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Multi-laminate model of clays - a numerical evaluation of the influence of rotation of the principal stress axes
49A
842073 On the formulation of plane strain problems for elastic perfectly-plastic medium Gao Yu-chen, Hwang Keh-chih int d Engng Sci V21, N7, 1983, P765-780 Starting from the three dimensional baste equations for an elastic, perfectly plastic medmm, plane stram-h~storydependent yield conditions and constitutive equations for plane strain problems are derived
842074 Multi-laminate model of clays - a numerical evaluation of the influence of rotation of the principal stress axes Pande, G N, Sharma, K G int J Num Anal Meth Geomeeh V7, N4, Oct-Dec 1983, P397-418 A MultMammate model for normally consohdated clays has been presented The model predicts stress-strata behawour closely tallying with that predicted by the Cntmal State model m situations where no rotation of the principal stress axes takes place However, if there is a rotation of the pnnc~pal stress axes, the Multi-laminate model predicts plastm stratus considerably more than the Crmcal State model The model is used to study the collapse of footings
842075 Material model for inelastic rock deformation with spatial variation of pore pressure Smith, M B, Pattdlo, P D lnt J Num Anal Moth Geomeek V7, 314, Oct-Dec 1983, P457-468 This paper sets forth the theoretical background and basic numerical expressions for the incorporation of elastm-plast~c constitutive equations for ductile rock into a fimte element computer code The derivation of an expression for the total strain rate is performed both for a total stress formulation and for a formulation that employs the concept of effective stress for inelastic behaviour Specific expresmons for the incremental strain rate are presented for the case of a porous material having a quadratic imtlal yield surface and observing the associated flow rule with a special hardening law for subsequent plashc deformation A final section of the paper summarizes the expressions required to insert the quadratic yield surface model into a finite element code Auth
842076 On the solution of plane flow of granular media for jump non-homogeneity. Short communication Mlchalowskl, R L Int J Num Anal Merh Geomeeh V7, N4, Oct-Dec 1983, P485-492 Examines the plane plastic eqmhbnum of a cohesive frictional material in the case of a jump non°homogeneity Three types of interlace separating ngld-plastm bodies with different material parameters are distinguished (I) a perfect adhesion contact, (2) a thin layer of a material different from the adjacent bodies, and (3) a combined frictional-adhesive contact. The problem of stability of a slope, being continuously non-homogeneous in one region and homogeneous in another, ts shown in an example
842077 Fundamentals of rook joint deformation Ban&s, S C, Lumsden, A C, Barton, N R lnt J Rock Meek Min Sci V20, N6, Dec 1983, P249-268 This paper describes laboratory investigations of the deformation charactensucs of rock jomts under normal and shear loading Normal deformability was studied by conducting loading/unloading and repeated load cycling tests on a wide
vanety of fresh and weathered joints in five different rock types The data mva.nably showed non-hnear behaviour, irrespecuve of the rock and joint type. A hyperbohc function is suggested to describe the stress-closure/opening curves of joints Quantitative relations between normal deformability and relevant joint parameters (aperture, wall strength and roughness) are developed Tentatwe conclusions on the changes m normal stiffness during sheanng are also presented The behaviour of dislocated (mismatching)joints is studied qualitatively and analytically Shear deformabdlty was studied by performing direct shear tests under normal stresses m the range of engmeenng interest It is shown that behavtour in the pre-peak range ~s mvanably non-hnear depending on the joint type, and can be adequately described by easily measured parameters and hyperbohc functions Auth
842078 Plasticity model for flow of granular materials under triaxial stress states Dorns, J F, Nemat-Nasser, S Int d Solids Struct V18. N6, 1982, P497-531 For finite deformations of granular materials, a plasuclty theory is developed which accounts for the true stress trlaxiahty, pressure sensmvity and ddatancy As an example, a true tnaxial test on a cubical sample is analysed in detad, and the results are compared w~th expenmental results from true tnaxlal tests on loose and dense samples of sand Good correlation is obtained. 43 refs
842079 Nonlinear constitutive model for granular materials: applications to gravity flow McTigue, D F d Appi Meek (Trans ASME, Set E) V49, N2. June 1982. P291-296 842080 Elastic modnli, thermal expansion, and inferred permeability of two granites to 350 (leg C and 55 megapascals Heard, H C, Page, L J Geophys Res V87, NBI1. 10 Not' 1982, P9340-9348 Tnaxml tests were performed on Westerly and Stnpa granites and displacement measurements were made on three samples from each of three orthogonal directions The results were used to calculate the coefficient of linear thermal expansion, Young's modulus and the bulk modulus The directional values of these three parameters were found to be the same, so both rock types were lsotroptc w~th respect to the parameters The changes m values of these parameters with changing pressure and temperature conditions were consistent with mlcrocracks controlling the thermoelasuc response, with cracks opening with increasing temperature and closing with increasing pressure Changes m crack porosity due to bulk compresslblhty and thermal expanslon were calculated for both granites
842081 Elasticity of pyroxenes: effects of composition versus crystal structure Wodner, D, Vaughan, M T J Geophys Res V87, NBII, 10 Not' 1982, P9349-9353 Measured elastic properties of 5 pyroxenes were used to evaluate the influence of structural and compositional variations upon elastic moduh
