Author(s): Keiichi Toda; Toshiyuki Nishikori; Taisuke Ishigaki
Linked Author(s): Keiichi Toda, Taisuke Ishigaki
Keywords: Evacuation; Inundation; Underground space; Urban flood countermeasures
Abstract: Due to heavy rainfall, flooding occurs so often especially in urban area. Underground spaces are developed in the center of large cities, and if water on the ground flows into there, it may cause a very dangerous situation as the water depth rises quickly and the flow velocity through a staircase is very high. In order to avoid human casualties, evacuation is very important. Evacuation in inundated underground space is very difficult and complicated, therefore a further study is required from the disaster prevention and mitigation point of view. This study treats an evacuation from a multi-layer underground space in urban flooding. We have developed a mathematical evacuation model based on the network theory, in which the evacuation actions with inundation flow were taken into account. The model was applied to the underground space in the center of Kyoto, Japan. The underground is complex and comprises a shopping mall, parking lots and a subway station. Through the analysis, it was confirmed that the important factors for safe evacuation are evacuation order and its issuing time. Also, the effects of flash-board and step of stair entrance were studied in detail by the inundation simulation and evacuation analysis. As a result, these devices are found to be very effective for safe evacuation as they protect or retard inundation water intrusion into underground space.
Year: 2018