Author(s): Mitsuhiro Terada; Taisuke Ishigaki; Taira Ozaki; Keiichi Toda
Linked Author(s): Taisuke Ishigaki, Taira Ozaki, Keiichi Toda
Keywords: Subway; Pluvial flood; Fluvial flood; Evacuation; Simultaneous occurrence
Abstract: In Japan, flood disasters induce by typhoons and heavy rains are getting more serious. There are many underground spaces including the subway in Japanese urban cities such as Tokyo, and Osaka. In this paper, numerical simulations of inundation in Osaka, Japan, are conducted by using the general-purpose software Infoworks ICM. Study area Ebie and Ono treatment areas located on the both sides of Yodo River. In this paper, the impact of inundation on underground spaces is predicted when pluvial and fluvial flooding occur simultaneously. Numerical model includes a sewer system, an underground mall, and 15 subway lines. These underground spaces are prone to inundation by pluvial and fluvial flooding. The overtopping discharge by fluvial flood is calculated in the case of the maximum rainfall predicted by the Ministry of Land, Infrastructure, Transport and Tourism. Pluvial flooding is calculated by using extreme rainfall condition occurred in 2008 Okazaki flood. Almost all area on the ground is inundated, and there are some places where the flood depth is up to several meters. It is found that a large amount of flooded water flows into the underground spaces when pluvial and fluvial flooding occur simultaneously. The subway lines are also flooded and flood water spreads through tunnels to wide-ranging areas, and this brings catastrophic damage.
Year: 2020