流木による河道閉塞に対する防止技術の基礎的研究

抄録

Rotators with asymmetrical projections could prevent a flood disaster due to a congeries of driftwood around a bridge pier and a bridge girder. In this study, two types of the rotator are proposed as a protection against driftwood at a bridge. One is a caterpillar-type rotator which a bridge pier is wrapped with. Another is a structure set in front of a bridge. Those rotators could be revolved by hydrodynamic force of flood flows. The mechanism of rotation is the same as that of Robinson cup anemometer. The effect of the rotation-type protections from a flood disaster was investigated by physical experiments.

As a result of this study, it is made clear that the rotators are able to control the congeries of driftwood. In addition, the latter rotator can prevent congeries of driftwood to some extent even if it never turns round in an unforeseen situation. Therefore, the rotation-type protections against driftwood are effective to protect bridges and prevent inundations.