- Email: [email protected]
Preliminary results of plane-strain testing of soft rock
284A 925086 Material behaviour of coal under high stresses and temperatures Meissner, H; Rogmann, F
P2465-2471. Publ Rotterdam: A A Balkema, 1990
925090 Hollow-cylinder collapse: measurement of deformation and failure in an X-ray CT scanner, observation of size effect Kooijman, A P; van den Elzen, M G A; Veeken, C A M Rock 34echanics as a Maltidiscip~nary Science: Proc 32nd US Symposium, Norman, 10-12 July 1991 P657-666. Publ Rotterdam: A A Balkema, 1991
The behaviour of coal under elevated temperatures and pressures is important to design of in-situ gasification projects. Samples of bituminous coal were taken from blocks mined at about 800m depth in the Camphausen mine, Germany. Triaxial tests were carried out in the temperature range 20-200 deg C on samples of diameter 70-120mm. The anisotropic behaviour seen can be described in terms of Damage Tensor Analysis (Kawamoto, 1988). Anisotropy can be related to the three dimensional area density of microfractures: the intact rock is probably isotropic.
Hollow cylinder specimens of Castlegate Sandstone were tested to failure in compression, with CT density imaging carfled out. Development of volume strain and progressive failure were examined. Volume strain prior to failure initiation deviates from linear elastic response. Collapse occurs when breakout reaches a critical size due to progressive spalling. A series of specimens was prepared with hole size 8-180mm but constant (6:3:1) ratio of length to inner and outer diameters. 50% strength reduction is seen from one end of the range to the other.
925087 Residual strength envelopes using the confined shear test method Gyenge, M; Jackson, R; Gorski, B Rock Mechanics as a Maltidisciplinary Science: Proc 32nd US Symposium, Norman, 10-12 July 1991 P629-635. Publ Rotterdam: A A Balkema, 1991
925091 Preliminary results of plane-strain testing of soft rock Labuz, J F; Papamichos, E Rock Mechanics as a Maltidisciplinary Science: Proc 32nd US Symposium, Norman, 10-12 July 1991 P667-674. Publ Rotterdam." A A Balkema, 1991
The confined shear test method is described which uses three equally spaced core sticks arranged around a longer central sample. Various normal loads can be applied along the contact lines. The force necessary to initiate sliding of the central core is measured. Analysis is presented which allows simple and consistent determination of the corresponding shear strength envelope. Results are presented for granite and compared to those from multi-stage triaxial testing.
A plane strain apparatus has been developed by the University of Minnesota for testing of rocks with unconfined compressive strength below 35MPa. It is based on a passive, stiff frame design, but the upper platen is mounted on a linear bearing, which allows the specimen to deform as t~o elastic bodies separated by a Iocalised zone of deformation. No kinematic constraints are imposed on the formation of shear bands. The apparatus gives the advantages of both the direct shear and conventional compression tests.
Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 ~'4.
925088 Consolidated undrained triaxial test procedure for shales Steiger, R P; Leung, P K Rock Mechanics as a Maltidisciplinary Science: Proc 32nd US Symposium, Norman, 10-12 July 199I P637-646. Publ Rotterdam: A A Balkema, 1991
925092 Micro-experimental study on damage behaviour and investigation of damage variable in rock Qinxue Xiao; Ye Xiaomin; Lou Wentao Rock Mechanics as a ;~lultidisciplinary Science: Proc 32nd US Symposium, Norman, 10-12 July 1991 P675-682. Publ Rotterdam." A A Balkema, 1991
The complex hydration behaviour of shales and their low permeabilities cause problems in obtaining representative undamaged samples and in pore pressure measurement, respectively. A detailed test procedure, for which a patent has been applied, is presented for measurement of shear strength and pore pressure of low permeability shales in consolidated undrained triaxial tests. The triaxial cell and sample configuration are illustrated. The pore pressure measuring system, sample jacket, stress measurement, preparation of samples to specified water content and/or dimensions, and test procedure are described.
The progressive deformation behaviour of Chongqing sandstone under uniaxial load was studied using AE monitoring and electron microscopy. Up to stress level about 47MPa, initial pores, cracks, and cement are compressed. Above this level, crack initiation begins and linked cracks parallel to the loading direction are found at about 82MPa. Dilatancy commences with crack growth. A new damage variable is proposed, based on volume strain, to describe the damage deformation behaviour of rocks.
925089 Use of a simple index test in petroleum rock mechanics Santarelli, F J; Detienne, J L; Zundel, J P Rock Mechanics as a Multidisciplinary Science: Proc 32nd US Symposium, Norman, 10-12 July 1991 P647-655. Publ Rotterdam: A A Balkema, 1991
925093 Role of wetting fluids during the indentation of porous rocks Suarez-Rivera, F R; Cook, P J; Cook, N G W; Myer, L R Rock Mechanics as a Multidisciplinary Science: Proc 32nd US Symposium, Norman, 10-12 July 1991 P683-692. Publ Rotterdam: A A Balkema, 1991
A simple index test, based on Brinell hardness measurement, has been developed for the oil industry, where shortage of core material is often a problem. Specimen preparation and test procedures are described. Correlation of test results with uniaxial compressive strength for several reservoir sandstones is illustrated. The test may also be used to assess degree of damage. Developments towards improvement and standardisation of the procedure are suggested.
