El Salaam Syphon under Suez Canal

Employer Ministry of Public Works and Water Resources, North Sinai Development Organization.

The El Salaam Syphon consists of four tunnels, each 750 metres long with an altimetric profile formed by an initial downward tract 200 metres long, an intermediate flat tract 350 metres long and an additional 200 metre uphill tract.

The lowest point of the tunnel (de-watering point) is approximately 43 meters under sea level. Inlet and outlet structures, built using traditional reinforced concrete, are supported by a system of Lacor poles that average approximately 30 metres in length.

Excavation was carried out using a Mix Shield TBM with an excavation diameter of 6.52 metres. Concurrently with excavations, the first lining was laid down made up of pre-cast concrete rings, each composed of eight segments connected amongst themselves and with the following ring by means of steel curved bolts.

The thickness of the pre-cast rings, 120 cm long, was 30 cm and the internal diameter of the tunnel, after first lining was 5.74 metres.

Once the excavation was finished and the first lining was set, the project provided for the setting of a second 32 cm thick concrete lining, for which two self-propelled full round 10 metres long quarter-decks were used.