Customer: Delhi Metro Rail Corporation Ltd.
Construction period: 09.2007 – 07.2010
Location: New Delhi
The project included planning and construction of a tube using the NATM (New Austrian Tunnel Method). The clear diameter was about 10 m and its length about 2.4 km. The tunnel is approached simultaneously from four sides from two access points at km 3+861 and 4+600. Once completed it will also house two railway tracks. To separate the two railway tracks a 40 cm strong reinforced concrete wall will be constructed between the two tracks. The tube will also receive a 35 mm strong inner shell of reinforced concrete.
The decision was made to use mining technology for the construction of this tunnel as broken up and hard quartzite was expected for the most part of the tunnel. A ventilation building will be constructed at the access point 1 after the completion of the tunnel and interior work. At the end of the contract section an approximately 200-m-long section will be build using the open-cut-tunnelling method. This is at the change from the underground to the elevated railway (a ramp to switch from one to the other). The entire contract section has a length of 2.612 km. For its entire length it runs below the New Delhi forest reservation.