Load-displacement properties of gravity type breakwater reinforced by steel pipe piles

抄録

The coastal areas of the Pacific Ocean suffered extensive damage by the tsunami of the 2011 off the Pacific Coast of Tohoku Earthquake. Since then, it was necessary to develop reinforcement methods to strengthen the existing breakwaters against tsunamis. Therefore, the authors proposed a method to reinforce a breakwater against tsunami by backfilling the space between the breakwater and installed steel pipe piles. A series of model experiments was conducted. In the experiment, the embedment length and space between the piles were selected as parameters to improve the horizontal resistance of the caisson. A horizontal loading experiment was conducted to study the horizontal resistance of the model caisson. The model ground was prepared by dry silica sand #5 under 80% of relative density. Strain gauges were attached to the steel piles to measure the bending moment of the piles along the pile length. The experimental results suggest that the horizontal resistance of the caisson remained stable under a certain embedded length of the piles, and the horizontal resistance of the caisson decreases when the space between the piles is long although the flexural rigidity per unit horizontal length was constant.