Study On Dispatching Operation Of Continuous Blasting Energy In Multigate Holes In Medium Water Head Dam

The overflow dam of Nanjia Reservoir in Jianhe County of Guizhou Province is a middle head water(60m)dam.This paper takes optimization operation of discharge energy dissipation in the continuous tailings of the dam as research object,and uses Flow-3d software to establish mathematical model,which is verified by physical model.The results proved that the experiment was basically consistent with the numerical simulation.Based on characteristics of engineering gate dispatching,this paper sets a three-level flow of Q=300m~3/s,Q=600m~3/s,and Q=900m~3/s to discharge at normal operating water level(560m)with numerical calculation methods.On the case of multiple gates combination opening methods at different discharge rates,by analyzing the flow state on crest,the average pressure on crest,the current on downstream bed,the floor pressure and the energy dissipation rate,hydraulic laws of the operation are given,so do the optimized dispatching methods at all levels.For the convenience of description,the opening of#1and#2 sluices at the same time is regarded as#1#2 sluice,while the#1,#2 and#3sluice is regarded as#1#2#3 sluice,and at the same time,#3,#4 and#5 are opened.The main results are as follows:(1)Through the numerical simulation of combined operation of gates of the Nanjia Reservoir,it is found that energy dissipation rate of the gates under small discharge is relatively large and can reach 39.7%at maximum.With increase of discharge,the energy dissipation rate accordingly decreases.There is limited change in the energy dissipation rate by adjusting opening of gates at the same discharge level.(2)Under normal operation,when the water level is small(Q=300m~3/s),the hydraulic parameters of each opening scheme are under the condition of less opening,1 hole is opened separately or 2 holes and 3 holes are combined to open.Within the scope allowed by the regulations,from the perspective of ensuring stability of flow,the impact on the dam site erosion and the relatively high energy dissipation rate,it is recommended that opening 2 holes,that is,#2#3 gates,is better.(3)Under the condition of normal operating water level medium discharge(Q=600m~3/s)scheduling operation,the comprehensive analysis is conducted under the principle of less opening hole or the principle of porous uniform opening,and it is found that each scheduling scheme does not have significant adverse water flow that would jeopardize the safety of the dam.From the perspective of opening gates as little as possible,reducing the workload of the gate scheduling and energy dissipation effect,it is optimal to open 3 holes,that is,#2#3#4.(4)When the normal operating water level(Q=900m~3/s)is scheduled to operate,comparing with 4-holes open,5 holes open schedule method is more stable and energy dissipation effect is better,so it is appropriate to choose it,that is,#1#2#3#4#5.