ABSTRACT
Many rock formations have properties that are directional and thus are anisotropic. Rock joint sets induce anisotropy at a meter scale even when the intact rock between joints is isotropic, although random jointing is likely to result in isotropy. Anisotropic rock and soil deformation begins in the elastic domain with an initial application of load. As the limit to a purely elastic response is reached, continued loading induces an elastic-plastic response. Isotropic and anisotropic plasticity in geomechanics is much less developed than in the case of metals. In case of anisotropy, extension of the anisotropic discussion by Hill to include anisotropic, pressure-dependent yield by Pariseau is a reasonable starting point for development of anisotropic geoplasticity. Anisotropy in elasticity is accounted for in a generalized Hooke’s law, which can be specialized to various forms of anisotropy that have applicability in engineering practice.
