海上风电嵌岩桩水平承载力特性数值模拟研究

Numerical Simulation Research on the Horizontal Bearing Capacity of Rock-Socketed Piles for Offshore Wind Turbines

[目的]主要对海上风电嵌岩桩的桩基尺寸与竖向荷载等因素对其水平承载特性的影响进行研究。[方法]文章采用有限差分的数值方法,基于一处现场试验建立数值模型并进行参数分析。[结果]结果表明:嵌岩桩基存在一个临界嵌岩长度(长径比),桩基尺寸的改变会影响桩-岩的相对刚度,进而使临界嵌岩长度随之改变,随着桩径的减小,嵌岩桩临界嵌岩长径比逐渐增加;在桩的承载能力范围内,在竖向荷载与水平荷载共同作用下,桩基的水平位移和桩身弯矩有较大程度的减小,如果认为竖向荷载引起的侧摩阻力在桩的两侧大小与方向相同,或将竖向侧摩阻力简化为作用在桩的轴线则会忽略这一效应的影响,会对计算结果造成误差。[结论]论文结果对于临界嵌岩长度以及竖向荷载影响的分析将有助于水平承载嵌岩桩的合理设计和深入研究。

[Introduction]The aim of this paper is to analyze the influence of the size and the vertical load of the pile foundation on the horizontal bearing capacity of rock-socketed piles.[Method]Based on a field test of the rock-socketed concrete pile under horizontal load,a 3-D finite difference numerical model was established and parametric analyses were performed.[Result]The results show that there is a critical rock-socketed length(ratio of length and diameter)for rock-socketed piles.Changes of the size of the pile will influence the relative stiffness of the pile and the rock,which will affect the critical rock-socketed length.With the decrease of the pile diameter,the critical socket length will increase.Within the scope of the bearing capacity of the pile and under the condition of combined vertical and horizontal load,the horizontal displacement and bending moment of the pile will have a pretty large decrease.This influence will be neglected if the vertical friction is assumed to be the same on the both sides of the pile or simplified to be at the center of the pile,which will cause error to the calculation results.[Conclusion]This study is supposed to provide contribution to the reasonable design and further research of the horizontal load of rock-socketed piles.