To investigate breaching mechanism of homogeneous river dikes due to overtopping and the impact of factors on the breaching processes,five experimental cases on dike breaching were conducted considering factors of inflow discharge,initial dike height and initial notch width.Results showed that breaching processes can be divided into four stages,namely initial stage of fast developing,middle stage of fast multiplying,later stage of developing gently and last stable stage.The head cut scour appeared during the first stage and the peak breaching discharge appeared at the second stage.When the initial notch width was wide,the breaching width wasn't likely to expand in the first stage.The water level and flow were both asymmetrical near the breaching notch,which made the breaching notches on both upstream and downstream sides develop asymmetrically in the left and right.Lar-ger inflow discharge and dike height both resulted in larger peak discharge.While larger initial notch width resulted in variation of back slope erosion form.Increase of inflow discharge led to increase of initial breach widening rate,and the narrower the initial notch was,the faster breaching notch widen.The results can provide reference for dike construction and emergency treatment in flood controlling.
关键词
堤防溃决/漫顶水流/溃决机理/物理试验
Key words
dike breaching/overtopping flow/breach mechanism/physical experiment
维普
万方数据