【摘要】 单桩支承海上风机安装于地震活跃区域时，可能面临地震和冲刷带来的潜在风险。本文建立了考虑不同冲刷条件且安装于可液化海床的单桩支承海上风机数值模型，采用CycLiq本构模型描述可液化土体的动力特性，基于离心模型振动台试验证明了数值模型的有效性。开展了一系列考虑不同冲刷条件和输入地震动的海上风电单桩-海床-结构地震响应分析，揭示了冲刷对单桩支承海上风机整体结构动力响应与残余变形的影响机理。分析表明冲刷主要通过两个因素影响地震响应：一是改变结构一阶自振频率与地震动卓越频率的相对差异，影响结构共振效应，从而影响结构动力响应与残余变形；二是削弱桩-土相互作用，从而降低结构动力响应，加剧残余变形。受长周期地震动作用时，冲刷深度增大可能导致结构共振效应加剧，引发显著的结构动力响应和残余变形；受高频地震动作用时，冲刷深度增大可能导致结构共振效应衰减，进而削弱结构动力响应，但结构残余变形受上述两个因素联合影响而非单调变化。更多还原

【Abstract】 The monopile-supported offshore wind turbines(OWTs) installed in seismically active regions pose potential risks from seismic ground motions and post-scour conditions. In this study,numerical models with varying post-scour conditions are developed to simulate the monopile-supported OWT installed in liquefiable seabed,in which the CycLiq constitutive model is used to capture the dynamic behaviors of seabed soils. The numerical modeling approach is successfully validated using centrifuge shaking table tests. Seismic response analyses of structures subjected to seismic loading are conducted. Specifically,the influence mechanisms of post-scour conditions on seismic responses are uncovered. The analysis indicates that scour affects seismic responses primarily through two factors:i) altering the relative difference between the first-order natural frequency of structures and the predominant frequency of ground motions to change the resonance effect, thereby affecting both dynamic responses and residual deformations;ii) weakening the soil-pile interaction,which reduces dynamic responses but aggravates residual deformations. For long-period ground motions,increased scour depth may enhance the resonance effect,leading to greater seismic responses. In contrast,for high-frequency ground motions,increased scour depth may reduce dynamic responses,while the trend of residual deformation is non-monotonical due to the influences of the two mentioned-above factors.更多还原