Tunnel

Silver Line Phase III is an underground extension of the Silver Line from the current terminal at South Station into Downtown Boston. The tunnels through Boston's Chinatown lie up to 25m below surface and include ca. 1400m long-running tunnels, two stations and complex underground junctions. The NATM design alternatives for LRT / Busway tunnels are located beneath existing subway stations and running tunnels. 3D modelling tools were utilised to create multiple alignments.

Bond Street tube station is a major gateway to London's West End served by both the Central and Jubilee lines. As part of the LU tube upgrade plan, the station is undergoing a major upgrade to increase capacity, improve accessibility and create interchange with the new Crossrail station. The project provides two additional escalators from the interchange level to the Jubilee line, low-level interchange route between the Central and Jubilee lines, a new step-free entrance, ticket hall and new lifts. The majority of the tunnelling works will be mechanically excavated and lined with sprayed concrete.

Currently over 150,000 passengers use the station daily and with the completion of Crossrail in 2017, passenger numbers are expected to increase to over 200,000. The tunnels are of diameters between 4.0m and 11.0m and typically consist of a temporary sprayed concrete primary lining, a spray applied waterproofing membrane and a cast-in-place concrete secondary lining. Multiple transitions and interfaces to existing LU structures make for a challenging design and construction project under the busy streets of central London.

Farringdon station is now one of London's major rail interchange stations, providing connections between three networks. During the construction of the Crossrail project, it also received four earth pressure balanced tunnel boring machines (TBMs): the two Drive X TBMs, running from Royal Oak to Farringdon and the two Drive Y TBMs, running from Limmo to Farringdon. The complete station layout will comprise two ticket halls, two platform tunnels, connecting cross passages, escape and ventilation adits, two escalator - inclines and two concourse tunnels constructed using mainly SCL tunnelling.

Farringdon station is situated at the heart of London's rail network and will be one of its major rail interchange stations, which will link Crossrail, Thameslink services and London Underground trains. The station layout includes two ticket halls, two escalator inclines, two platform tunnels, connecting cross passages, concourse tunnels and ventilation adits. The chosen tunnelling system for Farringdon Station was sprayed concrete lining (SCL). The station comprised a total of 1km of SCL tunnels at depths of up to 35m below ground level and excavation cross-sections varying from 25m² to 110m².