Numerical verification of the Concentric Arches model for geosynthetic-reinforced pile-supported embankments: applicability and limitations

In this study, a series of three-dimensional finite element simulations of a geosynthetic-reinforced pile-supported embankment design was conducted. The effects of subsoil stiffness, friction and dilation angles of the fill, fill height, pile spacing, surcharge load on the embankment, and anisotropic tensile stiffness of the geosynthetic reinforcement (GR), ground reaction curve, and interfacial responses between the fill material and GR were scrutinized. Numerical results showed how transfer of the vertical load towards the piles (load part A) and the related soil arches change with subsoil stiffness, geometric parameters, and vertical pressure on the embankment. Furthermore, the vertical load transferred through the GR (load part B) is reduced significantly with increasing subsoil stiffness, while the load part carried by the subsoil (load part C) increases. The numerical results showed that the vertical stress distribution on the GR changes from an inverse-triangular shape for low subsoil stiffness to a uniform shape for high subsoil stiffness. This matches perfectly with the Concentric Arches model. For low subsoil stiffness, the tensile strains of the GR are concentrated at the corner of a square pile cap.