A spray grouting technique has been developed for hardening a 1 to 6 inch surface layer of weak sandstones such as the St. Peter Sandstone in Minnesota. When used on tunnel walls and roof it provides temporary excavation support in larger tunnels and a permanent lining in smaller utility tunnels. This eliminates or reduces the need for more costly conventional support. The research and development has cost about $100,000 in RANN funds and $50,000 of industry user funds. The technique is now being used in an 8000 foot long storm water tunnel and in a 6500 foot long utility tunnel. The estimated savings from the use of the new method is $1,300,000 on these two projects. Increased use of the method is expected.

  • Corporate Authors:

    University of Minnesota, Minneapolis

    Department of Civil and Mineral Engineering, 122 Civil and Mineral Engineering Building
    Minneapolis, MN  United States  55455-0220

    National Science Foundation

    Research Applied to National Needs
    Washington, DC  United States  20550
  • Authors:
    • Nelson, C R
  • Publication Date: 1975-12-8

Media Info

  • Pagination: 8 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00137160
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: NSF/RA/T-75/073
  • Contract Numbers: NSF-GI-37862
  • Files: TRIS
  • Created Date: Sep 4 1976 12:00AM