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Experimental detection of shear bands in a sandstone
10A
941073 One test determination of the failure curve of a granular soil by strain path testing. Technical note Lo, S C R; Chu, J Soils Found V33, NI. March 1993, P176-181 Determination of the curved failure surface of a granular soil can be expensive and time consuming, and errors can arise because of the problems in producing identical replicate samples. A new, simple procedure requiring only one test is presented, based on post-failure strain path testing. Microprocessor-based equipment is used to control the strain path followed in the post-failure domain. Reduction of platen restraint to a minimal level is essential for this method to succeed.
941074 Pore-pressure influence in the poroelastic behavior of rocks: experimental studies and results Laurent, J; Bouteca, M J; Sarda, J P; Bary, D SPE Form Eval V8, N2, June 1993, Pl17-122 Reservoir compaction and subsidence are poroelastic phenomena. The Biot coefficient is an important parameter used in study of influence of pore pressure on deformation. An apparatus for measurement of Blot's coefficient is illustrated and values obtained with it for limestone are presented. Values similarly obtained for Berea sandstone are in good agreement with published data. Biot's coefficient and Zimmerman's expression for Biot's coefficient are defined. Both increase with increasing porosity according to a law which is formally similar to a Hashin-Shtrickman's type law.
941075 Compressibility of jointed rock masses with specific reference to the chalk Matthews, M C; Clayton, C R I Proc ISRM Symposium: Eurock'92, Chester, 14-17 September 1992 P445-450. Publ London." Thomas Telford, 1992 Weak rocks often show high compressibility which can be dominated by the nature of the discontinuities within the rock mass. Factors affecting the compressibility of fractured rock are examined, then data from large scale loading tests and foundations in jointed English chalk reviewed. Behaviour of the chalk is different from that which may be expected from the general rock mechanics literature. Yielding occurs at relatively low stresses in near-surface fractured chalks and there is a large decrease in stiffness with increasing load.
941076 Further developments for the determination of the stress-strain behaviour of jointed rock mass by large scale tests Mutschler, T; Natau, 0 Proc 7th ISRM International Congress on Rock Mechanics, Aachen, 16-20 September 1991 V3, P1557-1560. Publ Rotterdam: A A Balkema, 1993 Large scale triaxial tests have been carried out on undisturbed specimens of heavily jointed silty claystone, according to the ISRM Suggested Method. Results from 3 multistage tests are illustrated. Comparisons are made with behaviour of unjointed specimens and the effects of joints on the appearance of nonlinear and inelastic behaviour, nonlinear volume strain, pressure dependence of stiffness, and the ductile-brittle transition are discussed.
941077 Scale effects in the elastic moduli and strength of jointed rock masses
Moon, H K; Kim, C Y Proc Second International Conference on Scale Effects in Rock Masses, Lisbon, 25 June 1993 P39-48. Publ Rotterdam: A A Balkema, 1993 The discontinuous and inhomogeneous nature of rock masses leads to scale effects in their properties. The concept of REV is not relevant when joint orientations and numbers of joints and joint sets are arbitrary. A theoretical model is presented to determine rock mass moduli and strength under such conditions. Effects of joint properties and orientations are examined for a 3D rock mass. Results are applied to a real rock mass containing 11 joints in which a powerhouse cavern is excavated. Equivalent properties of each of the 2258 elements in the finite element analysis are estimated and the various scale effects illustrated.
941078 Structure of slip surface formed by rock block slide Hayashi, Y; Higaki, D; Ishizuka, T Proc 6th International Symposium on Landslides, Christchurch, 10-14 February 1992 I/1, P127-133. Publ Rotterdam." A A Balkema, 1992 The slip surface of the Kamenose slide in Osaka Prefecture, Japan, has been investigated. The surface was formed at the top of weakly consolidated tuffaceous sediments beneath andesite lava. Displacements of 40m and 20m respectively occurred in 1932 and 1967. The surface and its direction of movement have been mapped. Ductile and brittle failure has occurred along the shear surface, reducing the strength of the surface to a near residual level. This strength level is indicated by both ring shear tests and back analysis.
941079 Elasto-plustic analysis for deformation-failure behaviour of the rock specimen Lee, H K Proc International Symposium on Assessment and Prevention o f Failure Phenomena in Rock Engineering, istanbul, 5-7 April 1993 P93-99. Publ Rotterdam: A A Balkema, 1993 A new method for the elastoplastic analysis of deformation of rock is proposed in which the specimen is discretised and the strength distributed to the elements according to a regular distribution of Gauss random numbers. Splitting in uniaxial tension and post failure behaviour in uniaxial compression are analysed. Loading rate effects on failure patterns and fracture development as observed in laboratory tests can be reproduced.
941080 Mechanical properties and failure of porous rocks Tokashiki, N; Aydan, O; Kyoya, T; Ichikawa, Y Proc International Symposium on Assessment and Prevention o f Failure Phenomena in Rock Engineering, istanbul, 5-7 April 1993 P101-106. Publ Rotterdam: A A Balkema, 1993 Porous rocks generally consist of complexly oriented pores and matrices and are idealised as periodic on a microscopic scale. Two analytical methods for estimating the overall properties of such materials are described, the homogenisation method and a new averaging technique, the microstructure model. Overall moduli and strength properties predicted by these two methods are compared to each other and to data from other averaging methods and laboratory tests for a sandstone and a porous mortar. Effects of porosity on the mechanical response of rocks are discussed.
