Experimental evaluation method on capture performance of debris flow by steel open type Sabo dam

Joji SHIMA, Tomoo MATSUBARA, Nobutaka ISHIKAWA and Takahisa MIZUYAMA

Abstract

This paper presents an experimental evaluation method on the capture performance of debris flow by a steel open type Sabo dam (hereafter, steel open dam). First, the hydraulic tests for steel open dams are conducted to examine the outflow sediment, the capture height‐time relation and the grain size distribution of outflow sediment by changing the riverbed slope and slit interval of dams. Herein, the capturing performance types by a steel open dam are proposed as the classification such as “complete blockage type”, “partial blockage type” and “control type”. It was found that the steel open dam with narrow slit interval showed “complete blockage type” which represents a good capture performance, regardless of riverbed slopes. It was also discovered that the capture height‐time relation was a good measurement for the examination of capture process of debris flow. Second, the three different types of steel open dams in the most downstream are tested against three different scales of debris flow. It was confirmed that a new type steel open dam for the most downstream was proposed and showed good capture performance against different scales of debris flow.

Key words

steel open dam, capture performance type, debris flow, capture height‐time relation,