局部冲刷对风机支撑系统承载性能的影响

Influence of local scour on bearing performance of wind turbine supporting system

海上风力发电作为一种绿色能源越来越受到重视,单桩基础局部冲刷的研究受到广泛关注。建立了不同冲刷深度的海上风机系统模型,对各模型进行静力、动力分析。结果与前人冲刷模型试验吻合,随着桩基冲刷深度的增大,支撑系统的最大水平位移、最大水平应力和最大弯矩值逐渐增加。冲刷深度为两倍桩径时,最大水平位移、应力及弯矩分别比无冲刷条件下增加了3.61%、12.7%、10.3%。风机系统的自振频率随冲刷深度的增加而降低,高阶频率更易受影响。桩基冲刷对风机系统的动力特性有显著影响,塔顶水平位移时程曲线随冲刷深度不断上移。海上风机设计时必须考虑冲刷对支撑系统承载性能的影响。

As one type of green energy, offshore wind power has been paid more and more attention. There are extensive research focused on local scour of the monopile foundation. In this paper, a model of offshore wind turbine system with different scour depths is established. The static and dynamic analysis of the model is carried out. Results are in good agreement with the previous scouring model test. As the increase of scour depth, the maximum horizontal displacement, the maximum horizontal stress and the maximum bending moment values of the support system increase gradually. When the scour depth is twice the pile diameter, the maximum horizontal displacement, stress and bending moment are increased by 3.61%, 12.7% and 10.3% respectively, comparing to those under the condition without local scour. The natural frequency of the system decreases with increase of scour depth, and frequencies of high order are more susceptible. Scour around pile foundation has a significant impact on dynamic characteristics of system. The horizontal displacement at the top of the tower constantly increases with scour depth. The influence of scour on the bearing performance of the supporting system must be considered in the design of offshore wind turbines.