Application of Geofoam as a Backfill Material in Both Static and Dynamic Loading Condition on the Perspective of Bangladesh

Abstract

Expanded Polystyrene (EPS) geofoam works like a compressible material between the backfill soil and retaining wall. It absorbs a huge amount of both static and dynamic loads induced by the backfill soil and pass the rest to the retaining structures. Geofoam between retaining wall and backfill soil can control the development of deformation, that is caused by those loads. As Bangladesh is a seismic prone country, so in order to build sustainable structures, geofoam was needed to use as a backfill material behind retaining wall. In this study, a finite element model was used by employing PLAXIS2D software to evaluate the effect of installing geofoam as a compressible buffer between backfill soil and retaining wall on the soil of Dhaka and Chittagong against static and dynamic loading. The numerical analysis defined the advantages of geofoam on EPS density, EPS relative thickness and excavation depth with pile-raft foundation. The outcome of the numerical analysis presented that for excavation depth of 3m, the displacement reduction was achieved from 28.3% to 46.59% with increasing of thickness. Lower density of EPS geofoam was effective for this excavation depth. For excavation depth of 6m, with increasing of EPS thickness ratio, the displacement reduced from 29.91% to 49.65%, but here, higher density of EPS geofoam cooperated in reduction of the displacement.