CPT based prediction of foundation penetration in siliceous sand

Abstract

The load–penetration response of a foundation is one of the fundamental aspects of geotechnical engineering. In sand, the bearing capacity approach requires the operative friction angle to be known, which introduces significant uncertainty to the prediction. The predictive method developed in this paper eliminates the need to determine the friction angle. The central concept is the direct correlation of in situ piezocone penetrometer measurements to the load–penetration response of foundations.The correlation factor is shown to depend primarily on the sand relative density. The footing shape has a minor influence on the correlation factor. This study aims at large diameter foundations used in the offshore industry, where the variation in correlation coefficient is minor. However, context is provided to previous research on smaller diameter foundations, which shows the dependence on the footing diameter (through the well-known stress level effect).The proposed method is shown to perform well against load–penetration data from centrifuge experiments on footings of different diameters and elevation shapes. The performance against field data in particular provides significant confidence in the CPT based prediction method of foundation penetration in sand developed here.