Tehri Dam Project — CP Systems

Mega Project

Tehri Dam — India's Tallest Dam

Multiple phases of critical work at Tehri HPP (1000 MW) and Tehri PSP — including river dredging of the Bhagirathi River, construction of a 47m baffle wall, HRT/TRT tunnel repair with epoxy mortar, micro piling, drilling & grouting, and epoxy treatment at intake structures.

Client
HCC / THDCIL

Location
Tehri, Uttarakhand

Dredged Volume
~2.5 Lakh Cum (Phase 1+2)

Baffle Wall
47m across Bhagirathi

Phase 1 Feb – Jul 2023

River Dredging at Tehri

River dredging across 640 Rm of the Bhagirathi River downstream of Tehri Dam spillway — executed during zero schedule of Tehri HPP. Water level varied 8-10m twice daily, with only 3-4 hours of working time per shutdown.

Dredging per daily zero schedule by THDCIL
~1 Lakh Cum material dredged and transported 14-15 Km
12 Excavators (210), 2 Excavators (300) with long boom
50-60 Dumpers for muck transportation

12 dewatering pumps (50HP each, 7000-8000 LPM)
Dedicated 30 Cum Batching Plant, 6 Transit Mixers
Boom Placer for underwater concreting
All resources deployed 24 Hrs in two shifts

River dredging operations

Water level at 604+ MTR

Excavation in variable water

Dredging March 2023

Heavy machinery deployment

Water level 603.75 MTR

Phase 1 Feb – Jul 2023

Baffle Wall & Micro Piling Construction

Construction of approx 47m long Baffle Wall across the Bhagirathi River between Spillway & TRT of Tehri HPP (1000MW). Underwater concrete pouring, micro piling in saturated riverbed conditions.

47m Baffle Wall across flowing Bhagirathi River
~2000 Cum RCC constructed in 4 months
1000mm dia Hume Pipe in Baffle Wall
Micro Piling (700m) in saturated foundation

Baffle Wall built in 5-10m segments
Underwater concreting via mobile Boom Placer
Drilling & grouting of anchors on both banks
~400 Rm micro piling completed in 1 month

Baffle Wall construction

Micro piling operations

Concreting in progress

Wall segment formation

Foundation reinforcement

Completed Phase 1 baffle wall

Phase 2 Jun – Jul 2024 (35-Day Shutdown)

River Dredging Phase 2

The second phase involved dredging 150,000 Cum from Chainage 260m to 660m and construction of Ramps (5m wide, 70m long) upstream & downstream of the Baffle Wall — all within a strict 35-day shutdown window.

1,50,000 Cum dredging in 35-day shutdown
Continuous ILO discharge — water never below EL 601.5m
12-day approach road construction through river
Encountered 12m depth area across full river width

20 additional dumpers mid-project for muck transport
Emergency concrete wall for exposed THDCIL building foundation
Rain interruptions during operations
Completed successfully within 35 days

Phase 2 dredging operations

Excavation in progress

River bed operations

Machinery at work

Dumper loading operations

Approach construction

Phase 2 Jun – Jul 2024

Ramp Construction & Micro Piling Phase 2

Construction of 70m long, 5m wide Ramps upstream & downstream along the Bhagirathi River. Micro Piling (850m) in foundation. All carried out during the 35-day shutdown with underwater concreting via Boom Placer.

70m long Ramps upstream & downstream
14,400 Cum concreting
~850m Micro Piling in Ramp foundation
Underwater concrete via Boom Placer

Ramps built in 5-10m segments due to seepage
Foundation never below EL 601m (target: EL 598-600m)
Shuttering fixed in standing water
Formwork buried in muck, required excavation to remove

Ramp construction

Concreting by Boom Placer

Underwater concrete pouring

HRT/TRT Tunnel Repair Campaign

Tunnel Repair by Drilling, Grouting & Epoxy at Tehri PSP

Repair of 8.5m diameter Head Race Tunnels (HRT #3 and #4) at Tehri PSP via surge shaft at 100m vertical depth — involving massive quantities of epoxy mortar, underwater repair, and custom engineering solutions.