Abstract:

In Xiluodu Hydropower Project, a ventilation shaft with more than 200 m depth has been designed for the main transformer chamber of the underground powerhouse. Many unexpected problems, which have never been encountered in previous similar projects, have occurred during shaft sinking due to the high technological requirements, great construction difficulties, poor operating conditions and extreme safety risks. Shaft sinking sequences, shaft sinking methods, blasting parameters and survey points/lines have been determined on basis of the site resources and the geological conditions. The countermeasures for the geologic risks at the bottom opening of the shaft have also been fully considered. Thus, the sinking of the 221.86mdeep vertical shaft has been completed with high quality. The sinking of the ventilation shaft in Xiluodu Project is universe in hydropower fields, therefore the experience may serve as reference for the sinking of other shafts of future hydropower projects.

Key words: hydropowe project, underground powerhouse, ventilation shaf