Dynamic characterization of EPS geofoam

This paper attempts to describe the dynamic behavior of expanded polystyrene EPS geofoam, and shows the dependence of shear modulus, G, and damping ratio, λ, on shear strain, γ, density, ρ, and confining stress, σ3, through the results of a series of resonant column and strain- and stress-controlled cyclic compression tests. Shear modulus and damping ratio versus shear strain curves were obtained and a series of equations were developed to model the dynamic behavior of EPS. From stress-controlled cyclic compression tests the effect of the number of cyclic load applications, N, on the maximum axial strain ɛmax (for a specific static deviator stress, σe, plus the amplitude of the loading cyclic stress, σc) and on the dynamic modulus of elasticity Edyn was evaluated as a function of the EPS density, confining stress, and the applied cyclic stress amplitude σc.