Stability of Mound Breakwater's Head and Trunk

Abstract

The stability of a cubic armored breakwater head and trunk under monochromatic wave trains is experimentally studied. For the head there is a sector, roughly of 60°, where the unit stability is minimum. The stability function values (similar to Hudson's number) are 1.3‐three times higher there than those obtained from biodimensional tested sections. Head shape, at least for the cases tested, does not exert significant influence on the head stability. Trunk sections tested under long crested waves with a standing longitudinal wave height variation (here called quasi‐three‐dimensional [3D] tests) are less stable than two‐dimensional (2D) tested sections. Furthermore, trunk and head sections show a different behavior as the damage grows; the radio of initiation of damage wave height to destruction wave heights is much lower for head than for trunk sections. Head sections are more brittle than trunk sections. Additionally, exploration was carried out into standing longitudinal variation of wave height along the breakwater induced by different factors, such as the reflexion of the scattered waves on the lateral boundaries. Data from prototype failures that have occurred in Spain suggest that these wave patterns are worthy of further research.