三峡工程导流底孔体形研究

Geometry of Bottom Diversion Outlets

三峡工程导流底孔是三期导流期间洪水下泄的主要通道，运用条件复杂，研究了短管和长管两种方案：“短管”方案特点有压段短（长16．22m），弧形门位于坝体腹部，门后为明流段；“长管”方案有压管道长（82m），弧形门设在坝下明流段，对坝体削弱较小，闸门安装和拆除方便，封堵工作量较小。设计选用了“长管”方案。

The bottom diversion outlets at the Three Gorges Project will be a major way for flood discharge during the third -stage diversion period, with complicated operation conditions.Two layouts have been studied, including 'the short conduit' and 'the long conduit '. They are characterized by a 16. 22 m long pressure conduit connected with a open conduit and a radial gate located in the central part of the dam, and a 82 m long pressure conduit connected with a 28 m long open bucket and a radial gate, respectively for 'the short conduit' and 'the long conduit'. Finally, the latter has been selected by the designer due to its less reduction to the dam body, ease to install and remove the gate, and smaller plugging works.