The work on Metro-3 (Colaba-Bandra-SEEPZ), the city’s only fully-underground corridor, has been underway for a while. And, the MMRCL is all now set to take on under-river tunnelling for Colaba-Bandra-Seepz Metro project.
According to Indian Express, as work continues on India’s first completely underground Metro Rail line, the section between the Dharavi and Bandra Kurla Complex stations will also witness India’s second under-river tunnelling for a mass transit project. Apart from the BKC Metro station and a 170-metre section of tunnel will be constructed right under the Mithi river, only a little over a kilometre from where it empties into the sea.
Director (Projects) S K Gupta of MMRCL told the Indian Express, “When tunnelling below a water body, you have to almost feel the ground, watch it closely and see how it’s behaving, to understand to what extent it needs to be supported.” The area will have three tunnels; two tunnels will be dug using tunnel boring machines (TBMs) while the 150-metre long tunnel below the riverbed, will be dug using the New Austrian Technology method (NATM).
At BKC station a 153-metre section of the tunnels are to be built by the New Austrian Tunnelling Method (NATM). Work on the horseshoe-shaped tunnels has begun very slowly over the past few weeks but is expected to make real progress in the coming few days. The ceiling of these tunnels will be 8.5 metres to 12.5 metres below the riverbed. The MMRCL is also slowly progressing only a few metres every week, and tunnelling under the Mithi is expected to continue right into October. “Weak spots have been identified and designed for. People know beforehand and are prepared in terms of resources and equipment. And they are a qualified set of people overseeing the work,” Gupta told the Indian Express.
