EFFECT OF CONFINING PRESSURE ON THE FRACTURE BEHAVIOUR OF A POROUS ROCK

Triaxial compression tests were carried out on a porous sandstone from SW-Germany. The confining pressures ranged up to 200 mpa. Direct volumetric strain measurements indicated that pre-peak microfracturing is a precursory deformation process to the development of macroscopic shear faults in intact porous rock at low confining pressures. Post-peak dilation at low pressures is due to fault dilation. At high pressures multiple shear fractures develop with progressively less dilation. Transition from brittle to ductile deformation takes place at a confining pressure of 100 mpa. Ductile shear at high pressure occurs without any dilation, and leads to progressive compaction and homogeneous shear throughout the rock specimen. Applied to earthquake precursory phenomena this implies that dilatancy effects in low porosity fault zones may only exist at shallow depths. At greater depth compaction will dominate over dilation.(a) (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:
  • Gowd, T N
  • Rummel, F
• Publication Date: 1980-8

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 225-229
• Serial:
  • International Journal of Rock Mechanics and Mining Science
  • Volume: 17
  • Issue Number: 4
  • Publisher: Pergamon Press, Incorporated
  • ISSN: 0020-7624

Subject/Index Terms

• TRT Terms: Behavior; Brittleness; Compaction; Compression; Cracking; Deformation; Depth; Dilation; Ductility; Faults; Fracture mechanics; Porosity; Porous materials; Pressure; Rocks; Sandstones; Shear strength; Tests; Triaxial shear tests
• Uncontrolled Terms: Triaxial compression
• Old TRIS Terms: Shear cracks
• ITRD Terms: 9001: Behaviour; 5900: Brittleness; 5532: Compression; 5211: Cracking; 5595: Deformation; 6499: Depth; 5909: Ductility; 4068: Fault (geomorphol); 5938: Porosity; 5412: Pressure; 4154: Rock; 4104: Sandstone; 5531: Shear; 6255: Test
• Subject Areas: Geotechnology; Highways; I43: Rock Mechanics;

Filing Info

• Accession Number: 00324650
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: Sep 16 1981 12:00AM