By rosebell
Following completion of the longest tunneling drive for Delhi Metro Phase IV, the Delhi Metro Rail Corporation (DMRC) has celebrated a construction landmark.
On 5 December, TBM Amrit, operated by Afcons Infrastructure, broke through and completed the bore between the Tughlakabad Airforce launch shaft and Maa Anandmayee Marg Station on the Tughlakabad-Aerocity corridor.
Being located at an average depth of almost 16m, this tunnel has been constructed with around 1,894 rings installed, each with an inner diameter of 5.8m, whereas the rings were cast at a fully mechanised casting yard at Mundka and the concrete segments were cured with steam to achieve early strength.
According to Afcons managing director S Paramasivan: “TBM Amrit successfully completed 2.65 km of boring through mixed soil and hard rock strata today. It is the longest tunneling drive in Phase-IV of Delhi Metro. Frequent cutter replacements were required to bore through the hard rock. The tunnel drive alignment was meticulously planned to avoid passing beneath heritage structures adjacent to Mehrauli Badarpur Road.”
While the construction works of two parallel tunnels are currently being advancing along this stretch of the Aerocity-Tughlakabad corridor, the scheduled date for breakthrough on the second tunnel is January.
May 2023 was the date of commissioning TBM Armit, which is a 6.5m-diameter refurbished Robbins EPBM and it was the first of four machines to be deployed by Afcons to build the twin tunnels on the 6.9km-long DC-07 package between Sangam Vihar Station and Sarita Vihar Depot.
DC-07 includes three stations, 11.26km of tunneling, a 223m ramp, and a 119m cut-and-cover section. The three underground stations are Maa Anandmayee Marg Station, Tughlakabad Railway Colony Station, and Tughlakabad Station.
Almost 40.1km of underground lines are being constructed that are the part of the Phase 4 work approved so far and the Aerocity-Tughlakabad corridor has underground sections totalling 19.34km.
