Rapid penetration of spudcans in sand

The growing pressure for jack-up rigs to relocate during more challenging metocean conditions for offshore wind turbine installation and maintenance has increased the risk of dynamic leg loading during the set down of the spudcan footings into the seabed. To better understand the rapid sand-spudcan interaction, this study presents experimental results of a model spudcan jacked at a range of penetration rates into dry and saturated sand at both 1g and 50g gravitational acceleration. In order to achieve a wide range of consolidation conditions, the sand was saturated using both water and a viscous pore fluid (methocel cellulose ethers) with kinematic viscosity 680 times higher than water in the 50g centrifuge tests. The results indicated up to 120% increase in spudcan penetration resistance due to the dilatancy-induced suction when the consolidation response changes from drained to undrained. This change in spudcan penetration resistance is quantified using a proposed backbone curve framework.