Intensive investigation and evaluation of ground conditions, and the application of modern developments in the design process were necessitated by an unusually wide range of ground conditions, limited cover, large size and location of a tunnel in a densely developed urban environment. The plan adopted called for two 3-lane tunnels with construction initially limited to one of these. The functional requirements are detailed. The geometrics called for a basic carriageway of three 3.66 m wide lanes with 3 m and 1.8 m shoulders on the inside and outside of the carriageway respectively. Throught the planning and design, particular attention was given to the long-term 6-lane development. environmental factors and aesthetics exercised a major influence on design and construction. The geology of the locality, and the materials were logged and evaluated. Thirty boreholes were drilled along the length of the site with emphasis on locations of structural significance in the vicinity of tunnel portals and high retaining walls. An investigation drive of 2.4 m by 2.4 m horsehole cross-section was constructed along the length of the tunnel and a program of in situ testing and instrumentation was carried out as excavation progressed. The soil investigation report and the engineering geological report were made part of the tender documents. In an effort to achieve consistency of tenders, the design method to be used and the soil parameters to be applied in the design of temporary support was specified for each location in accordance with ground conditions and adjacent property risk entailed. By this approach, scheduled rates provided a valid basis for the comparison of tenders, and fair adjustments as contract work progressed was ensured.

  • Availability:
  • Corporate Authors:

    Technical Publications Limited

    C.P.O. 3047
    Wellington,   New Zealand 
  • Authors:
    • Preston, R L
  • Publication Date: 1975-8-15

Media Info

  • Features: Figures; References;
  • Pagination: p. 217-220
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00128561
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 10 1976 12:00AM