Numerical evaluation of EPS geofoam inclusion for reducing earth pressure and structural loads in retaining walls

This study developed and applied two complementary numerical–analytical frameworks to evaluate the behaviour of rigid retaining walls, one incorporating expanded polystyrene (EPS) geofoam and the other without geofoam. Both frameworks employ finite-difference simulations in FLAC2D; the initial phase of the study validates the numerical implementation by comparing model predictions with measurements from a small-scale laboratory experimental setup. Close agreement between simulated and experimental results demonstrates the fidelity of the modelling approach. The subsequent parametric study investigates how EPS geofoam properties and configuration influence the structural response of the retaining system. Variables considered include geofoam density, compressible-layer thickness, and imposed surcharge magnitudes. Response metrics comprise lateral earth pressures, bending moments, shear forces, and wall displacements. Results indicate that increasing the thickness of the geofoam layer substantially reduces lateral pressures on the wall, while lower-density EPS (with reduced stiffness) further diminishes lateral loading. Consequently, bending moments, shear forces, and wall strains are markedly reduced when geofoam is used as a compressible inclusion. The findings underscore the effectiveness of EPS geofoam in mitigating earth pressures and enhancing the performance of rigid retaining walls under a range of loading scenarios.