Effects of Local Scouring on Load-Bearing Behaviors of Monopile–Friction Wheel Hybrid Foundations on Sandy Deposit Soil under Lateral Loading
Publication: International Journal of Geomechanics
Volume 24, Issue 6
Abstract
This paper focuses on the horizontal bearing behaviors of an innovative type of foundation, the monopile–friction wheel hybrid foundation, for offshore wind turbines (OWTs). First, the scouring morphology of a monopile–friction wheel composite foundation under unidirectional flow is obtained by means of laboratory flume model tests. Then, the effects of key scouring parameters and the height of the loading point are further investigated through numerical simulations in terms of deformations, soil resistance distributions, and bearing ratios. The results indicate that for composite foundations, the effects of scouring parameters and the height of the loading point on the lateral bearing behaviors are not negligible, with the scouring depth having the most significant effect, followed by the scouring angle, and finally the scouring extent. Between them, the friction wheel contributes more than 40% to the bearing capacity while about 50% is borne by the pile side. In addition, the prediction formulas for the bearing ratios are obtained taking into account the scouring pits. The results provide valuable insights into understanding the load-bearing behaviors of composite foundations and their engineering applications.
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Data Availability Statement
All data and models generated or used in this study are available from the corresponding author by request.
Acknowledgments
This research is supported by the National Natural Science Foundation of China (Grant No. 52178329), the science and technology Program of Hunan Provincial Departent of Transportation (Grant No. 201414).
Author contributions: Xinjun Zou: methodology, conceptualization, writing—review and editing, funding acquisition, supervision; Shun Chen: methodology, derivation, visualization, formal analysis, writing—original draft preparation; Xinyao Tu: methodology, formal analysis and writing—review; Zijiang Yang: formal analysis, writing—review and editing.
Notation
The following symbols are used in this paper:
- Dp
- pile diameter;
- Dw
- friction wheel diameter;
- Dwh
- friction wheel diameter;
- Dwhe
- effective friction wheel diameter;
- d
- maximal scouring depth;
- Ep
- elastic modulus of pile;
- e
- loading eccentricity;
- f
- scour angle;
- H
- lateral load;
- Lp
- pile length;
- l
- maximal scouring length;
- Pp
- lateral earth pressure along the pile;
- Pv
- passive earth pressure under the wheel;
- R
- pile radius;
- Sd
- scour depth;
- Sw
- scour extent;
- Swh
- friction wheel square ;
- Swhe
- effective friction wheel square;
- s
- deformation of the friction wheel;
- tw
- friction wheel thickness;
- x
- distance from pile center along 1 → 2;
- y
- distance from pile center along 3 → 4;
- z
- pile buried depth;
- φ
- internal friction angle of the sand; and
- ν
- Poisson’s ratio.
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Received: May 29, 2023
Accepted: Nov 28, 2023
Published online: Mar 19, 2024
Published in print: Jun 1, 2024
Discussion open until: Aug 19, 2024
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