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USE OF A TILTING TABLE TO DETERMINE THE BASIC FRICTION ANGLE OF HARD ROCK SAMPLES

A tilting table can be used to determine the basic friction angle of a rock. Dolostone and quartzite sliders with natural and sanded surfaces move at similar angles on sanded plates of dolostone and quartzite. Friction angles measured from conventional direct shear tests on the same specimen are similar. When the natural or sanded sliders are tilted on polished plates, lower friction angles result: about 12 deg for quartzite and 16 deg for dolostone. The dolostone sliders leave a loose powder on the polished plates. If the powder is accumulated over successive slides, tilt angles for sliding increase to 30 deg. Friction angles on polished plates approach a minimum, the mineral friction angle, phi sub m, which represents the friction between the minerals making up the rock surfaces. The basic friction angle, phi sub b, is the sum of phi sub m and the surface roughness produced by sanding. Tests of a new tilting table design suggest that basic friction angles should be determined with naturally surfaced sliders on plates wet lapped with No. 80 grit. Vibrations from the electric motor driving the table reduce measured friction angles by about 1 deg. Sliding angles increase up to 2 deg in very humid conditions.

  • Corporate Authors:

    National Research Council of Canada

    Research Journals
    Ottawa, Ontario K1A 0R6,   Canada 
  • Authors:
    • Bruce, I G
    • CRUDEN, D M
    • Eaton, T M
  • Publication Date: 1989-8

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 474-479
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00488248
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 30 1989 12:00AM