THE NUMERICAL AND EXPERIMENTAL EVALUATION OF BREAKWATER OVERFLOW TO THE STABILITY OF ARMOUR BLOCKS OF BREAKWATERS

Abstract

 In recent years, many studies on the stability of breakwater against overflows have been conducted. New types of breakwaters have been proposed to detach the plunging point of the overflows from the caisson and avoid instability of blocks on the levee crown and the face of slope. The evaluation of the stability of blocks against overflows is critical examination item to the designing. In this study, laboratory and numerical experiments have been carried out to examine overflow forces acting on the armour blocks. The laboratory experiments with two dimensional water channel were carried and the numerical study with the SPH model had the same condition with the experimens. The relationship between displacements of the blocks and forces acting on them are clarified. The damage of blocks on levee crown are explained quantitatively by the rotation moment caused by the overflow forces. The stability of blocks on the slope can be reduced by vortices of high speed-flows even if plunging point of the overflow is far enough from the blocks.