DMRC achieves tunnel breakthrough on Delhi Metro Phase 4 Golden Line

New Delhi, India (Metro Rail Today): The Delhi Metro Rail Corporation (DMRC) has reached a significant construction milestone with the successful completion of a major underground tunnel segment in Phase 4 of its Golden Line project. This pivotal achievement was marked by the breakthrough of the Tunnel Boring Machine (TBM) at Chhatarpur Mandir Station, a key point on the Tughlakabad-Aerocity corridor.

The breakthrough ceremony, held earlier today, was attended by several distinguished guests, including Vinai Kumar Saxena, the Lieutenant Governor of Delhi; Kailash Gahlot, the Transport Minister of the Government of National Capital Territory of Delhi (GNCTD); Naresh Kumar, Chief Secretary of GNCTD; Ashish Kundra, Principal Secretary to the Lieutenant Governor; and Jaideep, Officer on Special Duty (UT) at the Ministry of Housing and Urban Affairs (MoHUA). The event was also graced by DMRC Managing Director Dr. Vikas Kumar and other senior officials.

The successful completion of this underground tunnel segment involved the use of a massive 97-meter-long Tunnel Boring Machine. This TBM drilled through an impressive 865-meter stretch to achieve a breakthrough at Chhatarpur Mandir Station. The project includes the construction of two parallel circular tunnels for both up and down movement along the Aerocity-Tughlakabad corridor, with the second parallel tunnel expected to be completed by September this year.

The newly constructed tunnel, which averages a depth of about 15 meters, has been built with 618 tunnel rings. Each ring was carefully installed within a tunnel featuring an inner diameter of 5.8 meters. The tunneling process utilized the Earth Pressure Balancing Method (EPBM) and incorporated precast concrete tunnel rings, cast at a mechanized facility in Mundka. To ensure the durability of these segments, the concrete was cured using a steam curing system to expedite strength development.

This tunneling effort was not without its challenges. One major obstacle included the relocation of a 66 KV high-tension electrical line. Additionally, the TBM needed to navigate beneath the existing Yellow Line viaduct while maintaining uninterrupted Metro train operations on the Yellow Line. Throughout the construction process, stringent safety measures were observed, including real-time monitoring of ground movements with sensitive instruments affixed to nearby structures, ensuring the stability of the surrounding area.

As part of the ongoing Phase 4 expansion, DMRC is constructing a total of 40.109 kilometers of underground lines, with the Aerocity-Tughlakabad corridor alone accounting for 19.343 kilometers of this underground network.

Tunnel Boring Machines, essential to modern tunneling operations, are designed to excavate tunnels with a circular cross-section through various types of soil and rock. These machines have significantly advanced tunneling technology, allowing for the excavation of tunnels with minimal disruption to surface structures and existing buildings.

This milestone marks a crucial step forward in the development of the Delhi Metro's Phase 4 Golden Line, reflecting DMRC's commitment to expanding and enhancing the city's transit infrastructure.