The work and the technique: Red Line North underground - Doha Metro System, Qatar

Doha's 'Red Line North Underground' and three other metro lines are part of Qatar National Vision 2030, a project drafted by the country to diversify its economy and become less dependent on the sale of its oil and gas deposits.

The two tunnels for this line are 6.17 metres in diameter and were built using four TBMs, and innovative fully fibre-reinforced prefabricated blocks.

The stations were built with the cut-and-cover method, which comprises digging a trench at the site and then building walls, flooring and ceilings with poured concrete. Two of the seven stations required diaphragm walls and provisional works, while for the others, a combination of piles, ground nailing and sprayed concrete was sufficient.  

Including the tunnels and the stations, 2,700,000 cubic metres of material were excavated (530,000 cubic metres recovered), and 725,000 cubic metres of conventional concrete were used.