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Study of undrained shear strength using various vanes
7A 941046 Stress-strain response of Cold Lake oil sands Wong, R C K; Barr, W E; Kry, P R Can Geotech J V30, N2, April 1993, P220-235
Bitumen is extracted from Cold Lake oil sands using cyclic steam stimulation. The sands may reach temperatures over 300 deg C and pore pressures can exceed overburden stress. The geomechanical behaviour of these uncemented deformable materials can influence distribution of heat and fluids in the reservoir. A series of cyclic triaxial tests on the oil sands has been carried out under different stress paths simulating insitu conditions. Deformation mechanisms have been investigated. Development of a constitutive model is proceeding. 941047 Compression characteristics and index properties of tills and intertili clays in southern Saskatchewan, Canada Sauer, K; Egeland, A K; Christiansen, E A Can Geoteeh J V30, N2, April 1993, P257-275
Compression characteristics and index properties were measured for unweathered tills and clays from repeated glaciations at l0 sites across a 1300km transect. Degree of overconsolidation increased with age of the till. Variations in lithoiogy are small for individual formations at each site, but may be large between some formations. Plasticity, in situ dry density, and in situ degree of saturation were measured. Results are discussed considering use of these soils in construction projects. 941048 Mining4nduced deformation in potash yield pillars, Vanscoy, Saskatchewan Chen, R; Brisbin, W C; Stimpson, B Can Geateeh J V30, N2, April 1993, P297-307
Potash yield pillars have been monitored at Vanscoy over an 8 year period to study the long term deformation, interpret the large scale features seen, interpret the microfabric anisotropy as an indicator of ductile strain, and help develop a model of progressive pillar failure. Pillar deformation proceeds by bulk rock flattening, development of shear zones at pillar corners, development of shear wedges at pillar margins, and detachment of these wedges. A combination of brittle deformation of halite, plastic deformation of sylvite, and grain boundary sliding is involved.
assess the displacement of a rigid block sliding on a plane surface. The results of the analysis show earthquake-induced displacements on pre-existing shear surfaces are significantly influenced by the soil behaviour under dynamic loading conditions. These findings are consistent with observed performance of extant slides in cohesive soils during earthquakes.
941051 B-value measurements for granular materials at high confining pressures Yamamuro, J A; Lade, P V
Geotech Test J V16, N2, June 1993, P165-171 Skempton's pore pressure coefficient, B, is often used to check degree of saturation of triaxiai specimens, a value approaching unity being taken to indicate full saturation. B values measured on a uniform sand at confining pressures 0.07-69MPa were found to be much less than unity, despite full saturation. This can be explained in terms of creep effects of the granular materials at high confining pressure. It is suggested that degree of saturation be checked by measuring B at low confining pressure before consolidation at higher pressures.
941052 Study of undrained shear strength using various vanes Siivestri, V; Aubertin, M; Chapuis, R P
Geoteeh Test J V16, N2, June 1993, P228-237 Vane shear tests carried out in a sensitive clay using rectangular, Nilcon, rhomboidal, triangular, and elliptical vanes are reported. Results are analysed in terms of two commonly used stress distributions, uniform and triangular. For rectangular and Nilcon vanes, both distributions are considered equally valid for interpretation of results, but for the other shapes the uniform stress assumption gives better fit to observed behaviour. Anisotropy does not seem to be an important factor.
941053 Indirect tension tests on rock - analytical/numerical correction for material bimodularity. Technical note Chen, R; Stimpson, B
Geotech Test J V16, N2, June 1993, P238-245 941049 Measurement of rock elastic moduli in tension and in compression and its practical significance Stimpson, B; Chen, R Can Geoteeh J V30, N2, April 1993, P338-347
Many rocks show different elastic moduli in tension and compression (bimodularity). A new technique has been developed where both moduli can be measured on the same specimen and in the same compressive loading frame. Specimen geometry and preparation are described. Results are presented for halite, potash, limestone, and granite and are validated against data from conventional tests. Practical significance of bimodularity is discussed with reference to beam loading and prediction of roof deflection in underground openings. 941050 Seismic displacements on shear surfaces in cohesive soils Tika-Vassilikos, T E; Sarma, S K; Ambraseys, N N Earthq Engng Struct Dynam V22, NB, Aug 1993, P709-721
Ring shear test data indicate the strength of pre-existing shear surfaces at high strain rates depends on displacement and rate of shearing. These results are used in numerical analysis to
Many rocks show different deformational behaviour in tension and compression. The effect of this bimodularity on four commonly used indirect tensile test methods, three-point beam bending, Brazilian, ring, and hydraulic extension tests, is examined. It is shown that if equal moduli are assumed in tension and compression, the tensile strength calculated from the test results will be overestimated.
941054 Soft oedometer - a new testing device and its application for the calibration of hypoplastic constitutive laws. Technical note Kolymbas, D; Bauer, E Geoteeh Test J VI6, N2, June 1993, P263-270
A new device called the soft oedometer, characterised by extensible lateral support rings, is proposed to allow homogeneous deformation in laboratory testing of soils. Both vertical and lateral stresses and strains can be measured. Test results for Karlsruhe sand are presented and analysed using a procedure which allows determination of the friction angle and other parameters for hypoplastic constitutive equations without the need to enter the limit state.
