Study on Sediment Sorting Characteristic sand Transport Mechanism of Engineering Accumulation Slope Erosion

 In order to reveal the sorting characteristics and transport mechanism of sediment on the steep slope Of engineering accumulation driven by runoff,three simulated runoff scour experiments were designed under The conditions of 10,20,and30 L/min from above to analyze the particle distribution characteristics of erosion sediment on the steep slope(32°) of the accumulation body of the Yangling project. The results showed that the clay and fine silt in the eroded sediment (before dispersion) increased significantly compared with the original soil, which was easy to produce erosion. The influence of runoff on aggregate fragmentation of erosion sediment clay content and the influence of runoff on pellet crushing effect on clay content is negative when runoff power is less than 1.709N/(m•s), but positive when runoff power is greaterthan3.89N/(m•s). In sediment，fine and coarse silt particles are mainly transported in the form of single grain, while clay and sand particles are mostly transported in the form of aggregates. Clay particles are enriched and sand particles are depleted. The sediment particle size determines the main transport mode,<0.11mm sediment particles are mainly suspended saltation transport,>0.11mm sediment particles are mainly rolling transport,More than 80% erosion sediment particles are transported by suspended saltation, and the contribution rate of rolling transport increases first and then decreases with the increase of runoff transport capacity. The conclusion of this study will help to reveal the micro mechanism of slope water erosion process of engineering accumulation body, and provide scientific basis for improving the prediction accuracy of slope water erosion model of engineering accumulation.