Waterproofing & Water Control

University Link is a 5km light rail extension that runs in twin-bored tunnels from Downtown Seattle north to the University of Washington, with stations at Capitol Hill and on the University of Washington campus. The twin-bored tunnels are connected with 20 cross passages. Dr. Sauer & Partners performed the temporary and final support design for the cross passages. This included the design of excavation and support measures and the development of specific ground support categories, settlement analyses, and the structural analyses of initial and permanent lining.

Beacon Hill Station is part of the 22.5 km initial segment of Sound Transit's Central Link Light Rail. It is located 49 m below the ground surface in complex glacial soils with multiple groundwater horizons. The project comprises deep mined station tunnels and two 1.5 km long running tunnels excavated using a tunnel boring machine. The mined station was excavated through compressible glacial soils with multiple groundwater horizons using conventional mining techniques. The access shafts and station headhouses were constructed using slurry walls and cut-and-cover techniques.

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 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.

British Gypsum's operation at Leicestershire, a plaster production plant, improved infrastructure by establishing 2 new tunnels on site. Ground treatment for the control of water ingress during construction, drift excavation, final lining and a water ingress guarantee had to be taken into consideration. By applying NATM, the tunnel was excavated by roadheader and supported with lattice girders followed by shotcrete. The construction met the final water ingress guarantee by installing a PVC waterproofing membrane between the primary shotcrete lining and the final unreinforced in-situ concrete lining which is of a watertight quality in the invert.