Double Strength Reduction Method for Slope Stability Analysis Based on Water Content Variation: A Study and Engineering Application

Abstract

Soil moisture content changes caused by rainfall and other factors can significantly affect slope stability and potentially lead to geological disasters, such as landslides and debris flows. However, conventional finite element methods for strength reduction do not consider the impact of water content on slope stability. This paper examines classical finite element methods for reducing the double strength coefficient and then introduces a novel approach using changes in moisture content. The new method is implemented through the use of an ABAQUS FE program’s USDFLD user-defined subroutine. This paper concludes by contrasting the outcomes derived from the limit equilibrium technique and other techniques and verifying the accuracy of the suggested approach through theoretical and numerical simulations. The numerical calculations for the stability evaluation of the Azhuoluo slope in the Chinese province of Guizhou, Shuicheng county were performed utilizing the ABAQUS FE platform’s USDFLD user-defined subroutine based on the double-strength discounting method, in response to the large landslide disaster in the region. The results show that the red clay, formed from the weathering of basalt in the area, experiences asynchronous decay in both friction angle and cohesion as the water content increases, with a significantly higher decay rate in the internal friction angle compared to cohesion. This indicates that traditional finite element methods that synchronously discount the internal friction angle and cohesion do not correspond to reality, whereas this proposed double-strength discounting method, based on water content changes, accurately reflects the essential characteristics of slope instability and has clear physical meaning and practical engineering applications.