開水路流れに設置された橋脚周辺の水理特性について(4)

Abstract

In order to anticipate various aspects of local scouring phenomena around a bridge pier, adynamic and flexible model will be necessary which reflects the essence of the phenomena. Sucha model was constructed considering tractive force due to horseshoe vortex, geometrical similarityof scour hole and mass balance of sediments in the scour hole. The model explained the feature ofscouring process which has been observed in flume experiments under steady flow conditions, suchas development of scour depth with time under the condition of clear water scour, oscillation ofscour depth associated with migrating dunes, relation between the amplitude of the oscillation andthe expected dune height and so on.The response of scour depth during a flood in a river was simulated using present scourmodel, and a suggestion for design criteria was discussed on the basis of the information obtainedby the model.