ABSTRACT
Marol station, a part of 33.5 km underground metro line from Seepz-Colaba in Mumbai, is situated at a road junction and surrounded by hotels, commercial establishment, and a Fire Station. It passes underneath an operating elevated metro pier at a shallow depth of 26 m between its two successive spans of 28.63 m. While the vertical circulation of passengers and services in the underground station are accommodated in two box structures constructed by Cut and Cover method on either side of the elevated metro piers on two different roads, its platforms have been constructed by first driving both UP and Down alignment tunnels by TBMs and then widening them by conventional tunneling method. Both the platforms are connected to the vertical circulation of the station by 16 cross-passages. This paper discusses in detail the various challenges faced during construction of widening Tunnel without restricting any operation of existing metro piers.
