Abstract: In order to solve the lack of energy dissipator and the low flood control capacity of spillway, rubber dam was constructed to improve the potential efficiency of spillway. To explore the effects of building rubber dam in the control segment on the hydraulic characteristics of spillway, factors such as the flood discharge capacity of spillway, the characteristics of flow and the effect of export energy dissipation were analyzed in association with engineering example. Research results show that: the discharge capacity of spillway decreases when being constructed with rubber dam, but safety operation of spillway can be guaranteed because the capacity still meets the damand of engineering design; the rubber dam has a little influence on flow velocity of spillway , and flow velocity variation of front of the dam is bigger than that of back of the dam; under the condition of rubber dam collapse or water filling, variation trend of water surface profile is similar, and sudden changing points are located near rubber dam or the position where gradient changes; moreover, the effect of rubber dam on energy dissipation and scouring prevention is slight, so it is feasible to construct a rubber dam in the control segment of spillway. The results can also be taken as reference for similar engineering design and disaster relief and strengthening of small and medium-sized reservoirs.

Key words: spillway, rubber dam, discharge capacity, flow characteristics, energy dissipation and scouring prevention