Coupled micromechanical modelling for the analysis and prevention of erosion in hydraulic and offshore infrastructures

用于分析和预防水力和海上基础设施侵蚀的耦合微机械建模

• 批准号: 406907912
• 负责人: Dr.-Ing. Pablo Cuéllar
• 金额: --
• 依托单位: Abteilung 7: Bauwerkssicherheit
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/406907912?language=en
• 关键词: Coupled; micromechanical; modelling; analysis; prevention

The scope of this project concerns the water-flow erosion of geomaterials in relation to the failure of civil engineering infrastructures with large socio-economic relevance such as flood protection dykes and offshore wind-farm foundations. We aim to clarify the underlying mechanisms by which such systems are stressed by a fluid flow until a local dislocation is finally generated within the solid medium, leading to a material loss and eventually to the mechanical instability of the whole structure.For this, we want to bridge the gap between the micromechanical phenomena at the grain scale and the macromechanical application for engineering problems by developing efficient large-scale coupled simulation models that reproduce directly the interactions between a fluid phase and the bonded assembly of solid particles. To this end, we will couple relevant simulation techniques for the fluid and solid phases (the Lattice Boltzmann Method and the Discrete Element Method, respectively).We envisage a progressive development of representative models at different scales, at first on a meso-scale to reproduce local phenomena in small setups of our laboratory tests, and then increasing in size and complexity up to the real scale of the engineering problems. The models shall feature a solid contact scheme for intergranular cohesion and transient material damage, which are key elements that may govern the macromechanical failure modes of geotechnical systems. A key task at the development stage will be the adaption of our algorithms for parallel computation by means of graphical processors and clusters.A first field of application shall be the assessment of erosion in hydraulic constructions such as a river levee. In this respect, we will develop detailed micromechanical models of typical erodibility assessment scenarios and analyse the dependencies of the resulting parameters on the granular properties and geotechnical characterizations of the soil. The validated scenarios shall then be upscaled to simulate locally their real-scale counterparts within a practical levee erosion problem.In parallel, the second field of application concerns the foundation structures for offshore wind-turbines. A detailed assessment of different scouring scenarios shall provide a basis for optimized foundation designs and help reduce the costs of windfarm developments. Besides, promising innovative foundations in the offshore field, such as the Suction Buckets, are still not well established due to largely unresolved questions concerning their dual interaction to both the marine soil and the pore water. The stability of the suction mechanism as well as the possibility of a localized hydraulic failure (piping) of the buckets during their installation are key questions that will be addressed here. The development of the intended models dealing with such phenomena from a micromechanical perspective shall provide answers which have been missing in the offshore practice so far.

该项目的范围涉及与具有较大社会经济相关性的土木工程基础设施的失败（例如防洪堤坝和近海风网基础）的水流侵蚀。我们旨在阐明这种系统会被流体流动压力的潜在机制，直到最终在固体介质中产生局部位移，从而导致物质损失，并最终导致整个结构的机械不稳定性。为此，我们希望在晶粒尺度和摩克机械上的微型机械上的相互作用之间弥合差距，以使粒度的相互作用与摩克机械相互作用，以使工程型逐步播放，以使摩克式的cOuluction conflo couou cou cou cou couou cou couou couou couou couou cou couou couou couou cou cous sypery sworge couou cou couou couse couou固体颗粒的相位和键合组件。为此，我们将对流体和实心阶段的相关模拟技术（分别晶格玻尔兹曼方法和离散元素方法）。我们设想在不同尺度上的代表性模型的逐步开发，首先是在中等规模上，以在我们的实验室测试中的小型设置中重现局部现象，并在我们的实验室测试中逐渐增加，并在尺寸上增加尺寸和复杂的规模，从而逐渐增加，并且在尺寸和复杂的范围中增加了尺寸和复杂的量表。该模型应采用固体接触方案，以实现晶间内聚力和瞬态材料损伤，这是可能控制岩土技术系统的宏观力学故障模式的关键要素。开发阶段的一个关键任务将是通过图形处理器和集群对我们的平行计算算法进行适应。应用的第一个领域应是评估液压结构（例如河堤岸）中侵蚀的评估。在这方面，我们将开发出典型可侵蚀性评估场景的详细微机械模型，并分析所得参数对土壤的颗粒特性和岩土技术的依赖性。然后，应对经过验证的方案进行审查，以模拟其在实际堤防侵蚀问题中的实际规模对应物。在同时，应用程序的第二个领域涉及海上风盘的基础结构。对不同冲刷方案的详细评估应为优化基础设计提供基础，并有助于降低风力发展的成本。此外，由于在很大程度上尚未解决有关它们与海洋土壤和孔隙水的双重相互作用的问题，因此在海上领域的有希望的创新基础（例如吸盘桶）仍未得到很好的确定。吸气机制的稳定性以及在安装过程中固有的液压故障（管道）的可能性是这里将要解决的关键问题。从微机械角度来看，针对此类现象的预期模型的开发应提供到目前为止在海上实践中缺少的答案。