A new method for designing cube armours for low-crested and submerged breakwaters

Abstract

Recently, coastal structures designers have paid more attention to low-crested/submerged breakwaters due to their significant inherent advantages. Although many formulae can be found in the literature for the design of breakwater armour layer, the majority of them are proposed for high-crested breakwaters. Currently, there is no comprehensive formula for the design of the cube armour layer for low-crested/submerged breakwaters. Among the important parameters affecting the armour layer stability of low-crested/submerged breakwaters, the most effective ones are crest width, packing density and placement pattern of the armour units. These parameters, however, are not directly included in the existing design formulae. In this article a comprehensive and complete formula for design of the armour layer for low-crested/submerged breakwaters based on the results of a large number of experimental investigations is presented. The proposed formula contains the most important parameters such as the crest width, armour units packing density and placement pattern, slope, freeboard, as well as the wave characteristics. The comparison between the armour layer's hydraulic stability number obtained from this formula and the corresponding values recorded at the laboratory reveals its favorable accuracy indicating the applicability of the proposed formula for safe design of the cubic armour layer for low-crested/submerged breakwaters.