Improved Prediction of Peak Resistance for Spudcan Penetration in Sand Layer Overlying Clay

Abstract

A reliable assessment of peak resistance is the key aspect of geotechnical design for spudcan installation in sand-over-clay soil profiles. The most recent failure stress–dependent method has been validated against a large number of centrifuge tests and proved to provide satisfactory accuracy. However, additional centrifuge tests collected in this study indicated that, under certain circumstances, the recently proposed method provides significant overestimations. Further investigation was carried out through centrifuge model tests and large-deformation finite-element analyses covering a comprehensive range of soil parameters and geometries. The measured and computed results confirmed that there is a blind zone for the recently proposed method, where an immoderately higher peak resistance is predicted. The overestimation was found to be related to the overestimated distribution factor. The formula for the distribution factor was therefore modified based on the experimental and numerical results. The modified formula was shown to provide an improved prediction for peak resistance.