DAM ON THE WADI AL QATTARAH - BENGHAZI (LIBYA)

Works for the rehabilitation and reinforcement of the main dam body and demolition and reconstruction of the secondary dam located 9km South of the main dam. Features: main dam with height 375 m, height 52 m, secondary dam with 235 m length and height 34 Im.. The rehabilitation project involved the partial demolition of the Main Dam and its transformation from simple barrier to a rockfill dam. The secondary dam, about 9 km downstream along the same river, was completely demolished and replaced by a new rockfill dam. At the foot of the main dam runs a tunnel, at the top of the waterproof screen with drainage and inspection functions. The secondary dam is instead defined at the foot by a cut-off in reinforced concrete anchored to the rock. The bottom drains of the two dams are made up of tunnels executed with TBM (Tunnel boring machine) and constructed with double shield with a diameter of 4.80m and coated with precast segments with a thickness of 0.25 m. The main tunnel of the dam consists of two sections executed with TBM and a section of the junction in overburden. The sector of underground works is completed by the two "grouting tunnels" excavated in the shoulders of the main dam. It is to be remarked that the discharge tunnels have been executed during the period April 2001 to May 2003. Bottom drainage tunnel of the Main Dam Excavation diameter = 4.80 m Int diameter = 4.30 m Length = 1520 + 1610 in TBM + 160 in overburden tot = 3290 m Depth (max covering) = 87 m. Bottom drainage tunnel of the Secondary Dam Excavation diameter = 4.80 m Int diameter = 4.30 m Length = 1,580 m in TBM Depth (max covering) = 73 m

TECHNICAL SPECIFICATIONS