1st Rescue TBM Commissioned for Delhi Metro’s Pink Line
This news is just in!
On this Wednesday, the CEC-CICI JV for contract CC-04 of Delhi Metro’s Phase 3 project commissioned the 1st of 2 ‘rescue’ TBMs from the Majlis Park shaft! This TBM will be used to construct the 58.596 km Pink line’s remaining down-line tunnel towards the Rameshwar Nagar mid-shaft. It was not part of the original tunneling plan, but became necessary to be deployed as the original 2 TBMs commissioned from Azadpur towards Majlis Park, with a tunneling distance of 1100m, got stuck mid-way.
Roughly 600m of tunneling on both tunnels is left which the contractor expects to complete in Q3 (July-September) 2016. In January, the contractor began lowering this TBM’s parts – see images here.
Note: As of the night of April 1, the TBM has completed building 11 permanent rings covering a distance of 15.4 meters.
Here’s a little history:
The contract for CC-04 was awarded on December 29 2011 with a completion deadline of September 28 2014, but things started going wrong in early 2014 after CEC-CICI launched the initial drives of both TBMs from Azadpur. The ‘Tunnels and Tunneling’ magazine recently published an article with a brief history of the difficulties faced and what CEC-CICI tried to do to resolve:
Both TBMs met with a large mass of intact rock which infringed the lower portion of the tunnel face and extended for approximately 30m. The TBMs used were both soft ground machines which have been used on a previous phase of the metro, and experienced high torque and overheating when attempting to cut through the rock zone. An attempt was made to break up the rock ahead of the cutter face by drilling and placing an expanding chemical to burst the rock and allow the cutter head to rotate and advance one ring at a time. The space within the chamber available to manage this exercise was very limited and matters were made worse by the presence of wet running sand above the rock zone which dictated working under compressed air.
Majlis Park Shaft (at the southern end of the ramp):
Fun Fact: Both rescue TBMs for this section have been leased from HCC-Samsung who built the Magenta line’s 4.5 km section between Vikaspuri – Janakpuri West – Dabri Mor – Dashrathpuri – Palam under contract CC-34.
As I’ve mentioned in the past, this section is located right by the Mukundpur depot (see map above) and trial runs on any part of the 58.596 km Pink line in north, west and south Delhi hinges upon the completion of these tunnels. Due to the delay in completing this section, the Pink line will now only be able to open in mid 2017 and not by December 2016 as originally planned. The DMRC’s MD recently admitted about the delay in an interview, but the DMRC is yet to officially announce the new revised deadline.
For more updates on the Delhi Metro, please visit the Delhi section of The Metro Rail Guy!
When will the breakthrough between Chirag Delhi and Greater Kailash take place?
Breakthrough at GK for the up-line tunnel just got done! Down-line will take another month.