3D Modeling of EPS Geofoam Buffers Behind Diaphragm Walls

Abstract

In an attempt to reduce lateral earth pressures acting on diaphragm walls, decrease the dependency on anchors, and optimize the wall structural design, expanded polystyrene geofoam (EPS) was introduced as a compressible buffer between the wall and the retained soil. Based on verified outcomes from the literature, EPS buffers is an effective solution that can significantly reduce the static lateral earth pressure acting on flexible walls. In this paper, a 3D numerical model was developed for a small-size diaphragm wall with EPS buffer using the finite element (FE) program PLAXIS 3D. The constitutive properties utilized in the model were measured as part of the material characterization phase of this research project, and the model was intended to capture the short-term behavior of the retained soil using EPS buffers with various thicknesses. To verify the FE results, a physical instrumented prototype was assembled to mimic the modeled diaphragm wall with EPS. The comparison showed a decent agreement between the FE results and the prototype measurements. From the main outcomes, lateral pressure on diaphragm walls was significantly reduced by around 37% using a relatively thin EPS buffer.