Banverket plans freezing at HallandsasThe TBM advancing the east tube of the Hallandsas tunnel in southwest Sweden will enter the unstable Molle Back zone towards the end of 2009, some 1 km ahead of its present position. In preparation, a freezing unit has been located 1.8 km inside the north portal, from where horizontal holes have been drilled around the periphery of the proposed alignment. A circulating cold saline solution will produce a 15 m-diameter frozen column through which the TBM can safely bore. Specially-formulated, extra-strong concrete will be placed behind the TBM to overcome both the ground pressure and the added pressure of thawing. For the Hallandsas archive, click se/26. More from Nellie Larsson at Banverket, tel +46 431 442117 or visit www.banverket.se/hallandsas. 50/08.