竹粉模型沙特性试验研究

Experimental research on characteristics of bamboo powder model sediment

对竹粉模型沙物理特性(容重、干容重、水下休止角等)和运动特性(沉速、起动流速和糙率)分别进行了试验研究。物理特性试验表明:其容重受粒径变化影响较小;干容重随粒径增大而增大;水下休止角随粒径增大而减小,并提出计算竹粉模型沙水下休止角的经验公式。运动特性试验表明:竹粉单颗粒沉速随粒径增大而增大,相对沉速随含沙浓度增加先增大后减小;起动流速随粒径增大而增大,随水深增大而增大,并提出估算竹粉模型沙起动流速的经验公式;糙率随水深增大而减小,随流速增大而增大。

Physical characteristics（including unit weight, dry unit weight and submarine rest angle）and mo- tion characteristics （ including settlement characteristics, incipient velocity and resistance characteristics） of bamboo powder model sediment are studied by test in this paper. Experimental study of physical characteristics shows that the particle size variation has little effect on unit weight, but the dry unit weight increases with the particle size, the submarine rest angle increases with the decrease in particle size and an empirical formula for calculating submarine rest angle of bamboo powder model sediment is proposed. Experimental study of motion characteristics finds that the single particle falling velocity of bamboo powder model sediment increases with the particle size, the relative falling velocity initially increases and then decreases with the increase of sediment concentration. The incipient velocity increases with the particle size and water depth, the roughness coefficient decreases with the water depth and increases with the flow velocity and an empirical formula for calculating the incipient velocity of bamboo powder model sediment is proposed.