Hydraulic model tests of an innovative dike crest design

Abstract

Report on laboratory tests on a crest drainage dike; investigation if a channel in the crest of the dike is able to decrease the amount of overtopping over the dike. Chapter 2 provides details about findings from previous studies and the relevance of those findings to this research project. Available literature on wave run-up and wave overtopping are also reviewed and summarised. Research performed on wave overtopping layer thickness and the overtopping flow velocities are studied. Formulae to calculate layer thickness and velocity are summarised in this section. Additionally, scaling laws and scale and model effects will be explained. Section 2.6 describes the fundamentals of the crest drainage dike and the expected behaviour during an overtopping event. After the literature review, the objectives and methodologies were considered. The final section of Chapter 2 is focused on revising objectives and methodology. In Chapter 3 the model setup, measurement techniques and test programme are described. Chapter 3 also includes the calibration of measuring devices and methods of data analysis. During the physical model study four different measurements (wave parameters, layer thickness, velocity, weight of overtopping water) were taken. Methods for measure each of these parameters are described with instructions about the instruments. Calibration methods for each measuring devise are then explained. Chapter 4 presents the most important results from the model testing: primarily the reductions of mean overtopping rates due to different configurations. The influence of the crest drainage dike in reducing the overtopping volume per wave is explained and results from tests with different drainage options, overtopping layer thickness, and overtopping flow velocities for the crest drainage dike are given. Lastly, the results from selected tests on re-curve wall configurations are presented.