Combined diversion and service tunnel spillway of the Tashkumyr hydroelectric station

1. The designed diversion-service spillway with the combined functions of a diversion tunnel during construction and a spillway during service made it possible to eliminate the construction of a temporary tunnel and, thanks to this, to save about 4 million rubles. 2. The presence of a developed design of the gate equipment for the diversion tunnels of the Rogun hydrostation served as the cause of the layout of the tower intake with three intake openings at the Tashkumyr hydrostation. 3. A lightweight drained lining bolted to the rock and operating with the use of the load-bearing properties of the rock mass is used in the tunnel part of the spillway in relatively preserved-rocks. 4. The design of the anchor-grout cutoff is reliable in undisturbed rocks. In tectonic crush zones it is necessary to provide for other designs to protect the end structures of spillways from undercutting or to use additional measures along with the anchor-grout cutoff.