波浪荷载及土体特性对风电单桩基础水平变形影响规律

大直径单桩基础是海上风电应用广泛的一种基础形式,严格控制桩基泥面处的位移是保证基础稳定和风机安全运营的关键因素.通过数值方法建立了单桩—海床的三维模型,将可以描述海洋砂土超固结性和结构性的弹塑性本构模型通过UMAT子程序嵌入有限元软件ABAQUS中,桩基承受的波浪荷载通过Morison方程进行计算模拟.针对无波浪荷载、仅作用于海床的波浪荷载、同时作用于桩基和海床的波浪荷载三种情况,分析了海床土的动力响应以及桩基的水平位移之间的差异,探讨了海床土体参数对桩基水平变形的影响.研究结果表明海床土体液化会导致桩基水平变形增加,海床土渗透性、超固结性、结构性对桩基水平位移影响显著,研究成果可为海上风电单桩基础的设计与运维提供参考.

Influence of cyclic wave load and soil characteristics on horizontal deformation of wind power monopile foundation

Large diameter monopile foundation is a foundation form widely used in offshore wind power. Strictly controlling the displacement of monopile foundation is the key factor to ensure the stability of foundation and the safe operation of wind turbine. A three-dimensional monopile-seabed numerical model is established. The elastic-plastic constitutive model, which can describe the over-consolidation and structure of marine sand, is embedded into the finite element software ABAQUS by UMAT subroutine. The wave load on monopile foundation is calculated by Morison equation. Three cases, including no wave load, wave load acting only on the seabed, wave load acting on both monopile foundation and seabed, are adopted to analyze the dynamic response of seabed soil and horizontal displacement of monopile foundation. The influence of seabed soil parameters on seabed liquefaction and horizontal displacement of monopile is discussed. Numerical results show that the liquefaction of seabed soil will lead to a significant increase in the horizontal deformation of monopile foundation. The soil permeability, over-consolidation, and structure of seabed soil have significant impacts on the liquefaction of seabed soil and the horizontal displacement of monopile foundation under cyclic wave load. The research results can provide reference for the design, operation and maintenance of offshore wind power monopile foundation.