The formation mechanism of debris flow head

1991

11 S.

13 Abb., 2 Tab., 5 Lit. Ang.

Bandaufführung

165146

It is observes in lavoratory and in field that debris flow has a convex head and a following quasi-steady flow in which the flow depth is unchangeable. These parts of debris flow travel down, keeping a definitive shape. Takahashi (1977) explained this mechanism, but the autohors obtained another results and process. The experiments in two conditions were made, one is saturated bed, the other is wet bed. The remarkable difference was recognized by the observation of these experiments. Namely, in case of the former the deposition layer was started to move before the head was formed. In the letter case the flow picked up the bed materials for the surface of the bed after the head passed and those grains were conveyed to the head. This head has the unsaturated part and the velocity of the suturated part is equal to that of the bore shape. Ther are three parts in debris flow, head part, quasi-teady part and following part. This quasi-steady part dominates whole part of debris flow.