为了深入研究三峡工程建成后长江中下游干流河道及湖区河网的泥沙运动、江湖关系变化、洪水演进等问题，拟建长江防洪模型，同时利用数学模型计算和原型资料分析对模型中主要关键技术如河网中非恒定水流数值模拟技术、实体动床模型模拟技术等进行了初步研究。提出了如何确定变态模型泥沙悬移相似条件、天然河流泥沙起动流速值、水流挟沙比尺λs等问题，并探讨了解决这些问题的途径。

 For further studying the problems on the sediment movement in the stem stream and river net of lake region, river and lake relation change and flood routing of Yangtze River middle and lower reaches after the Three Gorges Project being completed, a Changjing River's flood prevention physical model is suggested to be built, together with developing mathematic model calculations and prototype measurement analysis. Several key technology problems related to the models are primary researched, e.g., numerical simulation techniques for unsteady flow in river net, physical model movablebed simulation techniques, etc.. Some problems, e.g., how to determine similarity criterions of suspened sediment in distrted model, sediment incipient velocities in natural rivers, and flow sediment laden scale, etc., are proposed. And routes to solve these problems are explored.