Athens metro line 4

Location Greater Athens area, Greece

Project Duration 2021 to 2029

Industry Infrastructure Transportation

Client J&P AVAX, GHELLA SPA and ALSTOM TRANSPORT / ATTIKO METRO S.A.

Obermeyer was appointed by the Design and Build Contractor as the nominated Consultant for Geotechnical Evaluation, Temporary Excavation Support Design, TBM Tunnel Design, NATM Tunnel Works Design, Architectural and Structural Design of Stations / Shafts. The scope included the provision of geotechnical, tunnel, architectural and structural engineering services for all stations, shafts, and associated structures. Designs in BIM environment.

Section Α’ “Alsos Veikou – Goudi” has been planned so as to serve several densely populated areas of Athens, as well as important buildings and facilities such as hospitals, educational institutions, courthouses, and buildings of public organizations or ministries. The total length of the section is approximately 12.8 km and it includes fifteen (15) new underground stations, nine (9) intermediate and/or terminal shafts, TBM double-track tunnel approximately 10,300 m long, underground single-, double-, triple-track and turnout tunnels bored by conventional mechanical means, two forestations, and Operation Control Centre.

Technical details:

Tunnels bored based using Tunnel Boring Machines (TBM)

Total length 10,300 m

Precast segment ring’s outer diameter / inner diameter 9.18 m / 8.48 m, EPB TBM bore diameter 9.52 m

4- or 5- or 6- or 7- level metro stations being constructed using a mixed construction method (Platform level bored using conventional means (NATM), while remaining sections of station and entrances constructed using the Cut and Cover method

Side-platform NATM tunnels ~80 m long, net inner width 15.04m

Crossover tunnels, entrance tunnels, stairs/escalators tunnels, ventilation tunnels

Entrance and Ventilation Cut and Cover shafts

5-level Cut-and-Cover Maintenance Forestation 215.80 m long – inner dimension, 13.8 m to 28.7 m wide, 35 m deep

Triple-track Forestation Tunnel, 295m long, net inner width 14.30 m

Trumpet Tunnel, 59m long, maximum net inner width 13.87 m

Shaft for Ventilation, emergency exit and recess for traction power switchgear