关键词: 起动流速;起动切应力;孔隙比;水流流速;冲蚀率;

Abstract: The erosion of riverbank sand has a great influence on the stability of the bank slope. It is difficult for traditional erosion instruments to conduct quantitative research on the soil initiation and erosion rate during the erosion process. A new type of erosion device for testing the erosion resistance of the soil was designed and produced. Based on the soil mass loss,the erosion state of the river bank was simulated. A mathematical model of soil erosion was established by a single variable starting test and erosion test. The results show that:(1) when the scouring rate of riverbank sand reaches 2 × 10-5～ 4 × 10-5 s-1,the starting velocity is reached．(2) The starting velocity is proportional to the void ratio and inversely proportional to internal friction angle. The starting shear stress can be expressed by void ratio and internal friction angle．(3) The erosion rate of soil is positively correlated with void ratio and water flow velocity．(4) The erodibility coefficient of the same kind of sandy soil is proportional to the 5. 5 th power of the flow velocity. The erosion rate can directly reflect the erosion resistance of the river bank.

Key words: starting velocity; starting shear stress; void ratio; water flow velocity; erosion rate;