Centrifuge experiments on the settlement of circular foundations on clay

Abstract

Centrifuge experiments were conducted to investigate the mechanisms governing the settlement of shallow circular foundations on clay. Model tests were performed on both soft and firm beds of overconsolidated kaolin clay. Foundation loads were applied as dead-weight and also through pneumatic loading. A Perspex window in the centrifuge package allowed digital images to be captured of a vertical cross section during and after the application of loading. Soil displacements deduced by particle image velocimetry (PIV) allow deformation mechanisms to be presented for undrained penetration, creep, and consolidation caused by transient flow. A technique is presented for discriminating consolidation settlements from the varying rates of short- and long-term creep. The mobilizable strength design (MSD) method is shown to make useful predictions of the undrained penetration using an estimated stress–strain behaviour of the clay with allowances made for anisotropy and rate effects. Subsequent creep and consolidation settlements were then determined using established correlations.