Shear stress enhancement of void compaction

Technical Report · Thu Sep 01 00:00:00 EDT 1977

DOI:https://doi.org/10.2172/6740082· OSTI ID:6740082

Curran, J H; Carroll, M M

Since the spherical model was successful in predicting the volumetric compaction behavior of both porous rocks and metals to a uniform pressure, the applicability of the spherical model to nonhydrostatic loading conditions was considered. Specifically, the spherical model is used to examine the influence of the presence of a shear stress on the volumetric compression of a porous solid. First the linear, elastic solution was obtained for a hollow sphere subject to homogeneous tractions on the outer boundary. Then, assuming that the matrix material is governed by the Drucker-Prager yield criterion, the elastic solution was used to derive an analytic expression for the onset of yield in the hollow sphere. The expression for the initial yield surface shows that the presence of a shear stress hastens the onset of yield in the sphere in comparison to a purely hydrostatic loading condition. This result agrees well with experimental data which show that, for porous solids, permanent crush-up begins at a lower mean stress under a nonhydrostatic loading than when the applied loading is a uniform pressure. At this point, due to difficulty in obtaining an analytic solution, a numerical scheme (finite element method) was used to extend the analysis of the hollow sphere problem into the elasto-plastic range. The spherical model results clearly exhibit the experimental finding that the presence of a shear stress tends to enhance the volumetric compaction of porous solids in comparison to a purely hydrostatic loading condition. For both a porous rock and metal sample, agreement between the spherical model and experimental results is excellent.

• Research Organization: Univ. of California, Berkeley, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6740082
• Report Number(s): UCRL-13858
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
36 MATERIALS SCIENCE
15 GEOTHERMAL ENERGY
METALS
COMPACTING
SHEAR PROPERTIES
POROUS MATERIALS
ROCKS
COMPARATIVE EVALUATIONS
DIAGRAMS
ELASTICITY
FINITE ELEMENT METHOD
MATHEMATICAL MODELS
MATRIX MATERIALS
POROSITY
PRESSURE DEPENDENCE
ROCK MECHANICS
STATIC LOADS
STRESSES
VOLUME
ELEMENTS
MATERIALS
MECHANICAL PROPERTIES
NUMERICAL SOLUTION
REACTOR MATERIALS
TENSILE PROPERTIES
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