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Discrete fracture propagation in rock: Laboratory tests and finite element analysis
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793020 C O M I ~ MODEL. FOR BLOCK SIZE ANALYSIS OF JOINTED ROCK MASSES Dinis da Gama, C In: APCOM 77 (Papers liesented to 15th APCGM Symposium, Brisbane, 4-8 July 1977), P305315. Publ Parkville: AIMM, 1977 A method for computing the block size analysis of a Jointed rock mass is described, using as input the common geologic data (dip amd strike) of fracture planes existing in a rock bench prior to blasting. The sizes of the ir~ividual blocks and their volumes are represented by histograms and ctm~lative curves, obtained as output from the computer program. A real example of a Jointed basaltic mass is treated amd well c~related with experimental results.
F r a c t u r e processes 793021 FRACTURE PROPAGATION IN ROCK BY TRANSIENT COOLING Fimtle, I; COOper, G A; Berlie, J Int J Rock Mech Min Sci, VI6, N1, Feb 1979, PSI- 21 Calculations made for a seml-infinite slab cooled on its face by liquid nitrogen indicate that crack velocities are limited by the poor heat transfer rates associated with film boiling. Experiments on i0 cm cubes of Solnhofen limestone with liquid nitrogen injected into a central 5 cm long by i cm dia hole generally confirm the predictions. Crack propagation rates were slow and crack directions somewhat unpredictable.
793022 CRACK GRg;TH AND DEVELOPMENT DURING CREEP OF BARRE GRANITE Kranz, R L Int J Rock Mech Min Sci, VI6, NI, Feb 1979, P23-35
within individtmul grains. Obse~v~ions of crackcrack amd crack-lx~e interactions can be used to infer the local and reglomal stress directions, with some ambiguity. Two basic types of mlcrocrack lir~klmgs termed en echelon ar~ en passant are delineated. 793024 FRACTURE TOUGHNESS OF TENNESSEE SANDSTONE AND CARRARA MARBLE USING THE DOUSLE TORSION TESTING METHOD. TECHNICAL NOTE Atkinson, B K Int J Rock Mech Min Sci, V16, N1, Feb 1979,
1~-53 Gives a theoretical nn~]ysis of the double tarsion specimen and describes its use. Claims that the method has the following advantages over ohher fracture mechanics techniques: fracture toughness is calculated using only the critical load for catastrophic crack liopagation, specimen dimensions ard Poisson's ratio, compressive loading is used, and specimen preparation is simple.
793025 ,~2~CT OF ~ % I N
RATES FROM .01 TO l0 PER SECOND IN TRIAXIAL COMPRESSION TESTS ON THREE ROCKS Blanton, T L Ph D thesis, Texas A & M Univ, 1976, 77P Room temperature tests were carried out on Charcoal Granodiorite to 0.45GPa confining liessuce and on Berea Samdstone arzl Indiana Limestone to 0.25GPa confining pressure. Taking inertia of the testing machir~ into accour~, the failure stress is relatively independent of strain rate, while the strain at the onset of fracture decreases with increasimg strain rate, suggesting that the energy necessary to fragment the rocks is lower at higher strain rates. Avail: University Microfilms, 18 Bedford Row, London WCIR 4EJ, UK
793025 DISCRETE Samples of Barre granite were subjected to a unlaxial stress equal to 87 per cent of their fracture strength far various lengths of time. Crack growth and develol~nent as a function of time under load was studied with the scanning electron microscope. New stress-induced cracks appear to be continuously generated. Average crack lengths increased with time as much or more than they did upon loading, but average crack widths remained relatively unchanged. Crack interaction with other cavities seemed to increase in time as the numbers of individual cracks increased, until near the onset of tertiary creep crack coalescence may have become more important than the slow growth of individual cracks. The tensile character of stressinduced cracks was confirmed. 793023 CRACK-CRACK AND CRACK-PORE INTERACTIONS IN STRESSED GRANITE Kranz~ R L Int J Rock Mech Min Sci, V16, N1, Feb 1979,
~ 7 -47 Scammlng electron microscope observations of stress-imduced crack growth, causing crack-crack amd crack-l~re interactions within indivldual grains of Barre granite, show that photoelastic models of cracks are essentially correct and applicable to rock. The stress placed externally on a sample of rock is not the same stress, in magnitude or direction, experienced by cracks
FRACTURE PROPAGATION IN ROCK: LABORATORY TESTS AND FINITE ELEMENT ANALYSIS I~graffea, A R Ph D thesis, Colorado Univ, Boulder, 1977, 374P Predictions of fracture initiation load and angle of propagation given by 3 fracture mechanics theories were analysed. Fracture from both lie-existing notches and cracks was considered. Material parameters were determined experimentally for limestone and granodiorite using plates loaded in compression in a membrane loading test cell. Experimental and numerical results compared well. Avail: University Microfilms Ltd, 18 Bedford Row, Lomdon WCIR 4EJ, UK
793027 FHCTCEIASTIC TECHNIQUE FOR THE I~VgERMINATION OF STRESS INTERSITY FACTORS Jolles, M I Ph D thesis, Virginia Polytechnic Inst and State Unlv, 1976, 100P RepOrts stress intensity determination for Sdimensional cracked bodies without resc~timg to stress separation methods. Avail : University Microfilms Ltd, 18 Bedfard Rc~, London, WCIR 4EJ, UK
793020 C O M I ~ MODEL. FOR BLOCK SIZE ANALYSIS OF JOINTED ROCK MASSES Dinis da Gama, C In: APCOM 77 (Papers liesented to 15th APCGM Symposium, Brisbane, 4-8 July 1977), P305315. Publ Parkville: AIMM, 1977 A method for computing the block size analysis of a Jointed rock mass is described, using as input the common geologic data (dip amd strike) of fracture planes existing in a rock bench prior to blasting. The sizes of the ir~ividual blocks and their volumes are represented by histograms and ctm~lative curves, obtained as output from the computer program. A real example of a Jointed basaltic mass is treated amd well c~related with experimental results.
