Behavior of a Monopod Bucket Foundation Subjected to Combined Moment and Horizontal Loads in Silty Sand
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 147, Issue 5
Abstract
Korea has started to build wind farms in the Yellow Sea, with the seabed consisting of a thick silty sand deposit. It is therefore important to understand the behavior of potential foundations of wind turbines. This paper reports results from a series of model tests undertaken to provide insight into the behavior of a bucket foundation subjected to monotonic horizontal and moment loading in silty sand. The tests were carried out at 70g in a beam centrifuge. The silty sand materials were cored directly from a wind farm site of Yellow Sea. The considered dimensions of the model bucket foundation and loading conditions represented those for a 3 MW wind turbine. The windward and leeward side, and inside and outside, of the model bucket was instrumented with 13 pressure transducers to obtain information in regards to soil-bucket interactions. The horizontal capacity or failure load increased with decreasing loading height due to decreasing induced moment at the load reference point (LRP). A horizontal-moment failure envelope was proposed calibrating against centrifuge test data. A loading rate 20 times faster augmented the horizontal failure load by 1.5 times. This was a consequence of dilation-induced excess pore water pressure. With the drainage valve on the lid shut, the soil inside the bucket was in tension and suction prevailed. The leeward outside of the skirt experienced significantly higher pressure, and that increased with the angle of rotation. Suction inside the skirt and resistance on the leeward outside dominate the capacity of the bucket foundation.
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Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
This study was partially supported by (1) Hyundai Engineering and Construction; (2) a University of Western Australia (UWA) Research Collaboration Award (RCA); and (3) the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. 20183010025540). The fourth author is an Australian Research Council (ARC) Future Fellow and is supported by the ARC Project FT190100735. This support is gratefully acknowledged. The authors also acknowledge lab support personnel at KOCED Geotechnical Centrifuge Center at KAIST.
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 147 • Issue 5 • May 2021
Copyright
© 2021 American Society of Civil Engineers.
History
Received: Nov 19, 2019
Accepted: Jan 25, 2021
Published online: Mar 13, 2021
Published in print: May 1, 2021
Discussion open until: Aug 13, 2021
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