Set Up and Resulting Punch-Through Risk of Jack-Up Spudcans during Installation

Abstract

This paper addresses a three-dimensional consolidation problem through experimentation in a geotechnical centrifuge. During a discontinuous footing installation, which is typical for mobile offshore drilling rigs, periods of consolidation are encountered as part of the installation process. While this is acknowledged to expose the platforms to potentially severe consequences due to the risk of rapid uncontrolled leg penetration, to date no method has been established to predict this risk and thus enable its mitigation. The findings of this experimental study show that while the peak penetration resistance postconsolidation is mainly influenced by the duration of the consolidation period, as is expected, the load magnitude held during consolidation also significantly influences the severity of capacity reduction postpeak. The consolidation and postconsolidation behavior is discussed for various penetration depths relevant to typical jack-up installations in the field. The key findings of this study are summarized in nondimensional graphs to facilitate application in practice.