Integrated prediction of 3D wave-induced liquefaction around breakwater heads

海岸带是一个独特的地质、自然和生物区域，具有重要的经济、文化和环境价值。世界三分之二以上的人口集中在沿海地区，那里的海岸线对贸易、运输、旅游、休闲和海洋食品的收获具有中心或非常重要的意义。通常采用防波堤来保护和提高海岸线的效用。在世界范围内，每年建造新的防波堤和维护现有防波堤的总成本约为数百亿英镑。防波堤很容易受到海底地基液化的影响，这一过程往往会在施工后短短几年内导致地基严重退化，有时甚至会导致完全坍塌。防波堤的设计或维护不当可能导致灾难性的沿海灾害。例如，葡萄牙锡尼什防波堤的失败造成的损失，不包括对该地区的巨大经济和社会影响，仅重建费用就相当于近10亿美元。最近一个因防波堤失效而导致沿海悲剧的例子是新奥尔良在卡特里娜飓风期间，80%的城市被淹没在6米深的水下，造成人员死亡，个人和经济混乱。这场灾难造成的经济损失超过150亿美元。在本研究中，我们将首先将现有的二维波浪和土壤模型扩展到三维，然后将它们整合到一个单一的模型中，以便更好地预测防波堤周围波浪液化。为了验证所提出的理论模型，将进行一系列的物理模型实验。提出的研究是朝着显著改进工程设计和补救行动的重要一步，以解决与基础有关的海岸结构的损害。该项目潜在的概念创新来自三个因素，这些因素结合在一起，使人们能够正确理解WSSI现象：1)防波堤头周围波浪/海底相互作用的所有三个组成部分的整合；2)海床作为大变形的一般多孔介质处理；3)使用3D而不是2D建模。这种方法是必不可少的，因为它是模拟防波堤头周围波浪模式，模拟海洋沉积物中波浪能量耗散（包括通过多孔介质流动的临界现象）和充分考虑波浪，海底和结构之间相互作用的唯一方法。

The coastal zone is a unique geological, physical and biological area of vital economic, cultural and environmental value. More than two-thirds of the world's population is concentrated in coastal zones, where the coastline is either central or of great importance to trade, transport, tourism, leisure and the harvesting of marine food. Breakwaters are commonly adopted to protect and enhance the utility of coastlines. Worldwide, the combined costs for building new breakwaters and maintaining the existing ones are in the order of tens of billions of pounds a year.Breakwaters are vulnerable to the liquefaction of the seabed foundation, a process that can often lead to significant degradation of the foundation in as little as a few years after construction and sometimes even result in total collapse. The inappropriate design or maintenance of breakwaters can lead to catastrophic coastal disaster. For example, the failure of Sines Breakwater in Portugal caused damage equivalent to almost US$1 billion in reconstruction alone, excluding the huge economic and social impacts on the region. A recent example of coastal tragedy due to failure of breakwaters is that of New Orleans during Hurricane Katrina, putting 80% of the city under as much as 6 m of water and causing deaths and personal and economic chaos. The economic loss from the disaster was more than US$15 billion.In this study, we will firstly extend the existing 2D wave and soil models to 3D, and then integrate them into a single model to provide a better prediction of the wave-induced liquefaction around breakwater heads. A series of physical model experiments will be conducted for the verification of the proposed theoretical models. The proposed research is an essential step towards significantly improved engineering design and remedial action to address foundation-related damage to coastal structures. The underlying conceptual innovation of the project comes from three factors that combine to enable the proper understanding of the WSSI phenomenon: 1) the integration of all three components of wave/seabed interactions around breakwater heads; 2) the treatment of the seabed as a general porous media with large deformation; and 3) the use of 3D rather than 2D modelling. This approach is essential as it is the only way to simulate wave patterns around breakwater heads, model wave energy dissipation in marine sediments (including the critical phenomenon of flow through porous media) and account fully the interactions between waves, seabed and structures. .