Many of the tunnels and rock cuttings in the swedish railway system are old and badly affected by frost action and frozen groundwater. This ice is a serious problem because in bad cases it may intrudeon the track structure from the walls, and in periods of thaw it may loosen and fall on the track. It is therefore necessary to remove the ice. This work is both expensive and dangerous, and high costs and risks might be avoided if the seepage of water could be reduced or the water prevented from freezing. deep drainage, widening the tunnel section, caulking with sprayed concrete, grouting, and insulation used to be used for this purpose. Since 1979 an entirely new method of insulating with cellular plastic has been used. Details of thismethod are discussed: choice of material, joining, installation anddimensioning, and cost. An account is given of the work that has been completed and of the results that have been achieved. conclusionsthat may be drawn from experience to date are presented. This paperappeared in transportation research record no. 1150, tunneling. forcovering abstract see irrd no 818446.
Abstract