The Delhi Metro Rail Corporation (DMRC) has commenced the tunneling process for the Magenta Line extension (Line-8) with the deployment of the Tunnel Boring Machine (TBM) called “Bhoomi.” The initial tunneling drive began from Derawal Nagar to Pulbangash on June 2.
The tunnel between Derawal Nagar and Pulbangash spans approximately 3 km, with varying depths ranging from 12.4 m at Derawal Nagar station to 25.9 m near the Najafgarh drain. The TBM will navigate through different geological layers underground.
In a remarkable move, the Delhi Metro has equipped all its TBMs with the Bore Tunneling Electrical Ahead Monitoring (BEAM) System for this phase. This system allows the TBM to predict the geological strata up to 20 m ahead in real time, enabling early identification of potential hazards such as filled wells, cavities, and aquifers. This proactive approach prevents ground settlement in case of unexpected encounters.
BEAM utilizes non-intrusive focused-electrical induced polarisation technology specifically designed for underground construction projects. It can be utilized in various geological conditions, including hard rock, soft ground, mixed ground, and even below the groundwater table. The system is compatible with different types of boring machines, irrespective of the manufacturer.
The tunnel route will pass beneath several residential and commercial areas along GT Karnal Road, including Derawal Nagar, Rana Pratap Bagh, Shakti Nagar, Kamla Nagar, Ghanta Ghar, Subzi Mandi, and Roshanara Road.
Currently, there are four operational TBMs across the city, working on priority corridors under Phase IV, namely Janakpuri West-RK Ashram Marg, Majlis Park-Maujpur, and Tughlakabad-Aerocity. These projects aim to construct a total of 28 kilometers of new underground corridors.
The launch of “Bhoomi” marks another significant step in expanding the Delhi Metro network, enhancing connectivity and easing travel for the residents of the capital city.