在大体积坝中排水设备起着重要的作用:排水设备能大大减小渗透水压力,能在必要时防止混凝土受水的化学作用,亦能保证建筑物的永久性等等。混凝土坝的排水设备通常做成一排或数排在坝的全长上都有的垂直孔,垂直孔距坝的上游面为2～5米(取决于水头)。在各排内排水孔间的水平距离一般采用约为1.5～2米。排水孔的直径,正如实践所证明的,为了避免被碳酸钙所堵塞。应采用150～200毫米。 Drainage facilities play an important role in large-volume dams: drains can significantly reduce permeate water pressure, prevent concrete from being affected by water when necessary, and ensure permanent building and so on. Drainage facilities for concrete dams are usually made up of one or more rows of vertical holes all over the length of the dam, with vertical holes 2 to 5 meters upstream from the dam (depending on the head). Drainage holes in the horizontal distance between the general use of about 1.5 to 2 meters. The diameter of the drain hole, as proven by practice, is to avoid being clogged with calcium carbonate. Should be used 150 ~ 200 mm.