El-Salam Syphon under Suez Canal

El-Salam syphon was constructed in order to pass irrigation water underneath the Suez Canal to Sinai for the purpose of land reclamation and full development of the peninsula. 

The syphon consists of four parallel tunnels, 775 m long each. One 6.56 diameter bentonite slurry TBM was used to advance the four tunnels. The tunnels were provided with two linings with a waterproofing membrane in between. The primary lining consisted of solid precast reinforced concrete segments, 30 cm thick. The secondary lining was a 32 cm thick cast in place plain concrete. The function of the primary lining was to enable the unreinforced secondary lining to be constructed in a safe and dry environment. The secondary lining was designed to carry the full overburden and hydrostatic pressures.

Construction of the first tunnel started in 1995 and the syphon was inaugurated in 1997.