抄録
This paper deals with the results of field observation on the body change of Tri-Pyra groynes after floods and its consideration. Nine groynes which were made only by stone and gravel were constructed at the gravel and stone bed channel of the Kinu River. The length and the height of the groyne are about 10m and 2m respectively. Soon after the construction, floods occurred 4 times in 2 years. Field investigation and 2D flow calculation lead to the conclusions that the local erosion around the groyne during the floods was negligible and that the deformation occurs according to the coming off phenomena of surface stones of 20cm in diameter at high flow velocity larger than 3m/s. This information is considered to contribute to practical application.
