Geological Engineering

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 project further includes 20 cross passages located in soft ground and a maximum design water head of 60m. To deal with the prevailing geological conditions, specific ground support categories were developed. Steel fibre reinforced initial lining, sheet membrane waterproofing and CIP final lining were utilised.

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.

Crossrail is a 118km railway line along an east-west route across London. Its central section runs via 21km twin-bore tunnels connecting eight underground stations and represents one of the world's largest infrastructure projects. Dr. Sauer & Partners was assigned to provide Category III independent design checking services on the Sprayed Concrete Lining works for the complete Whitechapel and Fisher Street SCL structures. Additional 3D non-linear FEA and assessments were carried out for the wraparound and junction structures of the Liverpool St Station and the Bond St Station.

Los Bronces copper mine, an open-pit operation at an altitude of 3500m ASL in the Chilean Andes, planned to utilise a tunnel for further deposit exploration and development. The project consisted of an 8.2km tunnel link between Los Bronces and Confluencia, connecting two processing plants. By applying drill and blast methods, a chamber was prepared to launch a 4.5m diameter tunnel boring machine which took over further excavation. A difficult geological and hydrological setting, extreme weather conditions as well as the high altitude and the rough terrain, provided a challenging environment.

The station is located in central London between Tottenham Court Road and Liverpool Street Crossrail (CRL) Stations. Constructed in the geologically most complex area in the whole of CRL, an optimised geotechnical and SCL tunnel design was implemented, which resulted in significant time and cost benefits for the project. Using a dynamic 3D geological model in conjunction with SCL tunnelling represented a key element of the geotechnical risk management framework.

Green Park tube station is a LU station situated on the north side of Green Park in central London. The station serves as an interchange between the Piccadilly, Victoria and Jubilee lines. As part of Transport for London's (TfL) investment programme, LU is implementing capacity enhancement and step‐free access (SFA) works to various stations. Dr. Sauer & Partners was responsible for the design of the primary support, i.e. sprayed concrete lining (SCL) and for providing construction support services including supervision of the excavation works and installation of the primary lining.

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.

Contract C305 is the biggest design-bid-build construction contract of the Crossrail (CRL) project and includes the eastern running tunnels of CRL's central section with launch shafts and SCL launch adits for TBMs at Limmo Peninsula, SCL caverns and launch adits for TBMs at Stepney Green and 10 SCL cross passages between the running tunnels with lengths up to 30m. At the Limmo Peninsula site a 40m deep and 30m diameter SCL shaft was built. At the shaft bottom in Stepney Green, two 30m long and up to 10m wide SCL launch adits were constructed followed by two 14m high and up to 18m wide, SCL caverns with single sidedrift and double sidedrift cross sections.