EXPERIMENTAL STUDY ON LATERAL CYCLIC LOADING OF COMPOSITE MONOPILE OF OFFSHORE WIND TURBINE

Gao Luchao; Zhang Jisheng; Ma Qiang; Yao Zhongyuan; Lu Jieyi

doi:10.19912/j.0254-0096.tynxb.2024-0938

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Acta Energiae Solaris Sinica ›› 2025, Vol. 46 ›› Issue (10) : 581-588. DOI: 10.19912/j.0254-0096.tynxb.2024-0938

EXPERIMENTAL STUDY ON LATERAL CYCLIC LOADING OF COMPOSITE MONOPILE OF OFFSHORE WIND TURBINE

Gao Luchao^1,2, Zhang Jisheng¹, Ma Qiang², Yao Zhongyuan², Lu Jieyi²

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Abstract

The monopile foundation of offshore wind turbines is subjected to cyclic loads such as wind, waves and currents for a long time, resulting in excessive cumulative deformation of the pile foundation. The monopile foundation is strengthened in the shallow layer with cement-soil to form a composite pile, so as to achieve the purpose of reducing the cyclic cumulative deformation. To research the cyclic behavior of monopile in cement-improved clay, a series of model tests on the lateral bearing capacity of monopile in cement-improved clay under lateral cyclic loading were carried out. The variation characteristics of monopile bearing capacity, pile bending moment, accumulated deformation, cyclic unloading stiffness and cyclic bending moment before and after reinforcement were analyzed. The test results show that the initial stiffness and ultimate bearing capacity of single pile are significantly strengthened by cement-improved soil, and the maximum bending moment of pile is reduced, which improves the overall load performance of pile. Regardless of the reinforced or the unreinforced pile, with the increase of cycle times, the cumulative displacement of pile top cycle increases rapidly initially, and then gradually stabilizes. Cement-soil reinforcement can effectively improve the horizontal stiffness of pile foundation, but it cannot change the law of attenuation with the increase of circulating load amplitude. There is a significant accumulation of the bending moment of the unreinforced pile, but the cumulative effect of the decrease of the reinforced pile can be ignored.

Key words

offshore wind turbines / monopile foundation / cement-improved clay / model test / cyclic lateral loading

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Gao Luchao, Zhang Jisheng, Ma Qiang, Yao Zhongyuan, Lu Jieyi. EXPERIMENTAL STUDY ON LATERAL CYCLIC LOADING OF COMPOSITE MONOPILE OF OFFSHORE WIND TURBINE[J]. Acta Energiae Solaris Sinica. 2025, 46(10): 581-588 https://doi.org/10.19912/j.0254-0096.tynxb.2024-0938

