ANALYSIS OF CYCLIC WEAKENING CHARACTERISTICS OF COHESIVE SOIL AND CUMULATIVE DISPLACEMENT OF SINGLE PILE FOUNDATION OF OFFSHORE WIND TURBINES

Qiu Zining; Xu Chengshun; Yang Yurong; Liu Kaiyuan

doi:10.19912/j.0254-0096.tynxb.2024-0156

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Acta Energiae Solaris Sinica ›› 2025, Vol. 46 ›› Issue (5) : 619-628. DOI: 10.19912/j.0254-0096.tynxb.2024-0156

ANALYSIS OF CYCLIC WEAKENING CHARACTERISTICS OF COHESIVE SOIL AND CUMULATIVE DISPLACEMENT OF SINGLE PILE FOUNDATION OF OFFSHORE WIND TURBINES

Qiu Zining¹, Xu Chengshun¹, Yang Yurong¹, Liu Kaiyuan²

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Abstract

Offshore wind turbines are subjected to cyclic loads such as wind and waves over long periods during operation. The soil surrouding the piles is prone to stiffness degredation under the cyclic loads, leading to an increase in the cumulative displacement of the pile foundation, which endangers the normal operation of the wind turbine system. By carrying out indoor vertical-torsional two-way coupled shear tests on saturated clay, a clay stiffness softening model considering the continuous rotation of the principal stress axis was proposed and embedded into the Flac3D three-dimensional pile-soil interaction numerical model to analyze three types of silts：silty clay and clay. Cyclic cumulative deformation law of large-diameter pile foundations for offshore wind turbines in the Mediterranean Sea. The research results show that the mud surface displacement accumulation rate of the three types of sites first increases and then stablizes as the number of cycles increases; the lateral cumulative displacement of the pile foundation is closely related to the plasticity index of the site soil. The greater the plasticity index, the secant line The modulus decays slowly, and the cumulative displacement of the pile body develops slowly.

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offshore wind turbines / pile foundations / deformation / clay softening model / continuous rotation of the principal stress axis

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Qiu Zining, Xu Chengshun, Yang Yurong, Liu Kaiyuan. ANALYSIS OF CYCLIC WEAKENING CHARACTERISTICS OF COHESIVE SOIL AND CUMULATIVE DISPLACEMENT OF SINGLE PILE FOUNDATION OF OFFSHORE WIND TURBINES[J]. Acta Energiae Solaris Sinica. 2025, 46(5): 619-628 https://doi.org/10.19912/j.0254-0096.tynxb.2024-0156

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