Study on the alternative of reconstructing the diversion tunnel into rotation-flow flood-releasing tunnel for the Gongboxia Hydropower Station

In order to reduce the reconstruction risk of the flood releasing tunnel in the right bank of Gongboxia Hydropower Station, the Northwest China Investigation and Design Institute and the China Institute of Water Resources and Hydropower Research have jointly compared and proved the alternatives of the original flood releasing tunnel, and new shaft rotation flow and horizontal rotation flow flood releasing tunnel, in accordance with the technology, economy, geology, construction and the current actual conditions of the Gongboxia Hydropower Station. Meanwhile, the feasibility of the application of horizontal rotation flow flood releasing tunnel to the Gongboxia Hydropower Station was studied and stressed. The research results showed that the alternative of horizontal rotation flow tunnel has high energy dissipation efficiency, low project investment, and outstanding technical and economic benefits.