References

[1] 赖踊卿, 孙毅龙, 李炜, 等. 长期循环荷载作用对大直径单桩水平承载特性的影响分析[J]. 太阳能学报, 2024, 45(3): 116-121.
LAI Y Q, SUN Y L, LI W, et al.Effect analysis of long-term cyclic loading on lateral bearing characteristics for large diameter monopile[J]. Acta energiae solaris sinica, 2024, 45(3): 116-121.
[2] 张小玲, 周锐, 许成顺. 海上风电基础修正p-y曲线模型研究[J]. 太阳能学报, 2023, 44(12): 290-297.
ZHANG X L, ZHOU R, XU C S.Study on corrected p-y curve model of pile foundation of offshore wind turbines[J]. Acta energiae solaris sinica, 2023, 44(12): 290-297.
[3] 柳涛, 秦梦飞, 施伟. 基于离心机实验的海上风力机大直径单桩桩土作用研究[J]. 太阳能学报, 2024, 45(8): 537-545.
LIU T, QIN M F, SHI W.Soil-structure interaction analysis of large-diameter monopile of offshore wind turbine based on centrifugal model test[J]. Acta energiae solaris sinica, 2024, 45(8): 537-545.
[4] 刘松玉, 周建, 章定文, 等. 地基处理技术进展[J]. 土木工程学报, 2020, 53(4): 93-110.
LIU S Y, ZHOU J, ZHANG D W, et al.State of the art of the ground improvement technology in China[J]. China civil engineering journal, 2020, 53(4): 93-110.
[5] HONG Y, HE B, WANG L Z, et al.Cyclic lateral response and failure mechanisms of semi-rigid pile in soft clay: centrifuge tests and numerical modelling[J]. Canadian geotechnical journal, 2017, 54(6): 806-824.
[6] LIU C Y, SOLTANI H, MURALEETHARAN K K, et al.Cyclic and seismic response of single piles in improved and unimproved soft clays[J]. Acta geotechnica, 2016, 11(6): 1431-1444.
[7] TAGHAVI A, MURALEETHARAN K K, MILLER G A, et al.Centrifuge modeling of laterally loaded pile groups in improved soft clay[J]. Journal of geotechnical and geoenvironmental engineering, 2016, 142(4): 04015099.
[8] TARIQ K A, MAKI T.Use of cement-treated sand to enhance the lateral capacity of pile foundations[J]. International journal of physical modelling in geotechnics, 2019, 19(5): 221-233.
[9] DAI G L, OUYANG H R, GAO L C, et al.Monotonic and cyclic lateral behavior of semi-rigid pile in cement-improved clay: centrifuge tests and numerical investigation[J]. Acta geotechnica, 2023, 18(8): 4157-4181.
[10] 王安辉, 章定文, 刘松玉, 等. 水平荷载下劲性复合管桩的承载特性研究[J]. 中国矿业大学学报, 2018, 47(4): 853-861.
WANG A H, ZHANG D W, LIU S Y, et al.Bearing capacity behavior of strength composite pipe pile subjected to lateral loading[J]. Journal of China University of Mining & Technology, 2018, 47(4): 853-861.
[11] 何杰, 郭端伟, 宋德新, 等. 循环荷载下楔形劲芯水泥土复合桩工作特性试验研究[J]. 岩土力学, 2023, 44(5): 1353-1362, 1374.
HE J, GUO D W, SONG D X, et al.Dynamic response and characteristics of tapered rigid core composite cement-soil piles under cyclic loading[J]. Rock and soil mechanics, 2023, 44(5): 1353-1362, 1374.
[12] 韦古强, 何子睿, 刘广东, 等. 水泥土复合单桩水平承载性能模型试验研究[J]. 太阳能学报, 2022, 43(12): 353-359.
WEI G Q, HE Z R, LIU G D, et al.Experimental study on lateral bearing behavior of cement composite monopiles[J]. Acta energiae solaris sinica, 2022, 43(12): 353-359.
[13] 林军, 蔡国军, 邹海峰, 等. 基于随机场理论的江苏海相黏土空间变异性评价研究[J]. 岩土工程学报, 2015, 37(7): 1278-1287.
LIN J, CAI G J, ZOU H F, et al.Assessment of spatial variability of Jiangsu marine clay based on random field theory[J]. Chinese journal of geotechnical engineering, 2015, 37(7): 1278-1287.
[14] LEBLANC C, HOULSBY G T, BYRNE B W.Response of stiff piles in sand to long-term cyclic lateral loading[J]. Géotechnique, 2010, 60(2): 79-90.
[15] BROMS B B.Lateral resistance of piles in cohesive soils[J]. Journal of the soil mechanics and foundations division, 1964, 90(2): 27-63.
[16] 王晓伟, 叶爱君, 商宇. 砂土地基小直径单桩的浅层土p-y曲线[J]. 岩土工程学报, 2018, 40(9): 1736-1745.
WANG X W, YE A J, SHANG Y.Shallow-layer p-y curves for single micropile in sands[J]. Chinese journal of geotechnical engineering, 2018, 40(9): 1736-1745.
[17] KUMAR N D, RAO S N.Lateral load: deflection response of an embedded caisson in marine clay[J]. Marine georesources & geotechnology, 2012, 30(1): 1-31.