2019 Volume 75 Issue 2 Pages I_367-I_372
A series of hydraulic model experiments was conducted to grasp the fundamental characteristics of the Isbash number of armor units against tsunami-induced current. From the experimental results of various slope angle of the mound, it became clear that the Isbash formula overestimates the influence of the slope angle. It was found that the armor units on the shoulder are structurally weak in the case of trapezoidal shaped mound. In the case of the breakwater head, the armor units near the corner of the caisson and the armor units on the mound ridge line on the downstream side were easily damaged, and the Isbash number decreased slightly compared to the two-dimensional experiments using trapezoidal shaped mound. Regarding the definition of the flow velocity in the Isbash formula, it is better to evaluate the Isbash number by using the cross-sectional average flow velocity from the viewpoint of consistency with the design method.
