Erodibility assessment of Armour Blocks causing Damage to Breakwaters

Abstract

Empirical equations such as the Hudson, van der Meer-de Jong, and Yoo equations were compared for estimating the armour block weight of the breakwater by introducing an incremental factor based on the Hudson equation. The equation for deriving the critical wave height of erosion at the structure toe was developed for additional consideration of the armour-blocked breakwater stability. All empirical equations were reformed according to the Hudson equation, which has been widely employed in engineering design, and an incremental factor was added to each reformed empirical equation. This factor reflects the characteristics of each empirical equation. The equation in the present study incorporates wave including wave height at the local depth in the place of interest. The wave celerity was calculated using the modified solitary wave theory, which is valid for a wide range of applications. The equation for deriving the critical wave height of erosion was employed to test the sea bottom stability, and its inclusion improved the credibility by up to 87.7%. By employing the local value of wave celerity at the place of interest, the new Yoo-Lim equation was significantly improved over the previous estimation, as published by Yoo who introduced the wave action slope to define the local condition of wave motion.