Deepest below Tilak Bridge at 18 metres below the surface
The Delhi Metro Rail Corporation completed the tunnelling work between Central-Secretariat and ITO stations under Phase-III of constructions when the second and final tunnel breakthrough was achieved on Tuesday.
The breakthrough at the ITO station was achieved in the presence of DMRC Managing Director Mangu Singh after completing the 700-metre-long tunnel on the down line of the Mandi House-ITO stretch.
The tunnel is deepest below the Tilak Bridge with a maximum depth at 18 metres below the earth’s surface. The internal diameter of the tunnel is 5.7 metres. A total of 467 rings were inserted in the tunnel with each ring consisting of six segments. The casting of the segments was done at the Mundka casting yard.
According to a DMRC statement, the excavated earth was deposited at the Mukundpur depot. Earth-pressure-balancing type TBM from the Shanghai Metro Shield Corporation was used to concrete the tunnel.