842073 On the formulation of plane strain problems for elastic perfectly-plastic medium Gao Yu-chen, Hwang Keh-chih int d Engng Sci V21, N7, 1983, P765-780 Starting from the three dimensional baste equations for an elastic, perfectly plastic medmm, plane stram-h~storydependent yield conditions and constitutive equations for plane strain problems are derived
842074 Multi-laminate model of clays - a numerical evaluation of the influence of rotation of the principal stress axes Pande, G N, Sharma, K G int J Num Anal Meth Geomeeh V7, N4, Oct-Dec 1983, P397-418 A MultMammate model for normally consohdated clays has been presented The model predicts stress-strata behawour closely tallying with that predicted by the Cntmal State model m situations where no rotation of the principal stress axes takes place However, if there is a rotation of the pnnc~pal stress axes, the Multi-laminate model predicts plastm stratus considerably more than the Crmcal State model The model is used to study the collapse of footings
842075 Material model for inelastic rock deformation with spatial variation of pore pressure Smith, M B, Pattdlo, P D lnt J Num Anal Moth Geomeek V7, 314, Oct-Dec 1983, P457-468 This paper sets forth the theoretical background and basic numerical expressions for the incorporation of elastm-plast~c constitutive equations for ductile rock into a fimte element computer code The derivation of an expression for the total strain rate is performed both for a total stress formulation and for a formulation that employs the concept of effective stress for inelastic behaviour Specific expresmons for the incremental strain rate are presented for the case of a porous material having a quadratic imtlal yield surface and observing the associated flow rule with a special hardening law for subsequent plashc deformation A final section of the paper summarizes the expressions required to insert the quadratic yield surface model into a finite element code Auth
842076 On the solution of plane flow of granular media for jump non-homogeneity. Short communication Mlchalowskl, R L Int J Num Anal Merh Geomeeh V7, N4, Oct-Dec 1983, P485-492 Examines the plane plastic eqmhbnum of a cohesive frictional material in the case of a jump non°homogeneity Three types of interlace separating ngld-plastm bodies with different material parameters are distinguished (I) a perfect adhesion contact, (2) a thin layer of a material different from the adjacent bodies, and (3) a combined frictional-adhesive contact. The problem of stability of a slope, being continuously non-homogeneous in one region and homogeneous in another, ts shown in an example
842077 Fundamentals of rook joint deformation Ban&s, S C, Lumsden, A C, Barton, N R lnt J Rock Meek Min Sci V20, N6, Dec 1983, P249-268 This paper describes laboratory investigations of the deformation charactensucs of rock jomts under normal and shear loading Normal deformability was studied by conducting loading/unloading and repeated load cycling tests on a wide
vanety of fresh and weathered joints in five different rock types The data mva.nably showed non-hnear behaviour, irrespecuve of the rock and joint type. A hyperbohc function is suggested to describe the stress-closure/opening curves of joints Quantitative relations between normal deformability and relevant joint parameters (aperture, wall strength and roughness) are developed Tentatwe conclusions on the changes m normal stiffness during sheanng are also presented The behaviour of dislocated (mismatching)joints is studied qualitatively and analytically Shear deformabdlty was studied by performing direct shear tests under normal stresses m the range of engmeenng interest It is shown that behavtour in the pre-peak range ~s mvanably non-hnear depending on the joint type, and can be adequately described by easily measured parameters and hyperbohc functions Auth
842078 Plasticity model for flow of granular materials under triaxial stress states Dorns, J F, Nemat-Nasser, S Int d Solids Struct V18. N6, 1982, P497-531 For finite deformations of granular materials, a plasuclty theory is developed which accounts for the true stress trlaxiahty, pressure sensmvity and ddatancy As an example, a true tnaxial test on a cubical sample is analysed in detad, and the results are compared w~th expenmental results from true tnaxlal tests on loose and dense samples of sand Good correlation is obtained. 43 refs
842079 Nonlinear constitutive model for granular materials: applications to gravity flow McTigue, D F d Appi Meek (Trans ASME, Set E) V49, N2. June 1982. P291-296 842080 Elastic modnli, thermal expansion, and inferred permeability of two granites to 350 (leg C and 55 megapascals Heard, H C, Page, L J Geophys Res V87, NBI1. 10 Not' 1982, P9340-9348 Tnaxml tests were performed on Westerly and Stnpa granites and displacement measurements were made on three samples from each of three orthogonal directions The results were used to calculate the coefficient of linear thermal expansion, Young's modulus and the bulk modulus The directional values of these three parameters were found to be the same, so both rock types were lsotroptc w~th respect to the parameters The changes m values of these parameters with changing pressure and temperature conditions were consistent with mlcrocracks controlling the thermoelasuc response, with cracks opening with increasing temperature and closing with increasing pressure Changes m crack porosity due to bulk compresslblhty and thermal expanslon were calculated for both granites
842081 Elasticity of pyroxenes: effects of composition versus crystal structure Wodner, D, Vaughan, M T J Geophys Res V87, NBII, 10 Not' 1982, P9349-9353 Measured elastic properties of 5 pyroxenes were used to evaluate the influence of structural and compositional variations upon elastic moduh