Finite Element Analyses for Centrifuge Modelling of Narrow MSE Walls

High transportation demand has led to widening of existing roadways to improve traffic flow. In some cases, the space available on site is limited and the construction of earth retaining walls is done in front of previously stabilized walls. This can lead to retaining wall designs that are narrower than those addressed in current design guidelines. Narrow walls are Mechanically Stabilized Earth (MSE) walls having an aspect ratio (L/H) less than 0.70. Previous studies have suggested that the internal and external behavior of narrow retaining walls differ from that of traditional walls. This paper presents a study of the behavior of narrow MSE wall models tested in a centrifuge using the finite element program Plaxis. The results predicted by the finite element model are in a good agreement with the experimental data from centrifuge tests at working stress and failure conditions. Finite element study also shows that a zero pressure zone is observed at the interface between the reinforced backfill and stable wall and extends farther below the surface as the wall width becomes narrower. As a result of this zero pressure zone, the crest of the MSE wall has a tendency to settle at the interface. This settlement leads to instability and, finally, the failure of the wall. The implications of the finite element study are addressed in this paper as design considerations to improve the stability of narrow walls.