Delhi Metro Launches TBM 'Bhoomi' For Second Tunnel On Janakpuri West-RK Ashram Marg Corridor

The Delhi Metro Rail Corporation (DMRC) today started a tunneling drive by the Tunnel Boring Machine named “Bhoomi” from Derawal Nagar to Pulbangash on the Janakpuri West to RK Ashram corridor.

The length of the tunnel between Derawal Nagar and Pulbangash is approximately 3 km. The depth of tunneling will vary from 12.4 m at Derawal Nagar station upto 25.9 m near the Najafgarh drain. Therefore, the TBM will traverse through varying geological levels underground.

The stretch between Derawal Nagar and Pulbangash will comprise three underground Metro stations – Derawal Nagar, Ghanta Ghar, and Pulbangash. These areas are extremely congested and there are innumerable buildings which are centuries old and some are not in very good condition.

The tunnel shall pass below many residential and commercial areas on GT Karnal Road like Derawal Nagar, Rana Pratap Bagh, Shakti Nagar, Kamla Nagar, Ghanta Ghar, Subzi Mandi, Roshanara Road etc.

Janakpuri West to RK Ashram corridor

The 29-km line Janakpuri West to R.K. Ashram corridor is the extension of Magenta line and will connect the Janakpuri West Metro station on the Magenta line and the RK Ashram station on the Blue line.

This stretch has a total of 22 stations, including 11 underground stations and runs through areas like Haiderpur, Sadar Bazar, Azadpur, Bhalswa, Pushpanjali Enclave, Mangolpuri and Paschim Vihar.

So far, the DMRC has completed 2.2 km of underground tunnels (for up and down movement) between Janakpuri West and Krishna Park Extension on the Janakpuri West – RK Ashram Marg corridor.

The entire Janakpuri West-RK Ashram Marg corridor is expected to be ready by September 2025.

A Tunnel Boring Machine (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 revolutionized the way tunneling work is done worldwide, as tunnels can now be bored without disturbing the buildings and other structures on the surface. TBMs are especially useful for underground tunneling work in congested urban areas.

DMRC has been using TBMs for its tunneling work since Phase 1. In Phase-3, when about 50 km of underground sections were built, about 30 TBMs were pressed into service in the national capital.

At present, four TBMs are operational across the city in the three priority corridors (Janakpuri West-RK Ashram Marg, Majlis Park-Maujpur and Tughlakabad – Aerocity) under Phase IV. A total of 28 kilometres of new underground corridors are being constructed as part of this phase.

BEAM System

In a first of its kind exercise, Delhi Metro is equipping all its TBMs with the BEAM (Bore Tunneling Electrical Ahead Monitoring) System in this phase.

It enables the TBM to predict on a real time basis the geological strata up to 20m ahead of the machine’s cutter head face and predict any unexpected encounter with filled wells, cavities, and aquifers which may lead to settlement over the ground if hit by the TBM without proper treatment.

BEAM is a non-intrusive focused-electrical induced polarization ground predicting technique especially designed for the underground construction industry. It can be used in any hard rock, soft and mixed ground geology, under or below the ground water table and thus in any type of boring machine like EPB, Slurry, Gripper, Single or Double shielded TBMs, independent from the TBM manufacturer.