Excavation pit construction for Ismailia Tunnels

The Ismailia Road Tunnels are twin tube tunnels passing the new and old Suez Canal in Ismailia ciy of Egypt. The twin tunnels were constructed using Tunnel Boring method with 2 Tunnel Boring Machines, each of 12.6 m cutting diameter reaching 53 m below sea level. The two parallel tunnels were connected by four Cross-Passages (CP) each 1 km distance, where personnel can access the other tunnel in case of an emergency. These Cross Passages are 13 m long and 5 m in diameter. Due to high hydrostatic water pressure of 5 bars in mostly sandy soil, Ground Freezing has been adopted & the excavation was carried out in the protection of 2 m thick frozen bodies. The frozen bodies served two main purposes during the excavation process of each cross passage, as structural elements of "temporary excavation support" and to provide water tightness.