FOCUSED LASER BEAMS TO ASSIST ROCK EXCAVATION

A study was performed to assess the feasibility of using a focused CO2 laser beam to cut the gage of a hard-rock tunnel being excavated by a continuous tunnel-boring machine. Laser rock-kerfing tests were conducted on isolated samples of granite, diabase and quartzite rock with a Navy-owned electric-discharge CO2 laser located at the United Aircraft Research Laboratories. The tests were performed to verify previously made extrapolations which were used to predict full-scale power requirements for the laser gage-kerfing concept. Laser powers and kerfing speeds were extended from previously tested maximum values of 5 kW and 21.2 cm/sec to 16.5 kW and 125 cm/sec. In addition, the test program included a comparison of the use of 50.8 cm-focal-length spherical and cylindrical focusing mirrors.

• Corporate Authors:

  United Aircraft Corporation

  Research Laboratories
  East Hartford, CT  United States 

  Federal Railroad Administration

  Office of Research and Development, 1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Jurewicz, B R
  • Greenwald, L E
  • Brown, C O
• Publication Date: 1974-11

Media Info

• Features: Figures; References; Tables;
• Pagination: 166 p.

Subject/Index Terms

• TRT Terms: Computer programming; Cutting; Excavation and tunneling; Excavations; Granite; Laser beams; Lasers; Quartzite; Rock excavation; Rock fracture; Rock mechanics; Rocks; Tunneling; Tunneling machines
• Uncontrolled Terms: Diabase; Gas lasers
• Old TRIS Terms: Focusing; Hard rock excavation; Kerfing; Rock kerfing
• Subject Areas: Bridges and other structures; Construction; Geotechnology; Highways;

Filing Info

• Accession Number: 00090403
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: FRA-ORD&D 75-20 Final Rpt., UARL-N971543-11
• Contract Numbers: DOT-FR-20021
• Files: NTIS, TRIS, USDOT
• Created Date: May 29 1975 12:00AM