Mumbai, May 17: A significant milestone has been reached in the Mumbai-Ahmedabad bullet train project. The first cutterhead of the Tunnel Boring Machine (TBM) was successfully lowered into the shaft in Vikroli, Mumbai. This cutterhead, measuring 13.6 meters in diameter and weighing approximately 350 tons, symbolizes the final stage of the primary assembly of the TBM’s main shield.
Two TBMs are being assembled for the construction of the 16-kilometer section of the 21-kilometer-long Mumbai tunnel. This includes a 7-kilometer tunnel beneath Thane Creek, which will be India’s first underwater rail tunnel. Each TBM weighs over 3,000 tons, making them the largest machines used for rail tunnel construction in the country to date.
This engineering feat is remarkable; the 13.6-meter-diameter cutterhead is capable of excavating a tunnel that will accommodate both up and down lines of the high-speed corridor within a single structure. Its weight of 350 tons is equivalent to that of approximately 250 mid-sized SUVs. The unit was delivered to the site in five separate shipments and assembled using 1,600 kilograms of high-precision welding. It features 84 cutter discs, 124 scrapers, and 16 bucket lips, all designed to enhance the excavation and debris removal process. The cutter discs are the primary tools responsible for cutting through rock, while the scrapers attached to the cutterhead help remove and clear debris.
The bucket lip on the cutterhead is the open section through which debris enters the machine’s spoil chamber. It assists in collecting debris and directing it towards the pipeline system, facilitating its removal from the tunnel.
This TBM will travel approximately 6 kilometers from Vikroli, passing through dense urban areas and beneath the Mithi River, before reaching the under-construction Mumbai bullet train station at Bandra-Kurla Complex (BKC), where it will be extracted.
To ensure safe excavation of the tunnel and monitor surrounding structures, various monitoring devices are being utilized. These include Surface Settlement Points (SSP), Optical Displacement Sensors (ODS) or tilt meters, BRIT (By Reflect Target/3D Target), strain gauges for measuring microstrain on the tunnel surface, and seismographs for monitoring peak particle velocity (PPV) or vibrations and seismic waves.
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My name is Bhupendra Singh Chundawat. I am an experienced content writer with several years of expertise in the field. Currently, I contribute to Daily Kiran, creating engaging and informative content across a variety of categories including technology, health, travel, education, and automobiles. My goal is to deliver accurate, insightful, and captivating information through my words to help readers stay informed and empowered.
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