EXPERIMENTAL STUDY ON STABILITY AGAINST SCOURING OF ARTIFICIAL REEFS WITH HIGH CROWN HEIGHT

Abstract

 Since the mechanisms of scour near artificial reefs by waves and currents are complex, scour protection at the toe of artificial reefs should be considered by using hydraulic model experiments ideally. However, in many cases, its countermeasures are determined by following past desk studies. Especially for artificial reefs with as high crown height as the design high tide level, it is not clear to be able to apply previous knowledges on standard scour protection methods. In this study, we clarified damage mechanisms and assessed scour protection of artificial reefs with high crown height using two-dimensional hydraulic model experiments with movable bed. The results showed that the artificial reefs settled down by scouring at the toe on the seaward side initially, and that asphalt mats were effective as a countermeasure for the scouring. Moreover, the results implied the necessity to pay attention to scour at the toe on the landward side in case of waves with small steepness.