Three-dimensional evaluation of EPS geofoam elastic parameter sets and vehicle load configurations using large-scale field tests

This article presents numerical modeling results using the Finite Element Method (FEM) of a large-scale experimental embankment built with Expanded Polystyrene (EPS) blocks over a soft soil subgrade. The study addresses technical gaps and economic implications, as EPS design parameters derived from small-scale laboratory tests may not accurately represent full-scale field behavior, potentially affecting design decisions and construction costs. A Benkelman Beam Test (BBT) and a Load Test (LT), performed with a six-axle truck, were conducted on the experimental embankment. Several three-dimensional FEM simulations of both tests were performed to determine stress and deflection responses under different load configurations and EPS elastic parameter conditions. Simulations considered three-axle load configurations representing the entire vehicle, the entire axle, and the half-axle. FEM simulations were performed using EPS elastic parameter sets representative of small laboratory specimens and of large-scale or field-derived behaviour, as reported in the literature. FEM results were also compared with responses obtained using Layered Elastic Theory (LET) software for both tests. Results showed that elastic parameters obtained from small-size laboratory samples do not represent the behavior observed in the experimental and numerically modeled embankment. In contrast, elastic parameters obtained from large-scale samples showed good agreement with field results for both FEM and LET models. Additionally, vehicle load configuration proved to be a crucial input parameter for pavement stress and deflection analyses using FEM and LET simulations.