Slope stability analysis of saturated–unsaturated based on the GEO-studio: a case study of Xinchang slope in Lanping County, Yunnan Province, China

Yunnan Province of China is located in the southwest frontier, with high altitude, fragile geological environment, uneven spatial and temporal distribution of rainfall, and more localized rainfall and landslide geological hazards caused by rainfall are extremely common. Therefore, based on saturated–unsaturated seepage theory, it is of great engineering significance to deeply study the change law of internal seepage of slopes under different rainfall conditions and the influence of dynamic seepage on slope stability. In this paper, based on the saturated–unsaturated seepage theory, the soil–water characteristic curve and unsaturated permeability coefficient prediction model are determined, and GEO-Studio finite element software is used to explore the changes of seepage field, stress field, displacement field, and stability coefficient of the slope under different rainfall conditions from the perspectives of seepage mechanics and rock mechanics, and to reveal the changes of unsaturated soil The mechanical response mechanism of unsaturated soil slopes in the process of dynamic seepage and the influence of seepage on the stability of slopes. The results show that: (1) the volumetric water content and saturation of the shallow soil will increase rapidly when the unsaturated soil slope is affected by rainfall, and the pore water pressure, maximum shear stress, and total displacement in the corresponding area will increase with the increase of rainfall time; (2) the stability of the slope is closely related to the rainfall time, and the longer the rainfall time, the lower the stability coefficient. At the same time, it provides theoretical support for the study of similar landslide mechanisms and prevention engineering.