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 language | English |
|---|---|
| Title of host publication | Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE |
| Publisher | The American Society of Mechanical Engineers (ASME) |
| ISBN (Electronic) | 9780791858769 |
| DOIs | |
| Publication status | Published - 1 Jan 2019 |
| Event | ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2019 - Glasgow, United Kingdom Duration: 9 Jun 2019 → 14 Jun 2019 |
Publication series
| Name | Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE |
|---|---|
| Volume | 1 |
Conference
| Conference | ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2019 |
|---|---|
| Country | United Kingdom |
| City | Glasgow |
| Period | 9/06/19 → 14/06/19 |
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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 paper › Conference paper
TY - GEN
T1 - Centrifuge modelling of a novel skirted spudcan for penetration in layered soil
AU - O’Loughlin, Conleth
AU - Gaudin, Christophe
AU - Quah, Matthew
AU - Perry, Michael
PY - 2019/1/1
Y1 - 2019/1/1
N2 - 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.
AB - 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.
KW - Centrifuge
KW - Layered soil
KW - Skirts
KW - Spudcan
UR - http://www.scopus.com/inward/record.url?scp=85075817495&partnerID=8YFLogxK
U2 - 10.1115/OMAE2019-96541
DO - 10.1115/OMAE2019-96541
M3 - Conference paper
T3 - Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE
BT - Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE
PB - The American Society of Mechanical Engineers (ASME)
ER -