Author(s): T. Ishigaki; T. Keiichi; I. Kazuya
Linked Author(s):
Keywords: Inundation; Urban area; Underground space; Hydraulic model test
Abstract: Japanese megalopolises are highly urbanized. The urbanization increases the peak discharge of flood and induces new types of disasters, one of which is an inundation into an underground space. Hydraulic model tests on the inundation into underground space have been planed and some experiments have been conducted. The objective of the model tests is to get precise data for the improvement of numerical models and to investigate the behaviour of local flow in the underground space and streets. Two models have been used here. The one is a ground-surface model (GS Model) of 1/100 scale to simulate surface flow and discharge into underground spaces. The other one is an underground-space model (US Model) of 1/30 scale to simulate flow in an underground shopping mall, a parking lot and a subway platform. GS model covers an area of 1km by 2km with two underground spaces. US model has three stories and covers an area of 650m by 40m. In the model tests, discharge, water depth and velocity are measured and flow is visualized by a tracer method. The discharge is measured by using weirs or buckets. The water depth is measured with an ultra sonic level meter. The velocity is measure by PIV method. Results of a predictable case are shown in this paper. The results show that about 50 percent amount of total volume of inundation water flows into underground spaces and that high speed flow over 2 m/s runs through a wide street. These results indicate that the flood hazard in urban area including underground space should be much taken care of.
Year: 2003