The pressure shaft, partially horizontal and mainly vertical is an underground structure to convey the water from HRT to the powerhouse for Power generation. The shaft is of 3.9m diameter and 419 m long out of which 32.6m is a top horizontal portion, 114.4m vertical portion, and balance 272m of the bottom horizontal portion. The pressure shaft is steel-lined to support the pressure of water.
Pressure shafts are underground circular openings like tunnels in which full pressurized flow of water is expected like in pipes. They can be simply realized as pressurized headrace tunnels but with smaller diameters and greater slopes (can go even vertical). They are useful when a quick drop in the waterway is required, for instance, in front of an underground powerhouse where almost horizontal headrace tunnels are to be connected with penstock. Depending on the water pressure and rock cover above the pressure shaft, they can be either lined with concrete or steel linings.
SALIENT FEATURE OF PRESSURE SHAFT
|BRANCH PIPES||3 nos.|
|SHAPEFINISHED DIAMETERSHAPE||Varying from 3.2m to 2.2m|
|BRANCHED PIPE LENGTH||140.14m|