Analysis of Slope Stabilized with Piles Under Earthquake Excitation

A slope may fail as a result of overstress or a decrease in the soil’s shear strength. Piles in single or multiple rows have been widely used as earth retaining systems to stabilize active landslides and improve the slope stability. However, limited studies are available on the effect of pile stabilization on the seismic stability of slopes. Therefore, this study presents two-dimensional and three-dimensional finite element analyses based on the strength reduction technique to investigate the seismic response of slopes stabilized using piles. The effect of the length and configuration of the piles on the stability of the slopes is examined, where five configurations are considered. These configurations are single pile, two piles distributed in one row, four piles distributed in one row, four piles distributed in two rows, and eight piles distributed in two rows. These cases have been compared with a reference case of an unreinforced slope in both dry and saturated conditions. It was found that the number of piles has a remarkable influence on the mobilized factor of safety, and its influence is higher than the pile length. In addition, using the piles in two rows increases the safety compared to using the same number of piles but in one row. Furthermore, the slope yielded a higher factor of safety in the dry cases compared to the saturated cases. More importantly, it was found that the earthquake remarkably affected the mobilized factor of safety of the slope, and thus, the real intensity of the earthquake should be utilized in the assessment and design of slopes. The results presented in this paper are useful to engineers working on the stabilization, assessment, and design of slopes in areas prone to earthquakes.