结合上海市合流污水治理二期工程排放管稀释扩散规律及泥沙冲淤规律的研究，利用泥沙运动相似理论，通过模型试验，从环境泥沙淤积在上升管喷口上的最不利条件出发，分析喷口对泥沙的冲淤规律，提出喷口冲淤临界流速的概念，并据此提出适宜的上升管高度及喷口射流角度。 Based on the research on the law of dilution and diffusion of discharge pipe and the rules of sediment erosion and sedimentation in the second phase project of Shanghai Convergent Sewage Treatment Project, by using the similarity theory of sediment movement and through the model tests, starting from the most unfavorable conditions of sediment deposition in the ascending pipe, Analyze the scouring and silting law of the spout on the sediment, and put forward the concept of the critical flow velocity of scour and silt in the spout, and put forward the suitable riser height and the angle of the spout jet.