ABSTRACT
ABSTRACT: On March 11, 2011 the huge tsunami after the biggest earthquake with the magnitude 9.0 devastated the Tohoku Pacific Ocean offshore of Japan. Especially, it was seemed that the impulsive fluid force due to the huge tsunami has caused the devastating damage of seawall structures in Tohoku regions of Japan. One month later, we investigated the tsunami disaster area at the Taro district in the Tohoku region, where was very famous for seawall with 10 m high. The aim of this study is to examine the collapse mechanisms of the biggest seawall protective structure in the world destroyed by the March 11 Japan tsunami. This chapter involves the site investigation, the damage extent of seawall by the tsunami numerical calculation, the overflowing behavior of tsunami for the seawall by the MPS (Moving Particle Semi-implicit) method, the laboratory tsunami test of model seawall, the possible collapse mechanisms of seawall and the countermeasure against huge tsunami.
