Delhi Metro has announced the simultaneous use of 34 tunnel boring machines to deliver the next phase of the complex infrastructure project in India’s capital city. This will be a record number of machines used at any one time in one city.
Phase III of the metro is made up of 74 tunnels, 53 kilometres in length. To monitor the progress of the TBMs, the developer is procuring and installing a Centralised Data Management System.
The system will allow easy, instantaneous data acquisition, visualization and reporting to help minimise risk, track physical progress, ensure the accuracy of tunnel alignment, ensure proper ground settlement and view the status of existing buildings and structures along the project’s path.
Project-specific trigger levels have been set which will automatically set off an alarm in real time via numerous communication devices, including mobile and email, so that any issues can be acted upon as they happen.
The engineering team has to deal with numerous difficult stretches, so this reporting function is integral to safe delivery.
The tunnels in Phase III are going to pass under railway tracks at Palam and Tilak Bridge. Near Nizamuddin, tunnels will be made in high ground water level, at Vasant Vihar below a Bio-Diversity Park which is rocky in nature, and in various other locations they will pass under high rise building and ring road flyovers.
For the first time in the history of Delhi Metro’s construction, four different tunneling stretches will pass below existing underground Metro stretches in the city posing another major construction challenge to the engineers.
During the second phase of Delhi Metro’s construction, there was only one instance when a new corridor had to cross below an already operational corridor. At Connaught Place, a 45-metre deep tunnel was constructed for the Airport Express Link below the Rajiv Chowk Metro station, which is currently the deepest point of the Delhi Metro system.
The proposed new corridors under Phase III will cross the existing operational corridors at 14 different points. While 10 of these crossings will be under the already operational stretches, four crossings will be elevated above the operational Metro viaducts.
Three tunnels have already been completed with the rest of the tunneling of Phase III scheduled for completion by mid-2015.