Underground Metro stns being made with top-down method

Kanpur: The construction work of Nayaganj underground Metro station reached the platform level stage. Underground Metro stations are being constructed with top-down method
The casting work of the platform-level of Nayaganj Metro station under Chunniganj-Nayaganj underground section of Kanpur Metro Rail Project began on Friday. It is the last level of this underground station being built with a top-down method. A retrieval shaft will be built here to retrieve the ‘Nana’ and ‘Tatya’ TBMs presently moving from Bada Chauraha towards Nayaganj. Later, this shaft will become a part of Nayaganj Metro station.
The work of casting the roof and concourse slabs of about 225 metre long and 22.3 metre wide Nayaganj Metro station has already been started. About 60 percent work of casting of roof slab (roof of station) and about 40 percent work of concourse has been completed. For casting at the platform level, 15 percent of the area has been excavated under the scope of work.
Making an underground tunnel from Bada Chauraha to Nayaganj, ‘Nana’ TBM has moved up to 650 metre downline and Tatya TBM by 230 metre upline. After construction of about 990 metre long tunnel, both the TBMs will be taken out from the retrieval shaft from the starting end (towards the LIC Building) of Nayaganj Metro station. These machines will again be sent inside for excavation from the launching shaft constructed in Chunniganj, from where they will build a tunnel till Bada Chauraha Metro station while passing via Naveen Market Metro station.
The four Metro stations covered in the Chunniganj-Nayaganj underground section are being constructed by top-down method, that is the construction process is being done from top to bottom. The concourse level in the underground station, the first floor, which houses the passenger facilities, such as ticket counters and security check booths, is situated one floor below the road, just opposite to the concourse level of the elevated stations. Under the top-down method, firstly the roof slab of the station is constructed, followed by the construction of the concourse level and then the platform level.
Cut-outs have been made at each level to allow construction materials and excavator machines to reach this level. This system is being adopted to minimize the traffic impact due to the ongoing work at the under-construction station as the barricading on the road will be reduced after the construction of the first floor starting from the road level. The construction work of the station below the road will continue and the movement of vehicles on the road will also continue smoothly.
The construction work of about 4 km long underground section between Chunniganj and Nayaganj under the first corridor of Kanpur Metro (IIT-Naubasta) is going on in full swing. Four underground Metro stations are being constructed under this section--Chunniganj, Naveen Market, Bada Chauraha and Nayaganj.