Extended concentric arches model for piled beam-supported embankments

Abstract

Geosynthetic-reinforced embankments founded on piled beams have emerged as a new ground modification technique for supporting earth embankments over deep soft subsoil. This paper presents an analytical model for this technique that combines parts of two existing analytical design models. The soil arching behaviour that divides the vertical embankment load into a part that is transferred to the piled beams directly, and the residual load part that rests on the geosynthetic, is described by the 3D part of the Concentric Arches (CA) soil arching model of van Eekelen et al. (2013 and 2015), which was adopted in CUR226:2016. The paper also compares the difference between adopting the 2D or the 3D part of this CA model. The tensioned geosynthetic effect was described by the membrane action equation of Pham (2020b). This equation calculates the geosynthetic strain and includes load–deflection behaviour, adhesion, and friction along the geogrid/soil interface. Two field studies and fully coupled hydromechanical finite element analyses were used to verify the proposed analytical approach and its assumptions. The paper compares the effect of founding geosynthetic-reinforced embankments on piles or piled beams. Finally, a parametric study showed the impact of beam width, center-to-center pile spacing, and geogrid stiffness on load transfer efficiency.