By rosebell
Following tunneling under the operational Red Line of the Delhi Metro network,the Delhi Metro Rail Corporation (DMRC) has marked a landmark on its Phase 4 expansion, whereas this tunnel is part of the Janakpuri West–RK Ashram Marg extension of the Magenta Line.
Considering that the trains on the busy Red Line above were not halted for a single day, even as the TBM constructed the tunnel below the elevated viaduct on which trains were operational, the tunneling work between Pulbangash and Sadar Bazar stations was especially challenging as DMRC said.
With the aim of ensuring its safety,so several engineering precautions were used for the Red Line viaduct stands on open foundations with a balanced cantilever span.
In order to strengthening the ground around the viaduct, tube a manchette grouting, with 180 TAM boreholes, was used. Also, the process of monitoring ground movement, pier behaviour, and building safety was done by deploying instrumentation and real-time monitoring. The equipment included surface settlement markers, deep inclinometers, building settlement points, pier tilt meters and load cells.
While for monitoring the readings, specialised personnel were deployed around the clock, DMRC said all parameters remained well within permissible limits during the entire operation.
According to DMRC: “The construction of the downline tunnel on this section has now been completed. Work on the upline tunnel is under way with the same level of precautions and monitoring. This was an extremely critical construction work since the Red Line, on average, carries about 700,000 passengers every day.”
