A refurbished 6.52-m diameter TERRATEC Earth Pressure Balance (EPB) Tunnel Boring Machine has been delivered to a Joint Venture between Hindustan Construction Company Ltd. of India and Vensar Constructions Company Ltd. for the Line-8 – Magenta Line of the Delhi Metro, in New Delhi, India.
Followed by a successful Site Acceptance Test, the JV began work to install the first tunnel ring segment for constructing a 2.03-km underground extension of the Delhi Metro’s 38.235-km Magenta Line (Line-8) from the Vikaspuri Park Shaft to Vikaspuri Ramp near Keshopur. As part of this tunneling drive, two tunnels (for up and down movement) with a length of 1,400 m will be bored between Vikaspuri and Krishna Park Extension.
The contractor selected TERRATEC Ø6.52-m EPB Tunnel Boring Machine with a traditional soil configuration, equipped with a Spoke-Type Cutter Head with a 57% opening ratio which has been proven to be very efficient to excavate this type of soil in previous DMRC Phases. This refurbished machine has previously completed tunnels for Delhi Metro project CC-34 and Lucknow Metro project LKCC-06.
TERRATEC has designed the cutterhead to allow the cutting tools to be exchangeable for 17-in. roller disc cutters, making the TBM to be able to bore through the D-walls and cope with the presence of any unexpected obstacle on its way, such as old wells or foundations. The geology is composed of silty sand, fine sand & sandy silt and clayey silt.
The segment lining will be made of RC segments with an outer diameter of 6,350 mm, inner diameter of 5,800 mm and width of 1,400 mm. The total distance that the TBM will bore to is approximately 2,030 m.
The tunnel will be excavated at an average depth of 14-16 m. As the drives progress, the machines will install reinforced concrete universal-style, pre-cast lining rings – comprising five segments + key. This section includes a 365-m long ramp and approximately 220-m long station, hence roughly 2,100 segments will be installed.
In January 2020, DMRC had awarded a contract to the consortium of HCC-VCCL for building the construction of twin tunnels from the Vikaspuri Park Shaft to Vikaspuri Ramp, with one underground station at Krishna Park Extension under contract package DC-06 of Delhi Metro Phase 4. The work is expected to be completed in 36 months.
After successful completion of Delhi Metro Phase 3, TERRATEC has been chosen again for the first underground tunnel package in DMRC Phase 4. TERRATEC’s continuing success on projects such as Phase 3 of the Delhi Metro, Lucknow Metro, Pune Metro, Ahmadabad Metro and Mumbai Metro is a result of tailor-made robust TBM design, prompt onsite assistance, readily available stock of TBM spares and highly skilled specialized TBM support throughout tunneling operations.