三峡水库淤积平衡后坝区附近过水面积预估研究

Study on estimated area of flow section nedr Three Gorges dam after reservoir sedimentation balancing

本文根据葛洲坝水库运用后三峡坝区库段淤积的实际资料，包括淤积过程、年内、年际间的变化、进入淤积平衡的时间，分析了葛洲坝水库三峡坝区库段平衡横剖面的情况，它的特点、及不同流量过水面积的变化。并进而研究了平衡坡降、平衡面积的规律，确定了平衡面积及淤积平衡后不同流量过水面积与河宽的关系。最后采用两种途径预估了将来三峡水库淤积平衡后的坝区平衡面积及过水面积。得到的结果较之两个实体模型试验结果要大，与另一个模型相近。可见，由于过水面积偏小，流速偏大，所以从航运角度看，实体模型试验结果是安全的。

The operation of the Gezhouba reservoir and the sedimentation in its Three Gorges dam region are first presented , including the' process of sedmentation, yearly and inter-yearly variation in sedimentation, and the time when the sedimentation balance began occurring. The balanced cross sections, their characteristics and the variation in area of flow section for various discharges in the Three Gorges dam region of the Gezhouba reservoir are then analysed. Successively, researches deep into the laws of the balanced bed slope and area are conducted, and the balanced bed area and the relation between the area of flow section and the water surface width for various discharges in the case of sedimentation balance are determined. The results from theoretical analyses are rather consistent with actual data. Finally, two approaches are adopted to estimate the balanced bed area and the area of flow section in the dam region of the Three Gorges reservoir after sedimentation balance in future.The values of the estimated results are greater than those obtained from two physical models, and close to those from another physical model. It can be seen that from the viewpoint of navigation the results obtained from the physical models have some security since the area of flow section is smaller and the velocity is greater.