Delhi Metro's Phase IV: "Bhoomi" TBM begins tunneling drive

The officials announced that the Delhi Metro initiated a tunnelling operation using the Tunnel Boring Machine (TBM) called "Bhoomi." This activity is taking place between Derawal Nagar and Pulbangash as part of the upcoming corridor in the 'Phase IV' project.

The TBM was launched at the Derawal Nagar metro station on 'Line 8,' which is being constructed from Janakpuri West to R K Ashram. The event was attended by Delhi Metro Rail Corporation (DMRC) Managing Director Vikas Kumar and other senior officials.

The tunnel spans approximately 3 km, with tunneling depths ranging from 12.4 m at Derawal Nagar station to 25.9 m near the Najafgarh Drain. Consequently, the TBM will traverse through various geological levels beneath the ground, as stated in the DMRC's official statement.

In an unprecedented move, the Delhi Metro is equipping all its TBMs in this phase with the BEAM (Bore Tunneling Electrical Ahead Monitoring) System, according to officials. This system allows the TBM to predict the geological conditions up to 20 meters ahead of its cutter head face in real time. It helps anticipate any unexpected encounters with filled wells, cavities, and aquifers. If these elements are hit by the TBM without proper treatment, they may cause settlement over the ground.

The BEAM system is a ground-predicting technique specially designed for the underground construction industry. It can be employed in various geological conditions, including hard rock, soft ground, and mixed ground, regardless of the type of boring machine used (Earth pressure balance, slurry, gripper, single or double-shielded TBMs). The system is independent of the TBM manufacturer.

The tunnel will pass beneath several residential and commercial areas along G T Karnal Road, such as Derawal Nagar, Rana Pratap Bagh, Shakti Nagar, Kamla Nagar, Ghanta Ghar, Subzi Mandi, and Roshanara Road.

Currently, four TBMs are in operation across the city, working on three priority corridors: Janakpuri West to RK Ashram Marg, Majlis Park to Maujpur, and Tughlakabad to Aerocity under Phase IV, according to the statement.

As part of this phase, a total of 28 km of new underground corridors are being constructed.