PRESTRESSING A POWER TUNNEL

The onerous physical requirements made on a power tunnel has been met by a technique of prestressing according to the Tiroler Wasserlkraftwerke AG (TIWAG) gap grouting method. In this procedure, concrete lining is prestressed by injecting cement grouting into the contact joint between the concrete lining and the rock. The pressure of the grout opens a gap and fills it with the grout, which at the same time penetrates the fissures and cracks of the adjacent rock and solidifies it. To make precise injection of the contact possible, a special system of synthetic hoses with valves is placed along the wall of the tunnel before concreting the lining. The details are described of the prestressing of a section of the power tunnel, of about 150 m, between the vertical intake shaft and the penstocks in the Jordon River project in Australia. This section of the power tunnel lies in quartzite and had been concreted in ten pours of about 15 m each. The 12.7 cm-diameter grout hoses were placed circumferentially at 2.5 m spacing. The complete success of the gap grouting technique was proven by checks on a test section installed in each of the central eight concrete pours.

  • Corporate Authors:

    IPC Electrical Electronic Press Limited

    Dorset House Stamford Street
    London SE1 9LU,   England 

    IPC Electrical Electronic Press Limited

    Dorset House Stamford Street
    London SE1 9LU,   England 
  • Authors:
    • Seeber, G
  • Publication Date: 1976-4

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Filing Info

  • Accession Number: 00135934
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 21 1976 12:00AM