Stability analysis of an unsaturated clay slope based on the coupled effect of temperature and saturation

Abstract

In view of clay slope instability caused by environmental temperature and rainfall infiltration in summer and autumn, the mechanism of the effect of temperature and saturation on unsaturated clay slope stability is discussed. To achieve this objective, this study uses theoretical and numerical methods. Based on the theory of unsaturated clay and the law of heat conduction, the relationship between cohesion and matrix suction of unsaturated clay was derived considering the influence of temperature and saturation. Taking into consideration the effects of temperature and saturation, the coupling equation for the shear strength of unsaturated clay was constructed under conditions of rainfall infiltration. The coupling equation for temperature and saturation was used using the strength reduction method, and the slope stability was analysed using FLAC software. The results show that: (i) cohesion in the unsaturated clay slope increases with increasing depth; (ii) the safety factor is smaller when taking into consideration the coupled effect of temperature and saturation than when the temperature effect is not taken into consideration; and (iii) the clay slope is unstable when the coupled effect of temperature and saturation is taken into consideration, but is stable when the coupled effect of temperature and saturation is not considered and soil saturation reaches 80%.Thematic collection: This article is part of the Role of water in destabilizing slopes collection available at: https://www.lyellcollection.org/cc/Role-of-water-in-destabilizing-slopes