MICROWAVE THAWING OF FROZEN SOILS AND GRAVELS

Mining and excavation are difficult during winter in northern climates and permafrost regions. Current techniques to weaken frozen ground by thawing with combustible materials or electric heaters are slow and need improvement. Instantaneous volume heating is achieved by radiation heat transfer with microwave energy. The United States Bureau of Mines initiated this study to determine the ability of microwaves to thaw frozen soil and gravel. The thawing rates and penetration depths as a function of soil types were experimentally determined at field test sites using a 6-kW microwave system operating at 2.45 GHz. Five soil types were studied ranging from washed sand to clay with moisture levels from 7 percent to 44 percent. Field thawing tests were conducted in Minnesota in winter, with ambient temperatures down to -23 deg C. The lowest specific energy observed during field tests was 18 kW for a run of mine gravel.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/13202939
• Corporate Authors:

  American Society of Civil Engineers

  345 East 47th Street
  New York, NY  United States  10017-2398
• Authors:
  • Lindroth, D P
  • Berglund, W R
  • Wingquist, C F
• Publication Date: 1995-6

Language

• English

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: p. 53-63
• Serial:
  • Journal of Cold Regions Engineering
  • Volume: 9
  • Issue Number: 2
  • Publisher: American Society of Civil Engineers
  • ISSN: 0887-381X
  • Serial URL: http://opjs.aip.org/cro

Subject/Index Terms

• TRT Terms: Field tests; Frozen soils; Gravel; Microwave communication systems; Permafrost; Thaw
• Old TRIS Terms: Microwave systems; Permafrost regions
• Subject Areas: Geotechnology; Highways; I42: Soil Mechanics;

Filing Info

• Accession Number: 00680585
• Record Type: Publication
• Files: TRIS
• Created Date: Jun 13 1995 12:00AM