Large deformation FE analysis of large diameter spudcan penetration into two-layer of uniform clays

Abstract

Jack-up rigs are a popular offshore structure in medium water depth due to its mobility. Spudcan foundations are normally used to support each individual jack-up leg. When the seabed soils display a strong soil layer overlaying a soft soil layer, during foundation penetration, punch-through failure may occur. In this study, large deformation finite element (LDFE) analyses have been conducted to simulate spudcan continuous penetration into strong over soft clay soils. The numerical simulation was carried out using Remeshing and Interpolating Technique with Small Strain (RITSS) model. The LDFE/RITSS results were compared with existing data. The effects of the relative thickness of the top strong clay, the strength ratio of clay layers and the size of spudcan foundation were investigated. The soil flow mechanisms at various penetration depths were also discussed. It was found that the spudcan punch-through failure potentials increase with increasing top layer thickness. Moreover, it was also noticeable that, with a constant relative top layer thickness, the punch-through failure potential increases with increasing spudcan diameter.