APPLICATION OF DRAG MODEL ON SPH-DEM COUPLING ANALYSIS METHOD FOR THE FAILURE SIMULATION OF RUBBLE MOUND FOUNDATION AT A CAISSON BREAKWATER DURING TSUNAMI

Abstract

In the 2011 off the Pacific coast of Tohoku Earthquake, caisson breakwaters in several ports were damaged by the tsunami. According to the acutual damage examples of the breakwater after the tsunami, it is considered that these failures were caused by not only horizontal large tsunami force, but also scouring destruction of foundation mound due to the tsunami overflow. In this paper, SPH-DEM coupling analysis method which is based on drag model is employed in order to analyze scouring and seepage flow phenomena at caisson breakwater during tsunami. Firstly, basic numerical tests are conducted to verify the coupling analysis method to calculate the interaction force between SPH and DEM. Secondly, parametric studies of the simulation on the tsunami overflow experiment are carried out to check the effect of the numerical parameter to express pore water flow influenced by rubble shape.