三峡工程导流底孔布置试验研究

Experimental study on layout of TGP diversion bottom outlets

三峡工程导流底孔布置在泄洪坝段，共２２孔，运行条件复杂，布置上需满足泄流能力和截流落差要求，同时还兼顾下游水流衔接与下游消能防冲。通过对长有压管导流底孔３种优化体型试验结果分析，将进口高程、鼻坎挑角和鼻坎高程各不相同的３种体型导流底孔组合布置，其中两个边孔为出口挑角和鼻坎高程最大的体型３，中间１６孔为出口挑角和鼻坎高程最小的体型１，其余４孔为体型２。经过局部整体模型验证，提出的导流底孔布置方案，满足了各项要求，为设计采用。

The diversion bottom outlets of the Three Gorges Project, 22 outlets in total, are arranged in the spillway dam section. Since the operation conditions of these outlets are very complicated, their arrangements need to meet requirements of discharge capacity and water drop at river closure gap, and also to take account of continuity condition of flow, energy dissipation and scour prevention downstream of the structures. By means of analysing the expeimental results of 3 optimized configurations of the diversion bottom outlets with a long pressure conduit,the three configurations different from each other in elevations at entrance and bucket lip and in deflection angle of the bucket are compositely arranged, of which 2 outlets of configuration 3 with greatest deflection angle and highest bucket lip elevation are distributed on the both sides of the dam section, 16 outlets of configuration 1 with least deflection angle and lowest bucket lip elevation are distributed on the central portion, the other 4 outlets are of configuration 2. The proposed layout scheme of the diversion bottom outlets has been verified by a locally comprehensive model, and meets all requirements. This composite arrangement is adopted by designers.