A phenomenological model is developed to represent failure in intact media as a consequence of shear-band formation. A stepped arrangement of connected flaws is assumed to be distributed within a planar shear-band inclined with respect to the applied deviatoric stresses. The flaws within the shear-band isolate a series of wedges that transmit tractions across the pre-failure zone. Gross stress transmission is controlled by static equilibrium with spatial stress inhomogeneity modulated through the distribution of flaws in the continuum adjacent to the shear-band. Under increased confinement, flaw closure beyond the shear-band results in a more homogeneous transmission of normal tractions across the failure plane. This stress dependent transition is based on physical arguments, related to mean flaw closure, to yield a distribution coefficient, W, that is controlled by macroscopic flaw rigidity, B. The model is able to replicate the power law dependency of ultimate strength with confining stress that is commonly observed. The model is specifically calibrated against experimental data for Daye marble. The phenomenological coefficients describing the failure process appear as material constants.
All Science Journal Classification (ASJC) codes
- Civil and Structural Engineering
- Geotechnical Engineering and Engineering Geology