EXPERIMENTAL STUDY ON EFFECTS OF REINFORCEMENT FOR CAISSON BREAKWATERS AGAINST ABNORMAL TSUNAMI

Abstract

 This study conducted hydraulic experiments to clarify effectiveness of reinforcement for breakwater stability against abnormal tsunami which exceeds the expected level, seen in the Great East Japan Earthquake Tsunami on 11 March, 2011. Though increasing the width of counter mounds reinforcement can reduce displacement of breakwaters, increase of the height of reinforcement is simulteaneously needed against abnormal tsunami. The resilience of breakwaters differs even if the safety factors of breakwaters are the same for tsunami. The formulas to evaluate the horizontal displacement of breakwaters based on their safety factors against tsunami were proposed from the experimental investigation.