EPB Shields: safe in soft ground.
Herrenknecht Earth Pressure Balance Shields (EPB Shields) are in their element when the geology is soft. Cohesive and incohesive soils with a high clay or silt content and low water permeability are ideal conditions for EPB tunnelling.
M30 Tunnel, Madrid, Spain
This project is a challenge for the best. The start shaft, located in a densely residential area, was certainly compact, measuring 0.21km² in area. This is where, on 5th November 2005, the 4,364 tonne TBM colossus from Herrenknecht started its tunnelling work. Crucial factors in the success of this project were the professional project management and the new machine concept with an inner cutting wheel (Ø 7m) and a coaxial outer cutting wheel (Ø 15.20m) mounted in the same working plane. After only eight months, the tunnelling team of the construction companies Acciona Infraestructuras S.A. and Ferrovial Agroman S.A, using the S-300 Earth Pressure Balance Shield, arrived at the target shaft of the new North tunnel for the M-30 urban motorway.
Download the project folder S-300.
Eastside LRT Project Los Angeles, USA
In an effort to deal with the metropolis' gridlocked freeways, Los Angeles County Metropolitan Transportation Authority is extending its railroad network. The "Gold Line" linking the long-distance Union Station with the North-Eastern suburb of Pasadena is being extended by about 10km towards the South-East. When tunnelling anywhere in the Los Angeles basin there is always the possibility of encountering methane because of the local mineral oil, so both machines were protected against firedamp. Valves, engines and control cabins were also appropriately equipped. Even the buttons and switches of the control panel were spark-protected. The extended "Gold Line", which will take its passengers right up to the Pacific beaches, is scheduled to open in 2009.
Katzenberg Tunnel, Efringen-Kirchen, Germany
It's all happening at the Katzenberg. Here, two identically constructed, 200 meter long boring giants from Schwanau and each weighing 2,500 tonnes, are foraging forward, with a weekly advance of up to 148 meters per week, through complex stratification composed of limestone, sandstone and marl. The tunnel is due to be operational in 2012 and will be Germany's longest traffic tunnel excavated by mechanized tunnelling.
