FIELD OBSERVATION ON THE RCC STEPPED SPILLWAYS WITH THE FLARING PIER GATE ON THE DACHAOSHAN PROJECT

摘要

The Dachaoshan Project has adopted the flaring pier gates on the surface spillway, a small flip bucket at the end of the pier and a stepped spillway combined with RCC construction techniques on the main dam. The hydraulic field observation was made in June 2002 with the design reservoir water level and mainly concentrated on the pressures, velocities and aeration concentrations on four steps. Operation experiences for a dam height over 100 m and unit width discharge over 165 m~3/s/m were achieved by this project. The observation results show that a small flip bucket 2 meters high is very effective to let the trajectory flow away from steps and ensure enough aeration between the bottom of flow and steps.