Abstract
In the 2011 off the Pacific coast of Tohoku Earthquake, coastal areas of the Pacific Ocean suffered extensive damage. Breakwaters were also damaged extensively. There are needs to develop reinforcement methods of existing breakwaters. The authors proposed one of the reinforcing methods against tsunamis by constructing steel pipe piles or steel wall behind the breakwater. This report presents the experimental results of the breakwater improving method. In the series of loading experiment, the model caisson on the dry sandy ground wad loaded horizontally. Applying the combination of steel pipe piles or steel wall and filling between the wall and caisson improved the horizontal resistance of the caisson effectively. This research concluded there are optimum distances between the caisson and steel piles, considering the effective use of this method. The embedment depth of the piles should be properly decided, with considering the effect of scouring.
