Different types of infrastructures
Two alternatives are feasible for the metro infrastructure: underground or above ground. To assess the possible options, potential advantages and disadvantages of each have been looked very carefully by the project team. The Green Line will be above ground on the south-west part, underground on the north-east part.
Elevated metro from Moadamiyeh to Adab faculty
Implementing an elevated metro in a street is possible when the street is very large. This solution has been retained in the south-west part of the Green Line: the metro will run on a viaduct on Quneitra Road and Mezzeh Autostrad (half the length of the metro line). The elevated metro costs less to build than the underground infrastructures, and can be architecturally integrated to the cityscape. It will also provide the opportunity to enhance the areas along the route, with improvements of the streets. This solution has received considerable support from the community, according to the second stage of public consultation (62% of the respondents would accept a viaduct on Mezzeh Autostrad).
Example of elevated metro in Dubai
Underground metro from Adab to Qaboun
The North-East part of the Green Line will be underground (half of the metro line, between Adab and Qaboun). This solution is the only alternative in very crowded areas like in the city center, where it is not possible to have above-ground infrastructure. Two methods of excavation will be used:
- A deep tunnel in the very dense areas (city centre), built with a tunnel boring machine, around 15 to 20 meters below ground.
- A shallow tunnel, built just below the surface, where possible.
The stations will be the only external signs of the underground sections.
The deep tunnel will be built using a tunnel boring machine (from Adab to Hob-Hob / Al Thawra Square).