The article discusses the design and construction of the 2420 M long second bore of the Eisenhower Memorial Tunnel, Colorado, USA. Construction of the first bore, opened to traffic on highway I-70 in 1973, ran into difficult rock conditions causing a two-year delay. The first bore at an average elevation of 3383 M is the world's highest mechanically-ventilated tunnel. Three cross passageways will connect the second bore when completed in 1979. With the volume of ventilation capacity required, the actual roadway dimensions are 4.1 M high and 8.7 M wide. The previous difficulties with rock conditions are eliminated, by the alignment of the second bore, by including the pilot bore within its cross section. Another change from the previous tunnel construction is the adoption of the rock reinforcement, multiple-drift method of construction in the major fault area, and a top heading and bench mining method throughout the second bore. /TRRL/

  • Availability:
  • Corporate Authors:

    Morgan-Grampian Limited

    30 Calderwood Street
    London SE18 6QH,   England 
  • Authors:
    • Adams, J W
  • Publication Date: 1978-5


  • English

Media Info

  • Features: Figures; Photos;
  • Pagination: p. 20-23
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00182740
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Oct 31 1978 12:00AM