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In situ stress measurement in a jointed basalt: the suitability of five overcoring techniques
44A 852026 In situ stress measurement in a jointed basalt: the suitability of five overcoring techniques Gregory, E C; gundle, T A; McCabe, W M; Kim, K
Proc 6th Rapid Excavation and Tunneling Conference, Chicago, 12-16 June 1983 VI, P42-61. Publ New York." AIME, 1983 Five overcoring stress measurement techniques are assessed as to their suitability for stress determination in a jointed basalt. Considerable variation of stress results existed due to the presence of joints and because of operational difficulties. The borehole deformation gauge (BDG) and doorstopper techniques were selected for further investigation. 852027 Interpretation of virgin stress measurements with regard to large caverns Vreede, F A In: Rock Mechanics: Caverns and Pressure Shafts (paper to
the I S R M Symposium, Aachen, 26-28 May 1982) V3, PI1211126. Publ Rotterdam: A. A. Balkema, 1984 The stability of large caverns depends greatly on the virgin stress in the rock mass. The problems of obtaining reliable data and the interpretation of it is discussed in relation to the triaxiai strain cell designed by the Council for Scientific and Industrial Research of South Africa (CSIR). A numerical interpretation is possible through the concept of the basic stress field caused by tectonic and gravitational forces. Formulae for disturbed stresses for a cyclindrical hole in material subjected to a linear stress field are presented.
Time dependent behaviour 852028 Evaluation of a viscoplastic cap model Katona, M G
J Geotech Engng Div ASCE VIIO, NGT8, Aug 1984, Pl1061125 A time-dependent viscoplasticity model for rocks and soils based on Perzyna's elastic/viscoplastic theory and the inviscid cap model is developed. The model is compared with experimental data from examples: hard limestone in a variable loading history; soft sedimentary rock in triaxial creep tests; and well graded sand in slow and rapid loading. 852029 Influence of numerical and material approximations on the results of creep calculations (In German) Hebener, H; Richter, T; Borchert, K M In: Rock Mechanics: Caverns and Pressure Shafts (paper to
the I S R M Syn~oosium, Aachen, 26-28 May 1982) V3, P13131322. Publ Rotterdam: A. A. Balkema, 1984 In dimensioning deep underground excavations in rock salt it is of particular importance to find a way to account for the time dependent deformation behaviour of rock salt. Developing and proving a useful material law requires a sufficient number of laboratory test results, as well as in situ measurements. Furthermore, an appropriate method of calculation or a computer program is needed to calculate even more complicated boundary condition problems. The influence of some numerical and material approximations on the results of creep calculations with the Finite Element Method is presented. As an example, the rather simple boundary condition problem of a deep borehole is presented, where the chosen variations of the boundary conditions do not affect the results at all. The calculated creep deformations vary with respect to the chosen material model. Therefore, the effect of the variation of Poisson's ratio in the range of instantaneous deformation and the effect of dif-
ferent 3-D generalisations for the steady-state creep on the overall time dependent behaviour is examined. Physieo-chemical properties 852030 Some magnetic properties of Athabasca oil sand samples, Alberta, Canada Ellwood, B B; Pemberton, S G
Can J Earth Sci V21, N3, March 1984, P278-283 Using induced and remanent magnetic measurements, the magnetic properties of the four major Athabasca oil sand lithofacies are characterized. The lithofacies are: (1) laminated, bitumen free; (2) bioturbated, bitumen free; (3) bioturbated, moderate bitumen content; and (4) massive sand, bitumen rich, high percentage values of anisotropy of magnetic susceptibility. Magnetic fabric ranges progressively from undisturbed in type (1) to anomalous, considered highly disturbed in type (4). Only type (4) records a stable remanent magnetization. It is concluded that zone (4) may result from locally high concentrations of authigenic magnetic minerals such as maghemite or siderite. 852031 Grain shape effects on dielectric and electrical properties of rocks. Short note Sen, P N
Geophysics I:49, N5, May 1984, P586-587 It is suggested that the equation of Mendelson and Cohen for the conductivity of rock in terms of porosity and water conductivity is incorrect. It is concluded that the dielectric constant depends upon rock texture and not upon the porosity alone. The most important textural effects can be encapsulated by considering a distribution of spherical and platey grains. There can be a wide variation of dielectric constant depending upon salinity, porosity, concentration and aspect ratio of platey grains. 852032 Thermal conductivity determinations on solid rock - a comparison between a steady-state divided-bar apparatus and a commercial transient fine-source device Sass, J H; Stone, C; Munroe, R J
1 Voleanol Geotherm Res V20, N1-2, March 1984, P145-153 Thermal conductivity measurements were carried out on 17 samples of solid rock using the USGS divided-bar apparatus, a steady-state comparative method, and the Shotherm 'Quick Thermal Meter' (QTM), which employs a transient strip heat source. For isotropic material, either apparatus will yield the same value of thermal conductivity at room temperature over a large range of conductivities (1.4-5W/mK) and rock types. Although measurement times are comparable, sample preparation usually is simpler and quicker for the QTM provided suffÉcient material is available. The QTM is easily transportable and assembled quickly, requiring no more space than a desk top. In common with other line-source methods, it is difficult to characterise the conductivity of anisotropic materials in a given direction using the QTM. 852033
Example of application of rock behaviour mensuremem at high temperature: the determination of the 'admissible therm-.! loading' in geological formntions for the disposal of high-level radioactive waste (In French)
Come, B Rev Fr Geoteeh N27, 1984, P51-65
Proc 6th Rapid Excavation and Tunneling Conference, Chicago, 12-16 June 1983 VI, P42-61. Publ New York." AIME, 1983 Five overcoring stress measurement techniques are assessed as to their suitability for stress determination in a jointed basalt. Considerable variation of stress results existed due to the presence of joints and because of operational difficulties. The borehole deformation gauge (BDG) and doorstopper techniques were selected for further investigation. 852027 Interpretation of virgin stress measurements with regard to large caverns Vreede, F A In: Rock Mechanics: Caverns and Pressure Shafts (paper to
the I S R M Symposium, Aachen, 26-28 May 1982) V3, PI1211126. Publ Rotterdam: A. A. Balkema, 1984 The stability of large caverns depends greatly on the virgin stress in the rock mass. The problems of obtaining reliable data and the interpretation of it is discussed in relation to the triaxiai strain cell designed by the Council for Scientific and Industrial Research of South Africa (CSIR). A numerical interpretation is possible through the concept of the basic stress field caused by tectonic and gravitational forces. Formulae for disturbed stresses for a cyclindrical hole in material subjected to a linear stress field are presented.
