Finite Element Analysis of Polyurethane Injection Pile

Excessive post construction and differential settlements constitute engineering challenges for structure founded on soft cohesive soil which caused instability and crack to the existing structure. Inadequacy of design for foundation supporting structure during the early stage of construction and less information on site investigation might be the main reason for this problem. Polyurethane (PU) injection pile is proposed to replace the conventional underpinning pile. No excavation is required and only a small diameter of hole is drilled on the existing slab foundation before injection of PU. Analyses of the settlement problem and design of the remedial measures using PU injection pile were carried out using Two-Dimensional (2-D) finite element method (FEM) analyses. The sophisticated FEM is necessary because of the complexity of soil-structure interaction problem, involving subsoil-pile-slab-fill and vice versa.