Test Study On Measures Of Sluicing Sediment For Hydropower Station Project Of Gangqu He Stage Ⅱ

Sediment is the Universal problem of hydropower stations and reservoirs. Design of sediment protection and sediment ejection is key technology for hydropower station. After the construction of the dam, its form of movement is changed, velocity reduced in the reservoir, which leads to deposition of Sediment in Reservoir Area , Sediment Ejection is often encountered for design,operation,management of Reservoir.Hydropower station of GangQu River stage II is located in the mainstream of Shangri-La County of Yunnan Province, and it is a cascade hydropower station with a total installed capacity of 140 MW. It is consisted of 3 outlet sluices and retaining dam on each bank and a hole-ranked bleaching .The greatest height of dam is 29.1 m.This article establishes the normal hydraulic model by scale of 1:50, The bedding sand model is used in sediment test to study the engineering hub of the desilting measure.The three major research questions are as followed: (1) From of flood discharging and sediment in reservoir; (2) Form of the sediment deflecting sill. (3) Impact of demolition height of cofferdam to sediment ejection.For the erosion of project, the contrast test is done under a normal water level under the five typical conditions and three typical flows, the reault is as followed: there is no condition can get better result under normal water level, which required the emptying reservoir desilting,It can get a better result when it is open channel befor the gate and the gretter the flow,the better the result.At last,the flow of 169 m3 / s is relatively favorable.For Sediment deflecting sill of project, comparison is adopted for two shape and a straight-size, the two still relatively high, the two set point and sediment deflecting sill number are comparised.Man-made slopes with scales 1:20 in front of the platform diversion port benefit to flush before gate. The results showed that: a set point for the 60 o, the top elevation of 2372.0 m straight sediment deflecting sill can meet the engineering requirement.Through the three model tests of different remaining elevation for cofferdam, the impact on flow pattern and water level is demonstrated.The test result is showed that: under the condition of emptying the reservoir, demolition height of cofferdamheight has grest effect on flushing, the lower the retaining height,the better the result. Combining project practice and test result,the demolition elevation should be lower than the elevation of diversion plantform which is 2370.0m.