Corrugated plates for protection against water leakage in road tunnels can be damaged even by quite small ice loads. Liner plates in frost zones must therefore be insulated, and cold air must be prevented from flowing between the plates and the rock surface. The relative humidity of the air in the tunnel is usually high during summer, and low during winter. Humidity movements in the insulation material may, however, not be assessed in detail. It is therefore necessary to have the insulating material properly protected against humidity invation. The insulation material should not be inflammable. When constructing an insulated shielding, all kind of cold bridges through the insulating must be avoided. A construction consisting of two layers with insulation between is used in a few Norwegian tunnels. The installation is done by gluing the insulation material to the outer lining and pressing the inner lining against the insulation. The formula delta T times t equals (Z/lambda) times (q times t) expresses the frost quantity on the left side, and the frost resistance on the right side (fig. 3). Heat flow, q, consists partly of heat from the bedrock and partly of heat from leaking water. The formula may be used for dimensioning the insulation. To avoid icing on the road surface from water leakage through the tunnel sole, an insulation underneath the pavement is recommended. Underdrains may be located on a moderate depth, when insulated in the frost zone. /Author/

  • Corporate Authors:

    Norwegian Road Research Laboratory

    Postboks 8109, Gaustadalleen 25
    Oslo,   Norway 
  • Authors:
    • Skogseid, A
  • Publication Date: 1975-9


  • Norwegian

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00131565
  • Record Type: Publication
  • Report/Paper Numbers: No. 48
  • Files: TRIS
  • Created Date: May 14 1976 12:00AM