Abstract

In this study, a series of centrifuge tests are performed to investigate the ultimate lateral capacity of a pile group for offshore wind turbines. The validated Finite element models (FEMs) are established. The rotation center and the maximum bending moment occur at 9 D and 3 D of the pile length. A sensitivity study is performed by considering the soil parameters through numerical tests. The internal friction angle is the most influential factor by introducing 32% change in lateral capacity. The key factors of pile number, pile diameter, loading height, and pile spacing are investigated in the following parametric study. Increasing the pile number and the pile diameter is effective for enhancing the lateral capacity. In contrast, a larger eccentricity has a negative effect on the foundation stability. The failure mode of the pile group foundation tends to change from strain softening to strain hardening when the loading height reaches a threshold magnitude. The p-multiplier is calculated to demonstrate the shadowing effect in a pile group foundation. An optimal design method is proposed by integrating the pile number and the pile spacing factors. This study provides some instructions for the application of pile group foundations in the offshore wind industry.

摘要

在这项研究中，进行了一系列离心机试验，以研究海上风力涡轮机桩群的极限横向承载力。建立了经过验证的有限元模型 (FEM)。旋转中心和最大弯矩出现在桩长的9D和3D处。通过数值试验考虑土壤参数进行敏感性研究。内摩擦角是影响最大的因素，它会导致横向承载力发生 32% 的变化。桩数、桩径、加载高度和桩间距的关键因素在以下参数研究中进行了调查。增加桩数和桩径对于提高侧向承载力是有效的。相反，较大的偏心率对地基稳定性有负面影响。当荷载高度达到临界值时，群桩基础的破坏模式有由应变软化向应变硬化转变的趋势。计算 p 乘数以演示群桩基础中的遮蔽效应。结合桩数和桩间距因素提出了一种优化设计方法。本研究为桩群基础在海上风电行业的应用提供了一定的指导意义。