SCALE EFFECT IN THE SHEAR STRENGTH OF ROCK JOINTS . PROCEEDINGS OF THE FIRST INTERNATIONAL WORKSHOP ON SCALE EFFECTS IN ROCK MASSES, LOEN, NORWAY, JUNE 7-8 1990

In Rock Mechanics the representativeness of laboratory test data keeps on being a fundamental issue. The scale effect in the shear strength of rock mass joints was observed by many researchers, recording in the bibliography sometimes controversial assertions about it. Systematic tests on plaster samples with different dimensions and surface roughness were carried out by Bandis and a remarkable diminution in the shear strength with the increment of the sample size, was confirmed. With the aim of establishing an extrapolation model from laboratory test data to natural block dimensions, data provided by that author were used. The published profiles were digitalized and a theoretical model was developed, considering the JRC (joint roughness coefficient) in the Barton's strength equation, as the unique variable sensible to the scale effect. For an objective characterization of discontinuities 'slope diagrams' were made and a classification of pattern surfaces was proposed. After that, a group of case histories registered by The National Laboratory of Civil Engineers (of Lisbon) were selected and laboratory tests on samples of different length from the same discontinuity, were carried out. Data resulting of the extrapolation model application were confronted with the theoretical predictions and a good correlation were found. Besides, a simple safe estimation of scale-free shear strength is proposed, using virtual first degree asperity angles (Z2), measured in the direction of sliding. (Author/TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/9061916607
• Corporate Authors:

  AA Balkema

  P.O. Box 1675
  Rotterdam,   Netherlands  BR-3000
• Authors:
  • Sarra PISTONE, R
• Publication Date: 1990

Language

• English

Media Info

• Features: References;
• Pagination: p. 201-206
• Serial:
  • Publication of: Balkema (AA)
  • Publisher: AA Balkema

Subject/Index Terms

• TRT Terms: Conferences; Forecasting; Mathematical models; Rock jointing; Rock mechanics; Rocks; Shear strength
• Uncontrolled Terms: Discontinuity; Models; Scale effect
• Old TRIS Terms: Rock joints
• Subject Areas: Geotechnology; Highways;

Filing Info

• Accession Number: 00609539
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• ISBN: 90-6191-660-7
• Files: ITRD, TRIS
• Created Date: Jun 30 1991 12:00AM