西藏扎拉水电站枢纽布置与设计研究

Research on design and layout of Xizang Zhala Hydropower Station

扎拉水电站水头高,泥沙问题突出,工程区地质条件复杂,存在活动断裂带、倾倒变形岩体发育。为减轻泥沙对水轮机机组的磨蚀,缩短引水线路穿越活动断裂带宽度,避开倾倒变形岩体的不利影响。通过多方案比选,确定了“下坝址以库代池,拦蓄泥沙;南线引水隧洞,避开闹中断裂影响带;上厂址地面厂房,利用河岸阶地的枢纽布置方案”。该方案最大限度减少了泥沙对机组的影响,避开了不利地质条件,节省了工程投资,同时充分利用了河段水头,发挥了工程最大效益,研究成果可为类似水电站枢纽布置设计提供参考。

Zhala Hydropower Station has high water head and prominent sediment problem,its geological condition is complicated,and the active fault zone and toppling deformation rock mass are developed in the procject area.In order to reduce the abrasion of sediment on the hydraulic generator,shorten the width of the diversion line through the active fault zone,avoid the adverse influence of the toppled deformation rock mass,through the comparison and selection of multiple schemes,the general layout was determined.The gravity dam was arranged in the lower dam site using reservoir instead of sand basin and trapping sediment,while southern diversion tunnel avoided the zone af-fected by Naozhong active fault,the ground plant was arranged at the lower power station site using the bank ter-race.The scheme can reduce the influence of sediment on the unit and avoid the unfavorable geological conditions to the maximum extent,save the project investment,fully use the river head,and exert the maximum benefit of the project.The study results can provide a reference for the design and layout of similar hydropower stations.