Finite-element Analysis of Lateral Pressures on Rigid Non-yielding Retaining Walls with EPS Geofoam Inclusion

An elasto-plastic constitutive model for expanded polystyrene (EPS) geofoam was employed with a finite-element analysis addressing the lateral pressures on a rigid non-yielding retaining wall with geofoam inclusion. Experimental results from laboratory uniaxial and triaxial compression tests were used to derive the parameters of the elasto-plastic constitutive models for the geofoam inclusion and the backfill soil used in the finite-element investigation. The numerical study revealed that for the analyzed EPS density, specific combinations of geofoam panel thickness and retaining wall height may induce plastic strains in the geofoam. The results were compiled into design charts providing the distribution of lateral pressures on the wall and the geofoam isolation efficiency as a function of EPS panel thickness and wall height.