Large Deformation Analysis of Spudcan Penetration into Sand Overlying Normally Consolidated Clay

Abstract

SummaryInverted conical spudcan footings are the most popular foundation for jack-up platforms in the offshore industry. Before a jack-up can be located at a site, the penetration resistance during spudcan installation must be accurately predicted. This is usually performed using bearing capacity formulae from industry standards, with the use of site-specific numerical modelling not yet common place. In this paper, the Mohr-Coulomb sand model and Tresca clay model are incorporated with a large-deformation approach called the Coupled-Eulerian Lagrangian (CEL) method within the commercial package ABAQUS. It is used to simulate the installation process of spudcans in sand overlying clay. The robustness of this large-deformation analysis method is validated against published results of numerical analyses of spudcan penetration into clay. This comparison is performed to show that the numerical simulations are suited to capture the behaviour of spudcan penetration into seabeds. A series of parametric studies are then conducted to investigate the potential for punch-through during spudcan penetration in sand overlying clay. The influence of soil properties, such as the friction and dilation behaviour of sand, the normalised sand thickness and the undrained shear strength of clay, on the bearing capacity of the spudcan, the soil failure mechanism and the depth of peak penetration resistance are discussed.