多数水利枢纽拦河坝上设有泄洪道。为了泄洪、冲砂及放空水库,有些泄洪道采用底孔或中孔泄洪,孔中设闸门控制水流,闸墩胸墙均为钢筋混凝土结构。有些泄洪道,由于地基摩擦系数低,泄洪道抗滑稳定计算要求泄洪道混凝土量很大,这样钢筋混凝土结构强度不能充分发挥作用。为了节约混凝土,用一些石碴替代混凝土对泄水道进行压 Most of the dam hydroelectric dam has a spillway. In order to flood, flush sand and venting reservoirs, some of the spillway using bottom hole or hole discharge flood, the hole in the gate to control water flow, pier wall chest wall are reinforced concrete structures. Some spillway, due to the low coefficient of friction foundation, spillway slip stability calculation requires a large amount of concrete spillway, so that the strength of reinforced concrete structures can not fully play its role. In order to save concrete, some of the ballast instead of concrete to drain the pressure