Metro TBMs wait for Chinese drill experts
The machines have to be operated by engineers of the manufacturing company due to warranty conditions
BENGALURU: The stoppage of regular international flight operations by India is set to impact the commencement of tunnelling work in Metro’s Phase-II. The intricate and complicated task of drilling the soil 65 feet below requires Chinese expertise to operate its four Tunnel Boring Machines, say senior officials handling the project.
While three machines have been partially assembled with assistance from Chinese engineers, the fourth machine, is yet to be put together. However, even after the TBMs are assembled, drilling work cannot begin due to the pandemic, Radhakrishna Reddy, Director, Projects, Bangalore Metro Rail Corporation Limited, told TNIE.
“To start drilling, we will require experts from Chinese Rail Construction Heavy Industry (CRCHI), the supplier of the machines. The rear portion of one machine at Cantonment will be ready by end of June. If India opens up international travel, engineers can fly here immediately. If not, the tunneling work will get delayed,” he said.
Giving instructions via video conference is not possible, Reddy said, as engineers need to physically operate the machine for 1 kilometre and check it out as there is a warranty on the machines, each of which weighs 450 tonnes and costs Rs 70 crore (including shipping). Four TBMs given the Sanskrit names of Avni, Urja, Lavi and Vindhya were shipped from November to April to lay the underground rail line from Nagawara to Diary Circle of the Reach-6 Line. “We had to get special permission from the government to ship two of them which were stuck at the Tamil Nadu-Karnataka border for two weeks after the lockdown was enforced,” he added.
How the tunnels will be built
The two TBMs at Cantonment will drill toward Shivaji Nagar station. “One machine needs to move 40 to 50 metres and then we will begin the next one,” Reddy explained. After they reach the destination, they will be brought by road to Cantonment and drilling will begin in the reverse direction towards Pottery Town. The TBMs at Shivaji Nagar will drill towards MG Road Metro station. From there, they would be dragged along the base of the Metro station that is being built and will head to Vellara Junction Metro Station, the Director said. The underground metro line has a June 2024 deadline.