In the present study, a new type of slit caisson quay wall has been proposed to reduce the wave reflection and the stem wave simultaneously. The specialized configuration of the slit caisson quay wall was devised as a series of detached slit caissons which are connected by the open chamber. In order to verify the wave dissipation induced by the combined effect of the perforated wall and the open chamber, the physical model tests including the two-dimensional and the three-dimensional cases were conducted. As a result of the several tests, it was found that the proposed type of slit caisson quay wall has a sufficient dissipation effect against the oblique wave incidence.
A perforated-wall caisson quay wall is often used to remedy the drawbacks of a vertical caisson quay wall. It reduces not only wave reflection but also wave overtopping. It also reduces wave forces, especially impulsive wave forces, acting on the caisson (Takahashi and Shimosako, 1994; Takahasi et al., 1994). A conventional perforated-wall caisson consists of the front slit wall, back wall and the water chamber between the front wall and back wall. The weight of the slit caisson is less than that of a vertical solid caisson with the same width, and most of this weight is concentrated on the rear side of the caisson. Hence, the wider width of the perforated-wall caisson is often required to satisfy the design criteria against sliding and overturning. In addition, particularly in the case where the bearing capacity of the seabed is not large enough, the excessive weight on the rear side of the caisson may have an adverse effect. In order to solve these problems, a partially perforated-wall caisson is also often used, which provides an additional weight to the front side of the caisson. In this case, however, other hydraulic performance characteristics of the caisson such as wave reflection and overtopping may become worse compared with a fully perforated-wall caisson.
