海上风电四桩基础在软黏土中的水平承载特性

HORIZONTAL BEARING CAPACITY OF OFFSHORE WIND TURBINE FOUR-PILE FOUNDATION IN SOFT CLAY SOIL

为评估应变软化和应变率效应对四桩基础水平承载特性的影响,通过ABAQUS有限元软件,建立四桩基础二维平面应变模型,并在vumat用户子程序中定义软黏土不排水抗剪强度s_(u)随累积塑性剪切应变和最大剪切应变速率的变化关系,进而分析应变软化参数δ_(rem)、ξ_(95)和应变率参数μ对四桩基础水平承载特性的影响。分析结果表明:四桩基础水平承载力会随着应变软化参数δrem、ξ_(95)的减小而逐渐降低,其中δ_(rem)对水平承载力的影响较为显著;应变率参数μ与四桩基础水平承载力呈现线性正相关。最终,基于上述数值分析结果建立考虑应变软化和应变率效应的四桩基础水平承载力统一预测模型。

In order to evaluate the influence of strain softening and strain rate effect on the horizontal bearing characteristics of the four-pile foundation,a two-dimensional plane tetrapod pile foundation model by ABAQUS is developed.The relationship between the change of the undrained shear strength su of soft clay with the cumulative plastic shear strain and the maximum shear strain rate is defined in the vumat user subroutine,and the effects of the strain softening parametersδrem,ξ_(95) and the strain rate parameterμon the horizontal bearing characteristics of the four-pile foundation are analyzed.The analysis results show that the horizontal bearing capacity of the four-pile foundations decreases with the decrease of the strain softening parametersδ_(rem) andξ_(95),among whichδrem has a more significant effect on the horizontal bearing capacity;The strain rate parameterμshows a linear positive correlation with the horizontal bearing capacity of the four-pile foundations.Finally,based on the study findings,an unified prediction model of the horizontal bearing capacity of four-pile foundations considering strain softening and strain rate effect is established.