单桩基础型近海风机系统自振频率实用计算方法  

NUMERICAL METHOD FOR CALCULATING SYSTEM FUNDAMENTAL FREQUENCIES OF OFFSHORE WIND TURBINES WITH MONOPILE FOUNDATIONS

作　　者：杨春宝 王睿[1,2] 张建民[1,2] YANG Chun-bao;WANG Rui;ZHANG Jian-min(Institute of Geotechnical Engineering,Tsinghua University,Beijing 100084,China;State Key Laboratory for Hydroscience and Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学土木水利学院岩土工程研究所,北京100084 [2]清华大学水沙科学与水利水电工程国家重点实验室,北京100084

出　　处：《工程力学》2018年第4期219-225,共7页Engineering Mechanics

基　　金：国家重点研发计划项目(2016YFC1402800);国家自然科学基金面上项目(51678346)

摘　　要："软-刚"(soft-stiff)设计的系统频率限制是海上风电结构与基础设计的关键性难点之一。该文基于有阻尼系统运动方程,考虑桩土相互作用和风机塔筒的变截面特性,建立了单桩基础型近海风机系统自振频率求解数值计算方法。利用实际工程进行了方法应用和有效性验证。频率偏移因素分析表明,地基土模量非均一对系统自振频率影响较小;系统自振频率对地基弹性模量、海床高度变化、桩径的敏感性较强,对地基土阻尼的敏感性较弱。同时,该文方法可以精确分析海上风机在服役期间的系统自振频率的偏移,为近海风机的结构和基础设计提出有效评估,并建议减小频率偏移的工程措施。The restriction of system frequencies due to the“soft-stiff”design criterion is one of the key points for structure and foundation design of offshore wind turbines.This study proposed a practical numerical method for analyzing system fundamental frequencies of offshore wind turbines with monopile foundations.The method was based on the kinematic equation of the damped system,taking into account the pile-soil interaction and the variation of cross-sectional geometry of the wind turbine tower.The method was validated against finite element solutions of an actual wind turbine.Parametric studies were conducted using the proposed method,and showed that the soil elastic modulus,the seabed height,and the pile diameter were major factors affecting the system’s fundamental frequencies.However,the fundamental frequencies showed little sensitivity to soil damping and non-uniform distributing of the soil modulus.Furthermore,the method can be used to analyze the system frequency deviation during the operating period,allowing for an effective evaluation of the foundation design,and suggesting engineering measures.

关 键 词：近海风机 单桩基础 自振频率 桩土相互作用 数值计算 

分 类 号：TU473[建筑科学—结构工程]