观模型的可靠性，为降雨诱发红层浅表层滑坡的防治提供了理论依据。
