EXPERIMENTAL STUDIES OF SCALE EFFECTS ON THE SHEAR BEHAVIOUR OF ROCK JOINTS

The effect of scale on the shear behaviour of joints is studied by performing direct shear tests on different sized replicas cast from various natural joint surfaces. The results show significant scale effects on both the shear strength and deformation characteristics. Scale effects are more pronounced in the case of rough, undulating joint types, whereas they are virtually absent for planar joints. The key factor is the involvement of different asperity sizes in controlling the peak behaviour of different lengths of joints. It is shown that as a result both the joint roughness coefficient (jrc) and the joint compression strength (jcs) reduce with increasing scale. The behaviour of multiple jointed masses with different joint spacings is also considered. It is found that despite unchanged roughness, jointed masses consisting of many small blocks have higher peak shear strength than jointed masses with larger joint spacing. These scale effects are related to the changing stiffness of a rock mass as the block size or joint spacing increases or decreases. Economic methods for obtaining scale-free estimates of shear strength are described. (Author/TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00207624
• Corporate Authors:

  Pergamon Press, Incorporated

  Headington Hill Hall
  Oxford OX30BW,    
• Authors:
  • Bandis, S
  • LUMSDEN, A C
  • Barton, N R
• Publication Date: 1981-2

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: p. 1-21
• Serial:
  • International Journal of Rock Mechanics and Mining Science
  • Volume: 18
  • Issue Number: 1
  • Publisher: Pergamon Press, Incorporated
  • ISSN: 0020-7624

Subject/Index Terms

• TRT Terms: Behavior; Compression; Compressive strength; Deformation; Joints (Engineering); Location; Mass; Rock jointing; Rocks; Scale models; Shear strength; Size; Smoothness; Stiffness; Strength of materials; Structural models; Tests; Weighing devices
• Uncontrolled Terms: Rock mass; Scale
• Old TRIS Terms: Joint
• ITRD Terms: 9001: Behaviour; 5532: Compression; 5595: Deformation; 9014: Dimension; 3071: Evenness; 4089: Joint (geomorphol); 9061: Location; 6205: Model (not math); 4154: Rock; 6204: Scale; 5531: Shear; 5931: Stiffness; 5544: Strength (mater); 6255: Test
• Subject Areas: Bridges and other structures; Geotechnology; Highways; I43: Rock Mechanics;

Filing Info

• Accession Number: 00335226
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: Oct 28 1981 12:00AM