In order to study the influence of pore fluids on the indentation behaviour of porous rocks, experiments were carried out on Indiana limestone saturated with molten sulphur (wetting) or Wood's metal (non-wetting). The molten material was frozen in place by rapid cooling after indention so it could be examined. Non-wetting fluids only partially penetrate cracks leading to a positive pressure differential between pore fluid pressure and the unfilled crack tip. This acts as an effective
.© 1992 Pergamon Press Ltd. Reproduction not permitted
P2465-2471. Publ Rotterdam: A A Balkema, 1990
925090 Hollow-cylinder collapse: measurement of deformation and failure in an X-ray CT scanner, observation of size effect Kooijman, A P; van den Elzen, M G A; Veeken, C A M Rock 34echanics as a Maltidiscip~nary Science: Proc 32nd US Symposium, Norman, 10-12 July 1991 P657-666. Publ Rotterdam: A A Balkema, 1991
The behaviour of coal under elevated temperatures and pressures is important to design of in-situ gasification projects. Samples of bituminous coal were taken from blocks mined at about 800m depth in the Camphausen mine, Germany. Triaxial tests were carried out in the temperature range 20-200 deg C on samples of diameter 70-120mm. The anisotropic behaviour seen can be described in terms of Damage Tensor Analysis (Kawamoto, 1988). Anisotropy can be related to the three dimensional area density of microfractures: the intact rock is probably isotropic.
Hollow cylinder specimens of Castlegate Sandstone were tested to failure in compression, with CT density imaging carfled out. Development of volume strain and progressive failure were examined. Volume strain prior to failure initiation deviates from linear elastic response. Collapse occurs when breakout reaches a critical size due to progressive spalling. A series of specimens was prepared with hole size 8-180mm but constant (6:3:1) ratio of length to inner and outer diameters. 50% strength reduction is seen from one end of the range to the other.
925087 Residual strength envelopes using the confined shear test method Gyenge, M; Jackson, R; Gorski, B Rock Mechanics as a Maltidisciplinary Science: Proc 32nd US Symposium, Norman, 10-12 July 1991 P629-635. Publ Rotterdam: A A Balkema, 1991
925091 Preliminary results of plane-strain testing of soft rock Labuz, J F; Papamichos, E Rock Mechanics as a Maltidisciplinary Science: Proc 32nd US Symposium, Norman, 10-12 July 1991 P667-674. Publ Rotterdam." A A Balkema, 1991
The confined shear test method is described which uses three equally spaced core sticks arranged around a longer central sample. Various normal loads can be applied along the contact lines. The force necessary to initiate sliding of the central core is measured. Analysis is presented which allows simple and consistent determination of the corresponding shear strength envelope. Results are presented for granite and compared to those from multi-stage triaxial testing.
A plane strain apparatus has been developed by the University of Minnesota for testing of rocks with unconfined compressive strength below 35MPa. It is based on a passive, stiff frame design, but the upper platen is mounted on a linear bearing, which allows the specimen to deform as t~o elastic bodies separated by a Iocalised zone of deformation. No kinematic constraints are imposed on the formation of shear bands. The apparatus gives the advantages of both the direct shear and conventional compression tests.
Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 ~'4.
925088 Consolidated undrained triaxial test procedure for shales Steiger, R P; Leung, P K Rock Mechanics as a Maltidisciplinary Science: Proc 32nd US Symposium, Norman, 10-12 July 199I P637-646. Publ Rotterdam: A A Balkema, 1991
925092 Micro-experimental study on damage behaviour and investigation of damage variable in rock Qinxue Xiao; Ye Xiaomin; Lou Wentao Rock Mechanics as a ;~lultidisciplinary Science: Proc 32nd US Symposium, Norman, 10-12 July 1991 P675-682. Publ Rotterdam." A A Balkema, 1991
The complex hydration behaviour of shales and their low permeabilities cause problems in obtaining representative undamaged samples and in pore pressure measurement, respectively. A detailed test procedure, for which a patent has been applied, is presented for measurement of shear strength and pore pressure of low permeability shales in consolidated undrained triaxial tests. The triaxial cell and sample configuration are illustrated. The pore pressure measuring system, sample jacket, stress measurement, preparation of samples to specified water content and/or dimensions, and test procedure are described.
The progressive deformation behaviour of Chongqing sandstone under uniaxial load was studied using AE monitoring and electron microscopy. Up to stress level about 47MPa, initial pores, cracks, and cement are compressed. Above this level, crack initiation begins and linked cracks parallel to the loading direction are found at about 82MPa. Dilatancy commences with crack growth. A new damage variable is proposed, based on volume strain, to describe the damage deformation behaviour of rocks.
925089 Use of a simple index test in petroleum rock mechanics Santarelli, F J; Detienne, J L; Zundel, J P Rock Mechanics as a Multidisciplinary Science: Proc 32nd US Symposium, Norman, 10-12 July 1991 P647-655. Publ Rotterdam: A A Balkema, 1991
925093 Role of wetting fluids during the indentation of porous rocks Suarez-Rivera, F R; Cook, P J; Cook, N G W; Myer, L R Rock Mechanics as a Multidisciplinary Science: Proc 32nd US Symposium, Norman, 10-12 July 1991 P683-692. Publ Rotterdam: A A Balkema, 1991
A simple index test, based on Brinell hardness measurement, has been developed for the oil industry, where shortage of core material is often a problem. Specimen preparation and test procedures are described. Correlation of test results with uniaxial compressive strength for several reservoir sandstones is illustrated. The test may also be used to assess degree of damage. Developments towards improvement and standardisation of the procedure are suggested.
In order to study the influence of pore fluids on the indentation behaviour of porous rocks, experiments were carried out on Indiana limestone saturated with molten sulphur (wetting) or Wood's metal (non-wetting). The molten material was frozen in place by rapid cooling after indention so it could be examined. Non-wetting fluids only partially penetrate cracks leading to a positive pressure differential between pore fluid pressure and the unfilled crack tip. This acts as an effective
.© 1992 Pergamon Press Ltd. Reproduction not permitted