Numerical Investigation of Bearing Capacity of Spudcan Foundations in Clay Overlying Sand under Combined Loading
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 146, Issue 11
Abstract
The evaluation of the foundation capacity under combined vertical, horizontal, and moment loading is an essential element of the site-specific assessment that ensures mobile jackup rigs are safe to operate in large storms. However, the prediction approaches available in design guidelines are restricted to jackup spudcan foundations on homogeneous sand or clay. The aim of this study is to examine the ultimate bearing capacity for spudcan foundations in clay overlying sand under combined vertical, horizontal, and moment loading. This study investigates the effects of the underlying sand layer on the three uniaxial capacities and on the combined failure envelope, with results derived from three-dimensional finite-element analyses. The findings show that, as the spudcan nears the underlying sand layer, the absolute horizontal capacity remains relatively constant while the vertical and moment capacities increase at around the same rate. A closed-form expression for the failure envelope is proposed. It allows for easy assessment of the bearing capacity of a spudcan that remains in clay overlying sand. This new expression can be used during site-specific assessments of jackup platforms.
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Data Availability Statement
All data, models, and code generated or used during the study appear in the published article.
Acknowledgments
This work forms part of the activities of the Centre for Offshore Foundation Systems (COFS) at the University of Western Australia and the Geomechanics Group, Department of Infrastructure Engineering, University of Melbourne. The work was supported by the Lloyd’s Register Foundation. Lloyd’s Register Foundation invests in science, engineering and technology for public benefit worldwide. The first author acknowledges the financial support of an Australian Government Research Training Program (RTP) Scholarship and a COFS top-up Scholarship.
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 146 • Issue 11 • November 2020
Copyright
© 2020 American Society of Civil Engineers.
History
Received: Oct 3, 2019
Accepted: Jun 2, 2020
Published online: Aug 18, 2020
Published in print: Nov 1, 2020
Discussion open until: Jan 18, 2021
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