In order to analyze the worst successive collapse disaster that may occur in the cascade hydropower hub group under extreme conditions,this paper proposed two dam-break conditions:the first is for earth-rock dams or damaged and dangerous gravity dams and arch dams,in which dam breaches once overtopping.The second is for normal gravity dams and arch dams,in which the overtopping didn't cause dam breach,and the weir flow formula was suitable for discharge calculation.In both cases,the flood peak flattening formula was used to calculate the routing process of dam-break flood to the downstream.An analysis was carried out for 13 cascade hydropower hub groups in Dadu River Basin.The results show that the downstream Luding,Dagangshan and Pubugou hydropower stations can resist and dissipate part of the upstream dam-break flood,so they are considered as the control dams in the basin.The dam-break impact of condition 1(collapse once overtopping)is worse than that of working condi-tion 2(no collapse in overtopping),with water volume is larger,the duration is shorter,and the peak flow is larger.The discharge process is related to the storage capacity,distance and the water level for condition 1.However for condition 2,the discharge is closely related to the storage capacity,the water level and the dam type.The cascade hydropower stations layout of small reservoir at upper and large reservoir at lower and the selection of dam types mainly gravity dams and arch dams will effectively reduce the risk of dam successive break in cascade hydropower hubs.The research results can provide a theoretical basis for the risk analysis of successive dam failure of cascade hydropower stations.
关键词
梯级水电枢纽群/大坝连溃/溃坝洪水/极端工况/洪水演进
Key words
cascade hydropower complex group/successive dam break/dam-break flood/extreme condition/flood routing
维普
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