The Phase-1 network of Namma Metro in Bangalore, India consists of two corridors: East-West Purple Line, 18.1 km-long; and North-South Green Line, 24.2 km-long. The two corridors intersect at Kempegowda station, which is a two-level interchange station.
The contract for the 4.8 km-long underground section East-West Corridor, including tunnels and four stations (Cubbon Park, Vidhana Soudha, Sir M. Visveswaraya, Bangalore City) with ramps, was awarded to M/s CEC–Soma-CICI JV.
The contract for the construction of the underground Kempegowda Interchange Station was awarded to M/s GYT-Coastal JV.
The contract for the 4 km-long underground section North-South corridor, including tunnels and two stations (Chickpet and City Market) with ramps, has been awarded to M/s Coastal-TTS JV.
Tunnelling from South Ramp to Majestic
TBM Krishna completed 378 m of southbound tunnel from City Market to Chickpet Station; TBM Kaveri completed 229.5 m of tunnelling out of 747 m between Chickpet and Majestic Station.
Krishna, the fourth TBM involved in Namma Metro operations, will shortly enter the underground tunnel below the Kempegowda Underground station (formerly Majestic UG station) area and will bore the tunnel between Chickpet and Kempegowda Metro stations. The Kempegowda station intersection is the most crucial element in the completion of Metro Phase-I by the March, 2016 deadline.
Tunnelling from North Ramp to Majestic
The TBMs Godavari and Margarita, deployed in the 1 km-long underground stretch between the Mantri Square Sampige Road Metro station and Majestic underground station, stopped functioning months ago due to damage, after they completed work on the rockiest area.
In July, 2014 the TBM Godavari, supplied by Seli, after 350 m at a depth of 19 m from Mantri Square Sampige Road Station towards Majestic, broke down near Lakshmanapuri. The cutterhead developed serious cracks after encountering hard rock. Tunnelling in the remaining 615 m stretch from this point to Majestic is yet to begin. The old cutter head parts have been removed at 22 m below ground. The new 70 t cutter head, manufactured by Italian company Palmieri for the underground tunnel contractor M/s Coastal -TTS JV, was shipped from Italy on 25.02.2015. A vertical access shaft has been completed and preparatory works for installing the new cutter head are in progress at the site. Installation of the new cutter head should take about a month.
Repair work is also being carried out on TBM Margarita after completing 747 m of tunnelling between Majestic and North Ramp.
Boring work by all the TBMs is expected to be completed by December, 2015. Click here for more and here and in/54 for tunnelbuilder archive. Visit http://bmrc.co.in/news.htm. 27/15.
