Centrifuge Modelling of Pile Groups Adjacent to Surcharge Loads

Abstract

The behaviour of pile groups when adjacent surcharge loads are applied to a clay layer was studied using centrifuge model tests. Lateral soil movements due to the surcharge loading cause passive lateral pile pressures and traction under the pile cap. These loadings induce pile group displacement and rotation away from the surcharge load. This 3-d soil-structure interaction is complex and requires data upon which design rules can be based. Short-term loading was found to be the most critical case for design. Results are presented together with investigation of the long-term behaviour and the new ‘buttonhole’ foundation technique designed to reduce passive lateral pile pressures. Soil contact beneath the pile cap increased pile group loadings and enlarged the region of soil deformation compared to previously investigated geometries in which the pile cap was above the top surface of the deforming soil.