円柱橋脚の局所洗掘深さの予測 : 第1報,静的洗掘における水深/円柱直径≦1.2の場合

抄録

Previous experimental data concering to the terminal scour depth by clear-water scour around a circular bridge pier are examined thoroughly. The effects of the pier size D, the flow velocity U, the water depth h_o and the sand grain size d_s on the terminal scour depth are investigated. For the case of h_o/D≤1.2, which is a considerable effect on the scour, the main results obtained are as follows. The terminal scour depth Z_s/D is represented by a function of three dimensionless factors, the sediment number N_s=U/[(σ/p-1)gd_s]^0.5, the water depth h_o/D and the sediment Reynolds number Re_d=Ud_s/ν, where σ/p is the ratio of solid density to fluid density, and is formulated as Z_s/D=0.09N_s^0.24(h_o/D)^0.60Re_d^0.12. This equation agrees well with the former experimental data within ±7 %.