Detailed Design of 3E1 and 3E6 Deep Underground Stations for Riyadh Metro L3, including the dimensioning of all the permanent concrete and steel structures that conforms the deep underground station, including foundations, slabs, walls & columns, stairs, accesses and canopies, so as the temporary works necessary to proceed with the construction of the station, so as all other structures included in the general design of the station.
The Typical Deep Underground Station 3E1 and 3E6 consist in four different underground levels with a central atrium volume that configures all passenger flows. This Central Atrium is an open space that helps to carry natural light to platform level. Access to the station is provided through two glazed entrances located at street level, which form an integral part of the wider landscape and urban development, so as three emergency exits, located taking in account the space restrictions of the existing or future urban development of the area.
The Deep Underground Stations 3E1 and 3E6 consist in a concrete deep box 148 m long (measured at platform level) and variable external width 19.90 m to 28.30 m. The width of the permanent retaining walls existing all around the perimeter of the deeper section is variable with the station depth. For the lateral areas of the station this thickness is variable between 1.60 m at the deepest section and 0.80 m for the shallowest. At the central area the wall thickness adopts a constant value of 1.40 m because of the lack of any available support.
The volume was designed with a perimeter concrete wall 0.70-0.80 m thick, embedded in a 1.00-1.20 m concrete bottom slab designed to avoid the uplift pressures. The top slab is designed with transverse precast ‘I’ beams and a second phase slab with a total thickness of 2.30 m for 3E1 and 1.85 m for 3E6. The accesses to the concourse are designed in reinforced concrete (walls and bottom slab), and precast elements for the top slab with cast in situ concrete in a second phase.