市街地における洪水氾濫と土砂堆積に関する研究

Abstract

Nowadays, with the development of the outskirts of the big city and with the high degreeutilization of the land, gravitation of the population and property to the flood hazardous zones isadvancing. It is said that the potential of the flood disaster is increasing.Characteristics of the flood flows, for example, the advancing velocity of the front, unit streampower on the street and shape of the flood area in the urbanized city are much different from thoseof them in the plain field or suburbs.In this paper, by carrying out the hydraulic experiments, the characteristics of the overland floodflows advancing along the street in the modeled urban area were investigated. Numerical simula-tion was also carried out, and the calculated results were compared with the measured ones. Asthe results, it was found that the calculated results were in some agreement with the experimentalones, but flood water spread too much near the bank breaking point in calculation. This reason wasdiscussed from the view points of the experimental problems and the calculation methods.Moreover, concerning to the phenomena of the sedimentation due to breaking of the riverbanks in the modeled urban area, range and thickness of the sedimentation and grain-size distribu-tion were investigated based on the experimental results.