Two Robbins EPBMs have begun drives on Phase 2 of Delhi metro from Jor Bagh station to Green Park.

The 6.52m diameter TBMs are to drive a pair of 2km long tunnels for half of the BC-16 contract section of the metro being developed by Delhi Metro Rail Corp (DMRC). The first machine was launched in mid-May, the second late last month.

Robbins supplied the machines, which were manufactured in Dalian, China, and employ a design by Mitsubishi Heavy Industries (MHI). The contractor on the section of the metro is a joint venture of Continental Engineering Corp (CEC), of Taiwan, and local form Soma Enterprise.

Lowering of the TBMs follows the slightly earlier arrival on the section of metro of a pair of 6.54m diameter Herrenknecht EPBMs (S-411, S-412). Also on the BC-16 contract, the TBMs are driving in the opposite direction.

Geology along the alignment comprises sandy silt, silty sand and gravels, and the groundwater will be up to 14m over the TBMs. The TBMs are designed to take 3 bar pressure. Cover to the tunnels is about 15m. The lining (5+1) has 1.2m long rings of 275mm thick segments, and two internal diameters will be used on the metro – 5.7m and 5.8m, respectively.

The JV contractor is also building four 318m long stations for the BC-16 section.

A total of 14 TBMs are to work on the metro expansion project as the client has a tight deadline to have the project completed before the Commonwealth games in the city, in 2010. Herrenknecht has a further two machines (S-403, S404) in the ground, launched at the end of 2007 by Metro Tunnelling Group (MTG) on contract BC-18 (T&TI, March, p8).

Robbins and Herrenknecht are active in other major tunnelling projects in India. For the Alimineti Madhava Reddy (AMR) scheme, Robbins is supplying a pair of 10m diameter double shields for a 43.5km long water tunnel. The company is also to supply another 10m double shield for a different water transfer tunnel, on the Pula Subbaiah Veligonda project – for which Herrenknecht has a 7.9m double shield (S-370) onsite.


One of two Robbins EPBMs for Phase 2 of Delhi metro Lowering of one of two Robbins EPBMs for Phase 2 of Delhi metro