Underground stations of Riyadh Metro project line 3. Deep stations with counter-vault

Abstract

The deep stations with counter-vault of Riyadh Metro Project Line 3 are formed by four underground levels that constitute the deep box, where a central atrium configures all passenger flows. The temporary works consist of a bottom-up construction method. In one station, a continuous retaining wall has been designed based on secant piles with three retaining levels. The bottom slab of the deep box is a reinforced concrete counter-vault with continuous shear keys that resist the water pressure transmitting the axial compressive forces to the rock (arch mechanism). The intermediate and top levels have been designed with precast pre-stressed beams and concrete in-situ slabs, with an evolutional structural behaviour.