The Model Test And Hydraulic Calculation Research Of Labyrinth Weir Circular-ring Sediment Desilting Basin

The circular-ring sediment desilting basin has a good effect on solving water flushing problem. It still needs to make great improvements gradually in order to play its greater role. In this paper, the weir optimized round Central settling sediment pool, which named ring circle labyrinth weir type, to do the physical model test and hydraulic calculation analysis. It shown the effect of improving its results and settling of sediment concentration, and also provide reasonable basis for the layout design of the similar settling basin, as the main conclusions follow:Firstly, triangle palace labyrinth weir round Central settling sediment weir head on the pool make the same flow rate by an average of 1.34 mm, and geometric parameters of the palace meet the needs of hydraulic design.At the time, it also appropriately reduces the footprint and cost of the project, but the trapezoidal labyrinth weir palace would be better when the flow rate is small. Compared with the two wire types settling effect through model test,the sediment distribution of ring circle labyrinth weir,along the vertical and radial,which is basically the same with smooth wire, and the sediment inside of labyrinth weir decreases 16.5% in average than smooth weir,suggesting that has certain effect on changing the sand and water quality. To Q=4.09L/s center water outlet ring not heightened state as an example to make the analysis on the sand, that labyrinth weir type circular central silt in less than 0.1mm of fine sediment is higher than that of the smooth weir by 15.4%, and largest export heavy sand particle diameter is 0.2 mm,median grain size is 0.0635 mm. Which decreases11.19% than smooth weir(0.0715mm), indicating the adjustment to the labyrinth weir can effectively improve the suspended sediment sedimentation rate and to improve the efficiency of agricultural irrigation and to promote the development of the economy.Based on the sedimentation rate, calculation method of sedimentation rate and flushing time theory,the law of sediment settling velocity and different particle size range settling velocity formula; and the one-dimensional over saturation sediment transport of circular central sedimentation basin sediment sedimentation rate of each grain size and different flow sediment the total settlement rate made the theoretical calculation, the calculation value and test value of deviation is smaller, about 2.82% and 1.50%;and the sediment on the slope of the stress analysis, the sediment critical stress and converted to the critical velocity, namely that flushing the desired flow; and then calculate the three sand stage time, total duration and water consume rate, extremely close to the experimental value, indicating accurate and reliable calculation method and relevant parameter selection.Finally use the the formula of sediment deposition rate roll out the relationship between the diameter of the overflow weir and the water inflow and the minimum sediment particle size, then designed to the plane diameter, depth and slope when the basin conditions is given, provide a theoretical basis for rational design of similar sedimentation basin.