J Kumar’s Surat Metro TBM Diya (S28B) Starts Tunneling

J Kumar Infraprojects last week commissioned Terratec tunnel boring machine S28B at Surat Railway Station for Surat Metro Phase 1 project’s 3.56 km underground Package UG2 / CS3 (Surat Railway Station – Chowk Bazar Ramp).

Nicknamed Diya, this Ø 6.61m diameter refurbished earth pressure balance machine along with TBM S25B, nicknamed Amrit, had previously seen action at Delhi Metro’s Phase 3 Pink Line’s Package CC-24 (Lajpat Nagar – Hazrat Nizamuddin).

Following a final double breakthrough, they were then brought to Surat’s Palanpur for refurbishment in April 2021 and passed factory acceptance tests (FAT) in July 2022.

J Kumar’s team started lowering its parts into Surat Railway Station’s TBM launch shaft in late February and conducted site acceptance tests (SAT) in March.

In Surat, TBM Diya and TBM Amrit will each build 2 tunnels and approximately 2000 rings from Surat Railway Station to Chowk Bazar Ramp for 21.61 km Line-1’s 7.02 km underground section connecting Chowk Bazar and Kapodra Ramp.

Gujarat Metro Rail Corporation (GMRC) had awarded J Kumar Infraprojects with Package CS3’s Rs. 941.80 crore contract in December 2020.

Their scope includes constructing Line-1’s underground section from chainage 7160.6m to chainage 10720m with 3 stations at Chowk Bazar, Maskati Hospital and Surat Railway Station.

Per Terratec’s press release:

The geological conditions along the tunnel alignments will be sand, clay, gravel and silt. The versatile TERRATEC EPBM units have robust mixed-face dome-style cutterheads designed to work effectively in the expected geological conditions. As the TBMs progress, they will install 1,400mm wide by 275mm thick pre-cast concrete lining rings, which consist of five segments plus a key.

For added versatility, TERRATEC has designed the Cutter Head to allow the cutting tools to be exchangeable for 17’’ disc cutters, allowing the TBM to be able to bore through the D-walls and cope with the presence of any unexpected obstacle on its way, such as old wells or foundations.

With this development, TBM Diya has become the 3rd machine to start tunneling in Surat. Gulermak – SAM JV working on Package UG1 / CS2 currently has 2 Terratec machines (S94 and S78) tunneling from Kapodra westward towards Surat Railway Station.

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– TMRG