NUMERICAL AND HYDRAULIC EXPERIMENTS ON BORE PRESSURE DUE TO TSUNAMI

Abstract

The 2011 Tohoku earthquake tsunami struck a wide area of the northeastern coast of Japan, and many coastal structures and buildings were damaged by the tsunami. Most of the buildings were damaged by the tsunami wave pressure. After the tsunami, characteristics of tsunami waive pressures have been investigated by many researcher, and are being clarified. As shown in previous studies, there are three regimes charactering the vertical pressure profiles. The first one is the impulsive pressure, which is observed just after the tsunami-bore impacted structures. In this regime, strong hydrodynamic pressures are generated by the fluid-solid impact process. After that, the bore pressure is observed, and both the hydrodynamic and hydrostatic pressures contribute the pressure profile. After that, the flow near the structures reaches a quasi-steady state, and the pressure profile becomes hydrostatic. Most of the evaluation equations of tsunami wave pressure proposed by the previous studies can be used against the impulsive pressures and the pressures in the quasi-steady-state regime. On the other hand, the characteristics and quantitative evaluations of the bore pressure remain immature. In this study, in order to clarify the characteristics of the bore pressure, experiments on the bore pressure are carried out, and furthermore, three-dimensional numerical simulations are also carried out.