ABSTRACT
Amsterdam City Council is building a new metro line from the north part of the town to the south, called the North–South Line. The metro line passes under Amsterdam Central Station about 18m below street level. The design of the retaining wall underneath the building needed to build the tunnel was complicated, as the building has to remain in full service during construction and damage to the masonry is not acceptable (the station is a listed building). This paper gives an overview of the approach taken and the computation models used to design the innovative composite “sandwich” retaining wall. The wall consists of two parallel rows of steel Tubex piles interspersed with a solid mass of overlapping jet grout columns.
