STUDY ON LOCALIZATION AND BIFURCATION OF GEOMATER1ALS WITH DAMAGE EFFECT

摘要

To obtain the damage effect in the process of elasto-plasticity deformation of geomaterials, the isotropic damage loading-unloading equation and damage variable are introduced to the non-continuous bifurcation. The critical hardening modulus, localized orientation angle with consideration of stiffness degradation, and dilatancy are set up. The relationship of the localized orientation angle and the maximal hardening modulus depends on the degree of damage, and the initial Poisson's ratio of rock is explored. Comparative analyses are conducted to study the bifurcation of uniaxial tension-compression samples under the conditions of plane stress and plane strain. The variation of the orientation angle of localization and the maximum hardening modulus depends on the initial Poisson's ratio and the degree of damage, and the sum of the orientation angle under tension and compression conditions is 90°. Also, there are plane stress and plane strain cases of the maximum hardening modulus which is independent of the uniaxial compression and tension.