上软下硬黏土中四筒基础抗倾覆承载特性研究

The anti-overturning bearing capacity of four-bucket foundation in clay with soft layers on top and hard layers at the bottom

随着海上风电向深远海发展,四筒基础发展潜力巨大。中国大多数海域存在较厚的上覆软土层,对基础抗倾覆承载能力有着重大影响。采用有限元软件ABAQUS建立上软下硬分层黏土模型,对四筒基础在单向水平荷载和弯矩荷载作用下的承载力特性进行研究。研究结果表明:四筒基础在水平、弯矩荷载作用下主要运动模式为转动,对边加载时,转动轴靠近受压筒且随着软土层厚度增加不断靠近四筒基础平面中心,但变化幅度较小;水平和弯矩极限承载力对于不同的筒间距和长径比具有相同的变化趋势,当软土层厚度h/筒高L≤3/4时,水平和弯矩承载力随着软土层厚度的增加近似线性降低,当h/L>3/4后,承载力降低速率明显减小。

With the development of offshore wind energy in deep waters,the four-bucket foundation shows promising potential.In many sea areas,there exists a thick overlying layer of soft soil,which significantly influences the anti-overturning bearing capacity of foundations.Therefore,this study utilizes the ABAQUS numerical model to investigate the horizontal load and bending moment bearing capacity of a four-bucket foundation in layered clay,with a soft layer on top and a hard layer at the bottom.The analysis reveals that the primary displacement mode of the four-bucket foundation is rotational,with the rotation axis closed to the compression tube and approaching the center of the foundation surface plane.However,the rotation range remains limited.When the ratio of soft soil thickness to bucket height is below 3/4,the horizontal load and bending moment bearing capacity exhibit a linear decrease as the soft soil thickness increases.Beyond a ratio of 3/4,the reduction rate of bearing capacity decreases significantly.Notably,the variation in bearing capacity,both in terms of horizontal load and bending moment,follows the same pattern for different bucket spacing and length-diameter ratios.