环境荷载作用下复合筒型基础局部冲刷及耦合动力特性研究

Composite bucket foundation which is different from traditional bucket foundation is a new kind of foundation for offshore wind turbine. Because of the complex hydrodynamic processes of wave and current action on the large-scale arc transition, it is inaccurate to estimate wave force and scouring characteristics by empirical formulas. And the effect of soil scour is important to vibration of the system of wind tower based on composite bucket foundation which is shallow, especially to vibration of ground. The present proposal aims at the study of dynamic characteristics of composite bucket foundation subjected to wind, wave and current load, it takes the new type composite bucket foundation as the investigating object. Characteristics of linear and nonlinear wave force will be definite through theoretical derivation and physical model test, which will lay a foundation for the study of dynamic responses. Wave and combined current scour characteristics will be definite through physical model test. Based on ABAQUS software, dynamics integrated model is to be established by secondary development. The realization of nonlinear integrated interaction of wind tower, composite bucket foundation and scoured soil in the numerical model is regarded as the principle technology. The dynamic responses of the system are analyzed, and the vibration characteristics of wind structure and soil are definite. The study will lay a theoretical foundation for wind structure design of composite bucket foundation.

区别于传统的筒型基础，复合筒型基础是一种新型的海上风电基础。波浪、海流作用于其大尺寸的反弧段体型时水动力过程复杂，波浪荷载特性及地基冲刷特性难以由经验方法准确估算。同时，作为一种浅基础，环境荷载引起的地基冲刷对复合筒型基础结构体系动力响应尤其是地基振动的影响应充分考虑。本研究以风、波浪、海流作用下复合筒型基础动力响应分析为出发点，以复合筒型基础这种新型的风电基础为研究对象，通过理论推导、物理模型试验，明确复合筒型基础线性、非线性波浪荷载特性，为风机结构动力响应的研究奠定基础。通过物理模型试验，获取海流作用下及波流共同作用下复合筒型基础地基局部冲刷特性。以ABAQUS软件为基础，结合二次开发，构建环境荷载作用下结构动力一体化模型，以实现风机塔架、复合筒型基础、被冲刷地基的非线性耦合作用为关键技术，分析结构体系的动力响应，明确风机结构与地基的振动特性，为复合筒型基础风机的结构设计提供理论基础。

海上风电基础的局部冲刷与动力特性对风机结构体系的安全有重要影响。本课题以复合筒型基础这种新型的风电基础为研究对象，将理论分析、物理模型试验、数值模拟相结合，分析了复合筒型基础的波浪荷载特点，考察了波流共同作用下复合筒型基础的冲刷特性，揭示了考虑冲刷效应的风电结构体系动力响应规律。完成了本课题的预期研究目标，研究成果有助于促进复合筒型基础在我国沿海风电开发中的应用，并为工程设计提供指导。本课题的主要研究进展包括：基于绕射理论，提出了复合筒型基础波浪荷载的解析解，通过物理模型试验探讨了复合筒型基础波浪荷载随绕射参数、无量纲波高等的变化规律，明确了非线性波浪作用下复合筒型基础表面波浪压力的分布特征；开展了系列物理模型试验，考察了波流共同作用下复合筒型基础周围地基的冲刷过程与冲刷形态，深入分析了KC数等典型无量纲参数对复合筒型基础地基冲刷深度的影响；构建了考虑冲刷效应的风电结构-复合筒型基础-地基耦合动力分析模型，基于冲刷试验结果，在数值模型中实现了冲刷地基的准确建立，明确了考虑冲刷效应后风电结构体系自振频率的降低幅度与风电结构体系振动的增大幅度。本课题研究共发表学术论文4篇，其中：国际SCI期刊论文2篇，EI收录期刊论文1篇，申请发明专利2项（审查中），获批实用新型专利1项。另有3篇SCI期刊论文、1篇EI期刊论文等多篇论文整理待投稿。参加国内外学术会议3次，培养研究生3名。