FREQUENT DAMAGE OF GRAVEL GABIONS ON HITOTSUMATSU COAST IN SOUTH PART OF KUJUKURI BEACH

Abstract

 Gabions have been constructed as a measure against beach erosion on the Hitotsumatsu coast located in the south part of Kujukuri Beach. These gabions have been destroyed every time when storm waves hit the coast, and the recovery works to the original shape have been carried out. In 2019, these gabions were destroyed again. When investigating the cause of the collapse of these gabions, the steel covering the gravels inside gabion was broken by wave force against gravels, resulting in the scattering of the gravels. However, the gravel was stably deposited forming a steep slope near the shoreline, similarly to the gravel beach. It was concluded from this fact that it is better to carry out the gravel nourishment instead of the use of gabion with gravel inside.