EXPERIMENTAL ANALYSIS OF CRACK PROPAGATION IN GRANITE
An experimental approach is used to demonstrate the concept of an effective crack length with double-edge-notched specimens of charcoal and rockville granite. Crack propagation in rock is characterized by microcracking around the crack tip and interlocking along a portion of the crack; this region is called the fracture process zone, and together with the traction free length defines the effective crack length. Twenty closed-loop, strain-controlled fracture tests were conducted on charcoal and rockville granite. Crack growth was monitored with a travelling optical microscope (100 x magnification). By comparing the post-peak behaviour of both granites, it is suggested that the process zone is larger for the larger grain-sized rock (rockville). Conventional linear elastic fracture mechanics techniques are used to calculate the apparent fracture toughness of charcoal granite at various crack lengths. In addition, a j-integral expression is derived for the double-edged-notched geometry in terms of the area under the load-displacement record. The shortcomings of both analyses are discussed. An attempt is made to explain the inadequacies by including the process zone in the calculations of the fracture toughness. (Author/TRRL)
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/issn/01489062
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Corporate Authors:
Pergamon Press, Incorporated
Headington Hill Hall
Oxford OX30BW, -
Authors:
- Labuz, J F
- Shah, S P
- Dowding, C H
- Publication Date: 1985-4
Media Info
- Features: Figures; Photos; References; Tables;
- Pagination: p. 85-98
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Serial:
- Intl J of Rock Mech & Mining Sci & Geomechanic Abs
- Volume: 22
- Issue Number: 2
- Publisher: Pergamon Press, Incorporated
- ISSN: 0148-9062
Subject/Index Terms
- TRT Terms: Carbon; Cracking; Failure; Fracture mechanics; Granite; Length; Mathematical models; Microcracking; Rocks; Strength of materials; Testing; Tests; Toughness
- Uncontrolled Terms: Crack propagation; Microcracks
- Old TRIS Terms: Charcoal
- ITRD Terms: 5211: Cracking; 5520: Failure; 4101: Granite; 6488: Length; 6473: Mathematical model; 4154: Rock; 5544: Strength (mater); 6255: Test
- Subject Areas: Geotechnology; Highways; I43: Rock Mechanics;
Filing Info
- Accession Number: 00396932
- Record Type: Publication
- Source Agency: Transport Research Laboratory
- Files: ITRD, TRIS
- Created Date: Aug 25 2004 2:39AM