Influence of EPS Geofoam Buffers on the Static Behavior of Cantilever Earth-Retaining Walls

In this study, the effect of expanded polystyrene (EPS) buffers on lateral stresses and deflections of model retaining walls with various flexibility values were investigated. For this purpose. 0.7 m high model walls were instrumented and 1-g model tests were performed in laboratory environment. In the first group of tests. the wall models retain only granular cohesionless backfill whereas in the second and third group of tests. EPS defornlable buffers of two different thicknesses were installed between the wall and granular backfill. Tests were repeated for four different wall thicknesses and results were discussed comparatively. As wall flexibility increases. there is a decrease in the load reduction pattern of the buffer. On the other hand. utilization of geofoam buffers with flexible cantilever walls still provides substantial decrease in wall thrust and deflections thus leading to more economical retaining structure design. The lateral earth pressure coefficients determined through model tests were compared to those calculated from Coulomb's theory for active lateral earth stresses. A graph is provided for the estimation of lateral earth pressure coefficients for various combinations of wall flexibilities and buffer characteristics.