摘要:

AbstractResults are presented for three‐dimensional planar fracture propagation in the presence of variations in confining stress, reservoir properties and frac‐fluid viscosity when the well‐bore pressure is constant throughout the frac‐job. Solid rock deformation during the frac‐job is described by the dislocation method with singular integral equations, and the fluid flow in the fracture is represented by the finite element method. A convergence study is undertaken on the three‐dimensional numerical model, and good agreement is obtained with results from laboratory tests and from the simpler cir

ISSN:0363-9061    

DOI:10.1002/nag.1610120602

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe present paper models the behaviour of bimodular materials (materials with different tensile and compressive moduli) by using a three‐dimensional finite element method. Since there is no explicit and definite expression for the shear modulusGof bimodular materials, the analysis starts with a 3 × 3 elasticity matrix in the principal stress coordinate system, and then uses a transformation from principal to Cartesian coordinates to obtain the 6 × 6 elasticity matrix. A corresponding iterative technique is proposed, and multiloading sequences in non‐proportionate loading—which need more iterations because of the non‐linear elastic property—are also discussed. Numerical examples are presented which show good agreement with analyti

ISSN:0363-9061    

DOI:10.1002/nag.1610120603

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractZones of localized shear strain, called bands, are initiated numerically within idealized cohesive and frictional soil specimens both by inhomogeneities and by imperfect boundaries. Qualitatively the results agree with experimental evidence, and give promise of quantitative analyses using better soil models, when the presence of porewater pressures will be of particular significance.

ISSN:0363-9061    

DOI:10.1002/nag.1610120604

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractGarg's approximate analytical solutions of Biot's equations for wave propagation in a fluid‐saturated elastic porous solid of infinite extent subjected to a velocity boundary condition of a Heaviside function at one end are examined for small and large drag. Garg's approximations were apparently introduced to facilitate exact inversion of Laplace transforms of certain quantities. The approximate solutions are compared with carefully evaluated numerical inverses of the Laplace transform solutions for different soils with widely varying properties. It is seen that for most soils (clays, silts and, sands) the error in Garg's approximate solutions in insignificant, and the solutions can be used as benchmarks for verifying numerical analysis procedures such as finite element code

ISSN:0363-9061    

DOI:10.1002/nag.1610120605

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractAn analytical‐numerical examination has been made of the behavior of harmonic Rayleigh‐type waves in a compressible elastic half‐space of constant density and whose shear modulus increases linearly with depth. The dispersion law is presented for values of Poisson's ratio of 1/2, 1/3 and 1/4 for wide ranges of degree of inhomoge

ISSN:0363-9061    

DOI:10.1002/nag.1610120606

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractIn this work, the Direct and Indirect Boundary Element Methods as applied to dynamic soil structure interaction problems, are compared. Both the methods are used to find the dynamic stiffnesses of rigid surface and embedded foundations. For surface foundations, the results obtained by the two methods were very close for the frequency range considered, but for embedded foundations at higher frequencies, the Indirect Boundary Element Method produced erroneous values for the real part of vertical compliance. The possible reasons for this discrepancy are also studied in this paper.

ISSN:0363-9061    

DOI:10.1002/nag.1610120607

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractA relatively simple yield model is developed for isotropic, porous rocks which yield in a ductile manner. The flow rule and yield function are derived using an adaptation of the work‐balance approach of critical state soil mechanics. This adaptation allows for the dissipation of work by frictional and volume change mechanisms, including the dissipation of frictional work at sensibly constant plastic volumetric strain. The yield model uses two material parameters—a basic frictional parameter and a plastic volumetric strain adjustment parameter which is assumed to be constant for the yield locus corresponding to a particular specific volume. The model gives excellent fits to yield loci for two limestones, a chalk and gypsum plaster prepared at different initial void rat

ISSN:0363-9061    

DOI:10.1002/nag.1610120608

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610120609

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610120610

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610120601

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY