Experimental Research Of Pressure Characteristic On Stepped Overflow Dam

The stepped overflow technology used for release excessive water and dissipation flow energy have a long history. In recent years, along with the development of the roller compacted concrete(RCC) dam technique, the stepped overflow dam which with special type of figure and remarkable energy dissipation efficiency that have already plentiful adopted in small scaled hydraulic engineering in thedomestic and internationally, and start being used in the high head of water hydraulic structure gradually. Currently the study about hydraulic characteristic of the stepped overflow dam still being in the starting stage and mostly concentrated on the emery dissipation efficiency, the pressure characteristic that directly influence dam stability have no any system research result up to now. For this reason, according to the similarity criterion of gravity, we make a model test that mainly study the characteristic of mean pressure, peaks, amplitude and frequency spectrum of the pulsation pressure on the overflow dam which grade distinguish between 40° , 50° and 60° for the three different flow regime and three different step hight in 16cm, 8cm and 4cm, the experiment discharge is between 0.004—0.237m~3/(s·m)The conclusion can be drown through the model trial:(1)The flow regime on the overflow dam can be divided into the nappe flow, transitional flow and skimming flow.(2)The mean pressure on the step face follow the dam distance is bigger value and small value alternation emergence, whole negative mean pressure concentrated in the neighborhood of the step perpendicular face salient angle, With the aggrandizement of the discharge, the area of the negative pressure reduce and the value increase; The mean pressure appear in the step horizontal...