Flume experiment on the influence of particle size distribution on sediment capturing efficiency of open-type steel Sabo dams

Abstract

The purpose of this study is to clarify the influence of particle size distribution on the sediment capturing effect of open-type steel Sabo dams constructed in the sediment sheet flow section. First, we conducted a flume experiment in order to clarify the minimum boulder size contributing to blockage (flume gradient was 5 °). Based on the result, we set the particle size distribution for a flume experiment to clarify the effect of particle size distribution on the sediment capturing effect of the open-type steel Sabo dams in the sediment sheet flow section. We found that the minimum boulder size contributing to blockage is 1/3 to 1/2 of the individual grid width. We tested the volumetric effects of sediment larger than the minimum boulder size on sediment capturing efficiency through its contribution to blockage. In addition, we defined the value obtained by dividing the blockage-contributing sediment volume per unit area by the average particle size as "dimensionless sediment volume contributing to blockage". We found that this "dimensionless sediment volume contributing to blockage" and sediment capture rate have a logarithmic approximation relationship. Thus, this value can be expected as a new index for setting the individual grid width of the open-type steel Sabo dams.