Abstract
As long as enough high seawalls are constructed along the coast lines, industrial facilities in coastal areas can be protected against tsunami inundation. However, even when high seawalls exist, seawater will come into landside areas through water channels such as intakes, outfalls and drainage channels. Coming seawater will possibly induce inundation disasters, damaging electrical facilities and losing evacuation routes. In this study, an integrated numerical simulation model for inundations induced by tsunami overflows was developed. The simulation model consists of a 1-D pipe network flow model to simulate overflow volume from pits of a water channel and flow of the pipes and a 2-D inundation model to simulate inundation flow on the ground.
The developed simulation model was verified with hydraulic experiments. In the experiment, an idealized coastal industrial area, equipped with a drainage water channel network, was set in a wave basin with 1/30 scale. It was found that although the simulation model doesn't consider the effects of surface tension forces, which act in this experiment to some extent, it reproduces the inundation areas and the time series of inundation depths obtained by the experiment, relatively well. If the surface tension forces are programmed into the simulation model, the simulation results will surely show better agreements with the experiment. However, surface tension forces can be neglected in the real scale and therefore, in the practical situation where surface tension forces are enough small, the simulation model is applicable. Since it has advantages of requiring less computational efforts compared with a 3-D simulation model, it is helpful to analysis the risks of tsunami overflow inundation and to contrive suitable BCPs.
