Dynamic response of EPS geofoam blocks using vibration tests

Expanded Polystyrene (EPS) geofoams have become a practical geosynthetic for use in roadbeds, soil embankments and retaining walls. Evaluating the dynamic response of EPS blocks is essential for their application under vibration loads. This study used a Foundation Model Response Test (FMRT) apparatus to investigate the dynamic properties of EPS geofoams, of varying densities and thicknesses, under different angular dynamic moments and dead weights. Increasing the density of EPS blocks raised the resonant frequency, equivalent damping ratio and dynamic shear modulus, while reducing the resonant amplitude and dynamic shear strain amplitude. Conversely, increasing their thickness decreased the resonant frequency, equivalent dynamic stiffness and equivalent damping ratio but increased the equivalent shear modulus, resonant amplitude and dynamic shear strain amplitude. With dead weight, thickness and density constant, higher dynamic moments delivered lower resonant frequencies, equivalent dynamic stiffnesses and equivalent shear moduli but higher resonant amplitudes, equivalent dynamic shear strains and equivalent damping ratio values. Adding more dead weight decreased the resonant frequency, resonant amplitude, equivalent dynamic shear strains and equivalent damping ratio, but increased the equivalent dynamic stiffness and equivalent shear modulus. • Evaluating dynamic properties of EPS geofoam blocks using the FMRT Apparatus. • Evaluating wide shear strain range in free and steady-state vibration tests. • Evaluating dynamic properties vs. EPS density and EPS thickness. • Evaluating dynamic properties vs. angular dynamic moment and dead weight.