Tunnel cubes, one layer

Big size hollow armour units with a stem at one edge of the cube
forming single cover layer elements to be placed on a stable substructure (to be seen on the left)

or piled up regularly to form a stepped face multi-layer seawall structure (to be seen below).
Tunnel cubes, two layers
Tunnel cubes piled up
Wave energy at different slope faces
Hydaulic efficiency of hollow elements placed regularly on slopes exposed to the action of waves gets bigger the bigger the block dimensions are in relation to the wave length and the bigger the percentage of porosity.

Model results of the shown regular sloping structure (slope 1:2) and porosity 39% :

  • Reflection coefficients
    0.1 <= CR <= 0.3
    depending on wave length

  • Wave energy at structure toe: 25% of that at smooth slope.