Effect of Rainfall Infiltration on Deformation of Geobarrier Wall

Abstract

GeoBarrier system (GBS) is a system that combines geobag wall with capillary barrier concept as stabilization method against rainfall-induced failure, and vegetation as green cover. This paper presents deformation behaviour of a GBS wall constructed as pilot study when subjected to rainfall infiltration. The GBS wall was 4 m high with 70° slope angle. The wall was subjected to uniform surcharge of 10 kN/m2 and rainfall of 22 mm/h for 8 h. Recycled materials were used as components of the capillary barrier. Coupled deformation-seepage finite element analyses were carried out to evaluate the stress and pore-water pressure variations within and behind the GBS wall during and after rainfall. Limit equilibrium analyses were performed at various stages during and after rainfall to assess the near vertical wall stability. The results of the coupled deformation seepage analysis showed that the reinforced zone in the GBS remained unsaturated during rainfall, indicating that the GBS wall performed well in minimizing the rainwater infiltration. However, the GBS wall face deformation pattern altered during and after rainfall, indicating that the rainfall infiltration increased the lateral stress on the top part of the wall. The variation of lateral stress with depth agrees with field measurements from earth pressure cells.