A NEW METHOD FOR THE DETERMINATION OF THE ROUGHNESS OF ROCK JOINTS IN THE LABORATORY

The author states that the shear strength of rock joints, which predominantly determines the mechanical behaviour of the rock mass, is markedly influenced by the roughness of the rock joints. The necessity for a very exact determination of the joint surface roughness is discussed, and the development of an instrument for the measurement of roughness, known as a profilograph, with a high accuracy of measurement is described. A schematic diagram of the profilograph provides information on the instrument and its constituent parts, which can record a large number of highly accurate two-dimensional profiles in a relatively short time; a three-dimensional picture can be built up by a combination of a set of linear measurements. The author considers that the essential difference between this instrument, and the type of instruments known so far is that the horizontal movement of the stylus is not continuous, but intermittent, and that contact between the needle and the rock exists only at the intermittent periods of rest. This prevents the stylus from sticking. Data recording and the interpretation of the measurements are discussed. The object of the roughness measurements is to develop a roughness index, which will provide a parameter for quantifying the influence of stress and strain history on the residual shear strength of rock joints. /TRRL/

  • Availability:
  • Corporate Authors:

    Pergamon Press, Incorporated

    Headington Hill Hall
    Oxford OX30BW,   England 
  • Authors:
    • Weissbach, G
  • Publication Date: 1978-7

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Filing Info

  • Accession Number: 00184524
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Feb 3 1979 12:00AM