Skhalta Dam

 

Foundation Works executed by BAUER Georgia at four locations

 

  • Shuakhevi (Hydro Power House)
  • Didachara (Reservoir)
  • Chirukhistsqali (Weir)
  • Skhalta (Dam and Reservoir)

 

The Shuakhevi Hydro Power Plant (Skuakhevi HPP), is a run-of-the-river plant currently under construction in Adjara, Georgia. It will have an installed capacity of 185 megawatts. The plant will have the capacity for diurnal storage in two reservoirs (22-metre) Skhalta dam with a 19.4-hectare reservoir and 39-metre Didachara dam with a 16.9-hectare reservoir allowing Shuakhevi HPP to store water for up to 12 hours. Three main tunnels are to be constructed on the Shuakhevi project; the 5.8 km Chirukhistsqali to Skhalta transfer tunnel, the 9.1 kilometres, Skhalta to Didachara transfer tunnel and the 17.8 km Shuakhevi headrace and pressure tunnel.

 

 

The Shuakhevi HPP in the Adjara Autonomous Republic is part of a three-step cascade on the River Adjaristskali.

Client: Adjaristsqali Georgia LLC

Contractor: AGE Batum LLC

Consultant: Mott MacDonald

 

Adjaristsqali Georgia LLC is owned by the Norwegian Clean Energy Invest AS (40%), India’s Tata Power (40%), and IFC Infraventures (20%), an investment fund created by the International Finance Corporation. Company Alstom was chosen to supply the electromechanical equipment for the project.

Adjaristsqali Georgia LLC is owned by the Norwegian Clean Energy Invest AS (40%), India’s Tata Power (40%), and IFC Infraventures (20%), an investment fund created by the International Finance Corporation. Company Alstom was chosen to supply the electromechanical equipment for the project.

 

Shuakhevi - Hydro Power Hous   Execution Time: March 2014 - January 2015

Stage 1: Upper Cut-off Wall Scope of the Works:

  • Unreinforced Secant Pile Wall
  • Diameter: ø 880 mm
  • Quantity: 226 nosMax Pile Length: 20.00 m
  • Total Drilling Length: 3355 m

 

 

 

 

 

 

 

 

Stage 2: Lower Cut-off Wall

 

Scope of the Works: Reinforced-concrete Secant Pile Wall

    • Diameter: ø 1180 mm
    • Quantity: 162 nos
    • Max Pile Length: 15.80 m

 

  • Total Drilling Length: 1715 m

 

 

 

 

 

 

 

Stage 3: Temporary Ground Anchors


Scope of the Works: Pre-stressed Strand Anchors

  • Diameter: ø 168/150 mm
  • Quantity: 70 nos
  • Max Pile Length: 34.00 m
  • Total Drilling Length: 1933 m

 

 
 
 

 

 

 

 

Stage 4: Foundation Piles


Scope of the Works: Foundation Piles
Diameter: ø 1180 mm
Quantity: 16 nos
Max Pile Length: 18.00 m
Total Drilling Length: 210.50 m

 

 

 

 

 

 

 

 

 

Didachara - Reservoir

Execution Time: October 2014 – June 2015

 

a) Ghorjomi Bridge Project

Scope of the Works: Foundation Piles
Diameter: ø 1180 mm
Quantity: 16 nos
Max Pile Length: 20.00 m
Total Drilling Length: 304.50 m

 

b) Upstream Cut-off Wall Project

Scope of the Works: Secant Pile Wall
Diameter: ø 1180 mm
Quantity: 143 nos
Max Pile Length: 15.60 m
Total Drilling Length: 1681 m

 

 

c) Dam Protection & Ground Stabilization

Scope of the Works:

Stage 1: Contiguous Pile Wall ø1180: 311 m

Stage 2: Soil Nailing 12 m: 10000 m

 

Contiguous Pile Wall


Diameter: ø 1180 mm
Quantity: 19 nos
Max Pile Length: 20.00 m
Total Drilling Length: 311 m

Soil Nailing


Diameter: ø 150 mm
Quantity: 344 nos
Max Pile Length: 12.00 m
Total Drilling Length: 3336 m

 

Chirukhistsqali - Weir

 

Upstream Cut-off Wall

Execution Time: April 2015 – September 2015

Scope of the Works: Secant Pile Wall

  • Diameter: ø 1180 mm
  • Quantity: 77 nos
  • Max Pile Length: 17.00 m
  • Total Drilling Length: 1271 m

Foundation Piles

  • Diameter: ø 1180 mm
  • Quantity: 45 nos
  • Max Pile Length: 11.00 m
  • Total Drilling Length: 422 m

 

Skhalta Dam and Reservoir


Upstream Cut-off Wall

Execution Time: October 2016 – February 2017

Scope of the Works: PLASTIC CONCRETE Secant Pile Wall

  • Diameter: ø 1180 mm
  • Quantity: 133 nos
  • Max Pile Length: 34.30 m
  • Total Drilling Length: 3526 m

The plastic concrete secant pile cut-off wall was successfully completed February 2017.

 

133 nos. secant piles with a nominal diameter of 1500 mm were executed with 500 mm intersecting with adjacent piles. Average depth amounted to 26,5 m; the longest pile depth was 34,3 m. A total of 3526 m piling was installed using a BAUER BG 28 with a BV 1500 oscillator.

As specified, piles at the abutments had to be installed at least 1 m into the competent rock. Other piles were designed to be embedded into the coarse alluvium, a stratum below a 2 m thick clay layer. All pile depths and rock/alluvium levels were checked and confirmed by inspectors of Mott MacDonald. A rope inclinometer device was used to assure overcut at each pile for wall continuity within the designed tolerances.

The toughest part was working during heavy winter conditions.

 

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