基于均匀腐蚀模型的开孔单桩承载特性研究

Research on Bearing Characteristics of Perforated Single Pile Based on Uniform Corrosion Model

海上风电工程广泛采用大直径开孔钢管单桩作为基础,因此,开展钢管单桩腐蚀程度对其承载特性的研究具有重要的意义。基于均匀腐蚀模型,分析钢管桩腐蚀程度对桩身受力与变形的影响规律,得到以下结论:水平荷载作用下,开孔单桩挠度随腐蚀进程发展曲线分为3个阶段,第1阶段挠度增长较为缓慢,第2阶段桩顶挠度的增速为第一阶段的10倍,第3阶段增速则与第一阶段的持平;轴向荷载作用下,当荷载小于12000 kN时,腐蚀程度对开孔单桩的竖直承载特性的影响可以忽略不计,但当荷载大于12000 kN时有显著影响;水平荷载作用下,腐蚀程度对大直径单桩开孔处的应力集中现象影响并不明显,应力集中系数稳定在1.05~1.15之间;当轴向荷载大于2000 kN时,桩的开孔处出现明显的应力集中现象,应力集中系数约为4.1。以上研究成果可为开孔单桩的防腐设计提供参考。

Large-diameter perforated steel pipe single piles are widely used as the foundation of offshore wind power project.Therefore,it is of great significance to research the impact of corrosion degree of steel pipe single pile on its bearing characteristics.Based on the uniform corrosion model,the influences of the corrosion degree of steel pipe pile on the stress and deformation of pile body are analyzed,and the following conclusions are obtained:(a)under the action of horizontal load,the development of deflection curve of the perforated single pile with the corrosion process can be divided into three stages,that is,the deflection growth in the first stage is relatively slow,the growth rate of the pile top deflection in the second stage is 10 times that of the first stage,and the growth rate in the third stage is the same as that of the first stage;(b)under the action of axial load,the corrosion degree has negligible influence on the vertical bearing characteristics of perforated single pile when the load is less than 12000 kN,and has a significant influence when the load is greater than 12000 kN;(c)under the action of horizontal load,the effect of the corrosion degree on the stress concentration phenomenon at the opening of large-diameter single pile is not obvious,and the stress concentration factor is stable between 1.05 and 1.15;and(d)when the axial load is greater than 2000 kN,the stress concentration phenomenon at the opening of pile is obvious,and the stress concentration factor is about 4.1.The research results can provide references for the anti-corrosion design of perforated single piles.