Instability evaluation of rubble mound for breakwaters subjected to tsunami-induced overflow and seepage flow

Abstract

This paper presents a formula to estimate the stable weight of a rubble mound for breakwaters, considering the tsunami-induced overflow and seepage flow, based on the theoretical force balance among the frictional resistance of the rubble mound, the tractive force of the water flow over the caisson to the rubble mound and the seepage force of the rubble mound through the breakwaters. A series of hydraulic model tests was conducted on the scale of 1/100 for the Kamaishi Harbor Mouth Breakwaters in order to confirm the effectiveness of the proposed formula. Using the test results, the stability of rubble mounds for breakwaters was evaluated from the geotechnical engineering and hydrodynamical points of view.