STUDY OF INUNDATION AND EVACUATION ANALYSIS IN AN UNDERGROUND SPACE ASSUMING PLUVIAL FLOOD IN AN URBAN AREA

Abstract

 In urban areas of Japan, there are numerous underground spaces, such as subways and shopping malls. These areas hold the possibility of being inundated not only above the ground but also underground when intense rainfall causes pluvial flooding. For this reason, it is necessary to take measures to anticipate urban floods. In this study, an analysis of inundation on the ground surface and underground spaces is performed, and the risk of underground inundation was evaluated using the index of safe evacuation. In addition, as one of the countermeasures against underground inundation, the effect of flood boards on inundation prevention was examined. Furthermore, the factors for improving the success rate of evacuation were discussed by simulating the evacuation of users from an underground mall during inundation. From the results, the inflow to underground spaces is larger as rainfall is greater. Moreover, It is shown that the installation of flood boards reduces the number of inflow points and the amount of inflow, which increases the safe evacuation area of the underground space and improves the success rate of evacuation.