ROCK HARDNESS INDEX PROPERTIES AND GEOTECHNICAL PARAMETERS FOR PREDICTING TUNNEL BORING MACHINE PERFORMANCE

To bid a tunnel to be excavated by machine, a contractor must have reliable estimates of expected excavation time, cutter costs and overall feasibility. To assist in making such predictions, a series of rock index tests has been proposed, developed and related to boreability. The proposed index properties and other variables were evaluated by empirically relating selected rock properties to TBM penetration rates from recently machined tunnels. Samples were drilled from machine bored tunnel walls, tested parallel to the direction of machine penetration, and the results were compared to rates of penetration at respective sampling locations. Results indicate that the series of rock hardness index properties investigated in this study can be related to TBM penetration rates. With certain limitations and qualifications, acceptable empirical relationships have been developed between in situ Schmidt Hammer Hardness and unconfined compressive strength.

• Corporate Authors:

  University of Illinois, Urbana-Champaign

  Department of Civil and Environmental Engineering
  205 North Mathews Avenue
  Urbana, IL  United States  61801-2352

  National Science Foundation

  1800 G Street, NW
  Washington, DC  United States  20550
• Authors:
  • TARKOY, P J
  • HENDRON, A J
• Publication Date: 1975-9

Media Info

• Pagination: 347 p.

Subject/Index Terms

• TRT Terms: Boring; Compressive strength; Concrete tests; Estimating; Excavation; Excavation and tunneling; Feasibility analysis; Forecasting; Geological events; Geotechnical engineering; Hardness; Physical properties; Pile hammers; Rock excavation; Rock mechanics; Rocks; Tunneling; Tunneling machines
• Identifier Terms: Schmidt hammer
• Old TRIS Terms: Excavation technology; Geological conditions; Rock properties
• Subject Areas: Bridges and other structures; Geotechnology; Highways;

Filing Info

• Accession Number: 00094314
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: NSF/RA/T-75/030
• Contract Numbers: NSF-GI-36468
• Files: TRIS
• Created Date: Mar 29 1976 12:00AM