Bitumen is extracted from Cold Lake oil sands using cyclic steam stimulation. The sands may reach temperatures over 300 deg C and pore pressures can exceed overburden stress. The geomechanical behaviour of these uncemented deformable materials can influence distribution of heat and fluids in the reservoir. A series of cyclic triaxial tests on the oil sands has been carried out under different stress paths simulating insitu conditions. Deformation mechanisms have been investigated. Development of a constitutive model is proceeding. 941047 Compression characteristics and index properties of tills and intertili clays in southern Saskatchewan, Canada Sauer, K; Egeland, A K; Christiansen, E A Can Geoteeh J V30, N2, April 1993, P257-275
Compression characteristics and index properties were measured for unweathered tills and clays from repeated glaciations at l0 sites across a 1300km transect. Degree of overconsolidation increased with age of the till. Variations in lithoiogy are small for individual formations at each site, but may be large between some formations. Plasticity, in situ dry density, and in situ degree of saturation were measured. Results are discussed considering use of these soils in construction projects. 941048 Mining4nduced deformation in potash yield pillars, Vanscoy, Saskatchewan Chen, R; Brisbin, W C; Stimpson, B Can Geateeh J V30, N2, April 1993, P297-307
Potash yield pillars have been monitored at Vanscoy over an 8 year period to study the long term deformation, interpret the large scale features seen, interpret the microfabric anisotropy as an indicator of ductile strain, and help develop a model of progressive pillar failure. Pillar deformation proceeds by bulk rock flattening, development of shear zones at pillar corners, development of shear wedges at pillar margins, and detachment of these wedges. A combination of brittle deformation of halite, plastic deformation of sylvite, and grain boundary sliding is involved.
assess the displacement of a rigid block sliding on a plane surface. The results of the analysis show earthquake-induced displacements on pre-existing shear surfaces are significantly influenced by the soil behaviour under dynamic loading conditions. These findings are consistent with observed performance of extant slides in cohesive soils during earthquakes.
941051 B-value measurements for granular materials at high confining pressures Yamamuro, J A; Lade, P V
Geotech Test J V16, N2, June 1993, P165-171 Skempton's pore pressure coefficient, B, is often used to check degree of saturation of triaxiai specimens, a value approaching unity being taken to indicate full saturation. B values measured on a uniform sand at confining pressures 0.07-69MPa were found to be much less than unity, despite full saturation. This can be explained in terms of creep effects of the granular materials at high confining pressure. It is suggested that degree of saturation be checked by measuring B at low confining pressure before consolidation at higher pressures.
941052 Study of undrained shear strength using various vanes Siivestri, V; Aubertin, M; Chapuis, R P
Geoteeh Test J V16, N2, June 1993, P228-237 Vane shear tests carried out in a sensitive clay using rectangular, Nilcon, rhomboidal, triangular, and elliptical vanes are reported. Results are analysed in terms of two commonly used stress distributions, uniform and triangular. For rectangular and Nilcon vanes, both distributions are considered equally valid for interpretation of results, but for the other shapes the uniform stress assumption gives better fit to observed behaviour. Anisotropy does not seem to be an important factor.
941053 Indirect tension tests on rock - analytical/numerical correction for material bimodularity. Technical note Chen, R; Stimpson, B
Geotech Test J V16, N2, June 1993, P238-245 941049 Measurement of rock elastic moduli in tension and in compression and its practical significance Stimpson, B; Chen, R Can Geoteeh J V30, N2, April 1993, P338-347
Many rocks show different elastic moduli in tension and compression (bimodularity). A new technique has been developed where both moduli can be measured on the same specimen and in the same compressive loading frame. Specimen geometry and preparation are described. Results are presented for halite, potash, limestone, and granite and are validated against data from conventional tests. Practical significance of bimodularity is discussed with reference to beam loading and prediction of roof deflection in underground openings. 941050 Seismic displacements on shear surfaces in cohesive soils Tika-Vassilikos, T E; Sarma, S K; Ambraseys, N N Earthq Engng Struct Dynam V22, NB, Aug 1993, P709-721
Ring shear test data indicate the strength of pre-existing shear surfaces at high strain rates depends on displacement and rate of shearing. These results are used in numerical analysis to
Many rocks show different deformational behaviour in tension and compression. The effect of this bimodularity on four commonly used indirect tensile test methods, three-point beam bending, Brazilian, ring, and hydraulic extension tests, is examined. It is shown that if equal moduli are assumed in tension and compression, the tensile strength calculated from the test results will be overestimated.
941054 Soft oedometer - a new testing device and its application for the calibration of hypoplastic constitutive laws. Technical note Kolymbas, D; Bauer, E Geoteeh Test J VI6, N2, June 1993, P263-270
A new device called the soft oedometer, characterised by extensible lateral support rings, is proposed to allow homogeneous deformation in laboratory testing of soils. Both vertical and lateral stresses and strains can be measured. Test results for Karlsruhe sand are presented and analysed using a procedure which allows determination of the friction angle and other parameters for hypoplastic constitutive equations without the need to enter the limit state.