Double TBM breakthrough in Lucknow 05 Oct 2017

Breakthrough of a pair of Terratec 6.52m diameter EPBMs after completing their first 812m long twin running tunnels between Sachivalaya and Hazratganj Stations on the Lucknow Metro marked the completion of the first TBM driven tunnels in the State capital city of Uttar Pradesh in India. The twin breakthroughs at Hazratganj Station on the city’s new metro system was celebrated by the tunneling crews and managers of the Gulermak-TATA JV, representatives from Australian-based TBM manufacturer Terratec, and senior officials from the Lucknow Metro Rail Corporation (LMRC).

Twin EPBM breakthrough in Lucknow

The first of the two EPBMs working on the 3.44km underground section of the 22.88km-long Phase 1A North-South line of the project was launched from the Bapu Bhawan Shaft at Sachivalaya Station in January and took four months to complete the first 812m long down-line tunnel arriving at Hazratganj Station in late May (Fig 1). Following a 2.5-month wait for the official ceremony, the TBM broke through the station wall in August, followed a day later by its twin TBM on the up-line tunnel.

The EPB machines feature a classic spoke-style soil cutterhead with a 57% open ratio and interchangeable cutting tools with 17in disc cutters, allowing the TBMs to bore through station diaphragm walls and cope with the presence of any unexpected obstacles in the ground.

First TBM to arrive waited up for the official celebrations

The TBMs mined through geology consisting of stiff to hard clayey silt and medium to dense silty sand, passing beneath historic buildings in the Capital Plaza heritage district of Hazratganj without causing any disturbance to buildings, public utilities or traffic. The twin tunnels also passed under a number of commercial buildings with deep foundations. To clear the foundations, the track level in the running tunnels range from 12m-15m below ground surface.

Speaking at the ceremony, LMRC Managing Director Kumar Keshav said; “the tunnelling in this stretch posed several technical challenges as the route passes beneath highly congested areas and this breakthrough represents a milestone as the first TBM drives for underground metro works in the State of Uttar Pradesh."

"Due to many heritage structures, the stretch was highly challenging,” said TATA Projects Managing Director Vinayak Deshpande. “With a dedicated project team, the drives were completed to high quality and within programme.”

First TBM to arrive waited up for the official celebrations

With tunneling work completed between Sachivalaya and Hazratganj stations, there are now four tunnel drives remaining. The TBMs are currently being reassembled back at the western-end of Sachivalaya Station to excavate the twin 613m tunnels towards Hussainganj Station. From there, they will continue a further 419m, crossing underneath the Haide Nalah canal, to breakthrough at the cut-and-cover transition ramp to the surface alignment near Charbagh station (Fig 1).

The 36-month EPC (engineering, procurement, construction) contract was awarded to the Tata-Gulermak JV in April 2016 and includes construction of the three open-cut underground stations at Hussainganj, Sachivalaya and Hazratganj.

Detail design for the client for the underground alignment is Systra India.

Lucknow is the capital of Uttar Pradesh, the most populated state in India. The city’s rapid growth combined with substantial traffic congestion has prompted the need for a modern public transportation system. The system is being developed on a North-South and East-West corridor, both of which include underground and elevated sections. Aiming to bring world-class infrastructure to the city, the Phase 1 North-South line is being built at a cost of INR 6,928 crore (US$1 billion). The East-West Phase 2 line involves a longer length of twin running tunnels from Charbagh to near Thakurganj with six intermediate underground stations (Fig 1). Phase 2 of the system is due to commence in 2018.