Applied Research On Water Cushion Pond Energy Dissipator Of Xiaqiao Hydroelectric Power Station

Arch dam with high degree of whole security and efficient economy,is a common dam type in the dam labor construction in recent severaldozens years. Arch dam is generally constructed in the narrow partof valleys, therefore the condition of terrain and geology at thedam location is very complex. At thesame time, thestructure of archdam is thin, and the overfall surface is very short when crest outletoverflows current, and the current will centripetally concentratewhen it overflows as an arc excretes on the stream plan, those willmake energy dissipation and scour protection difficult. The researchon the energy dissipation and scour protection with high-head andlarge-capacity arch dam has already become an urgent problem to besolved in the dam construction.The energy dissipation and scour protection of arch dam ofXiaQiao Hydroelectric Power Station is studied in this paper.According to the basic documents provided by engineering designdepartment, and on the basis of analyzing the theories of energydissipation and scour protection, the project model is established in the laboratory. The overfall ability, energy dissipation and scourprotection of XiaQiao Hydroelectric Power Station are roundlystudied. The main contents are included as follows:1. The overfall ability of the overfall arrangement scheme oforiginal design is validated and revised. The revised scheme makesthe current flow smoother to merge the main channel of the river.Meanwhile, the original sand particle size choice of moving bed modeland the method of spreading sand are demonstrated.2. Through the comparison of the arrangement schemes of downriverwater cushion pond at the initial study stage, the arrangement schemeof water cushion pond energy dissipation is chosen.3. In the optimization experimental stage, through severalschemes of section model experiment, the position and the height ofthe energy dissipation blanks of the Three-Banks Water Cushion Pond,and the structure type of the Three-Banks Water Cushion Pond usedto the whole model experiment are firstly determined.4. According to the type of water cushion pond structuredetermined by the section model, the type is further optimized inwhole project model experiment. The feasibility that the height oftail bank of the water cushion pond is increased, as well as the effectthat energy dissipation of the T Narrow Gap Frusta is more obviousthan the Nose bank or not, is mainly studied. And finally, the water cushion pond structure type is determined.5. Through the structure type and arrangement scheme of the watercushion pond determined above, combining the situation of both sidesof mountain body actual slope excavation in the dissipation area,dispose the dissipator according to the scheme modified by thedesigner, inspect follow current surface line, main section watersurface changing range, distribution of velocity flow, the conditionof eroding and filling at the place after the tail bank of the watercushion pond and distribution of flowing water press. And proposethe normal operation way of crest outlet strobes.Through the project model experiment, using the Three-BanksWater Cushion Pond can efficaciously solve the energy dissipationand scour protection problem of XiaQiao Hydroelectric Power Stationunder the bad geological condition. The experimental achievement hasbeen applied and validated to the XiaQiao Hydroelectric PowerStation.