Refurbished EPBM starts work on Delhi Metro Phase 4 04 Feb 2021

A refurbished 6.5m diameter Terratec EPBM has been delivered to a joint venture of the Hindustan Construction Company and Vensar Constructions Company, for the Line 8 Magenta Line of the Delhi Metro, in India. After a successful site acceptance test, the EPBM has started to install the first ring of segmental lining for the 2km underground section of the 38km Magenta Line 8. The TBM will excavate 1.4km twin bores from Vikaspuri Park shaft to the Vikaspuri ramp near Keshopur (Fig 1).

Refurbished Terratec EPBM set for 2km drive

The Terratec EPBM has a traditional soil configuration, equipped with a spoke-type cutterhead with a 57% opening ratio. Cutting tools are exchangeable for 17in disc cutters to allow excavation through diaphragm end walls and the ability to cope with any unexpected obstacles such as old wells or foundations. The geology is composed of silty sand, fine sand and sandy silt and clayey silt.

The reinforced concrete segmental lining is of the universal design comprising five segments and a key in each 1.4m x 6.3m o.d. (5.8m i.d.) ring. Along with the TBM drives, at an average depth of 15m, the contract includes a 365m long ramp and a 220m long station box. Work is expected to take 36 months.

The refurbished EPBM was used previously on the Delhi and Lucknow metro projects. Other Terratec TBMs have recently completed work on the Delhi Metro Phase III and on the Lucknow, Pune, Ahmadabad and Mumbai Metros. Along with the TBMs, Terratec provides prompt onsite assistance, readily available stocks of TBM spares and skilled specialised TBM support throughout the excavation operations.