Modelling tsunami induced coarse clast transport , combination of physical experiments, advanced numerical modelling and field observations

模拟海啸引起的粗碎屑迁移，结合物理实验、高级数值模拟和现场观测

基本信息

批准号：
298757467
负责人：
Dr. Max Engel
金额：
--
依托单位：
Lehrstuhl und Institut für Wasserbau und Wasserwirtschaft
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/298757467?language=en
关键词：
Modelling tsunami induced coarse clast

项目摘要

While coastal areas are highly attractive for population and industry, they are also highly exposed to extreme-wave events (tsunamis, storm surges). Considering the expected continuing population and industrial growth, there is an urgent need to assess frequency-magnitude relationships and damage potentials with high accuracy. Based on such assessments, it is possible to develop hazard management plans and hazard-mitigation strategies. Even though high-magnitude tsunamis may cause disastrous impacts, their recurrence intervals are in the range of hundreds to thousand years. Thus, at particular coasts with short historical records, no observations or even measurements of such worst-case scenarios might be available. In this case marine sediments deposited onshore provide, evidence for an extreme-flooding event. By associating specific sediment characteristics with the necessary wave-energy for particle movements, distinct characteristics of the hydrodynamic process inducing the sediment transport (tsunami or storm surge/wave setup-up) can be derived. Since subaerial blocks and boulders are more resistant towards erosion and human impact as fine sediments, they are more suitable for such investigations. However, distinguishing between storm and tsunamis is in most cases a tough task. Numerical models can support such interpretations, but still suffer from several simplifications as negligence of sedimentary load, interactions between multiple boulders or complex boulder shapes. Furthermore, these factors are also neglected in state-of-the-art physical laboratory experiments. Likewise, only experiments utilizing idealised shaped body-models on uniform shaped bathymetries and coastal topographies are known.The proposed project aims at bridging four substantial gaps in the state-of-the-art. Firstly, the behaviour of (i) complex and idealised model boulders and (ii) interactions between them during the tsunami runup will be analysed and compared by laboratory experiments. Investigations of the influences on boulder transport mode, path, and distance due to (iii) non-uniform bathymetric settings and (iv) sedimentary load follow afterwards. The next step comprises the development, calibration, and validation of a numerical two-phase model by using results of the physical experiments. Based on photo-technically recorded and numerically implemented data for topography and block deposits, the model shall be able to simulate tsunami-induced transport events with an unprecedented accuracy by project close-out. For the post-project future, the model application is intended for the island of Bonaire (Netherlands Antilles), where the coastal boulder sedimentology is already documented in high detail.

虽然沿海地区对人口和工业极具吸引力，但它们也极易遭受极端波浪事件（海啸、风暴潮）的影响。考虑到预期的人口和工业持续增长，迫切需要高精度评估频率-幅度关系和潜在损害。基于此类评估，可以制定危害管理计划和危害缓解策略。尽管高强度海啸可能造成灾难性影响，但其复发间隔在数百年至数千年之间。因此，在历史记录较短的特定海岸，可能无法对这种最坏情况进行观察甚至测量。在这种情况下，沉积在岸上的海洋沉积物提供了极端洪水事件的证据。通过将特定的沉积物特征与颗粒运动所需的波能联系起来，可以得出引起沉积物输送（海啸或风暴潮/波浪设置）的水动力过程的独特特征。由于地下块体和巨石作为细沉积物更能抵抗侵蚀和人类影响，因此它们更适合此类调查。然而，在大多数情况下，区分风暴和海啸是一项艰巨的任务。数值模型可以支持这种解释，但仍然存在一些简化问题，例如忽视沉积载荷、多个巨石之间的相互作用或复杂的巨石形状。此外，在最先进的物理实验室实验中也忽略了这些因素。同样，已知的只有在均匀形状的测深和海岸地形上利用理想化形状的身体模型进行的实验。拟议的项目旨在弥合现有技术中的四个重大差距。首先，将通过实验室实验来分析和比较（i）复杂且理想化的模型巨石的行为以及（ii）海啸爆发期间它们之间的相互作用。随后调查了 (iii) 不均匀的测深设置和 (iv) 沉积负荷对巨石运输模式、路径和距离的影响。下一步包括利用物理实验结果开发、校准和验证两相数值模型。基于地形和块状沉积物的摄影技术记录和数值实现数据，该模型将能够在项目收尾时以前所未有的精度模拟海啸引发的运输事件。对于项目后的未来，该模型应用程序适用于博内尔岛（荷属安的列斯群岛），那里的沿海巨石沉积学已经有详细记录。