NEW DELHI: Construction on the much-awaited Phase IV metro corridor from Janakpuri West to RK Ashram Marg began on Friday. The work has started on the underground section of the 28.92-km-long corridor, which is an extension of the Magenta Line. The length of the underground section is 7.74 km. The corridor will have 22 stations. As part of the work, construction of the D wall as well as the casting of tunnel segments has been started.
“The work commenced for the construction of D walls or Diaphragm walls at the Krishna Park Extension metro station and the tunnel segments shall be used for tunneling with tunnel boring machines on a 1.4-km-stretch between Janakpuri West and Keshopur. The stretch will also have the Krishna Park Extension station in between as well as a 365 metre ‘cut and cover’ open ramp near Keshopur leading to the elevated section,” said a senior DMRC official.
D Walls are structural concrete walls constructed in deep excavation based projects. They are often used at congested sites, close to existing structures, where there is restricted headroom, or where the excavation is of a depth that would otherwise require the removal of greater volumes of soil. “The excavated area is secured by these walls and then the construction work of the underground station is commenced. This technology has been used for Delhi Metro’s underground stations right since Phase 1,” said DMRC.
“This work was awarded in December last year…Despite constraints like shortage of labourers and materials due to the lockdown, the milestone could be achieved on time. On June 24, the casting of u-girders was started,” said an official. In Phase IV, three different corridors of 61.68 km in length — 22.35 km of which will be underground — will be constructed. These new sections may provide better interconnectivity between the already operational metro lines.