一、问题的提出及研究途径对于大中型水利枢纽主体工程施工期间有通航要求的明渠导流方案,整个导流系统可以看作是由导流明渠、明渠进出口与天然河道衔接的引航段、及上下游挡水围堰这三个子系统组成的。 I. Issues raised and research approaches For the diversion plan of open channels required for navigation during the construction of large and medium-sized hydroprojects, the entire diversion system can be regarded as the pilot section connecting with the natural river channel by the diversion and open channels, the open channel import and export, And the upper and lower water retaining cofferdam three subsystems.