Parametric study of embankment stabilization by pile reinforcement

Abstract

Stabilising piles have been proven as an effective slope stabilization approach. This study aims to investigate the optimal location of stabilising pile for an embankment slope with a surcharge loading at crest. A series of finite element analyses were performed to determine the optimal location of the pile with considerations of varying slope gradients. An additional analysis was performed to compare the factor of safety computed from the present 2D analysis with the previous 3D analysis. The results showed that the introduction of the stabilising pile could effectively minimise the deformed soil mass and slip surface, with the greatest improvement recorded for the embankment of 1.5V:1H gradient. The optimal pile location was found to be at the middle of the slope. The pile influence zone (Wpile) obtained from the present numerical study showed reasonably good agreement with previous results of centrifuge experiments. Based on the comparison of factor of safety computed from the present 2D analysis with a previous 3D analysis, the 2D analysis generally yielded a more conservative FOS (about 20% lower) than the more rigorous 3D analysis because of the absence of soil arching effect. As conclusions, it is recommended to install piles at the middle of slope to yield the most favourable slope stabilization effect. A simple 2D analysis can be used to analyse the problem of pile stabilised embankment with a slightly more conservative FOS was expected than the rigorous 3D analysis.