BENGALURU: BMRCL’s tunnel boring machine Rudra finally resumed its operations on Monday towards Lakkasandra. Five months after it ground to a halt 50 feet below the ground after encountering a humongous garbage mound at Dairy Circle, Bangalore Metro Rail Corporation Limited's Tunnel Boring Machine (TBM) `Rudra' finally resumed operations on Monday towards Lakkasandra. In an unprecedented exercise undertaken anywhere in the country, BMRCL had to send a special steel drum-like structure (Pile Liner) underground to carry out garbage clearance.
None of the nine TBMs involved in building the underground corridor for the Nagawara-Kalena Agrahara Line (Red Line) encountered this weird issue. Sometime in mid-July, Rudra stopped work just near the Bosch Factory as sink holes cropped up due to the boring through the garbage. Speaking to The New Indian Express, a top official said, "We undertook a very complicated exercise. The entire ground was shaking when we started working on the garbage clearance. As a precaution, eight sheds of a granite factory above were vacated before work commenced. We spent over a month deliberating on the best and safest method possible and narrowed down on this strategy. This was a completely new experience for us."
Contractor AFCONS Infrastructure created a mammoth drum open at both ends and running to a length of 13 metres and a diameter of 1.2 metres, he said. "A Piling Rig facilitated the process and the Pile Liner was driven through the garbage. As soon as some of the garbage was removed using the drum, it was emptied on the sides and the empty space was filled with concrete. The process was done 260 times over a period of 2.5 months from early October till last week. A concrete mass was created here using piling machines" the official explained.
This is Rudra's second outing and it is expected to complete the 400-metre stretch within three months. It had successfully completed the first leg from Jayadeva Fire station to Dairy Circle.