Metropolitan Tel Aviv, LRT Red Line Project- Elifelet Tunnel

Structure Type: Cut & Cover Tunnel
Client: IMB, Israel Metro Builders
Cost: 200 Million INS
The light train system consists of 4 routes currently designed as part of the mass transit project in Tel-Aviv metropolis. The first route designed and constructed is the main one; the Red Line.

The Red Line is 23 Kilometers long and will connect Petah-Tikva with Bat-Yam through Tel Aviv. Out of these, 11.5 kilometers between Geha interchange and Elifelet st. are underground. Gash was hired by the concessionaire MTS, for prime coordination and for the structural design of Elifelet section which includes: 680 meters length tunnel to be constructed in the cut & cover method and 260 meters portal including Elifelet station, track-side technical rooms and pumping stations.

Special Characteristics:
  • The general cross-section of the tunnel is a double box serving double track and a pocket track segment (illustration below).
  • The tunnel is dynamically designed for an explosion of a car bomb above the tunnel.
  • The general cross section of this project also includes a vehicle underpass on top of the Red Line tunnel. The design of this tunnel as a separate structure will be done also by Gash for Ayalon HighWays at a later stage.
  • Soil excavation of 20-25 meters below ground level adjacent to existent buildings. The route is bordered by private property and interfering is not allowed. Therefore, reinforced concrete slurry walls with horizontal struts of 14-20 meters are designed.
  • As a result of this site condition and its closeness to existent private property, there is a special requirement for tight monitoring during the construction. Gash responsibility includes the monitoring system as well as structure survey of the tunnel vicinity.
  • The deepest section of the tunnel is about 7 meters below Underground water level. A temporary bottom floor is constructed to allow working in dry condition and to avoid long term dewatering.
  • Construction stages and the structure characteristics are deeply affected by the mutual interaction between the soil and structure. Therefore a finite element analysis of the soil-structure interaction is used.