Numerical studies on the performance of hybrid-geosynthetic-reinforced soil slopes subjected to rainfall

Slope instability due to rainwater infiltration poses a serious problem, and causes thousands of deaths and severe damage to infrastructures each year. In the present study, the effect of inclusion of hybrid-geosynthetic layers within a slope subjected to rainfall was investigated numerically. The analysis was done with and without hybrid-geosynthetic layers embedded in a silty sand slope having 2V:1H inclination with rainfall intensities ranging from 2 mm/h to 80 mm/h. The rainfall was simulated numerically for 24 h, and seepage, deformation and stability analyses were performed at the onset of rainfall, during rainfall, and up to 24 h after rainfall. Further, the need for both drainage and reinforcement function in the reinforced slope was highlighted by analysing the effect of geotextile and geogrid layer inclusions separately on the slope subjected to rainfall. The results indicate that, the inclusion of hybrid-geosynthetic layers was effective, as it lowered the phreatic surface by causing a reduction in excess pore water pressure. Further, the static global stability of a hybrid-geosynthetic-reinforced slope was found to increase considerably under all intensities of rainfall, while the deformation values were significantly lower for the reinforced slope as compared with that of the unreinforced slope.