Centrifuge Modeling and Piv Analysis of Geogrid Reinforced Pile Supported Embankments over Soft Clay

Basal reinforcement of embankments and supporting with piles is one of the most recent solutions for rapid embankment construction on soft foundation soils. This paper uses the Particle Image Velocimetry (PIV) to evaluate the performance of unreinforced and reinforced embankments over soft foundation soils in terms of maximum settlement at the embankment base, lateral displacements of the embankment toe and the strains in the reinforcement layer using the digital images captured during the centrifuge model tests at 40g. The reinforcement consisted of a single layer of a scaled-down model basal geogrid and additional support from end-bearing or floating piles. The paper examines the effect of varying embankment heights on the geogrid strains and deformation characteristics of subsoil under rapid embankment construction over unreinforced and reinforced soft foundation soil with varying support conditions. The unsupported reinforced embankments showed a peak geogrid axial strain near the toe, whereas it peaked near the mid-section of the embankment for pile supported reinforced embankments. The study also investigates the failure mechanisms of unreinforced and reinforced embankments, with and without pile support, using shear strain contours derived from PIV analysis. The paper underscores the efficacy of PIV as a tool for visualising the deformation behaviour and failure mechanisms in soil during centrifuge model studies. Additionally, the research provides insights into the operation of an in-flight sand hopper used for embankment construction in centrifuge model studies. Post-investigation studies contribute to understanding the potential failure mechanisms in embankments supported by end-bearing and floating piles. Overall, this paper showcases the practical application of PIV in studying the challenges related to rapid embankment construction on soft foundation soils.