Effect of Rainfall Infiltration on the Hydromechanical Behavior of Slopes under Unsaturated Conditions

Abstract

Nowadays, slopes forming transportation infrastructure are highly sensitive to hydraulic conditions such as rainfall, triggering negative impacts on ecosystems and road infrastructure. In this regard, this research analyzes the hydromechanical influence of a frequent rainfall intensity in northern Peru of 10 mm/h on the stability of slopes (T1, T2, and T3) under unsaturated conditions. For this purpose, simulations were performed using Plaxis 2D software, considering three slope geometries based on regulatory criteria for clayey gravel soils with fines content and groundwater table conditions. The input parameters for the soil were based on the Hardening Soil model, while the Van Genuchten model was used for flow analysis. The obtained results indicate that, within the analyzed section measured from the upper surface downward, maximum saturation reached a depth equivalent to 33% of the slope height for model T1, 11.8% for model T2, and 6.4% for model T3. In addition, the effective surface suction produced reductions lower than 3 kN/m² after 24 hours of continuous rainfall. Finally, the factor of safety was affected under the same scenario, decreasing by up to 59.11% for model T1, 49.2% for model T2, and 42.80% for model T3. It should be noted that the most significant transition toward instability occurred after 10 hours.