Robbins and Mitsubishi Heavy Industries (MHI) are working together to supply two EPBMs to drive two 2km long twin tubes for half of a section of the phase II extension of New Delhi’s metro.
The 6.5m diameter machines will be assembled at Dalian Heavy Industry (DHI) facility in Dalian, China, then be supplied by the team to the JV contractor along with back-up systems and cutting tools. Assembly is to be completed in Q3 for the contractor to start boring in January 2008 from a launch box near the new Jor Bagh station to Green Park Station.
Geology along the route consists of sandy silt, silty sand and gravels. The EPBMs will bore 8.6m -14m below the water table with various tungsten carbide bits (drag, knife edge, fish tail, and peripheral protection) to handle the soft, abrasive strata.
The machines will take 3 bar pressure, and cutterheads will have a 55% opening to avoid clogging and enable smooth spoil flow to the open gantry, circular back-up systems. The 5.8m i.d, 5+1 segmental lining will be 1.2m long, 275mm thick, and be cast in New Delhi.
The contract for the pair of EPBMs is with Robbins, which is employing a design by MHI through a subcontract arrangement that will also involve some engineering and supply of key components. Robbins will perform design and management of the contract and assembly through its separate subcontract in Dalian. However, through its co-operation with MHI and its own designs, Robbins plans to makes moves into the soft ground EPBM market (see p12).
The JV contractor is a pairing of Continental Engineering Corp (CEC), of Taiwan, and Soma Enterprise, of India. The contract (BC-16) calls for construction of 5.3km long section of the phase II extension, including four stations by cut and cover, each 318m long – including Jor Bagh.
All civils works on the phase II contracts are to be completed by August 2008 and the metro rail link commissioned by June 2009 – in advance of the 2010 Commonwealth games, which are being hosted by the city.
