Experimental Investigation and Numerical Analysis of the Behaviour of Plate Anchor Foundations Subjected to Cyclic Loading in Sands

砂土中循环荷载作用下板锚基础性能的实验研究和数值分析

• 批准号: 2888310
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2888310
• 关键词: Experimental; Investigation; Numerical; Analysis; Behaviour

EPRSC Project DescriptionExperimental Investigation and Numerical Analysis of the Behaviour of Plate Anchor Foundations Subjected to Cyclic Loading in SandsOver the past several decades, offshore wind farms have been undergoing significant development and expansion in terms of their power capacity and operating regions. While most of the offshore wind turbine (OWT) structures are supported by fixed foundations (e.g. monopile, jacket foundations, etc.), alternative foundation types have been investigated as options that are more suitable to large OWTs and deeper waters. Specifically, plate anchor foundations have been considered a feasible and efficient foundation type for applications in floating OWTs with mooring systems [1], [2].Foundations of floating OWTs are subjected to a combination of uplift and horizontal loads, which are induced by the environmental loads acting on the OWT structure and mooring lines. Due to the cyclic nature of the loads, the foundation is subjected to a significant number of loading-unloading cycles during its service lifetime [3]. Although relatively limited, several experimental studies have been carried out to investigate the behaviour and capacity of plate anchors under cyclic loading. Overall, the studies showed consistent results, where the cyclic loading results in an increase in the foundation capacity in both silt [4] and sands [5], [6]. While the change in the foundation capacity has been simulated on a theoretical basis for silts [4], there has been limited analysis on the methods for quantifying the capacity change of plate foundations in sands.Thus, this research project aims to investigate the response of plate anchor foundations subjected to cyclic loading in sands. In addition, it is aimed to develop analytical and numerical models for predicting the effects of cyclic loading on the foundation capacity. The consideration of the strength gain effects due to cyclic loading would allow for more optimal and economic foundation design solutions for offshore applications. This project falls within the EPSRC "Engineering" research area, within the context of the "Energy and Decarbonisation" theme.For this project, a series of laboratory tests will be carried out to investigate the behaviour of plate foundation models under loading-unloading cycles in saturated sand. The foundation models will be subjected to cyclic loading with different frequencies and magnitudes. The effects of the loading characteristics on the foundation capacity and behaviour will be analysed and quantified. Based on the analysed mechanism behind the foundation behaviour after cyclic loading, an original analytical model will be suggested for the prediction of the post-cyclic monotonic capacity. In addition, three-dimensional finite element analysis (FEA) will be carried out for the numerical simulation and parametric studies on the foundation behaviour. Based on the results of the parametric studies, optimal design parameter values would be suggested for the maximisation of the post-cyclic foundation capacity. Finally, a general design framework for plate foundations of OWTs will be newly suggested by incorporating the developed analytical models for estimating the post-cyclic monotonic capacity or the FEA model.

在过去的几十年里，海上风电场在其发电能力和运行区域方面经历了重大的发展和扩大。虽然大多数海上风力涡轮机（OWT）结构都是由固定基础支撑的（例如单桩基础、夹套基础等），但人们已经研究了更适合大型海上风力涡轮机和较深水域的替代基础类型。具体而言，板锚基础被认为是一种可行且有效的基础类型，适用于具有系泊系统[1]，[2]的浮式owt。浮式水轮机的基础是由环境荷载作用于水轮机结构和系泊线而引起的，其基础同时承受着隆起和水平荷载的作用。由于荷载的循环特性，基础在其使用寿命期间要经受大量的加载-卸载循环。虽然相对有限，一些实验研究已经进行了调查的行为和能力的板锚在循环荷载下。总体而言，研究结果一致，循环荷载导致粉土[4]和砂土[5]、[6]地基承载力增加。虽然已经在理论基础上模拟了粉砂地基承载力的变化，但对砂土中板基承载力变化的量化方法分析有限。因此，本研究项目旨在研究砂中板锚基础在循环荷载作用下的响应。此外，还旨在建立预测循环荷载对基础承载力影响的解析和数值模型。考虑到循环载荷带来的强度增益效应，可以为海上应用提供更优、更经济的基础设计解决方案。该项目属于EPSRC“工程”研究领域，在“能源和脱碳”主题的背景下。在本项目中，将进行一系列实验室试验，以研究饱和砂土中板基础模型在加载-卸载循环下的行为。基础模型将承受不同频率和震级的循环荷载。将分析和量化荷载特性对地基承载力和性能的影响。在分析循环荷载作用下基础受力机理的基础上，提出了一种预测循环后单调承载力的原始分析模型。此外，还将进行三维有限元分析（FEA），对基础性能进行数值模拟和参数化研究。根据参数化研究结果，提出优化设计参数值，使地基循环后承载力最大化。最后，结合已开发的循环后单调承载力分析模型或有限元分析模型，提出了一种新的板式基础设计框架。