波浪与冲刷作用后吸力式基础承载力分析

Bearing capacity analysis of suction bucket foundations after wave loading and scouring

吸力式桶形基础是一种应用于海上风机的典型基础形式,波浪循环荷载与海流引起的冲刷会影响基础的承载力,进而危及结构的安全。采用模型试验手段和有限元软件数值方法,分析了基础的长径比(0.50、0.75和1.00)、冲刷和波浪荷载作用对基础的承载特性的影响。研究发现:随着长径比的增加,吸力式桶形基础承载力(水平和竖向抗拔)的增长速率明显加快而冲刷作用会降低其增长速率;静力荷载作用下分为弹性变形、塑性变形和失稳破坏3个阶段;试验中前期波浪作用扮演改变砂土密实度的角色,不同波浪作用下的砂土会发生剪胀和剪缩,结合数值计算结果说明了砂土剪胀角对基础承载力的影响;随着波浪荷载和冲刷深度的增加,吸力式基础的承载力呈下降趋势。

A series of suction bucket model tests carried out in sand under wave cyclic loading detailed,the bearing capacity and stability of the foundation was analyzed with respect to three aspects:the length-to-diameter ratios of the suction bucket,the magnitude of cyclic load,and the scour depth.It was verified by the analysis of the finite element software.It was revealed that the increase of the length-diameter ratios can accelerate the growth rate of the foundation bearing capacity and the scour hole would reduce the rate of growth.The behavior of the foundation bearing capacity can be divided into three stages:the stage of elastic deformation,the stage of plastic deformation and the stage of instability failure.Under different wave loading,the sand would be dilated and shrunk.It was discussed that the dilation angle of sand influence on the bearing capacity of the foundation combined with the numerical results.The bearing capacity of the suction foundation decreases with the increase of the cyclic load and the depth of the scour.