941073 One test determination of the failure curve of a granular soil by strain path testing. Technical note Lo, S C R; Chu, J Soils Found V33, NI. March 1993, P176-181 Determination of the curved failure surface of a granular soil can be expensive and time consuming, and errors can arise because of the problems in producing identical replicate samples. A new, simple procedure requiring only one test is presented, based on post-failure strain path testing. Microprocessor-based equipment is used to control the strain path followed in the post-failure domain. Reduction of platen restraint to a minimal level is essential for this method to succeed.
941074 Pore-pressure influence in the poroelastic behavior of rocks: experimental studies and results Laurent, J; Bouteca, M J; Sarda, J P; Bary, D SPE Form Eval V8, N2, June 1993, Pl17-122 Reservoir compaction and subsidence are poroelastic phenomena. The Biot coefficient is an important parameter used in study of influence of pore pressure on deformation. An apparatus for measurement of Blot's coefficient is illustrated and values obtained with it for limestone are presented. Values similarly obtained for Berea sandstone are in good agreement with published data. Biot's coefficient and Zimmerman's expression for Biot's coefficient are defined. Both increase with increasing porosity according to a law which is formally similar to a Hashin-Shtrickman's type law.
941075 Compressibility of jointed rock masses with specific reference to the chalk Matthews, M C; Clayton, C R I Proc ISRM Symposium: Eurock'92, Chester, 14-17 September 1992 P445-450. Publ London." Thomas Telford, 1992 Weak rocks often show high compressibility which can be dominated by the nature of the discontinuities within the rock mass. Factors affecting the compressibility of fractured rock are examined, then data from large scale loading tests and foundations in jointed English chalk reviewed. Behaviour of the chalk is different from that which may be expected from the general rock mechanics literature. Yielding occurs at relatively low stresses in near-surface fractured chalks and there is a large decrease in stiffness with increasing load.
941076 Further developments for the determination of the stress-strain behaviour of jointed rock mass by large scale tests Mutschler, T; Natau, 0 Proc 7th ISRM International Congress on Rock Mechanics, Aachen, 16-20 September 1991 V3, P1557-1560. Publ Rotterdam: A A Balkema, 1993 Large scale triaxial tests have been carried out on undisturbed specimens of heavily jointed silty claystone, according to the ISRM Suggested Method. Results from 3 multistage tests are illustrated. Comparisons are made with behaviour of unjointed specimens and the effects of joints on the appearance of nonlinear and inelastic behaviour, nonlinear volume strain, pressure dependence of stiffness, and the ductile-brittle transition are discussed.
941077 Scale effects in the elastic moduli and strength of jointed rock masses
Moon, H K; Kim, C Y Proc Second International Conference on Scale Effects in Rock Masses, Lisbon, 25 June 1993 P39-48. Publ Rotterdam: A A Balkema, 1993 The discontinuous and inhomogeneous nature of rock masses leads to scale effects in their properties. The concept of REV is not relevant when joint orientations and numbers of joints and joint sets are arbitrary. A theoretical model is presented to determine rock mass moduli and strength under such conditions. Effects of joint properties and orientations are examined for a 3D rock mass. Results are applied to a real rock mass containing 11 joints in which a powerhouse cavern is excavated. Equivalent properties of each of the 2258 elements in the finite element analysis are estimated and the various scale effects illustrated.
941078 Structure of slip surface formed by rock block slide Hayashi, Y; Higaki, D; Ishizuka, T Proc 6th International Symposium on Landslides, Christchurch, 10-14 February 1992 I/1, P127-133. Publ Rotterdam." A A Balkema, 1992 The slip surface of the Kamenose slide in Osaka Prefecture, Japan, has been investigated. The surface was formed at the top of weakly consolidated tuffaceous sediments beneath andesite lava. Displacements of 40m and 20m respectively occurred in 1932 and 1967. The surface and its direction of movement have been mapped. Ductile and brittle failure has occurred along the shear surface, reducing the strength of the surface to a near residual level. This strength level is indicated by both ring shear tests and back analysis.
941079 Elasto-plustic analysis for deformation-failure behaviour of the rock specimen Lee, H K Proc International Symposium on Assessment and Prevention o f Failure Phenomena in Rock Engineering, istanbul, 5-7 April 1993 P93-99. Publ Rotterdam: A A Balkema, 1993 A new method for the elastoplastic analysis of deformation of rock is proposed in which the specimen is discretised and the strength distributed to the elements according to a regular distribution of Gauss random numbers. Splitting in uniaxial tension and post failure behaviour in uniaxial compression are analysed. Loading rate effects on failure patterns and fracture development as observed in laboratory tests can be reproduced.
941080 Mechanical properties and failure of porous rocks Tokashiki, N; Aydan, O; Kyoya, T; Ichikawa, Y Proc International Symposium on Assessment and Prevention o f Failure Phenomena in Rock Engineering, istanbul, 5-7 April 1993 P101-106. Publ Rotterdam: A A Balkema, 1993 Porous rocks generally consist of complexly oriented pores and matrices and are idealised as periodic on a microscopic scale. Two analytical methods for estimating the overall properties of such materials are described, the homogenisation method and a new averaging technique, the microstructure model. Overall moduli and strength properties predicted by these two methods are compared to each other and to data from other averaging methods and laboratory tests for a sandstone and a porous mortar. Effects of porosity on the mechanical response of rocks are discussed.