Study of lateral earth pressures on nonyielding retaining walls with deformable geofoam inclusions

This paper proposes a method to predict the lateral earth pressures on nonyielding retaining walls with geofoam inclusions. The previous study of the lateral stress-strain relation of the backfill was extended, and the solution was derived by the iterative method. The proposed solution could be applied without the known value of the compression of the geofoam inclusions. Model tests for nonyielding retaining walls with expanded polystyrene (EPS) geofoam were also conducted to investigate lateral earth pressures. The accuracy of the proposed solution was verified by comparison to test data in the absence of surface loading. The proposed solution was also validated by a previous study of laboratory-scale model tests with surface loading as well as numerical simulations for field-scale applications with a vehicle load. Furthermore, the effect of the density and thickness of EPS on the reduction of lateral earth pressures was discussed, and appropriate design parameters of EPS were suggested for nonyielding retaining walls with EPS geofoam.