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Characteristic threshold and infrared vibrothermography of sand
218A 866O38 Deformation of a rock in diffe~m tensile tests Pandey. P: Singh, D P Engng Geol I"22. N3. April 1986. P281-292
866O42 Deformation phenomena in jointed rock Barton. N R Geotechnique V36. N2. June 1986. P147-167
Three tensile tests, viz. uniaxial tension, the Brazilian and four-pomt bending tests were conducted on specimens of a fine-to-medium-grained homogeneous rock. "Chunar" sandstone. Parameters such as uniaxial tensile strength, modulus of deformation in tension and Poisson's ratio in tension were obtained directly from the uniaxial tension test, and the Brazilian tensile strength, the modulus and Poisson's ratio were also determined by the Brazilian test. The bending tensile strength was obtained from the beam bending test using the four-point loading system, and the tensile modulus of elasticity was estimated from observations of the beam bending and uniaxial compression tests, using "double elasticity' relationships. The nature of the tensile deformation in the region of maximum tensile stress is found to be strikingly similar in all the three tensile tests under study.
The role of rock joints in rock mass deformauon phenomena is described. Examples of compaction in jol nted reservoirs and leakage phenomena in pressure tunnels are cited, each of which may be caused by changes in effective stress. The presence of rock joints is seen to affect stress slabbing phenomena in tunnels and it is the suspected cause of depth-dependent contrasts of stress in sedimentary rocks. The phenomenon of hydraulic shearing of joints is discussed with particular reference to geothermal reservoir simulation. A method of modelling this dilation-conductivity coupling is presented. The role of joint dilation in stress transformations and in the behaviour of underground openings is analysed. 35 refs.
866039 Correction equation on the influence of length-to-diameter ratio on the uniaxial compressive strength of rocks Turk. N: Dearman. W R Engng Geol I~22. N3. April 1986. P293-300 A general equation, derived from three published equations, is propo,~d for the correction of uniaxial compressive strength test results to a length-to-diameter ratio of two. In addition. an equation is given tbr standardization of test results to a length-to-diameter ratio of two and 50ram diameter. The methods were tested by analysis of over thirty sets of test data from the litcrature. Results for correction to length-to-diameter ratio of two fall within a 10% error band of the experimcntaI value equivalent to a length-to-diameter ratio of two. The two-stage correction to a length-to-diameter ratio of two and 50mm diameter, from a range of specimen lengths and diameters. gave results which were lower than the direct tests values Ibr specimens vdth these dimensions. Auth. 866040 Fluid pressure response to undrained compression in saturated sedimentary rock Green, D H: Wang, H F Geophy.~ics VSI. N4. April 1986. P948-956 The pore pressure response of saturated porous rock subjected to undrained compression at tow effective stresses is investigated theoretically and experimentally. The results agree with the theories of Gassmann (1951) and Bishop (1966), which assume a locally homogeneous solid framework. The implications of these results for rock petrography, crustal pore pressures, and aquifer and reservoir parameters are discussed. 86604 I Characteristic threshold and infrared vibrothermography of sand Luong, M P Geoteeh Test J vg. N2. Jlme 1986. P80-86 Rheological properties of granular soils under vibratory, cyclic and transient loading can be interpreted in terms of the interaction of grains, compaction, gram sliding and attrition. Infrared vibrothermography records the heat patterns produced by the dissipation of energy caused by friction between grains. This technique, which couples mechanical and thermal energy, offers the potential to directly monitor the stress state and particle rearrangement or characteristic threshold and predict the macroscopic response of granular materials.
866043 Sand sheared by stresses with cyclic variations in direction Wang, R K S: Arthur, J R F Geotechnique 1/36. N2. June 1986. P215-226 The effects of rotating principal stress directions cyclically m sand under drained conditions are described. The necessity of distinguishing between cyclic stress paths involving different rotations of principal stress directions is demonstrated. New aspects of material behaviour observed include a strong tendcncy of the major principal strain increment dircction to follow with a phase lag the change m direction of the stress increment rather than stress. A ne~' stress-dilatancy relationship is found in continuous cyclic rotation. Findings should bc hctpful in assessing the effects and risks of particular cyclic loading stress paths. 866044 Cone penetration lest in sands: part I, stale parameter interpretation Been. K: Crooks. J H A: Bccker. D E: Jcfferics, M G Geotechnique 1/36. N2. June 1986. P239-249 The state parameter is a quantitative measure of the state of a sand that combines the effects of void ratio and effective stress in a unique way for each sand. Application of the state parameter concept m practice requires the ability to measure the state parameter in situ. The interpretation of the cone penetration test in sand in terms of the state parameter concept Is examined. Existing data obtained from calibration chamber tests are reinterpreted to provide the relationship of cone tip resistance to state parameter. To compare data from different test programmes, data must be adjusted lbr chamber boundary effects. It is concluded that cone resistance provides a good measure of the state parameter. Auth 866045 Residual shear strength of clays and shales. Technical note Mesri, G: Cepeda-Diaz, A F Geotechnique 1/36. N2. June 1986. P269-274 Data and an interpretation on the residual friction angle of clays and shales are presented, and are intended to complement Skempton's (1985)data and analyses. 866046 Stability of rock mass Ramamurthy, T Indian Geotech J VI6. NI. Jan 1986. PI-74 The 8th Indian Geotechnical Society Annual Lecture has as tts theme an attempt to describe how strength of intact-isotropic and amsotropic rocks can be simply predicted with knowledge
~; 1986 Pergamon Journals Ltd. Reproduction not permitted
866O42 Deformation phenomena in jointed rock Barton. N R Geotechnique V36. N2. June 1986. P147-167
Three tensile tests, viz. uniaxial tension, the Brazilian and four-pomt bending tests were conducted on specimens of a fine-to-medium-grained homogeneous rock. "Chunar" sandstone. Parameters such as uniaxial tensile strength, modulus of deformation in tension and Poisson's ratio in tension were obtained directly from the uniaxial tension test, and the Brazilian tensile strength, the modulus and Poisson's ratio were also determined by the Brazilian test. The bending tensile strength was obtained from the beam bending test using the four-point loading system, and the tensile modulus of elasticity was estimated from observations of the beam bending and uniaxial compression tests, using "double elasticity' relationships. The nature of the tensile deformation in the region of maximum tensile stress is found to be strikingly similar in all the three tensile tests under study.
