The invention provides a rock-plug type
water intake for the circulating water of power plants, as well as a construction method thereof. The rock-plug type
water intake is arranged near a deep
pool and mainly comprises a rock plug, a
ballast collection pit and a derivation tunnel behind the
ballast collection pit, wherein the derivation tunnel is arranged in a mountain body; an axis close to an inlet segment declines so as to keep the axis of the rock-plug type
water intake at an upward inclination angle between 35 and 60 degrees; the outlet end of the derivation tunnel is directly connected with an inflow forebay of a
circulating pump room; the sinking-type
ballast collection pit is built between the derivation tunnel and the rock plug; the cross sections of the derivation tunnel and the rock plug are round, similarly round, square or rectangular; and the thickness-
diameter ratio of the rock plug is between 1.13 and 1.50. The construction method comprises the following steps: the excavation construction of the derivation tunnel and the ballast collection pit is performed according to a new Austrian method; whether to line or not is determined according to the conditions of
bedrock; the rock plug is blasted by use of a presplitting and
millisecond time
interval method; and once the rock plug is blasted, all ballast of the rock plug enters the prearranged ballast collection pit under the action of external
water pressure. The construction method has the advantages of reducing project investment, shortening construction period, improving the operation efficiency of a circulating water
system, and the like.