The capital of Qatar, Doha is being increasingly turned into a modern centre for industry, trade and sport. One essential precondition for this is the development of high‐capacity infrastructure with modern means of transport. This includes the construction of an underground railway network, which has to be completed in a very short time due to the football World Cup taking place in Qatar in 2022. The (part) project ”Metro Green Line Underground“ was awarded in summer 2013 to a Joint Venture comprised of Porr (lead), the Saudi Binladin Group and the local construction company HBK. It includes the turnkey completion of the underground part of the Green Line in the future underground system. This includes two tunnels with a length of 17 km each, six stations, crossover structures, several emergency exits and 32 cross passages and two road underpasses. The shield drive for the running tunnels began in late summer 2014 and could be completed after only 18 months of construction time in early 2016. In addition to explaining how the simultaneous operation of six EPB machines was successfully mastered, this article also describes the conventional tunnelling of the various connection and underpass structures under inner‐city conditions.

The contract C310 comprises the construction of the Plumstead and North Woolwich Portals and the twin tube Thames Tunnel, which has a length of approximately 2.6 km between the two portals. The two TBMs used for the construction of the Thames Tunnel will drive through varying ground conditions (Thanet Sand, River Terrace Deposit (gravel), and chalk) below the water table. During the drive under the River Thames, the tunnels will only have an overburden of approximately 12 m. The effect of pressure variation due to the tidal River Thames has to be accounted for in the control of the tunnelling. The tunnel will pass underneath several grade II listed buildings, utilities, adjacent to operational railway tracks and close to existing subway tunnels. Previous experience of the handling and disposal of excavated chalk has been gained on several tunnelling projects in chalk, most notably the Dartford Road Tunnels, the Channel Tunnel, the Brighton Stormwater Tunnel, the Lille Metro Tunnel, the Socatop Road Tunnel near Paris and Channel Tunnel Rail Link CTRL 320. The Contract allowed for both Mixshield and EPB TBM Technology. The advantages and disadvantages of a TBM-S with Earth Pressure Balanced face support (EPB-TBM) and a TBM-S with Slurry Face support (Mix-Shield TBM) for the C310 Thames Tunnels were discussed after contract award and a comparative risk assessment was developed. A Mixshield TBM is more expensive but outperformed the EPB TBM in the overall scoring of risk assessment and therefore it has been decided to use this type at C310.

Doha, the capital of Qatar, is being developed into a modern centre for trade and industry. One essential part of the implementation of this aim is the provision of modern mass-transport. The "Qatar Integrated Railway Project" includes both high-speed railway lines and a metro system in Doha. Die Doha Metro has three lines. The network will have a total line length of 216 km in the first extension stage, of which 96 km run underground. The Green Line was awarded to a Joint Venture of Porr (lead), Saudi Bin Laden Group and the local construction company HBK. The contract includes turnkey completion of the underground section of the Green Line with a tunnel length of 2 × 17 km, six stations, gauge changing equipment and switches as well as cross-passages and emergency exit shafts. The project is being implemented as design and build. The paper reports on experience with assembly work under the difficult conditions of the Middle East as well as the first few weeks of tunnelling.

As part of the Qatar National Vision 2030, the capital of Qatar – Doha – is being expanded into a modern centre for economy, trade and sport. A main part of this plan is the establishment of an efficient infrastructure with modern means of transportation. The Design & Build – Project Green Line Underground was awarded to a Joint Venture (JV) composed of PORR (lead), the Saudi BinLadin Group and the local construction company HBK in summer 2013. It contains the turnkey construction of the underground part of the Green Line with a total length of 2 × 17 km tunnel, six stations, switching areas as well as cross passages and emergency exit shafts. The 34 km of tunnelling, bored by six EPB machines simultaneously, has now been completed. The expectations for the project, especially concerning the TBM tunnelling, are compared to the knowledge gained. The following topics are highlighted: – climate and culture, – personnel of different origins/education, – working with unskilled/semiskilled workers, – TBM/logistic concepts, – performance, wear and tear, – geological conditions, – segment design, – health and safety. The tunnel drives were completed in 18 months despite all challenges. Im Rahmen der Qatar National Vision 2030 wird die Hauptstadt Katars – Doha – zu einem modernen Zentrum für Wirtschaft, Handel und Sport ausgebaut. Ein wesentlicher Bestandteil zur Realisierung dieses Ziels ist die Errichtung einer leistungsfähigen Infrastruktur mit modernen Massentransportmitteln. Das Design & Build‐Projekt Green Line Underground wurde im Sommer 2013 an ein Joint Venture (JV) aus Porr (Federführung), der Saudi BinLadin Group und dem lokalen Bauunternehmen HBK vergeben und beinhaltet die schlüsselfertige Errichtung des unterirdischen Abschnitts der Green Line mit einer Tunnellänge von 2 × 17 km, sechs Stationen, Spurwechsel‐ und Weichenanlagen sowie Querschlägen und Notausstiegsschächten. Die Vortriebe der ca. 34 km langen Tunnel, die mit sechs EPB‐Maschinen hergestellt wurden, sind mittlerweile abgeschlossen. In einem Rückblick werden die Erwartungen an das Projekt, insbesondere an den TVM‐Vortrieb, mit den gemachten Erfahrungen verglichen. Hier werden speziell folgende Themen beleuchtet: – klimatisches und kulturelles Umfeld, – Personal unterschiedlichster Herkunft und Bildung, – Arbeiten mit ungelerntem/angelerntem Personal, – Vortriebs‐ und Logistikkonzepte, – Leistungen, Verschleiß, Schäden, – geologische Verhältnisse, Vorauserkundung, – technische Ausführung der Tübbinge, inkl. Dichtung, – Arbeitssicherheit, Gesundheitsschutz. Trotz aller Herausforderungen konnten die Vortriebsarbeiten in ca. 18 Monaten abgeschlossen werden.

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