Abstract
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.
Highlights
Red-bed weathered soil is widely distributed in southern China
In this study, aiming to model the soil expansion characteristics of rainfall-induced red-bed shallow landslides based on the Gouy-Stern electric double-layer theory, a microscopic model of the electrical double layer of red-bed weathered soil that considers the hydration force and particle orientation was established
The model combines the characteristics of soil and the influence of water on soil in the expansion model, thereby solving the problem that previous research on the expansion mechanism of expansive soil did not consider the influence of hydration and particle orientation
Summary
Red-bed weathered soil is widely distributed in southern China. Because soils of this type contain large amounts of clay minerals such as montmorillonite and illite, they have properties of expansion and contraction. When large amounts of rainfall occur, long-term changes in saturation and pore-fluid chemical changes in red weathering soil can lead to the expansion and fracture of engineering structures, especially due to shallow landslides, which will affect the safety of engineering [1,2,3,4]. Research on the expansive properties of some other expansive soils has been conducted at the microscopic level [5, 6], experimental and theoretical research on red-bed weathered soil is insufficient.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
