Among large-scale dams with high water head in our country,the Laxiwa Hydropower Station is the first project that adopts counter-arched water cushion pool as its downstream energy dissipator.It is also a cushion pool with the shortest length and the narrowest width among the existing extra-high arch dams in China.Its energy dissipation ratio of unit water body ranks the first among ones of its own kind and close to the highest standard of other countries.Designs of counter-arched water cushion pool structure and drainage-pumping system and so on are optimized after a series of research,experimentation and computation without clear provisions of codes and shortage of engineering data.The design experience of counter-arched water cushion pool enriches contents of the downstream energy dissipator for China,but also has important referent value for the design code and other large scale high-head dams.

The dam for the Laxiwa Hydropower Station is a double-curvature thin arch dam with the maximum dam height of 250m and is located in the cold highland area.The concrete of dam body adopted the pouring throughout working surface.To ensure the concrete quality and according to the characteristics of the Laxiwa Hydropower Project,we determined that the technical requirements of raw materials of concrete and the design principle of concrete mix proportion and put forward the concrete mix proportion that is suitable to this project.