Influence of Key Design Parameters on Piled Raft Foundation Performance: a 3D Finite Element Study

This study utilized a 3D finite element analysis, modeling all components (piles, raft, soil) using solid elements. Using an elastoplastic continuum approach for the soil, the analysis captured both elastic and plastic behavior realistically. It systematically explored the influence of key parameters (e.g., pile spacing, length, number, diameter, raft thickness, soil properties) on piled raft performance, covering crucial design criteria such as settlement and bending moment. Key findings indicated significant roles for pile spacing and length on the design criteria. It was found that a pile spacing equals to four times the pile diameter considerably minimizes the differential settlements, while the lowest bending moment occurs at six times the pile diameter spacing. It is also revealed that longer piles reduced average settlement, yet increased differential settlement, bending moment, and pile load share. Pile number and diameter were found to have minor effects, with diameter minimally impacting load share. Soil properties could notably influence foundation behavior; the higher friction angles and cohesion tend to reduce settlement and increase differential settlement, bending moment, and pile load share. These findings, which were obtained using a comprehensive parametric investigation, offer a valuable guide to designers and help optimize safety and cost-effectiveness in piled raft foundation design.