Metro Tunnel
The Metro Tunnel (sometimes also known as the Melbourne Metro Rail Project or the Metro Rail Capacity Project) is a metropolitan rail infrastructure project currently under construction in Melbourne, Australia. It includes the construction of twin 9-kilometre rail tunnels between South Kensington station (north west of the Melbourne City Centre) and South Yarra (in the south east) with five new underground stations. The southern portal for the tunnel is to be located to the south of South Yarra station. As a result, the tunnel will connect the Pakenham and Cranbourne lines with the Sunbury line, and allow these lines to bypass Flinders Street station and the City Loop while still stopping in the Melbourne central business district.
Line 3 (Mumbai Metro)
Two 5.2 metre diameter twin tunnels of 33.5 km each will be dug at a depth of 20–25 metres. Seventeen tunnel boring machines (TBMs), each weighing around 1400 tonnes and costing , will be used to dig the tunnels. The TBMs will be lowered through shafts or pits using a specialized crane. Pre-cast segments will be put on the tunnels' diameter to prevent cave ins, after the TBMs bore 1.2 metres. Tunnels will have to be dug through a mix of soil and basalt rock, and is expected to be difficult. TBMs can dig at an average rate of 8 metres per day through rock, and at a rate of 14 metres per day through soil. After TBMs bore through section, the metro tunnel will be lined with pre-cast concrete rings to strengthen the tunnels. Boring and placing rings occurs sequentially. For the entire Metro 3 corridor, around 40,000 concrete rings were cast in 65 moulds. Casting of the rings took place at six casting yards - four in Wadala, one each at Darga, and on the Jogeshwari-Vikhroli Link Road (JVLR). The first concrete ring was fabricated at a Wadala casting yard on 7 March 2017.