Dynamic analysis of a rubble-mound breakwater subject to earthquake including seawater–structure-foundation interaction

Abstract

Rubble-mound breakwaters are generally subjected to strong seismic waves propagating even when seated on weak soil deposits, and they interact with seawater in most cases. The purpose of this article is to understand the dynamic response of a rubble-mound breakwater with seawater–breakwater-foundation interaction after a real earthquake shock. In this study, employing the arbitrary Lagrangian–Eulerian approach and dynamic finite element method, in which the seawater and the foundation of rubble-mound breakwater are considered, the dynamic responses of rubble-mound breakwater during earthquakes are simulated using the LS-DYNA finite element program. It is found that the seawater–breakwater-foundation interaction does have a considerable effect on residual displacements of the rubble-mound breakwater. The influence on horizontal residual displacement caused by the effect of seawater-breakwater interaction is greater than that on the vertical residual displacement, and the seawater–breakwater-foundation interaction does not necessarily reduce the horizontal and vertical displacements but also increases them. The vertical component of earthquake has a considerable effect on hydrodynamic pressure on the breakwater face. This investigation considers the seismic behavior of rubble-mound breakwaters by taking into account the coupling between the hydrodynamic loading and the shaking of the structure. According to the results, presented in this study, it is significant to consider the effect of interaction for rubble-mound breakwaters seismic safety evaluation.