小湾水电站施工导流总体设计

Overall design of construction diversion of Xiaowan Hydropower Station

小湾水电站施工导流流量大、导流建筑物规模大、运行期长、坝址段河床堆积渣严重、围堰基础防渗处理困难。施工期对导流建筑物等级,施工时段划分,各时段导流方式,导流标准、导流程序和导流建筑物等进行了优化。由于河床堆渣严重,给导流隧洞工程和围堰工程的施工造成的困难也采取了对策,取得了显著效果。

The construction diversion of the Xiaowan Hydropower Station is mainly characterized by large diversion discharge, large size of the diversion structure, long operation period of time, heavy spoils accumulated in the dam site section and difficult cofferdam foundation leakage control. The paper gives a presentation in its first part of the overall design conception of grade determination of the diversion structures, division of their construction stages and diversion approaches at each stage, diversion criteria, diversion procedures and diversion structures. The paper describes in its second part the staging of river closure, criteria and method of river closure. The paper deals with the priorities, major difficulties and engineering measures taken in construction of both the diversion tunnels and the cofferdams in its third part.