摘要
风致灾害对陆上风电机组运行已造成重大威胁,从风电机组地基基础结构的力学条件出发,根据风机系统各组件的强度差异性,结合塔筒-基础-地基界面特性和边界条件,建立了基础-土体结构粘性阻尼二自由度系统受迫振动的振动模型、振动方程、上弯下剪振型特征及频率型特征方程式,获得了风机基础-土体的多个固有频率解析式,还得到了基础顶部风致剪力和风致弯矩的解析式。依据风振响应地基土体的加速蠕动变形特征,运用土体的Mohr-Coulomb塑性屈服条件,构建了能反映土体加速蠕变的非线性西原蠕变模型、非线性粘滞系数和粘弹性及粘塑性速率控制方程,提出了风振响应土体加速蠕变破坏的时间,还进一步得到了风振响应土体蠕变的运动方程和基础底部最大附加应力。结合算例验证:考虑风振作用和地基土体蠕变效应风机结构的垂直位移变化率最为显著,且基础-土体结构还呈现出弯剪、压剪、剪切破坏形态,因此必须对风电机组基础-土体结构界面、持力层浅表层土体、基础顶部主风向区域等范围进行及时加固,这为风电机组地基基础加固设计的理论研究和实践提供有益参考。
Wind disaster has posed a major threat to the operation of wind power units on land. Starting from the mechanical conditions of the foundation structure of wind power units, according to the strength difference of each component of the fan system, combined with the characteristics of the tower barrel-foundation-foundation interface, The vibration model, vibration equation, characteristics of the upper bending shear type and the frequency characteristic equation of the forced vibration of the foundation-soil structure viscous damping two-degree of freedom system are established, and various natural frequencies of the fan base-soil body are obtained. The analytical formula of wind shear force and wind bending moment at the top of the foundation is obtained. Based on the characteristics of the accelerated peristaltic deformation of ground soil in response to wind vibration, and using the Mohr-Coulomb plastic yield condition of soil, a nonlinear West Plain creep model,nonlinear viscosity coefficient, and viscoelastic and viscoplastic rate control equations that can reflect the accelerated creep of soil are constructed. The time of wind vibration response to accelerated creep failure of soil is presented, and the motion equation of wind vibration response to soil creep and the maximum additional stress at the bottom of the foundation are further obtained. The results show that the effect of soil creep effect on the vertical displacement of the wind vibration response is significantly increased and the structure of the soil mainly shows bending, shear and shear failure. Therefore, it is necessary to reinforce the basic structure interface of the wind turbine unit, the shallow surface soil body of the holding layer, and the main wind direction area at the top of the foundation. This provides a useful reference for the design of the foundation reinforcement of the wind turbine unit.
作者
王军
曾宪桃
刘杰
梁桥
WANG Jun;ZENG Xiantao;LIU Jie;LIANG Qiao(Department of Building Engineering,Hunan Institute of Engineering,Xiangtan 411104,China;School of Resource & Environment and Safety Engineering,Hunan University of Science and Technology,Xiangtan 411201,China)
出处
《自然灾害学报》
CSCD
北大核心
2019年第3期141-149,共9页
Journal of Natural Disasters
基金
国家自然科学基金项目(51804110)
湖南省自然科学基金项目(2019JJ40056)
湖南省教育厅资助科研项目(18A345,18B391,12C0126)
湖南省应用特色学科建设项目~~
关键词
风电机组
风荷载
基础-土结构的力学条件
振动方程
蠕变特性
wind turbine
wind load
mechanical condition of foundation-soil structure
vibration equation
creep properties
