Abstract
Laboratory experiments were conducted for the disaster reduction performance of coastal dike against tsunami overflow with an objective of understanding the benefit of the enhanced renovation of the dike combined with a high bank as planned on the Suruga Coast, Japan. More than 11 runs of experiments were performed with enhancements to the top crown, the back slope and the back slope foundation. It was found that the enhancement of the structure successfully delayed the collapse of the dike by 3 to 5 minutes, which was equivalent with ductile seawalls introduced in the Sendai Coast after the 2011 Tohoku Tsunami. Furthermore, the height of the bank remained higher than the existing dike height, even in case Level-2 Tsunami overflowed the bank. Enhancement limited to the top crown of the dike was found enough in case where Level-2 Tsunami did not overflow the bank.
