Stability of Roundheads Armoured With Cubes

The paper presents the results of a hydraulic model test study of the influence of concrete mass density and placement method on the stability of cube armour in a 1:2 slope cone shaped roundhead exposed to short — crested seas. Location and development of armour displacements were studied for concrete cubes with mass density of 2.4 t/m³ and 2.8 t/m³ in random and regular placement. Significant increase in stability for the higher mass density cubes was found showing that the same dimension cubes can be used in roundhead and trunk, if for the top layer of the most exposed part of the roundhead are used cubes with concrete mass density 2.8 t/m³ instead of 2.4 t/m³. Significant smaller crane capacity is needed compared to the conventional solution of unchanged mass density which implies approximately a doubling the mass of the roundhead armour units.