RELATION OF FLOW VELOCITY AROUND RIVERBANK AND FORMATION OF OVERHANGING BANK

Abstract

There is a possibility of cohesive soil being used as a material of riverbank. For this purpose, it is important to investigate and estimate the erosive resistance of cohesive soils against the stream flow. Several studies on the erosion of cohesive soils have been made in recent years. In previous studies, the dynamic processes of bank erosion have been clarified. We have accumulated the knowledge about mechanism and process of erosion in cross and longitudinal directions. However, the knowledge is not sufficient in estimating the erosion amount and erosion speed.
The point of this paper is to examine the relation of flow velocity and erosion rate. Some hydraulic models were made to measure the flow velocity around eroded area in detail. One model reproduced faithfully the shape of erosion experiment to examine the longitudinal change in velocity, and another simplified the feature of overhanging bank to examine the effect of erosion angle. The important relations of flow characteristics and erosion mechanism are found as the consequence of those experiments.