1995-2003 “Complex of Hydraulic Structures for Diversion of the Vorotan River Runoff to the Basin of the Arpa River”

The Client:
Ministry of Urban Development of RA, State Enterprise “Hydraulic Structures”.

Hydraulic system of discharging Vorotan river runoff to the basin of Arpa river.

The hydraulic work comprises the following main objects:

1. 21.6 km long tunnel with 8.9 m2 section,
2. 4 shafts of 50-300m depth,
3. 2 approaching adits,
4. Headworks: the intake, water seals;
5. Spillway section at the exit gate.

The construction was commenced in 1982, but due to financial shortages the works on main structures were stopped in1993 and up to 1998 the works on pumping were performed to keep up the underground openings in working condition.
By the end of works the construction of tunnel has been carried out under highly complicated hydro geological and mining engineering conditions with frequent outbursts of rock mass on the stretch of about 800 m length in weakly waterlogged rocks, as a result of which special drifting methods was used to form a screen of pipes along the outline of underground opening, injection of grout behind an auxiliary reinforced concrete lining.

The following was implemented during the reported period:
1. Rehabilitation works on the water intake and headwork structures, hoisting mechanisms, gate adits, power supply system, repair works on sluice gates, repair works on buildings and structures.
2. Rehabilitation and drifting of underground openings
2140 m
3. Tunnel excavation works
38000.0 m³
4. Placing of concrete and reinforced concrete
17845 m³
5. Erection of reinforcement and steel structures
1393.2 t
6. Laying of pipelines and of screen pipes
197.4 km
7. Injection of grout
31113 m³
8. Shotcrete works
2850 m²
9. Laying of power and lighting cables
18.3 km