Short- and long-term behavior of EPS geofoam in reduction of lateral earth pressure on rigid retaining wall subjected to surcharge loading

Abstract

Retaining walls are subjected to dead loads from backfill and adjacent structures, live loads and other loads from the vicinity of the structure. Retaining walls need to withstand earth pressure generated from above mentioned loads satisfactorily throughout their service life. Lateral earth thrust on retaining walls can be minimized by placing a compressible inclusion, such as, EPS geofoam, between the backfill and retaining wall. The present study is aimed at understanding both short- and long-term influence of EPS geofoam on surcharge induced lateral earth pressures on retaining walls through 1-g model studies. Four densities of geofoam in the range of 10–25 kg/m3 and three thicknesses of geofoam in the range of 25–75 mm were used in the present study. Lateral earth pressure at several locations along the height of the wall were monitored using earth pressure cells. Geofoam compression and backfill settlements under the surcharge load were also quantified using image analysis. From the series of model tests, it was observed that with the use of geofoam, lateral earth pressure on retaining wall was reduced under both short- and long-term loading conditions. However, higher reduction was observed under long-term loading.