SEAWALLS IN DEEP SEAS

Abstract

Features in wave overtopping of two new types of seawalls designed to be built in considerably deep sea conditions are presented herein. One of those is the seawall of concrete caisson with a parapet wall and armor blocks on the top of the caisson, and another one is the seawall with a slitted box-type wave absorber. The former type of seawall has successfully been constructed in the Japan Sea and the Seto Inland Sea and is also to be constructed at a site directly exposed to an open sea of the Pacific Ocean in 1980 and 1981. The latter type of seawall was proposed in 1977 after numerous experiments and has been under construction in the Port of Osaka since 1978. The results of the experiments on the wave overtopping over the slit-type seawall were compared with the calculated results, obtained by an analysis in which the wave overtopping over a parapet wall was considered similar to the phenomenon of flow over sharp-edged weirs having time-dependent overflow-head. The calculated curves obtained are in good agreement with the experimental results. The designs of these two types of seawall are also presented herein.