On The Use Of High-Density Rock In Rubble Mound Breakwaters

Natural rock with high density is widely used in the Scandinavian countries. However, the use of natural rock with density higher than 2:9t=m3 is ordinarily associated with some kind of problem solving, e.g. where normal density stones have to be replaced with heavier stones without increasing the construction volume or layer thickness. Most common design formulae do not give a clear conclusion on the in°uence of the rock density on the stability. The present paper presents results of small and large scale model tests in which is used rock with different densities. It is shown that the positive effect on stability from the increased density is overestimated by conventional armour stability formulae in case of steep slopes. The infuence of the density depends on the slope angle and the type of armour units.