Time dependent behaviour 852028 Evaluation of a viscoplastic cap model Katona, M G
J Geotech Engng Div ASCE VIIO, NGT8, Aug 1984, Pl1061125 A time-dependent viscoplasticity model for rocks and soils based on Perzyna's elastic/viscoplastic theory and the inviscid cap model is developed. The model is compared with experimental data from examples: hard limestone in a variable loading history; soft sedimentary rock in triaxial creep tests; and well graded sand in slow and rapid loading. 852029 Influence of numerical and material approximations on the results of creep calculations (In German) Hebener, H; Richter, T; Borchert, K M In: Rock Mechanics: Caverns and Pressure Shafts (paper to
the I S R M Syn~oosium, Aachen, 26-28 May 1982) V3, P13131322. Publ Rotterdam: A. A. Balkema, 1984 In dimensioning deep underground excavations in rock salt it is of particular importance to find a way to account for the time dependent deformation behaviour of rock salt. Developing and proving a useful material law requires a sufficient number of laboratory test results, as well as in situ measurements. Furthermore, an appropriate method of calculation or a computer program is needed to calculate even more complicated boundary condition problems. The influence of some numerical and material approximations on the results of creep calculations with the Finite Element Method is presented. As an example, the rather simple boundary condition problem of a deep borehole is presented, where the chosen variations of the boundary conditions do not affect the results at all. The calculated creep deformations vary with respect to the chosen material model. Therefore, the effect of the variation of Poisson's ratio in the range of instantaneous deformation and the effect of dif-
ferent 3-D generalisations for the steady-state creep on the overall time dependent behaviour is examined. Physieo-chemical properties 852030 Some magnetic properties of Athabasca oil sand samples, Alberta, Canada Ellwood, B B; Pemberton, S G
Can J Earth Sci V21, N3, March 1984, P278-283 Using induced and remanent magnetic measurements, the magnetic properties of the four major Athabasca oil sand lithofacies are characterized. The lithofacies are: (1) laminated, bitumen free; (2) bioturbated, bitumen free; (3) bioturbated, moderate bitumen content; and (4) massive sand, bitumen rich, high percentage values of anisotropy of magnetic susceptibility. Magnetic fabric ranges progressively from undisturbed in type (1) to anomalous, considered highly disturbed in type (4). Only type (4) records a stable remanent magnetization. It is concluded that zone (4) may result from locally high concentrations of authigenic magnetic minerals such as maghemite or siderite. 852031 Grain shape effects on dielectric and electrical properties of rocks. Short note Sen, P N
Geophysics I:49, N5, May 1984, P586-587 It is suggested that the equation of Mendelson and Cohen for the conductivity of rock in terms of porosity and water conductivity is incorrect. It is concluded that the dielectric constant depends upon rock texture and not upon the porosity alone. The most important textural effects can be encapsulated by considering a distribution of spherical and platey grains. There can be a wide variation of dielectric constant depending upon salinity, porosity, concentration and aspect ratio of platey grains. 852032 Thermal conductivity determinations on solid rock - a comparison between a steady-state divided-bar apparatus and a commercial transient fine-source device Sass, J H; Stone, C; Munroe, R J
1 Voleanol Geotherm Res V20, N1-2, March 1984, P145-153 Thermal conductivity measurements were carried out on 17 samples of solid rock using the USGS divided-bar apparatus, a steady-state comparative method, and the Shotherm 'Quick Thermal Meter' (QTM), which employs a transient strip heat source. For isotropic material, either apparatus will yield the same value of thermal conductivity at room temperature over a large range of conductivities (1.4-5W/mK) and rock types. Although measurement times are comparable, sample preparation usually is simpler and quicker for the QTM provided suffÉcient material is available. The QTM is easily transportable and assembled quickly, requiring no more space than a desk top. In common with other line-source methods, it is difficult to characterise the conductivity of anisotropic materials in a given direction using the QTM. 852033
Example of application of rock behaviour mensuremem at high temperature: the determination of the 'admissible therm-.! loading' in geological formntions for the disposal of high-level radioactive waste (In French)
Come, B Rev Fr Geoteeh N27, 1984, P51-65