F r a c t u r e processes 793021 FRACTURE PROPAGATION IN ROCK BY TRANSIENT COOLING Fimtle, I; COOper, G A; Berlie, J Int J Rock Mech Min Sci, VI6, N1, Feb 1979, PSI- 21 Calculations made for a seml-infinite slab cooled on its face by liquid nitrogen indicate that crack velocities are limited by the poor heat transfer rates associated with film boiling. Experiments on i0 cm cubes of Solnhofen limestone with liquid nitrogen injected into a central 5 cm long by i cm dia hole generally confirm the predictions. Crack propagation rates were slow and crack directions somewhat unpredictable.
793022 CRACK GRg;TH AND DEVELOPMENT DURING CREEP OF BARRE GRANITE Kranz, R L Int J Rock Mech Min Sci, VI6, NI, Feb 1979, P23-35
within individtmul grains. Obse~v~ions of crackcrack amd crack-lx~e interactions can be used to infer the local and reglomal stress directions, with some ambiguity. Two basic types of mlcrocrack lir~klmgs termed en echelon ar~ en passant are delineated. 793024 FRACTURE TOUGHNESS OF TENNESSEE SANDSTONE AND CARRARA MARBLE USING THE DOUSLE TORSION TESTING METHOD. TECHNICAL NOTE Atkinson, B K Int J Rock Mech Min Sci, V16, N1, Feb 1979,
1~-53 Gives a theoretical nn~]ysis of the double tarsion specimen and describes its use. Claims that the method has the following advantages over ohher fracture mechanics techniques: fracture toughness is calculated using only the critical load for catastrophic crack liopagation, specimen dimensions ard Poisson's ratio, compressive loading is used, and specimen preparation is simple.
793025 ,~2~CT OF ~ % I N
RATES FROM .01 TO l0 PER SECOND IN TRIAXIAL COMPRESSION TESTS ON THREE ROCKS Blanton, T L Ph D thesis, Texas A & M Univ, 1976, 77P Room temperature tests were carried out on Charcoal Granodiorite to 0.45GPa confining liessuce and on Berea Samdstone arzl Indiana Limestone to 0.25GPa confining pressure. Taking inertia of the testing machir~ into accour~, the failure stress is relatively independent of strain rate, while the strain at the onset of fracture decreases with increasimg strain rate, suggesting that the energy necessary to fragment the rocks is lower at higher strain rates. Avail: University Microfilms, 18 Bedford Row, London WCIR 4EJ, UK
793025 DISCRETE Samples of Barre granite were subjected to a unlaxial stress equal to 87 per cent of their fracture strength far various lengths of time. Crack growth and develol~nent as a function of time under load was studied with the scanning electron microscope. New stress-induced cracks appear to be continuously generated. Average crack lengths increased with time as much or more than they did upon loading, but average crack widths remained relatively unchanged. Crack interaction with other cavities seemed to increase in time as the numbers of individual cracks increased, until near the onset of tertiary creep crack coalescence may have become more important than the slow growth of individual cracks. The tensile character of stressinduced cracks was confirmed. 793023 CRACK-CRACK AND CRACK-PORE INTERACTIONS IN STRESSED GRANITE Kranz~ R L Int J Rock Mech Min Sci, V16, N1, Feb 1979,
~ 7 -47 Scammlng electron microscope observations of stress-imduced crack growth, causing crack-crack amd crack-l~re interactions within indivldual grains of Barre granite, show that photoelastic models of cracks are essentially correct and applicable to rock. The stress placed externally on a sample of rock is not the same stress, in magnitude or direction, experienced by cracks
FRACTURE PROPAGATION IN ROCK: LABORATORY TESTS AND FINITE ELEMENT ANALYSIS I~graffea, A R Ph D thesis, Colorado Univ, Boulder, 1977, 374P Predictions of fracture initiation load and angle of propagation given by 3 fracture mechanics theories were analysed. Fracture from both lie-existing notches and cracks was considered. Material parameters were determined experimentally for limestone and granodiorite using plates loaded in compression in a membrane loading test cell. Experimental and numerical results compared well. Avail: University Microfilms Ltd, 18 Bedford Row, Lomdon WCIR 4EJ, UK
793027 FHCTCEIASTIC TECHNIQUE FOR THE I~VgERMINATION OF STRESS INTERSITY FACTORS Jolles, M I Ph D thesis, Virginia Polytechnic Inst and State Unlv, 1976, 100P RepOrts stress intensity determination for Sdimensional cracked bodies without resc~timg to stress separation methods. Avail : University Microfilms Ltd, 18 Bedfard Rc~, London, WCIR 4EJ, UK