低功率风机基础扩容改造优化设计研究

Research on Optimal Design of Low-power Wind Turbine Foundation for Expansion and Transformation

针对已建成的低功率风机扩容后其下部基础的改造问题,以1.65 MW风机扩容至2 MW的基础改造项目为研究对象,采用有限元建模的方法并结合第一强度理论的判别标准,提出了一种多排焊钉与混凝土环梁组合的改造形式,并根据基础中各部件的应力情况寻求最优的改造方案。结果表明:风机扩容会使原基础在极端工况下出现较大变形和应力激增的现象,当在基础上部增设高度为700 mm以上的环梁时,可有效解决基础变形过大的问题,但对基础内部应力的影响却十分有限;而采用焊钉与环梁组合的形式时,随着焊钉数量的增加,基础薄弱区的应力会显著减小,而环梁的应力则会急剧增加,甚至超过普通混凝土的极限强度。因此,建议采用具有较高强度的材料来砌筑环梁。通过对20种焊钉与环梁组合的算例研究得出,在4排焊钉与1000 mm高的UHPC环梁组合的形式下,基础薄弱区的应力将减小54%以上,同时,其他部件的应力也均能满足材料要求,故提出该种组合是风机基础扩容改造的最优设计方案。

Aiming at the transformation of lower foundation of low-power wind turbines after the expansion,taking the expansion of 1.65 MW to 2.0 MW of wind turbines as research objects,a transformation form of the combination of multiple rows of welding studs and concrete ring beams is proposed based on the finite element modeling method and the judgment criterion of the first strength theory,and the optimal transformation scheme is obtained according to the stress of each component in the foundation.The results show that the expansion of wind turbine will cause the original foundation to have a large deformation and a surge of stress under extreme working conditions.When a ring beam with a height of more than 700 mm is added on the upper part of the foundation,the problem of excessive foundation deformation can be effectively solved,but the influence on the internal stress of the foundation is very limited.When the combination of welding studs and ring beams is used,with the increase of the number of welding studs,the stress in the weak area of the foundation will be significantly reduced,while the stress of the ring beam will increase sharply,even exceeding the ultimate strength of ordinary concrete.Therefore,it is recommended to use materials with higher strength to build ring beams.Through the study of 20 kinds of welding stud and ring beam combination,it is concluded that,in the combination of four rows of welding studs and 1000 mm high UHPC ring beams,the stress in the weak area of the foundation will be reduced by more than 54%,and at the same time,the stresses of other components can also meet the requirements.Therefore,this combination is considered to be the optimal design scheme for the expansion and reconstruction of the foundation of wind turbine.