J Kumar Infraprojects completes First Silver Line Tunnel Drive on Delhi Metro Phase IV

New Delhi, India (Metro Rail Today): J. Kumar Infraprojects Ltd has achieved a major tunnelling milestone on the Delhi Metro Phase IV Silver Line, successfully completing the first tunnel drive using a 6.61-metre-diameter Terratec Earth Pressure Balance Machine (EPBM).

The breakthrough was achieved under Contract DC-08 for the Delhi Metro Rail Corporation (DMRC), with the tunnel boring machine, named ‘Narayani’, completing a 1.6-km tunnel between Vasant Kunj and Mahipalpur on the Aerocity–Tughlakabad corridor (Line 10).

TBM ‘Narayani’ Completes 1.6-Km Tunnel Drive

During the tunnelling operation, Narayani installed 1,400-mm-wide universal precast concrete lining rings along the tunnel. Each ring consists of five segments and a key segment, forming the permanent structural lining of the tunnel.

The excavated material and precast lining segments were transported using battery-powered, rail-mounted equipment, helping reduce emissions and minimise the environmental impact associated with conventional tunnelling logistics.

The successful completion of the drive marks an important construction milestone for the Silver Line, which is being developed as part of Delhi Metro's ongoing Phase IV expansion.

TBM Tackles Extremely Hard Rock Conditions

The tunnel drive presented significant geological challenges, according to TERRATEC. Several sections encountered extremely hard rock with uniaxial compressive strength exceeding 200 MPa, creating conditions considerably more demanding than those typically encountered in conventional urban metro tunnelling.

The geological conditions required the EPBM to operate in an environment more commonly associated with hard-rock mining than metropolitan underground construction.

To address the abrasive and challenging ground conditions, Narayani was equipped with a mixed-face cutterhead and specialised hard-rock cutting tools configured specifically for the project.

TERRATEC said the successful completion of the drive demonstrates the capability of the TBM and the project team's ability to maintain tunnelling progress despite highly challenging geological conditions.

Battery-Powered Logistics Support Sustainable Construction

Another notable feature of the tunnelling operation was the use of battery-powered, rail-mounted transport equipment for moving excavated material and tunnel lining segments.

The approach supports cleaner construction practices by reducing dependence on conventional diesel-powered underground transportation equipment and limiting emissions within the tunnelling environment.

Silver Line to Strengthen Southern Delhi Connectivity

The Aerocity–Tughlakabad Silver Line is a key component of Delhi Metro Phase IV. Once completed, the corridor will improve connectivity across southern Delhi by linking the airport district with major residential, commercial and employment centres.

The corridor will also provide additional interchange opportunities with the wider Delhi Metro network, strengthening connectivity between existing and upcoming metro corridors.

The latest tunnelling milestone reflects the increasing use of advanced underground construction technologies on Delhi Metro Phase IV, particularly for sections involving complex geological conditions and densely developed urban environments.