The last Tunnel Boring Machine (TBM) of DMRC’s current phase of construction started work today between Najafgarh and Dhansa Stand on the Dwarka – Najafgarh – Dhansa Stand corridor today.
The TBM will bore a 700-metre-long tunnel between Najafgarh and Dhansa Stand on the up line and the same machine will be subsequently used for tunnelling on the down line between the same stations. The entire tunnelling work on both the up and down lines will be completed by September later this year.
The total distance between Najafgarh and Dhansa Stand is 1.2 kilometres. The entire stretch is underground. While 700 metres will be constructed using TBM, the rest will be done by the Cut and Cover technology in which excavation is done for underground construction and then the area is covered again.
This section is an extension of the 4.295 kilometre long Dwarka – Najafgarh Metro corridor. The work for this section was formally awarded in late 2017 and the target date for completion is December, 2020. On the Dwarka – Najafgarh section, over 90 percent of construction work is complete and passenger services are expected to start by September this year.
As part of its third phase of expansion, DMRC has constructed close to 54 kilometres of underground sections, which is more than the under underground corridors constructed in its first and second phases. About 30 TBMs were put into use for carrying out such massive underground tunnelling work. It was a tremendous engineering challenge since Delhi is an extremely crowded city and tunnelling had to be done beneath centuries old buildings and congested localities.
TBMs were introduced for the first time by DMRC during the first phase of Metro construction. In Phase 2 of the Delhi Metro, 14 TBMs were used while the Phase 3, the number of TBMs used was 30.
Delhi Metro currently operates on a network of 327 kilometres with 236 Metro stations. This network includes over a hundred kilometres of underground lines spread across the national capital.