Gives details of the problems associated with the Kluuvi cleft region of the proposed Helsinki metro. The underground section passes through this glacial cleft which is filled with alluvial water-bearing deposits. Compressed air and grouting methods are considered to be unlikely to be satisfactory because of the high water table, instability of the fill and doubts as to the origin of the water. Ground freezing methods have therefore been proposed for this 40 M section of the tunnel, which is to be lined with a cast iron circular lining. The remainder of the tunnel is in strong rock requiring no lining. The article discusses the advantages and disadvantages of the two freezing methods that have been proposed. The vertical method involves freezing from the surface and avoids disturbance of the water table. However, it would interfere with surface activities and would need insulation to avoid the heave that would result from freezing the entire block of ground. The horizontal method would probably need drilling from two chambers and from both ends and would also require the provision of compressed air in the workings. Because neither method was obviously best, tenders were called for prices on either scheme. /TRRL/

  • Corporate Authors:

    Norwood Publications Limited

    Elm House, Elm Street
    London WC1X OBP,   England 
  • Publication Date: 1976


  • English

Media Info

  • Features: Figures;
  • Pagination: 2 p.
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00147940
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: May 11 1981 12:00AM