Numerical Study of the Stability of Armour Layers for High-Crested Breakwaters under Sea Waves Attack

Rubble-mound breakwaters protect ports and coastal areas against sea waves. In these structures, armour layers of rock or concrete blocks compose the outer surface and provide the stability for inner layers. Since 1977, many researches have been conducted about the stability of the armour elements under wave attacks. Most of these studies are experimental and the existing empirical design formulae provide the required armour weight with respect to the wave characteristics. A more rational approach to examine the stability of the armour layers is to compute the applied wave forces on the armour blocks and investigate their stability against these loads. This technique increases our understanding about the mechanisms of the armour layer failure and prevents its possible malfunction under marine circumstances. In this paper, a two-dimensional numerical model is presented to investigate the stability of the cubic concrete armours. Smoothed Particle Hydrodynamics (SPH) scheme is used to calculate the applied wave loads and moments to the armour elements. Then, a Discrete Element Method (DEM) code has been employed to inspect the stability of the armour layer based on the SPH results. This process is conducted for different wave conditions and armour diameters, and the numerical results are compared with the existing empirical formulae.