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Fractal analysis applied to cataclastic rocks
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912039 Hostun sand RF. Technical note (In French) Flavigny, E; Desrues, J; Palayer, B Rev Fr Geotech N53, 1990. P67-70 Hostun sand is widely considered as a 'standard" material. Its geological origins and formation, physical characteristics, grain size distribution, and chemical analysis are outlined. Factors to be taken into account when taking Hostun sand as a reference material are discussed.
912040 Fractai analysis applied to cataclastic rocks Zhao, Z Y; Wang, Y; Liu, X H Teetonophysics V178, N2/4, June 1990. P373-377 Particle size distribution of cataclastic rocks is investigated. Such rocks can be described by a fractal dimension, D, which is a function of B (the base by which the cell is divided into next order elements) and Nf, which characterises a specific mode of fragmentation. D can be determined from the slope of a least means squares plot of size-, area-, or volume-frequency on log-log coordinates, in this analysis, neither particle shape nor diameter measured for the cataclastic rock affect fractal dimension. The geological significance of D remains to be explored.
912041 Fractal analysis of fractures in rocks: the Cantor's Dust method Velde, B: Dubois, J; Touchard, G: Badri, A Tectonophysics VI79. N3/4. Juh" 1990, P345-352 The Cantor's Dust method has been applied to describe the fractal nature of fracture patterns seen on a two dimensional surl:ace. Determination of D indicates it varies regularly as a function of analysis dimension, suggesting an as yet unexplained relation between regularity of fracture pattern and the I'orces which created it. Fractal natures of naturally fractured materials with maximum dimensions from 3ram to 45m are described. The analysis may be used to identify local variations in the stress field which caused failure. 912042 Density difference method for relative density control of sand fills Sandroni, S S Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 VI. P309-311. Publ Rotterdam: A A Balkema. 1989 Based on the empirically established fact that maximum and minimum densities of sands are linearly correlated, relations are established between relative density and the difference between field density and minimum density. A method of density control of sands fills is proposed and explained. It has been used successfully in several projects, and attenuates fluctuations of relative density variations and is suitable for use in heterogeneous sand deposits.
912043 Evolution of cracks and pores: physico-chemical role of fluids Reuschle. T; Gueguen. Y; Darot. M Proc International Symposium on Rock at Great Depth, Pau, 28-31 August 1989 1/3. P1165-1175. Publ Rotterdam." A A Balkema. 1989 Fluid-rock interactions can have significant effects on pores and cracks, particularly at time scales much greater than laboratory scale. Slow (subcritical) crack growth is discussed, together with effects on strain rate dependency of strength, stress relief of cores from deep boreholes, and microcracking
around underground openings. The phenomenon of pressure solution is also examined, considering effects on compaction and cementation of rocks, and on modifications or porosity shape and structure.
Deformation and strength characteristics See also: 912212. 912241. 912244. 912247, 912263, 912277, 912284, 912044 Statistical evaluation of some engineering properties of eastern Canadian clays Windisch, E J; Yong, R N Can Geotech J k?7. N3, June 1990, P373-386 Data from Champlain, Goldthwait, Tyrell. and Laflamme marine clays and Barlow-Ojibway lacustrine clays are analysed. The soils are grouped into eastern Canadian marine, Champlain (an important part of the first group).and BarlowOjibway marine clays. Significant differences are seen to exist between eastern Canadian marine and Scandinavian clays. Some published relations based on plasticity index, liquidity index, and plastic limit do not hold for eastern Canadian marine clays. OCR is found to be equal to the ratio of in situ undrained shear strength to estimated normally consolidated undrained shear strength for eastern Canadian marine clays.
912045 Overall elastic properties of isotropic materials with arbitrary distribution of circular cracks Hudson, J A Geophys J VI02. N2. Aug 1990. P465-469 The transmission properties of the mean field in an elastic material with a random distribution of circular cracks of small aspect ratio are presented for the general case where the crack normals are distributed in any pre-determined way in space. Special distributions, where the crack normals lie in one direction only, or lie at a fixed angle to a fixed direction, reproduce established results. Expressions are given ['or the case of crack normals lying close to a given direction in a Gaussian distribution. All results are valid to second order in crack number density. Auth. 9 ! 2046 Seasonal variation in penetration resistance and shear strength of three rainforest soils from northeastern Queensland Spain, A V; Prove. B G; Hodgen, M J; Lee, K E Geoderma V47. NI,'2, Aug 1990. P79-92 Seasonal variation in penetration resistance and shear strength was studied for soils of basaltic, alluvial, and metamorphic origins. Both measures of strength were seasonally higher for the basaltic soils, and clearly decreased with increased gravimetric water content at all sites. Penetration resistance increased significantly with increasing bulk density, but shear strength was little affected. 912047 Instability mechanisms in rocks of variable stiffness (In German) Morgenstern, N R Geotechnik VI3. .V3. 1990. PI23-129 Instability mechanisms for unsheared stiff clays and mudstones are not well understood when compared to the case where pre-existing shears dominate. The contribution of four important mechanisms to failure of these materials is reviewed
~[, 1991 Pergamon Press plc. Reproduction not permitted
912039 Hostun sand RF. Technical note (In French) Flavigny, E; Desrues, J; Palayer, B Rev Fr Geotech N53, 1990. P67-70 Hostun sand is widely considered as a 'standard" material. Its geological origins and formation, physical characteristics, grain size distribution, and chemical analysis are outlined. Factors to be taken into account when taking Hostun sand as a reference material are discussed.
