Consolidation settlement and buoyancy behaviour for different thickness of polyurethane foam as a ground improvement

Abstract

Lightweight polyurethane (PU) foam is an alternative ground improvement method to resolve soft ground problem. In this study, Rowe Cell laboratory test is executed to determine the consolidation settlement of marine clay soil improved with polyurethane foam. The ground improvement is carried out by excavate the soft soil at shallow depth and replace with polyurethane foam. The performance for different thickness of PU foam as a ground improvement is evaluated. The comparison is made between partial replacement of PU foam on saturated marine clay and water in order to determine the buoyancy and uplift behaviour of the ground improved with lightweight PU foam. The percentage thickness of PU foam to soft clay layer and water varies from 20% to 80%. The correlation between PU foam thickness coefficient and compressibility index, Cc value for PU foam partial replacement on water and saturated soil are adopted in this study with the respective equations. The settlement reduces significantly with the increase of PU foam thickness for both soil and water conditions.