Abstract: After the running of the Lao-Mu-Kong hub, the water level in the reservoir area increased, flow rate generally decreased, the slope of the river became gentle, the capacity of sediment transport decreased, the sediment occurred cumulative siltation. In order to study the impact of siltation at the Le-Shan Giant Buddha in Le-Shan City, the sediment physical l model of river siltation at the reservoir area in reservoir area is created. Quantitative analysis of the amount of river siltation and sediment deposition distribution within 20 years, and predicted the river siltation at reservoir area. The results show that the sediment mainly siltation in perennial backwater area, but siltation little in fluctuating backwater area at the end of hub run 20 years. For all levels of frequency flood, flood level has not been more than the natural flood level of the same frequency before the construction after siltation at the reservoir area, so it has little effect on Le-Shan Giant Buddha and Le-Shan city.

Key words: waterway engineering, sediment physical model, siltation, perennial backwater area, fluctuating backwater area

摘要： 老木孔枢纽建成运行后，库区河段水位将有所升高，流速有所减少，比降将逐渐趋于平缓，水流输沙能力也会随之降低，泥沙沿河道易发生累积性淤积。通过历年实测资料结合动床物理模型试验，对水库运行20 a内河段泥沙淤积量、泥沙淤积分布情况做了定量分析。试验结果表明：枢纽运行20 a末，泥沙主要淤积在水库常年回水区，而变动回水区淤积甚少；库区泥沙淤积后各级频率洪水的洪水位仍未超过建库前同频率下的天然洪水位，对上游乐山大佛及乐山城区的影响不大。

关键词: 航道工程, 动床物理模型, 泥沙淤积, 常年田水区, 变动回水区