Results 171 to 180 of about 20,540 (222)
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Hydraulic fracturing stress measurement using a true triaxial apparatus
International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1997Abstract Generally, from pressure-time curves obtained in underground hydralulic fracture tests one can determine the breakdown pressure Pc, the fracture reopening pressure Pr and the shut-in pressure Ps. These pressure values are then used for the calculation of the in situ stress state.
Sibai, M., Henry, J.P., Gros, J.C.
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Shear strengths of sandstone fractures under true triaxial stresses
Journal of Structural Geology, 2013Abstract True triaxial shear tests have been performed to determine the peak shear strengths of tension-induced fractures in three Thai sandstones. A polyaxial load frame is used to apply mutually perpendicular lateral stresses (σp and σo) to the 76 × 76 × 126 mm rectangular block specimens.
Piyanat Kapang +3 more
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Strain Localization Conditions Under True Triaxial Stress States
2011This work uses a bifurcation approach to develop theoretical predictions for deformation band formation for a suite of true triaxial tests on Castlegate sandstone. In particular, the influence of the intermediate principal stress on strain localization is examined.
Kathleen A. Issen +2 more
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True Triaxial Experimental Study of Stress-Induced Anisotropy of Sand
Instrumentation, Testing, and Modeling of Soil and Rock Behavior, 2011A true triaxial testing apparatus with rigid compound and sophisticated loading system was applied to carry out series of tests to study the stress-induced anisotropy of sand under three dimensional stress states. The additional loads were applied from σ1, σ2, and σ3 direction based on initial three dimensional complex stress states.
Kunyong Zhang, Jai K. Jung, Ting Zhang
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Stress–strain behaviour of unsaturated soil in true triaxial tests
Canadian Geotechnical Journal, 2002A suction-controlled true triaxial apparatus for unsaturated soil was developed from the existing true triaxial apparatus for sand by attaching a device to supply matric suction to specimens. Using the developed apparatus, true triaxial tests (σ1 [Formula: see text] σ2 [Formula: see text] σ3; where σ1, σ2, and σ3 are the three different principal ...
Hajime Matsuoka +4 more
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Permeability evolution of shale under anisotropic true triaxial stress conditions
International Journal of Coal Geology, 2016Abstract Although permeability data for shale have been reported previously and permeability models have been proposed, studies on permeability for shale under anisotropic true triaxial stress conditions are lacking. In this work, the permeability of shale under true triaxial stress conditions was measured using a newly developed true triaxial ...
Minghui Li +4 more
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Petrophysical Properties Under True-Triaxial Stress For Hydrocarbon Recovery Prediction
SPE Permian Basin Oil and Gas Recovery Conference, 1998Abstract The production of fluids from a reservoir often reduces pore pressure such that there is an increase in its effective stresses. During water flooding orgas injection the equilibrium rock stresses can also be altered in a similar dynamic manner. An understanding of these changes are of fundamental importance
S.S. Al-Harthy +3 more
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On the determination of true stress triaxiality in sheet metal
Journal of Materials Processing Technology, 2007Abstract Material ductility, or the failure strain, is generally characterized by simple tensile tests. However, tensile tests on sheet samples lead to higher strain gradients than those observed in axisymmetric samples, so the classical Bridgeman correction is invalid.
A. Bacha, D. Daniel, H. Klocker
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True Triaxial Stresses and the Brittle Fracture of Rock
Pure and Applied Geophysics, 2006This paper reviews the efforts made in the last 100 years to characterize the effect of the intermediate principal stress σ2 on brittle fracture of rocks, and on their strength criteria. The most common theories of failure in geomechanics, such as those of Coulomb, and Mohr, disregard σ2 and are typically based on triaxial testing of cylindrical rock ...
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Modeling Unsaturated Soil Response under Suction-Controlled True Triaxial Stress Paths
International Journal of Geomechanics, 2012AbstractResults from a comprehensive series of suction-controlled hydrostatic compression, conventional triaxial compression, triaxial compression, triaxial extension, and simple shear tests, conducted on statically compacted specimens of poorly graded sand with clay, are presented.
Laureano R. Hoyos +2 more
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