VAISHALI (Metro Rail News): In a significant development towards providing a faster regional connectivity in NCR, the National Capital Region Transport Corporation (NCRTC) achieved today a major milestone with the TBM Breakthrough of Sudarshan 4.4 at Vaishali retrieving shaft, Ghaziabad. The tunnelling of the entire Delhi – Ghaziabad – Meerut RRTS corridor has now been completed with the completion of this 2 km long tunnel between Anand Vihar towards Sahibabad.
Mr Vinay Kumar Singh, MD, NCRTC, initiated the breakthrough by pressing a remote button in presence of the Directors and other senior officials of NCRTC. The Sudarshan 4.4 was lowered at the launching shaft constructed at Anand Vihar, which is now being retrieved from the Vaishali retrieving shaft.
The whole tunnelling has been completed in less than 18 months. Seven (7) state-of-the-art Sudarshan Tunnel Boring Machines (TBM) have been used to bore the 12 km long parallel tunnels of the underground section of the country’s first RRTS corridor. Rest 70 km long section of the corridor is elevated, where about 80% of the viaduct is completed.
To construct the tunnels, more than 80,000 pre-cast segments have been used. These high-precision pre-cast tunnel segments were cast at the state-of-the-art casting yards established at Kadkaddooma, New Delhi, and Shatabdi Nagar, Meerut. These segments, measuring 1.5 meters in length, joined together to form the tunnel rings. The diameter of the RRTS tunnels is 6.5 m which is highly optimised as compared to global benchmarks of tunnels for a similar design speed of 180 Kmph with wider and higher rolling stock.
A total of 4 tunnels have been constructed in Delhi from Anand Vihar underground RAPIDX station for to and fro movement of trains. Two parallel tunnels, each approximately 3 kilometres, are for connecting Anand Vihar station to New Ashok Nagar station, and approximately 2-kilometre-long parallel tunnels are for connecting Anand Vihar station to Sahibabad station.
Delhi section Tunnelling:
The tunnelling journey of NCRTC commenced in February 2022, when the tunnel boring machine (TBM) “Sudarshan 4.1” was lowered into the launching shaft at Anand Vihar, New Delhi to bore the tunnel between Anand Vihar towards New Ashok Nagar. Sudarshan 4.2 was launched soon after for tunnelling its parallel tunnel. These parallel tunnels are the longest tunnel in Delhi made by any Tunnel Boring Machine and are about 3 kilometres each. Sudarshan 4.1 made the breakthrough from the tunnel retrieval shaft constructed at Khichdipur, Delhi, in just over a year in April 2023. Sudarshan 4.2 also completed tunnelling for its parallel tunnel and made a breakthrough in June 2023.
Apart from these, two more Sudarshan, 4.3 and 4.4, were launched from Anand Vihar for tunnelling of 2-km long parallel tunnels towards Sahibabad RAPIDX Station for the Delhi-Ghaziabad Section in June and October 2022, respectively. One of these, Sudarshan 4.3, made a breakthrough from the retrieval shaft constructed near Vaishali Metro Station in May 2023. While the fourth and last TBM, Sudarshan 4.4 has achieved its breakthrough today.
Tunnelling in the Delhi Section was a complex and challenging task. Going towards Sahibabad from Anand Vihar, the underground tunnel was passing very close to the the industrial area buildings, passed below shallow over burden area ranging from 4m-6m and below the high-tension electric cables at an overburden of only 0.5m below the cables are few examples. Similar challenges were faced in the tunnelling towards, New Ashok Nagar when it navigated in close proximity to existing metro viaduct piling structures, crisscrossing expressways, and even non-engineered buildings in Patparganj and Khichdipur. All these challenges were tackled successfully by executing strategic planning and innovative methods.
Meerut Section Tunnelling:
Meerut, on the other hand, comprises three underground stations, namely Meerut Central, Bhainsali, and Begumpul. To connect these stations, six parallel tunnels have been constructed. The tunnelling activities started in Meerut with the launching of Sudarshan 8.1 in April 2022 and all tunnelling activities completed in July 2023.
In Meerut also, the tunnel’s path intersected densely populated urban zones, including its passage beneath the drain and foundations of the older buildings, Sharp bends etc., which was tackled with unwavering diligence and meticulous care.
After the completion of underground tunneling portions of the corridor, track laying and installation of OHE will pick up pace. The same has already been started from Anand Vihar underground station and Begumpul in Meerut.
NCRTC is targeting to open the entire 82-km long Delhi-Ghaziabad-Meerut for the public by 2025. Before that, it will operationalize a 17-km long Priority Section between Sahibabad and Duhai Depot shortly.
