砂土中海上风机四桩导管架基础水平受荷分析方法

Analysis approach of piled jacket foundation in sand for offshore wind turbines subjected to lateral loads

针对海上风机四桩导管架基础受荷特性与常规水平荷载作用位置较低的群桩基础不同的问题,提出适用于海上风机导管架基础的水平受荷分析方法.通过分析导管架基础离心模型试验的结果,发现海上风机导管架基础各基桩在承受水平荷载的同时也受到较大的轴向荷载作用,这会改变桩周土的有效应力和水平抗力.基此提出同时考虑群桩效应和基桩桩身轴力影响的p乘子,从而获得导管架基础基桩的p-y曲线.采用SACS数值分析软件获得导管架基础沿边长加载和沿对角线加载时基础的变形和内力.结果表明,根据该文提出的导管架基础水平受荷分析方法得到的计算结果与离心模型试验吻合较好,适用于砂土中海上风机四桩导管架基础的工程设计.

A new approach to analyze the lateral behavior of jacket foundation for offshore wind turbines was proposed to solve the problem that the response of the piles of the jacket foundation for offshore wind turbines is different from other conventional types of pile foundations whose loading points is relatively low.Centrifuge model tests were conducted on a tetrapod jacket foundation in sand subjected to monotonic horizontal loads.Results showed that the axial force of the pile shaft was the main reason for the change of effective stress and horizontal subgrade reaction of the soil around the piles.Then the modified pmultipliers concerning pile group effect and the axial force of the pile shaft were proposed as well as the corresponding hyperbolic-type p-y curves for the analysis of the complicated pile-soil interaction of the jacket foundation.The deformation and internal force of the piles of the jacket foundation loading along side or diagonal direction in saturated sand were analyzed by SACS software with the new analysis approach.Results show that the proposed analysis approaches can be used to analyze the lateral behavior of jacket foundation for offshore wind turbines,which was proved by the comparison with the result of centrifuge tests.