Soil arching in geosynthetic and steel grid-reinforced pile-supported embankments

High-density deformation measurements were used to investigate the load distribution on, and the deformed shape of the basal reinforcement in pile-supported embankments. Two cases were analysed: a geosynthetic-reinforced (GR) embankment in Woerden, the Netherlands, and a steel-reinforced (SR) embankment in a large-scale model test (PEBSTER), conducted at the TU Darmstadt in Germany. The SR has an axial stiffness over 20 times higher than the GR, yet both embankments exhibited an inverse-triangular load distribution on the reinforcement. This consistent behaviour indicates that soil arching is independent of reinforcement stiffness. Predictions with the Concentric Arches model closely match the measured deflections in both cases. However, the model does not yet include the reinforcement above the piles, where the bending stiffness of the SR plays a role.