Resumen de Comportamiento hidraulico de los aliviaderos escalonados en presas de hormigon compactado
Stepped spillways are hydraulic structures that have regained a recent renewal in interest, that is associated with the development of new construction methods like the roller compacted concrete (RCC) and gabions.
An important number of stepped spillways have been observed in RCC dams, these hydraulic structures are compatible with the construction method and allow much higher energy dissipation along the chute, reducing the size of the downstream energy dissipator.
The macro-turbulent flow over the stepped spillway causes hydrodynamic loads on the steps that are of interest to study and affect the design and safety of the structure.
The present study is based on a significant set of experimental data gathered in three different 1v:0.8h sloped stepped chutes. The developing flow region is characterised with the growth of the boundary layer being focused. The mean and turbulent velocity field is studied. Also the dynamic pressures on the steps are investigated. Pressure field on the horizontal and vertical faces are studied for skimming and transition flow regimes. The scale effects on the pressure field are evaluated by comparing the results from geometrically similar models with different scales. The risk of cavitation on stepped spillways is analysed.
Some design guidelines are presented for stepped spillways over RCC dams.
Key-words: stepped spillways; RCC dams; skimming-flow; velocity; turbulence; pressure; cavitation; air entrainment.
