Experimental Research on an Improved Slope Protection Structure in the Plunge Pool of a High Dam

Due to impinging jets, the hydraulic load in a plunge pool can be very large and may cause serious damage to the slope and bottom protection structures. Conventional research mainly focuses on the stability of the plunge pool floor, and studies on slope protection safety are still lacking. Based on the Wudongde project, a physical model (that does not consider the plunge pool floor) was established. A series of experiments were conducted to investigate the protective measures for slope protection. Experimental results showed that the high seepage pressure on the back surface of the slope lining plate and poor correlation between the fluctuating pressures on both plate surfaces may cause large pressure differences that seriously threaten the stability of the slope lining plate. Therefore, a self-drainage slope protection structure was proposed to reduce the hydraulic load on a slope lining plate. It must be noted that the slope lining plate with the most violent water level fluctuation and adverse operating conditions (when the drainage system and part of the waterstops were invalid) were considered in the model tests. Test results indicated that self-drainage slope protection could enhance the synchronism of the pressure and water-level fluctuations on both plate surfaces. Therefore, the proposed slope protection structure could effectively reduce the total pressure on the plate and significantly increase the operational safety of the plunge pool.