912040 Fractai analysis applied to cataclastic rocks Zhao, Z Y; Wang, Y; Liu, X H Teetonophysics V178, N2/4, June 1990. P373-377 Particle size distribution of cataclastic rocks is investigated. Such rocks can be described by a fractal dimension, D, which is a function of B (the base by which the cell is divided into next order elements) and Nf, which characterises a specific mode of fragmentation. D can be determined from the slope of a least means squares plot of size-, area-, or volume-frequency on log-log coordinates, in this analysis, neither particle shape nor diameter measured for the cataclastic rock affect fractal dimension. The geological significance of D remains to be explored.
912041 Fractal analysis of fractures in rocks: the Cantor's Dust method Velde, B: Dubois, J; Touchard, G: Badri, A Tectonophysics VI79. N3/4. Juh" 1990, P345-352 The Cantor's Dust method has been applied to describe the fractal nature of fracture patterns seen on a two dimensional surl:ace. Determination of D indicates it varies regularly as a function of analysis dimension, suggesting an as yet unexplained relation between regularity of fracture pattern and the I'orces which created it. Fractal natures of naturally fractured materials with maximum dimensions from 3ram to 45m are described. The analysis may be used to identify local variations in the stress field which caused failure. 912042 Density difference method for relative density control of sand fills Sandroni, S S Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 VI. P309-311. Publ Rotterdam: A A Balkema. 1989 Based on the empirically established fact that maximum and minimum densities of sands are linearly correlated, relations are established between relative density and the difference between field density and minimum density. A method of density control of sands fills is proposed and explained. It has been used successfully in several projects, and attenuates fluctuations of relative density variations and is suitable for use in heterogeneous sand deposits.
912043 Evolution of cracks and pores: physico-chemical role of fluids Reuschle. T; Gueguen. Y; Darot. M Proc International Symposium on Rock at Great Depth, Pau, 28-31 August 1989 1/3. P1165-1175. Publ Rotterdam." A A Balkema. 1989 Fluid-rock interactions can have significant effects on pores and cracks, particularly at time scales much greater than laboratory scale. Slow (subcritical) crack growth is discussed, together with effects on strain rate dependency of strength, stress relief of cores from deep boreholes, and microcracking
around underground openings. The phenomenon of pressure solution is also examined, considering effects on compaction and cementation of rocks, and on modifications or porosity shape and structure.
Deformation and strength characteristics See also: 912212. 912241. 912244. 912247, 912263, 912277, 912284, 912044 Statistical evaluation of some engineering properties of eastern Canadian clays Windisch, E J; Yong, R N Can Geotech J k?7. N3, June 1990, P373-386 Data from Champlain, Goldthwait, Tyrell. and Laflamme marine clays and Barlow-Ojibway lacustrine clays are analysed. The soils are grouped into eastern Canadian marine, Champlain (an important part of the first group).and BarlowOjibway marine clays. Significant differences are seen to exist between eastern Canadian marine and Scandinavian clays. Some published relations based on plasticity index, liquidity index, and plastic limit do not hold for eastern Canadian marine clays. OCR is found to be equal to the ratio of in situ undrained shear strength to estimated normally consolidated undrained shear strength for eastern Canadian marine clays.
912045 Overall elastic properties of isotropic materials with arbitrary distribution of circular cracks Hudson, J A Geophys J VI02. N2. Aug 1990. P465-469 The transmission properties of the mean field in an elastic material with a random distribution of circular cracks of small aspect ratio are presented for the general case where the crack normals are distributed in any pre-determined way in space. Special distributions, where the crack normals lie in one direction only, or lie at a fixed angle to a fixed direction, reproduce established results. Expressions are given ['or the case of crack normals lying close to a given direction in a Gaussian distribution. All results are valid to second order in crack number density. Auth. 9 ! 2046 Seasonal variation in penetration resistance and shear strength of three rainforest soils from northeastern Queensland Spain, A V; Prove. B G; Hodgen, M J; Lee, K E Geoderma V47. NI,'2, Aug 1990. P79-92 Seasonal variation in penetration resistance and shear strength was studied for soils of basaltic, alluvial, and metamorphic origins. Both measures of strength were seasonally higher for the basaltic soils, and clearly decreased with increased gravimetric water content at all sites. Penetration resistance increased significantly with increasing bulk density, but shear strength was little affected. 912047 Instability mechanisms in rocks of variable stiffness (In German) Morgenstern, N R Geotechnik VI3. .V3. 1990. PI23-129 Instability mechanisms for unsheared stiff clays and mudstones are not well understood when compared to the case where pre-existing shears dominate. The contribution of four important mechanisms to failure of these materials is reviewed
~[, 1991 Pergamon Press plc. Reproduction not permitted