India
Manipur
National Hydro Electric Power Corporation
3.81m. dia; 6,505m, long pressure tunnel surge shaft, pipe tunnel
The scope of work included construction of Head Race Tunnel, Pipe Tunnel, Shaft Tunnel, and Surge Shaft. Live storage of 39,655 hectare-meter in the Loktak lake was utilised for power generation at the Loktak hydro power station. The water conductor system for the power project consists of 3,490m. long power channel 3.81m. dia; 6,505m, long pressure tunnel surge shaft, pipe tunnel 273m. long feeding three penstocks 1,346m. long terminating in the power station on the bank of Leimatak River, Power state of operate under a gross head Q of 312m. with ultimate installed capacity of 3 units of 35 MW each, Tunnelling had to be done through very poor geological ground conditions consisting of highly, fractural shales, clay/silts of the formations of the terrace deposits and lake deposits. Highly flowing and running ground conditions were encountered. Explosive methane gas was also encountered in tunnels thus making the tunnel work very difficult and hazardous. Highly specialised and sophisticated precautionary measures and fire proofing equipment were used in the tunnelling work.
Power Channel 3490m. long
Pressure Tunnel 3.81m. dia x 6505m. long
Penstock (3Nos.) 1346m. Long