Wave-induced settlement behavior of caisson breakwater on sand

Breakwater settlement studies have been conducted primarily through numerical model tests and laboratory wave tank tests using scaled models. The study presented in this paper analyzed settlement data measured in an actual caisson breakwater over a long period of time and the characteristics and causes of wave-induced settlement in the caisson were examined qualitatively. The analysis revealed that waves clearly affect the settlement in breakwater, especially under high wave conditions, such as typhoons. Breakwater settlement is caused by ground liquefaction, which occurs due to the increase in excess pore pressure, the combination of oscillatory and residual excess pore pressures, and the solidification process of ground caused by the dissipation of the accumulated excess pore pressure. Solidified ground is not likely to experience liquefaction under such wave conditions, thus reducing the possibility of settlement.