Abstract
The paper analyzes boreholes under isotropic and anisotropic in-situ stresses using a large strain elastoplastic finite element model. The logarithmic strain and the Cauchy stress are used for the formulation of the material model which are accurate for materials that experience large volumetric strains often encountered in geomechanics. The model is first used to analyze uniaxial extension and necking of a ductile rod. Then the borehole is solved under both isotropic and anisotropic stresses. The results are compared with results from small strain analyses. They demonstrate a stiffer response at large strains not predicted by the small strain theory.