UNDERGROUND DESIGN

The engineering investigations undertaken to establish suitable design parameters for tunnel design, and the design approach adopted for both the underground and cut cover section of the tunnel are described. The special problems arising from the close proximity of the future second tunnel are outlined, and the planned installation of instrumentation and internal finishes are briefly described. Diamond core drilling in the portal areas assisted in establishing the location of tunnel protals. A full-length investigation drive has been excavated and an extensive program of testing has been undertaken. Since the plans call for 3-lane tunnels, and because the construction of the two tunnels will not be concurrent, an increased loading on the first tunnel (north bound) has been allowed for when the second tunnel (southbound) is constructed. For this large tunnel with high design loadings, economics has necessitated the utilization of steel sets (with anti-corrosion precautions) to permanently carry the loading of the first tunnel. The reinforced concrete lining will carry the 100 percent loading increase on the first tunnel when the second tunnel is constructed. Instrumentation during construction will establish induced loads to compare with those adapted for design. The curved flaring portions of the tunnel will be constructed as a series of truncated cones because of complex alignment. A secondary lining offset from the concrete lining will provide a smooth interior. A suspended ceiling will support the lighting system and provide ceiling space for maintenance work.

  • Availability:
  • Corporate Authors:

    Technical Publications Limited

    C.P.O. 3047
    Wellington,   New Zealand 
  • Authors:
    • Wilcox, P J
  • Publication Date: 1975-8-15

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 225-230
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00128558
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 10 1976 12:00AM