Delhi Metro achieves major milestone for Phase 4 project; completes first tunneling drive
Today, a major milestone was achieved in Delhi Metro’s Phase 4 construction work as the first-ever tunneling stretch of the Phase 4 project was completed at Krishna Park Extension on the Janakpuri West-RK Ashram Marg corridor with a 73 metre long Tunnel Boring Machine (TBM) breaking through after boring a 1.4 km long tunnel. On this stretch, the main tunneling work was commenced earlier this year in the month of April after the initial drive’s completion. Despite the many Covid constraints, work was continued and this major milestone could be achieved, according to a statement issued by Delhi Metro Rail Corporation (DMRC).
On this stretch, two parallel circular tunnels for up-down movement are being built which is a part of the 2.2 km long Janakpuri West-Keshopur underground section. Soon, tunneling work on the other parallel tunnel shall commence, DMRC stated. This new Delhi Metro’s tunnel is a continuation of the earlier tunnel of the Magenta line that was already developed for the currently operational Botanical Garden-Janakpuri West corridor. The construction of the tunnel has been done approximately at a depth of 14 to 16 metres. More than a thousand rings have been installed in the newly developed tunnel. It has 5.8 metres inner diameter. The tunnel’s alignment runs along the Outer ring road and below the multi-storied built-up structures.
The tunnel has been constructed with EPBM technology with concrete lining made up of precast tunnel rings. The rings of the tunnel have been cast at the fully mechanized casting yard setup at Mundka. To achieve early strength, these concrete segments were cured with a steam curing system. DMRC further claimed that all necessary safety precautions were taken by Delhi Metro while building the tunnel below the built up structures by monitoring the ground movements with the help of highly sensitive instruments fixed on the structures nearby. As part of the approved work for Phase 4 so far, nearly 27 km of underground lines will be developed. The corridor from Janakpuri West to RK Ashram Marg will have underground sections of 7.74 km in total.