Abstract
Prototype-scale numerical analyses are carried out to investigate wave force acting on the harbor side of a caisson during tsunami overflow and effectiveness of countermeasures against overturning of the caisson. Numerical results show that the wave force acting on the harbor side of the caisson is overestimated by the force calculated from water surface elevation on an assumption of hydrostatic pressure, and its overestimation becomes large with an increase in a relative overflow height. This relationship is found to be affected by the permeability of the rubble mound, suggesting that the permeability of the rubble mound is essential when evaluating the wave force. Furthermore, it is revealed that there are effective configurations of the upper part of the caisson to prevent its overturning motion, and the effectiveness of the change in the configuration can be assessed using the scale of vortices.
