Slope stability is directly related to engineering safety, and the nonlinear action mechanism of groundwater infiltration, as an important factor affecting slope stability, still needs in-depth study. Based on the numerical simulation method of FLAC3D, this study systematically analyzes the mechanism of nonlinear influence of groundwater infiltration on slope stability, and investigates the influence of different water level heights and inclination angles of structural surfaces on the slope safety coefficient. The study used Mohr-Coulumb model to construct the slope analysis model, and combined with Darcy’s law and finite element strength reduction method to calculate the slope stability. The results show that: when there is no structural surface, the slope safety coefficient decreases from 1.39 to 1.00 when the water level rises from 50m to 85m; when there is a structural surface, the slope safety coefficient of the structural surface inclination of 15° decreases by 0.67 with the rise of the water level, and decreases by 0.49 when the structural surface inclination of 20°; when the water level reaches 85m, the slope safety coefficients of the structural surface inclination of 15° and 20° decrease by 0.52 and 0.49 respectively. When the water level reaches 85 m, the coefficients of safety are 0.52 and 0.69 for 15° and 20° of structural surface inclination, respectively; the slope stability coefficient increases from 1.08 to 1.49 when the depth of groundwater level increases from 10 m to 30 m. The study confirms the significant effect of the position of structural surface within the slope on the slope safety coefficient, and clarifies the nonlinear relationship between the change of groundwater level and the stability of slopes. Based on the results of the study, control measures such as increasing hydrogeological investigation, strengthening hydrological monitoring, adopting engineering means of seepage control and strengthening drainage diversion are proposed, which provide theoretical support for slope stability design and disaster prevention.
