中文摘要：

通过典型库区交汇河段模型试验研究了在汇流比与坝前水位影响下,断面平均流速和水流挟沙力的沿程变化规律,阐释干流淤积沙坝的形成机理及汇流比与淤积沙坝分布的关系.结果表明：水流由干支流向交汇区下游运行过程中,断面平均流速与水流挟沙力均存在由增到减的转折点,转折点位于干流交汇区内;当汇流比大于0.56时,从支流河道到交汇区下游挟沙力出现了骤降.水流挟沙力的不均匀变化导致了干流淤积沙坝的出现,汇流比的大小则决定了淤积沙坝形成的部位.随着坝前水位的升高,交汇河段淹没程度增大,交汇区内的转折随之弱化.

英文摘要：

Model test was designed to analysis the formation and distribution of silt bar in typical con‐fluence reach in reservoir .With the variable confluence ratios and reservoir water levels ,the mean cross‐section velocity and sediment carrying capacity along the reach were investigated ,and connection between the confluence ratio and formation of silt dam was verified .Results show that flow velocity turns from rise to fall in intersection zone ,and changes obviously as the confluence ratio increases ;sediment carrying capacity turns similar to the velocity except w hen confluence ratio is larger than 0 .56 ,which would keep reducing from tributary channel to the intersection zone;silt bar appears due to the inhomogeneous changes of sediment carrying capacity ,while the distribution is due to conflu‐ence ratio ;as the water level rises ,both velocity and sediment carrying capacity decrease ,inflection point is w eakened .