Study of Stable Structure of the Breakwater for Tsunami with Steel Pipe Piles

The structure of a "tenacious" breakwater is required from the Great East Japan Earthquake in 2011. The widening work is one of existing reinforcement methods of tenacious breakwaters. However, it also has large cross section in port inside area. Furthermore, scouring due to the overflow decreases the bearing capacity of the rubble mound and it makes the breakwater easy to fall down. In "Tsunami-Resistant Design Guideline for breakwaters", by Ministry of Land, Infrastructure and Transport, the widening work is described, on the other hand, the reinforcing method to resist tsunami with steel pipe piles is proposed too. Therefore, we developed the reinforced method of a tenacious breakwater with steel pipe piles. The breakwater has filling stones between the caisson and the steel pipe piles, and it can resist a tsunami tenaciously. We call the method "Steel Pipe method".