A FUNDERMENTAL STUDY ON THE CHARACTERISTIC BEHAVIOR WITH A TSUNAMI ACTING ON A BREAKWATER

Abstract

 In order to establish a design method for a breakwater for tsunami, it is necessary to clarify the progressive fracture mechanism until the collapse of a breakwater during tsunami action. Nowadays, since discrete element method become popular, it has become possible to grasp the behavior at the time of tsunami action taking account of deformation of the ground. However, it is difficult to grasp how the progresses destruction progresses in deformation analysis, because sliding failure, overturn failure, bearing capacity failure and the like are mixed behavior. Therefore, in this research, sliding amount and rolling angle of breakwaters during tsunami action were grasped using tsunami wave force and lifting pressure calculated by CADMAS-SURF with the aim of revealing basic behavioral characteristics. We revealed amount of sliding and turning angle of breakwaters by the equations of motion and angular motion equations taking into consideration the penetration of breakwaters into the mound. We also examined bearing capacity fracture by toe pressure acting on the mound from the bottom of a breakwater. As a result, we are able to evaluate quantitatively that breakwater under the action of tsunami quantitatively shows that destruction progresses in the order of sliding, bearing capacity failure, and overturn. In addition, we also confirmed that there is the possibility of bearing capacity failure occurring in some cases before sliding occurred.