Run-up tests on a permeable slope

This report is an attempt to get insight into the influence that the roughness and the permeability of a slope have on the run-up on this slope. In order to achieve this goal, non-dimensional parameters are derived describing the roughness of a slope and its permeability. Firstly, the framework of the design of a breakwater is given in order to place the run-up on a rough, permeable slope. The run-up itself is dealt with separately. Experiments were performed in order to obtain data that can be used to quantify the influence of the roughness of the slope and its permeability. The experiments were performed leaving the permeability of the whole structure out of consideration. To achieve a difference in porosity of the armour layer, rock armour units were used as well as tetrapod armour units. Two approaches of data analysis are applied on the data obtained from these experiments. This first approach describes the run-up on a rough, permeable slope by a combination of a roughness parameter, a permeability parameter and the breaker parameter. The roughness parameter and the permeability parameter are derived by forming non-dimensional parameters that describe roughness and permeability. The run-up, usually made non-dimensional using the wave height (H) is made non-dimensional here using the nominal diameter. This gave better results in combination with the derived parameters describing the roughness and the permeability of a slope. The second approach describes the run-up on a rough, permeable slope by using the relative run-up Ru/H and a newly derived non-dimensional parameter resembling the Iribarren parameter, but incorporating the influence of the permeability of the armour layer. When the relative run-up is put against the Iribarren parameter and is put against the newly derived non-dimensional parameter, the appearing scatter is less in the latter case.本报告旨在探究斜坡粗糙度与渗透性对其表面波浪爬高（run-up）的影响。为达成该研究目标，本文推导了用以表征斜坡粗糙度与渗透性的无量纲参数。首先，本文给出防波堤（breakwater）设计的基本框架，以明确粗糙透水斜坡上波浪爬高的研究场景，随后单独针对波浪爬高本身展开分析。为获取可量化斜坡粗糙度与渗透性影响的实验数据，本研究开展了系列物理模型试验，试验过程中暂不考虑整体结构的渗透性。为实现护面层（armour layer）孔隙率的差异化设置，研究同时采用了抛石护面单元与四脚锥体护面单元（tetrapod）。针对上述试验获取的数据，本文采用两种数据分析方法开展研究：第一种方法通过结合粗糙度参数、渗透性参数与破波参数（breaker parameter），构建粗糙透水斜坡的波浪爬高预测模型；其中粗糙度参数与渗透性参数通过构建表征斜坡粗糙度与渗透性的无量纲参数推导得到。传统上波浪爬高通常以波高(H)进行无量纲化处理，而本研究采用公称直径（nominal diameter）作为无量纲化基准，该处理方式与前述表征斜坡粗糙度与渗透性的推导参数结合后，可获得更优的拟合效果。第二种方法则采用相对爬高Ru/H与新推导的无量纲参数来描述粗糙透水斜坡的波浪爬高；该新参数类同伊里巴伦参数（Iribarren parameter），但纳入了护面层渗透性的影响。将相对爬高分别与伊里巴伦参数、新推导的无量纲参数进行关联绘图后可见，后者的数据离散程度更低。