Dealing with Swelling Ground at Sedrun

摘要

THE 57 km St Gotthard rail tunnel currently under construction on Switzerland is perhaps one of the world's most challenging tunnelling projects, and the deep sedrun section is probably the most complex part of the whole operation. It involves some 6 km of twin drill and blast tunnels accessed via a pair of 800m deep verticals shafts, both of which have been constructed completely underground, and the valley near the small town of Sedrun in the Swiss Alps. There is provision in the plans for extending the difficult Faido TBM section, which holes into the Sedrun section, fall behind schedule.