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Tag Archives: Tunneling


Umbrella Arch

The umbrella arch is a temporary support system forming a structural umbrella from the insertion of an assortment of longitudinal support members installed from within the tunnel, above and around … Continue reading

New Austrian Tunneling Method (NATM)

The New Austrian Tunneling method (NATM) was developed between 1957 and 1965 in Austria. It was given its name in Salzburg in 1962 to distinguish it from old Austrian tunnelling … Continue reading