Sao Paulo collapse: NATM used despite failure history

摘要

Tunnelling experts last month questioned contractors' decision to use the New Austrian Tunnelling Method (NATM) on the section of the Sao Paulo Metro which collapsed in January. They pointed out that ground conditions made NATM a risky tunnelling option especially as the city has a history of similar failures. The collapse on 15 January at the site of Pinheiros station, near Sao Paulo University killed seven people.