Waves Under The Action Of The Perforated Caisson Vertical Direction By The Force Of The Pilot Study

With the recent developments in the design of vertical breakwater and pier, many researches to study new type of caissons have been done in order to reduce the total costs on project by diminishing the wave reflection and the wave forces. Since 1960s more and more emphases have been focused on the perforated caissons due to their high wave-absorbing ability and high stability against waves. But researches on perforated caisson in the past are mainly concerned about wave reflection coefficients and the horizontal wave forces on it without a ceiling slab. No accomplishments concerned about the vertical perforated caisson with the influence of a ceiling slab or emphasize the vertical wave forces on it and so far. Because perforated caissons have a wave chamber, vertical wave forces on it are more complicated than the traditional caissons. Therefore, this aspect is experimentally studied in this dissertation.Through 2D experiments in the wave flume at the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, systematical studies have been done on vertical wave forces acting on perforated caissons with a ceiling slab and also without the influence of ceiling slab. The methods for the calculation of vertical wave forces on perforated caisson are put forward under normal regular waves and irregular waves, which include method of the uplift force on the bottom and the method of the total vertical wave force on the whole caisson. New methods of calculating the simultaneously total horizontal wave force at the phase of the crest total vertical wave force are also given.The empirical relationships between the ratio of the vertical wave forces acting on perforated caisson without a ceiling slab to them acting on solid caisson and their mainly affecting factors are regressed from the experimental data through the Least Square Method. So do the empirical relationships between the ratio of the total vertical wave forces acting on perforated caisson with a ceiling slab to them acting on perforated caisson without a ceiling slab and their mainly affecting factors. These empirical relationships are simple in expression and also comparisons between calculated results by using these empirical relationships and experimental results show sound consistency with each other, which may be useful for engineering design and application.