Scour Effects on the Lateral Behavior of a Large-Diameter Monopile in Soft Clay: Role of Stress History
Scouring of soil around large-diameter monopile will alter the stress history, and therefore the stiffness and strength of the soil at shallow depth, with important consequence to the lateral behavior of piles. The existing study is mainly focused on small-diameter piles under scouring, where the so...
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| Format: | Article |
| Language: | English |
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MDPI AG
2019-06-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/7/6/170 |
| _version_ | 1818724839678017536 |
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| author | Ben He Yongqing Lai Lizhong Wang Yi Hong Ronghua Zhu |
| author_facet | Ben He Yongqing Lai Lizhong Wang Yi Hong Ronghua Zhu |
| author_sort | Ben He |
| collection | DOAJ |
| description | Scouring of soil around large-diameter monopile will alter the stress history, and therefore the stiffness and strength of the soil at shallow depth, with important consequence to the lateral behavior of piles. The existing study is mainly focused on small-diameter piles under scouring, where the soil around a pile is analyzed with two simplified approaches: (I) simply removing the scour layers without changing the strength and stiffness of the remaining soils, or (II) solely considering the effects of stress history on the soil strength. This study aims to investigate and quantify the scour effect on the lateral behavior of monopile, based on an advanced hypoplastic model considering the influence of stress history on both soil stiffness and strength. It is revealed that ignorance about the stress history effect (due to scouring) underestimates the extent of the soil failure wedge around the monopile, while overestimates soil stiffness and strength. As a result, a large-diameter pile (diameter <i>D</i> = 5 m) in soft clay subjected to a souring depth of 0.5 <i>D</i> has experienced reductions in ultimate soil resistance and initial stiffness of the <i>p-y</i> curves by 40% and 26%, and thus an increase of pile head deflection by 49%. Due to the inadequacy to consider the stress history effects revealed above, the existing approach (I) has led to non-conservative estimation, while the approach (II) has resulted in an over-conservative prediction. |
| first_indexed | 2024-12-17T21:32:48Z |
| format | Article |
| id | doaj.art-bfc3fe60619f4f538e38192286b90da3 |
| institution | Directory Open Access Journal |
| issn | 2077-1312 |
| language | English |
| last_indexed | 2024-12-17T21:32:48Z |
| publishDate | 2019-06-01 |
| publisher | MDPI AG |
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| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-bfc3fe60619f4f538e38192286b90da32022-12-21T21:31:50ZengMDPI AGJournal of Marine Science and Engineering2077-13122019-06-017617010.3390/jmse7060170jmse7060170Scour Effects on the Lateral Behavior of a Large-Diameter Monopile in Soft Clay: Role of Stress HistoryBen He0Yongqing Lai1Lizhong Wang2Yi Hong3Ronghua Zhu4Power China Huadong Engineering Limited Corporation, Hangzhou 310058, ChinaKey Laboratory of Offshore Geotechnics and Material of Zhejiang Province, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, ChinaKey Laboratory of Offshore Geotechnics and Material of Zhejiang Province, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, ChinaKey Laboratory of Offshore Geotechnics and Material of Zhejiang Province, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, ChinaMing Yang Smart Energy Group Co. LTD, Guangzhou 510000, ChinaScouring of soil around large-diameter monopile will alter the stress history, and therefore the stiffness and strength of the soil at shallow depth, with important consequence to the lateral behavior of piles. The existing study is mainly focused on small-diameter piles under scouring, where the soil around a pile is analyzed with two simplified approaches: (I) simply removing the scour layers without changing the strength and stiffness of the remaining soils, or (II) solely considering the effects of stress history on the soil strength. This study aims to investigate and quantify the scour effect on the lateral behavior of monopile, based on an advanced hypoplastic model considering the influence of stress history on both soil stiffness and strength. It is revealed that ignorance about the stress history effect (due to scouring) underestimates the extent of the soil failure wedge around the monopile, while overestimates soil stiffness and strength. As a result, a large-diameter pile (diameter <i>D</i> = 5 m) in soft clay subjected to a souring depth of 0.5 <i>D</i> has experienced reductions in ultimate soil resistance and initial stiffness of the <i>p-y</i> curves by 40% and 26%, and thus an increase of pile head deflection by 49%. Due to the inadequacy to consider the stress history effects revealed above, the existing approach (I) has led to non-conservative estimation, while the approach (II) has resulted in an over-conservative prediction.https://www.mdpi.com/2077-1312/7/6/170scoursoft claymonopilestress historyhypoplastic model |
| spellingShingle | Ben He Yongqing Lai Lizhong Wang Yi Hong Ronghua Zhu Scour Effects on the Lateral Behavior of a Large-Diameter Monopile in Soft Clay: Role of Stress History Journal of Marine Science and Engineering scour soft clay monopile stress history hypoplastic model |
| title | Scour Effects on the Lateral Behavior of a Large-Diameter Monopile in Soft Clay: Role of Stress History |
| title_full | Scour Effects on the Lateral Behavior of a Large-Diameter Monopile in Soft Clay: Role of Stress History |
| title_fullStr | Scour Effects on the Lateral Behavior of a Large-Diameter Monopile in Soft Clay: Role of Stress History |
| title_full_unstemmed | Scour Effects on the Lateral Behavior of a Large-Diameter Monopile in Soft Clay: Role of Stress History |
| title_short | Scour Effects on the Lateral Behavior of a Large-Diameter Monopile in Soft Clay: Role of Stress History |
| title_sort | scour effects on the lateral behavior of a large diameter monopile in soft clay role of stress history |
| topic | scour soft clay monopile stress history hypoplastic model |
| url | https://www.mdpi.com/2077-1312/7/6/170 |
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