巨石が点在する自然河川の河床安定化に関する実験

抄録

The bed stabilization effect of boulders in rivers was studied by a wind tunnel experiment. Boulders were modeled by metal spheres with diameter D = 2.0 cm and were set in a sand layer, and the boulder occupancy ratio αdefined as (πD²/4)/ℓ² (ℓ: boulder interval) in a square array was 0.014 - 0.087. The bed erosion velocity clearly decreased in the presence of boulders, and then, changed by the parameter α and would be the minimum around α = 0.056. In conclusion, it was found that boulders in rivers significantly stabilize bed variation, and that their effect will be great in the medium occupancy ratio.