海上风电大直径宽浅型筒型基础屈曲分析

Buckling analysis of large-diameter shallow bucket foundation of offshore wind power

大直径宽浅型筒型基础因其运输安装经济快速、抗倾覆能力强等优点,近年来得到广泛应用。钢制筒型基础因直径大、壁厚小,负压沉放过程易发生屈曲失稳,增大沉放阻力并严重影响结构安全,最终造成安装失败。借助ABAQUS有限元软件中Buckle特征值屈曲分析与考虑初始缺陷的非线性屈曲分析方法,分别对无顶盖圆柱壳、单筒基础、单筒多舱基础负压沉放过程进行屈曲分析。结果表明,可采用非线性方法确定筒体失稳的临界荷载;单筒多舱基础在调平工况下的临界压差小于整体下沉工况,工程设计中需单独校核调平工况的屈曲稳定性;纵向加劲肋对筒体屈曲临界压差有提升效果,不同型式加劲肋可提升8%~36%的屈曲临界压差,角钢型加劲肋抗屈曲能力最优。

Large diameter and shallow bucket foundation has been widely used in recent years due to its advantages of rapid transportation and installation,strong ability to resist overturning.As a result of its large diameter and small wall thickness,the steel bucket foundation is prone to buckling instability during the suction-assisted installation process,which will increase the resistance,leading to structural and installation failure.Eigenvalue and nonlinear buckling analysis considering initial defects were used in ABAQUS finite element software to analyze the buckling of cylindrical shell without lid,single bucket foundation and single bucket foundation with bulkheads during the suction-assisted installation process.The results show that the nonlinear method can be used to determine the critical pressure.The critical pressure of single bucket foundation with bulkheads under leveling condition is less than that under overall sinking condition,and the buckling stability of leveling condition should be checked independently in engineering design.Longitudinal rib stiffeners can improve the critical buckling pressure of the bucket foundation.Different types of rib stiffeners can improve the critical buckling pressure by about 8%-36%,and the angle steel stiffener has the best performance in improving the anti-buckling capability.