Abstract
Since the Great East Japan Earthquake, tenacity has been required for structures against Tsunami. Especially for the tsunami with extraordinary power, it is more realistic to adopt the multifaceted protection rather than a single structure. In this context, pile-type porous vertical barrier is expected to be effective. In this paper, a simple theoretical explanation on its tsunami mitigation effect was provided, and the model experiments were conducted to examine the influence of the porosity ratio and the material of the barrier. The results showed that the wave force on the barrier and the height of the tsunami behind the barrier in the trade-off relationship and are the functions of the loss coefficient, which is expressed by the friction factor and the porosity ratio. It was demonstrated that the effective barrier can be designed by choosing the adequate value of the loss coefficient. Finally, a case study of designing the barrier was introduced, by applying the experimental results to the full-scale case based on the Froude law.
