ICE-PICK: Installation effects on cyclic axial and lateral performance of displacement piles in chalk

在人类历史上，从来没有像现在这样迫切需要逐步改变能源生产方式。英国的目标是到2050年实现碳中和，是第一个通过净零排放法律的主要经济体，并以身作则。为了应对这种迫切的需求，海上可再生能源——尤其是风能——正在迅速扩张。英国许多海上风力涡轮机（OWT）的开发都需要固定或锚定在白垩中，白垩是一种高度可变的软岩石，覆盖了北欧大部分地区，广泛分布在北海和波罗的海。在大多数情况下，这将通过将大型钢桩推入海床下的软岩来实现。安装过程是困难的，因为一些基础（单桩）的规模前所未有，因为安装改变界面的白垩条件鲜为人知，白垩的机械行为很复杂，因为海上工作几乎没有误差的余地。除了其固有的困难，安装过程基本上修改了基础周围的粉笔。由于这些变化，我们在预测安全和高效运行的基本特性方面仍然存在一些重要的差距，例如单桩在其使用寿命期间的初始和演变的轴向容量和横向刚度，其特征是复杂的风浪循环荷载历史。通过严格的数值和实验模拟，提出的研究将提高软岩桩的效率和成本效益，以支持海上可再生能源结构的进一步发展。本文的主要目的是改进开放式桩基的可打性评估，并量化安装对开放式桩基长期使用性能的影响。主要成果将是开发实用工具，将这些影响纳入陆上和海上应用的工程分析和设计中。

Never in human history has there been such an urgent need for a step-change in energy production. With the goal of achieving a carbon neutral state by 2050, the UK is the first major economy to pass net zero emissions laws and lead the world by example. In answer to this impellent necessity, offshore renewables -particularly wind- are expanding at a rapid pace. Many of UK's offshore wind turbines (OWT) developments will need to be fixed or anchored in chalk, a highly variable soft rock that covers much of Northern Europe and is widespread under the North and Baltic Seas. In most cases that will be achieved by pushing or driving large steel piles into this soft rock under the seabed. That installation process is difficult because of the unprecedented scale of some of these foundations (monopiles), because the conditions of the chalk at the interface modified by installation are poorly known, the mechanical behaviour of chalk is complex and because working offshore leaves little room for error. Apart from its inherent difficulty, the installation process essentially modifies the chalk around the foundation. As a result of those changes, there are still some important gaps in our ability to predict properties that are basic for safe and efficient operation, such as the initial and the evolved axial capacity and lateral stiffness of monopiles through their in-service lifetime characterised by complex wind and wave cyclic load history. The research proposed will improve the efficiency and cost effectiveness of piles driven in soft rocks to support the further development of renewable energy structures offshore through rigorous numerical and experimental modelling. The key aims are to improve pile drivability assessment for open-ended piles supporting OWT and to quantify the effects of installation on long-term in-service performance of OWT foundations. The main deliverable will be to develop practical tools to incorporate these effects within engineering analysis and design suitable for both onshore and offshore applications.