German firm Herrenknecht AG has supplied an 11.46m diameter tunnel boring machine for the construction of a new metro line in Rio de Janeiro.
The 14km long Metro Line 4 will help relieve traffic routes in the Brazilian city, which is gearing up for a key role in the 2014 football World Cup and the 2016 summer Olympics.
This will be the first time a tunnel boring machine has been used in Rio, with all previous tunnels built conventionally or as cut-and-cover tunnels.
Herrenknecht designed the machine so it can be converted in the tunnel to adapt to different ground conditions along the tunnel route,.
Herrenknecht project manager Carlos Manzano Rey said: “It is planned that the machine will cover the first 300m in open mode, then be converted for about 3km in closed EPB mode. Finally, around 1.3km will again be tunnelled in open mode.”