Stability and profile development of coarse materials and their application in coastal engineering

Continued demand for relatively low-cost shore protection has resulted on one side in development of better design criteria and measures to improve the stability of rock materials, and on the other side in development of a great number of artificial untis. Although existing knowledge on this subject is limited, it is useful to systematize this knowledge and to make it available for designers. This paper presents briefly the stability characteristics of coarse materials in general use; the static equilibrium conditions of stones on a slope under wave attack and the profile development and its dynamic equilibrium when the critical static-conditions are exceeded. Some examples of practical application are given. The static criteria are mainly based on C.E.R.C. large wave tank data. The dynamic criteria are established through previous systematic model investigation carried out by the Delft Hydraulics Laboratory and commissioned by the Public Works Department.