A refurbished 6.52m 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 Limited, 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 tunnelling drive, two tunnels (for up and down movement) with a length of 1400 metres will be bored between Vikaspuri and Krishna Park Extension.
The Contractor selected TERRATEC Ø6.52m 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 Cutter Head to allow the cutting tools to be exchangeable for 17’’ 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 6,350mm, inner diameter of 5,800mm and width of 1,400mm. The total distance that the TBM will bore to is approximately 2,030 metres. The tunnel will be excavated at an average depth of 14-16 metres. 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 meter long ramp and approximately 220 meter long station, hence roughly 2100 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 III, Terratec has been chosen again for the first underground tunnel package in DMRC Phase-IV which proves that Terratec is the first choice for the contractors. TERRATEC’s continuing success on projects such as Phase III 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 specialised TBM support throughout tunnelling operations.
For more information visit: www.terratec.co .04/21.
