A method of describing the roughness of joint surfaces has been developed, which samples an area as a whole, leading to a roughness function which is specific to a given direction of shear. The acquired roughness data may be used in a rational model to estimate shear strength. Although a correction factor r must be introduced to allow for progressive failure of asperities and loss of interlock, this correction factor has a physical meaning and estimates of shear strength are not sensitive to the value of this correction factor. The results of direct shear tests on plaster replicas of the same joint surface show good agreement between measured and predicted shear strengths at different normal loads if a suitable value for r is chosen. If further experiments show that r remains constant for a larger range of normal stresses and a variety of joint surface geometries its value will have been determined once for all times. (Author)

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  • Accession Number: 00334910
  • Record Type: Publication
  • Report/Paper Numbers: ASCE 16238 Proceeding
  • Files: TRIS
  • Created Date: Oct 28 1981 12:00AM