Subsea power cable geotechnical stability for offshore wind applications

海上风电已经为向零碳过渡和向可再生能源转变做出了巨大贡献。这对英国来说尤其重要，英国的地理位置使其能够进行大规模的海上设施，其政策框架和研究计划使其成为欧洲海上能力的领先者。海上风电的进一步发展取决于提高可靠性和成本效益，并通过技术开发，设计优化和风险缓解来确保弹性。此外，部门能源相互依赖性的增加、近岸基础设施老化和重新供电潜力、深水风电场项目和更多极端天气事件，使得海上风电基础设施的开发和维护变得极其重要。这是指风电场的所有部分，包括负责在风力涡轮机和海岸之间传输电力和数据的海底电力电缆系统。对于大多数当前的海上风电应用，风力涡轮机和海上变电站是底部固定的，并且通过铺设在海底或埋入/倾倒岩石以进行保护的静态电力电缆阵列相互连接并与陆上变电站连接，并且它们通过管道接口连接到海上装置。环境条件和地质灾害对电缆施加载荷和运动，并可能影响其有效嵌入和承载能力。目前的岩土工程设计是基于管道设计的技术转移，没有考虑几何形状、配置和荷载的差异，忽视了动态行为。此外，目前的研究主要集中在新的基础设计和浮动风的应用，未能引起人们对输电系统可靠性和长期成本效益的重视。该项目的主要目标是确定当前管道设计知识转移中的研究差距和不确定性，研究嵌入式静态电缆的岩土性能，并提出可以为未来行业实践提供信息和优化的研究结果。这包括电力电缆-水流-海床相互作用的研究，以更好地了解岩土稳定性、故障时的运动学、嵌入损失、界面载荷，以及应用于集成结构建模以准确估计电缆性能。作为一个附带项目，探讨海洋粘土沉积物侵蚀与地质灾害的关系以及对电缆埋设的潜在影响，从而探讨岩土稳定性和结构性能。

Offshore wind is already making considerable contributions to the transition towards zero-carbon and the shift to renewable energy. This is particularly relevant for the UK, whose location enables large scale offshore installations, and whose policy framework and research initiatives have placed it on top of offshore capacity in Europe. The further development of offshore wind is dependent on improving reliability and cost-effectiveness and ensuring resilience via technology development, design optimisation and risk mitigation. Besides, increasing sectoral energy interdependencies, ageing nearshore infrastructure and re-powering potential, deep-water wind farm projects and more extreme weather events, make the development and maintenance of the offshore wind infrastructure extremely critical. This is in reference to all parts of a wind farm, including the subsea power cabling system responsible for transferring power and data between the wind turbines and the shore. For most current offshore wind applications, the wind turbines and offshore power substations are bottom fixed, and are linked with each other and with the onshore substations through arrays of static power cables either laid on the seabed or buried/rock dumped for protection and they are connected to the offshore units via tube interfaces. The environmental conditions and the geohazards impose loading and movement on the cables and may affect their effective embedment and bearing capacity. Current geotechnical design is based on technology transfer from pipeline design, not taking into account the differences in geometry, configuration and loadings and overlooking dynamic behaviour. In addition, current research focuses on new foundation designs and floating wind applications, failing to draw attention to the importance of the transmission system reliability and cost-effectiveness in the long term. The main objectives of this project are to identify the research gaps and uncertainties in the current pipeline design knowledge transfer, study the geotechnical behaviour of embedded static cables and propose findings that can inform and optimise the future industry practices. This includes the study of power cable -flow-seabed interactions to acquire a better understanding of the geotechnical stability, kinematics at failure, embedment loss, interface loading, and applications to integrated structural modelling for accurate cable performance estimations. As a side project, marine clayey sediment erosion is explored in relation to geohazards and potential effects to cable embedment and therefore the geotechnical stability and structural performance.