三峡工程坝下回流淘刷防治措施的研究

 三峡工程在三期围堰挡水发电期间，由于设在纵向围堰坝段上的排漂孔尚未建成，溢流坝段与下游纵向围堰之间存在宽50 m的空间，当泄洪深孔与导流底孔联合泄流时，坝下右侧的回流导致坝趾处严重淘刷。为解决这一问题，利用三峡枢纽局部整体模型，进行了多种工程措施的水力学试验研究，最后采用在防冲墙上桩号20+151及20+300处分别设置高10 m，18.5 m的隔流墩及坝下设护坦的措施。试验结果表明：护坦减轻了下游纵向围堰左侧坝趾处的回流淘刷，隔流墩明显减轻了防冲墙附近河床的冲刷，确保了坝基和下游纵向围堰的安全。

Study on measures to protect scouring caused by backward flow downstream from spillways of Three Gorges Project

During the third phase diversion of TGP,the floating debris outlets on longitudinal cofferdam will not have been built up.There will be a nonoverflow dam section of 50m long between the spillway and downstream longitudinal cofferdam.When deep outlets and diversion bottom outlets release flood together,the return flow at the right side downstream the dam will scour the dam toe seriously.In order to seek the protec measures a hydraulic experimental research has been conducted on the comprehensive model of Three Gorges Project.The final solution will be to set two current blocking piers of 10 m and 18.5 m high respectively at stake 20+151m and 20+300m on the scour resistant wall and an apron of 200m wide and 50m long starting from the dam toe and close to the cofferdam.The test results show that the apron can reduce back flow at the dam toe,and the piers can obviously diminish river bed scouring near the scour resistant wall.