TERRATEC has announced that the Ø9.86m Hard Rock Double Shield TBM being driven by Hindustan Construction Co. Ltd – primary contractor on the Vishnugad-Pipalkoti Hydropower Project in India – has made significant progress with an impressive 431m excavated in January 2024.
Situated in the Uttarakhand state, approximately 500km northeast of Delhi, the project encompasses the construction of dams, waterway tunnels, vertical shafts, and a powerhouse boasting a generating capacity of 444MW.
The Double Shield TBM has been specifically designed for the construction of a crucial low-pressure head race tunnel, integral to the hydroelectric power system. This TBM is outfitted with customised features aimed at completing the 13km tunnel.
The alignment for the Vishnugad-Pipalkoti Hydropower project primarily traverses Dolomitic Limestone (33%) and Slates (64%), with the remaining 3% passing through critical geological sections. These sections include Thrust Zones, Shear Zones, and Fault Zones, which pose significant challenges necessitating the TBM’s specialized engineering. TERRATEC is also providing the Continuously Advancing Tunnel Conveyor for the project.
Designed to meet the specific demands of the project, the Continuously Advancing Conveyor will have a length of 13km and operate at a rate of 1200t/h. The conveyor is capable of efficiently handling the various materials extracted by the TBM along the entire length of the tunnel. The conveyed materials are expected to vary from sandy gravel to boulders.
TERRATEC’s unique and patented design of the Advancing Tail Piece levels the Tunnel Conveyor using an active hydraulic system to match the steering/rolling position of the TBM. This enables the smooth negotiation of any horizontal and vertical curves.
The TBM’s Cutterhead boasts 19” disc cutters and twelve large bucket openings, facilitating excavation through expected hard rock with its 4,200kW electric main drive delivering a torque exceeding 22,000kNm. As the TBM advances, universal reinforced concrete lining rings, 1,500mm wide and 350mm thick, are installed, each comprising five segments plus a key.
The project entails the implementation of a run-of-river scheme, incorporating the construction of a diversion dam measuring 65m in height across the Alaknanda River, with power generation facilitated by a gross head of 237m. The reservoir is slated to hold a gross storage capacity of 3.63M cubic meters, of which 2.47M cubic meters will serve as live storage. A diversion/spill tunnel, intake tunnels, underground sedimentation chambers, a headrace tunnel, a surge shaft, pressure shafts, and penstocks, along with two separate underground caverns for turbine and transformer installations, constitute the water conductor system.
The addition of 444MW capacity in the Northern region will significantly alleviate peaking power shortages, with the project designed for 1657.09 MU energy generation. Notably, 13% of free power allocated to Uttarakhand will allocate 1% for local area development.
Terratec
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