Study On Hydrodynamic Characteristics Of Protecting Structure In Plunge Pool Of Jinpingyiji Hydropower Station

With the hydropower resources development in recent years, a batch of high dams is under design or construction in China, their common characteristics are:"with high water head, with large discharge and narrow valley. Most of these projects use the type of flood discharge and energy dissipation by surface-bottom ski-drop flow combined with plunge pool behind the dams. The safety of protecting structure in high dam plunge pool is the key to success or failure of energy dissipation. Combined with Jinpingyiji model experiment and one special model experiment , hydrodynamic characteristics and the safety of protecting structure is studied in this paper, and according to the results, the uplift force probability criteria for judging the safety of bottom concrete slabs is also put forward. The main research work details are as follows:(1) The time-averaged pressure, fluctuating pressure, uplift force and their distribution in non-impact high dam plunge pool are studied through Jinpingyiji model test, especially the uplift force's distribution.(2) The relationship between uplift force and impact pressure, fluctuating pressure is studied through Jinpingyiji model test.(3) The difference of concrete slabs'uplift force between free end and blind end is studied through Jinpingyiji model test.(4) The relationship between concrete slabs'uplift force and its displacement of high dam plunge pool, the concrete slabs'uplift force and its resistance is studied through a special model test, the uplift force criteria for judging the safety of bottom concrete slabs is put forward.