ROCK TUNNELING WITH HIGH SPEED WATER JETS UTILIZING CAVITATION DAMAGE

A test apparatus, capable of producing a 1/4-inch diameter jet up to 500 ft/sec was designed and built. Initial tests with this facility produced erosion intensities of 37 watts/sq. meter. This value was encouraging and demonstrated that the technique had potential. As a result a three-month extension of the contract was granted so that the operating parameters could be optimized thereby maximizing the erosion intensity. During this period the erosion intensity was improved from 37 watts/sq. meter to 670 watts/sq. meter. In addition those relationships such as the time dependence of erosion intensity and its variation with jet velocity were determined. The information was obtained for both a 1/4-inch and 1/8-inch nozzle. Once the behavioral relationships were established attention was directed to means by which the erosion intensity produced could be efficiently used. As a result a nozzle to specimen distance adjustment technique and specimen rotation technique were developed which improved volume removal by two orders of magnitude. Finally, the effect of heat treatment on reducing the strength of rock was briefly examined. (Author)

• Supplemental Notes:
  • Sponsored in part by Department of Transportation, Washington, D. C., Office of High Speed Ground Transportation.
• Corporate Authors:

  Hydronautics, Incorporated

  7210 Pindel School Road
  Laurel, MD  United States  20810
• Authors:
  • Kohl, R E
• Publication Date: 1968-6

Media Info

• Pagination: 52 p.

Subject/Index Terms

• TRT Terms: Excavating equipment; Intelligent transportation systems; Mining; Tunnels
• Old TRIS Terms: Advanced systems
• Subject Areas: Bridges and other structures; Operations and Traffic Management; Railroads;

Filing Info

• Accession Number: 00039107
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: 713-1 Final Rpt
• Files: TRIS
• Created Date: Nov 24 1973 12:00AM