Study On Incipient Motion And Transport Characteristics Of Non-uniform Silt

After the completion of the Three Gorges project into library, the sedimentdeposition in the reservoir area has been the focus of attention. According to the statisticalanalysis of hydrological data, medium diameter of sediment in the Three Gorges reservoiris basically less than0.05mm. This sort of sediment was researched mainly in the estuaryand coast. Silt in natural rivers, general as wash load, is less studied.Based on theprototype measurement data in recent years, the typical area of the sediment deposition inperennial reservoir of Yangtze River is the silt. As the wash load is not desirable, Startingand transport characteristics of this silt and the traditional sand are quite different. Theproblem of this silt with adhesiveness in hydraulic engineering is very common, startingand transport of this silt is significantly important for to port, the design of channel,maintenance, back silting volume. Resuspension quantity estimation and reservoir, lakeand river sediment scour, are also of the vital significance.Starting and transport is a basic problem to study the regular pattem of sedimentmovement. This thesis mainly proced field measurement test and water channel testresearch with natural sand of the three Gorges reservoir,Combined with the data, andanalyzed of the starting and transport characteristics of typical silt.In orde to providesupport to the study of regular pattem of sediment movement and channelimprovement,the specific works of this paper are as follows:①Collect in estuary, coast and reservoir about typical sediment movement researchresults from domestic and overseas, and the existing problems were summed up.②Acoustic doppler velocimetry and underwater camera observation system consistof prototype measurement system.prototype measurement in Huanghuacheng reach andFengjie reach,Study on the critical starting condition of the bed sediment in differentwater depths, different dry densities and different grain sizes.Provide deep watervalidation data for analysis of non-uniform silt starting characteristic.③Based on the water channel test and field measurements of non-uniform silt, andcombined analysis of typical results about starting with domestic and overseasscholars,Build up a starting formula of cohesive fine non-uniform sediment, verified bydata of field test measured and the results of others.④The acoustic signals AMP denoising with wavelet analysis,obtain valid data ofAMP.According to results of the field measurement demarcate relationship of acousticintensity BSI and sediment concentration.Analysis of suspended sediment concentration distribution along the depth, and compare with the Routh formula.Through the analysis ofsuspended sediment concentration distribution along the depth, the vortex motion andsediment concentration turbulence triggered picture.Put forward the vortex movementand sediment concentration of turbulence trigger prospect⑤Summ up the research of this paper,Point out the merits and demerits of startingand transport characteristics in this paper.It has been discussed and prospected that thefurther research can be carried out.