Elastoplastic Stress-Strain Relationship for Loose Sands with Anisotropic Fabric Under Three-Dimensional Stress Conditions

Abstract

ABSTRACT A three-dimensional stress-strain relationship for loose sands having the anisotropic fabric is derived from the elasto-plasticity based on the concept of non-associated flow rule. Yield function, plastic potential function and hardening function which are required to frame the theory for sand are formulated through the experimental study on the relationship between plastic strain increment ratio and stress ratio and the plastic strain work during shear under three different principal stresses. Parameters included in the proposed elastoplastic work hardening model can be determined easily from the conventional triaxial compression and extension tests and the isotropic consolidation-swelling test. Comparisons of the predicted and measured three-dimensional stress-strain relationships showed that the proposed theory is capable of simulating the anisotropic deformability obtained by two kinds of the drained true triaxial tests in which cubical Fuji river sand and Toyoura sand specimens are used by Yamada and Ishihara (1979) and present authors, respectively.