New Delhi, India (Urban Transport News): The HCC – VCCL JV team on 16th October 2020 has started lowering work of the first-ever Tunnel Boring Machine (TBM) of Delhi Metro’s Phase 4 at Vikaspuri on the Janakpuri West – RK Ashram Marg corridor. As part of this tunnelling drive, two tunnels (for up and down movement) of a length of 1.4 kilometres will be bored between Vikaspuri and Krishna Park Extension.
The tunnelling work with the TBM S-86 is expected to start next month after the lowering and assembling of the giant 73-meter long machine is completed. These tunnels will be located between the Janakpuri West and Krishna Park Extension stations of the corridor. The tunnelling will start from the Vikaspuri area in continuation of the Magenta line tunnel that has been already constructed for the presently operational Botanical Garden – Janakpuri West corridor.
The tunnel will be constructed approximately at a depth of 14 to 16 metres. About 2,040 concrete rings will be installed in these tunnels. Each tunnel will have an inner diameter of 5.8 metres. The entire tunnelling work on this stretch is expected to be completed in about 15 month’s time. The alignment of the tunnel will be along the Outer Ring Road.
As part of the Phase-4 work approved so far, about 27 km of underground lines will be constructed. The Janakpuri West – RK Ashram Marg corridor will have underground sections of 7.74 kilometres in total.
In January 2020, DMRC had awarded a contract worth Rs 489 crore to the consortium of HCC - VCCL for building construction of twin tunnels from the Vikaspuri Park Shaft to Vikaspuri Ramp, with one underground station at Krishna Park Extension under contract package DC-06 of Delhi Metro Phase 4. The work is expected to be completed in 36 months.
A TBM is a machine used to excavate tunnels with a circular cross-section through a variety of soil and rock strata. They can be designed to bore through anything from hard rock to sand. TBMs have revolutionised the way tunnelling work is done all over the world as now tunnels can be bored without disturbing the buildings and other structures on the surface.
TBMs are especially useful for underground tunnelling work in congested urban areas. DMRC has been using TBMs for its tunnelling work since Phase 1. In Phase 3, when about 50 kilometres of underground sections were built, about 30 TBMs were pressed into service in the national capital.
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