EPBM breakthrough in Delhi 15 Sept 2015

A Terratec EPBM achieves breakthrough on behalf of the Metrostroy OS (Russia)/ ERA Infra (India) JV to complete the third of four drives on contract C-07 of the Delhi Metro Phase III Heritage Line (Line 6, Violet).

S23 breakthrough ceremony at Lal Quila

The 6.61m diameter machine emerged in the Lal Quila cut-and-cover station at the end of a 1,351m drive on the upline after launching from the Kashmere Gate shaft on 26 December last year (2014). The same machine completed the 650m downline drive from Jama Masjid to Lal Quila on 31 July last year (Fig 1), before being transported back to the launch shaft at Kashmere Gate.

The latest breakthrough ceremony was held in the presence of Contractor representatives and the client, DMRC

The Contractor JV is using two Terratec EPBMs for the execution of the tunnelling works between Jama Masjid and Kashmere Gate stations, at the northern end of what will be the all-underground 9.3km Heritage Line (Line 6) in the Indian capital of Delhi. The S23 TBM emerged at Lal Quila Station site after excavating a 1,351m-long tunnel from Kashmere Gate Station. A total of 967 rings have been concurrently installed.

Another TBM, S24, is excavating the parallel 1,356m-long downline tunnel and was reported by Terratec this week to have completed 466m for a scheduled completion in December this year (2015). This machine completed the 627m Jama Masjid–Lal Quila upline section in December last year (2014).

Fig 1. Delhi Metro Line 6 (violet)

The alignment passes beneath the existing Kashmere Gate elevated metro station to within 1.2m of the foundation piles. The new stations at Kashmere Gate and Lal Quila are also being constructed by the same contractor JV using the cut-and-over method. An extensive instrumentation regime is in place to monitor and control ground settlement.

The Terratec EPBMs have been been specifically designed for the ground conditions of the contract. Tunnelling scope includes four separate drives totalling 2,050m of twin running excavation. Design features include a 900KW VFD electric-driven cutterhead, up to 33 versatile and interchangeable cutting tools and 17in roller disc cutters, active type articulation for the shield, and a built-in two-liquid backfilling system at the tail of the machine.

A total of 35 TBMs – of which Terratec has supplied eight ¬– are being used in the Indian capital city to complete 74 separate drives for a total of 37km of twin running tunnels as part of the 140km of Delhi Metro Phase III. Earlier this year the project owner, DMRC, reported 19 machines in operation at the same time. It is expected that a substantial part of all the running tunnels will be completed by the end of this year.