The role of rock joints in rock mass deformauon phenomena is described. Examples of compaction in jol nted reservoirs and leakage phenomena in pressure tunnels are cited, each of which may be caused by changes in effective stress. The presence of rock joints is seen to affect stress slabbing phenomena in tunnels and it is the suspected cause of depth-dependent contrasts of stress in sedimentary rocks. The phenomenon of hydraulic shearing of joints is discussed with particular reference to geothermal reservoir simulation. A method of modelling this dilation-conductivity coupling is presented. The role of joint dilation in stress transformations and in the behaviour of underground openings is analysed. 35 refs.
866039 Correction equation on the influence of length-to-diameter ratio on the uniaxial compressive strength of rocks Turk. N: Dearman. W R Engng Geol I~22. N3. April 1986. P293-300 A general equation, derived from three published equations, is propo,~d for the correction of uniaxial compressive strength test results to a length-to-diameter ratio of two. In addition. an equation is given tbr standardization of test results to a length-to-diameter ratio of two and 50ram diameter. The methods were tested by analysis of over thirty sets of test data from the litcrature. Results for correction to length-to-diameter ratio of two fall within a 10% error band of the experimcntaI value equivalent to a length-to-diameter ratio of two. The two-stage correction to a length-to-diameter ratio of two and 50mm diameter, from a range of specimen lengths and diameters. gave results which were lower than the direct tests values Ibr specimens vdth these dimensions. Auth. 866040 Fluid pressure response to undrained compression in saturated sedimentary rock Green, D H: Wang, H F Geophy.~ics VSI. N4. April 1986. P948-956 The pore pressure response of saturated porous rock subjected to undrained compression at tow effective stresses is investigated theoretically and experimentally. The results agree with the theories of Gassmann (1951) and Bishop (1966), which assume a locally homogeneous solid framework. The implications of these results for rock petrography, crustal pore pressures, and aquifer and reservoir parameters are discussed. 86604 I Characteristic threshold and infrared vibrothermography of sand Luong, M P Geoteeh Test J vg. N2. Jlme 1986. P80-86 Rheological properties of granular soils under vibratory, cyclic and transient loading can be interpreted in terms of the interaction of grains, compaction, gram sliding and attrition. Infrared vibrothermography records the heat patterns produced by the dissipation of energy caused by friction between grains. This technique, which couples mechanical and thermal energy, offers the potential to directly monitor the stress state and particle rearrangement or characteristic threshold and predict the macroscopic response of granular materials.
866043 Sand sheared by stresses with cyclic variations in direction Wang, R K S: Arthur, J R F Geotechnique 1/36. N2. June 1986. P215-226 The effects of rotating principal stress directions cyclically m sand under drained conditions are described. The necessity of distinguishing between cyclic stress paths involving different rotations of principal stress directions is demonstrated. New aspects of material behaviour observed include a strong tendcncy of the major principal strain increment dircction to follow with a phase lag the change m direction of the stress increment rather than stress. A ne~' stress-dilatancy relationship is found in continuous cyclic rotation. Findings should bc hctpful in assessing the effects and risks of particular cyclic loading stress paths. 866044 Cone penetration lest in sands: part I, stale parameter interpretation Been. K: Crooks. J H A: Bccker. D E: Jcfferics, M G Geotechnique 1/36. N2. June 1986. P239-249 The state parameter is a quantitative measure of the state of a sand that combines the effects of void ratio and effective stress in a unique way for each sand. Application of the state parameter concept m practice requires the ability to measure the state parameter in situ. The interpretation of the cone penetration test in sand in terms of the state parameter concept Is examined. Existing data obtained from calibration chamber tests are reinterpreted to provide the relationship of cone tip resistance to state parameter. To compare data from different test programmes, data must be adjusted lbr chamber boundary effects. It is concluded that cone resistance provides a good measure of the state parameter. Auth 866045 Residual shear strength of clays and shales. Technical note Mesri, G: Cepeda-Diaz, A F Geotechnique 1/36. N2. June 1986. P269-274 Data and an interpretation on the residual friction angle of clays and shales are presented, and are intended to complement Skempton's (1985)data and analyses. 866046 Stability of rock mass Ramamurthy, T Indian Geotech J VI6. NI. Jan 1986. PI-74 The 8th Indian Geotechnical Society Annual Lecture has as tts theme an attempt to describe how strength of intact-isotropic and amsotropic rocks can be simply predicted with knowledge
~; 1986 Pergamon Journals Ltd. Reproduction not permitted