Centrifuge modelling of a novel skirted spudcan for penetration in layered soil

Conleth O’Loughlin, Christophe Gaudin, Matthew Quah, Michael Perry

Research output: Chapter in Book/Conference paperConference paper

Abstract

This paper reports on a series of centrifuge tests to investigate the feasibility and performance of a novel spudcan foundation design featuring a peripheral skirt with side openings. The ‘skirted spudcan’, designed and patented by Keppel, is particularly beneficial in layered seabeds with a clay layer overlaying sand. The purpose of the side openings is to enable the clay trapped within the spudcan skirt to flow outside the skirt, so the skirt can penetrate into the sand and develop the required fixities against combined vertical, horizontal and moment loading. The centrifuge tests considered different skirted spudcan designs, each 10 m in diameter, but with a skirt length of either 1.38 m or 2.76 m, two spudcan invert shapes and various configurations of side and top openings. The model skirted spudcans were penetrated into a soil sample featuring a clay layer 6 m thick (in prototype scale) with an average undrained shear strength of about 15 kPa, overlaying a silica sand layer with a relative density of about 40%. The skirted spudcan embedded the sand layer by more than the skirt height at the maximum penetration resistance of about 4 MPa. However, examination of the model after retrieval demonstrated that a clay layer remained inside the skirt, despite the openings on the side of the skirt. The comparison between the eight tests demonstrated that the thickness of the clay plug reduces with the strength of the soil and with the size of the openings. Large horizontal openings located at the top of the skirt were shown to generate the lowest plug thickness and the largest skirt embedment into the sand. Somehow surprisingly, the addition of top openings (in addition of side openings) does not have beneficial effects. In general, the results demonstrated the efficiency of the skirted spudcan with side openings concept. Although the clay plug inside the skirt compartment was only partially expelled, significant skirt embedment into the sand layer (and hence high fixities) could be achieved. The high compressive stresses within the residual clay plug should limit concerns about potential rocking of the spudcan when clay remains trapped within the skirt compartment.

Original languageEnglish
Title of host publicationProceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE
PublisherThe American Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791858769
DOIs
Publication statusPublished - 1 Jan 2019
EventASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2019 - Glasgow, United Kingdom
Duration: 9 Jun 201914 Jun 2019

Publication series

NameProceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE
Volume1

Conference

ConferenceASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2019
CountryUnited Kingdom
CityGlasgow
Period9/06/1914/06/19

Fingerprint

Centrifuges
Clay
Soils
Sand
Silica sand
Compressive stress
Shear strength

Cite this

O’Loughlin, C., Gaudin, C., Quah, M., & Perry, M. (2019). Centrifuge modelling of a novel skirted spudcan for penetration in layered soil. In Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE (Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE; Vol. 1). The American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/OMAE2019-96541
O’Loughlin, Conleth ; Gaudin, Christophe ; Quah, Matthew ; Perry, Michael. / Centrifuge modelling of a novel skirted spudcan for penetration in layered soil. Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE. The American Society of Mechanical Engineers (ASME), 2019. (Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE).
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O’Loughlin, C, Gaudin, C, Quah, M & Perry, M 2019, Centrifuge modelling of a novel skirted spudcan for penetration in layered soil. in Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE. Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, vol. 1, The American Society of Mechanical Engineers (ASME), ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2019, Glasgow, United Kingdom, 9/06/19. https://doi.org/10.1115/OMAE2019-96541

Centrifuge modelling of a novel skirted spudcan for penetration in layered soil. / O’Loughlin, Conleth; Gaudin, Christophe; Quah, Matthew; Perry, Michael.

Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE. The American Society of Mechanical Engineers (ASME), 2019. (Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE; Vol. 1).

Research output: Chapter in Book/Conference paperConference paper

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O’Loughlin C, Gaudin C, Quah M, Perry M. Centrifuge modelling of a novel skirted spudcan for penetration in layered soil. In Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE. The American Society of Mechanical Engineers (ASME). 2019. (Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE). https://doi.org/10.1115/OMAE2019-96541