Reconstruction of the Angren pressure tunnel

1. The tunnel for diversion of the Angren River, constructed in 1971 for the first stage of operation, was designed in accordance with the then existing instructions [3]. 2. Publication of the new Instructions on the Design of Hydraulic Tunnels [5] made it possible to eliminate construction of the reinforced gunite ring planned for the second stage of construction, which saved 500,000 rubles. 3. The design of a similar pressure tunnel according to the new instructions [5] would save more than 1,300,000 rubles due to a reduction in the lining thickness and weigh of reinforcement, and the use of lightweight timbering of sprayed concrete and anchors instead of a protective roof.