Abstract: Based on the theory of comprehensive structure potential, the stress-strain relations of intact loess, remolded loess and saturated loess have been researched by independent developed true triaxial apparatus. It has been reflected that the relationship between stress ratio structure parameter and generalized shear strain along with consolidation pressure and stress path. The mathematical model has been established. Meanwhile, the reliability of true triaxial apparatus and stress ratio structure parameter has been validated. It is shown that the stress-strain relations have distinct difference for different soil states. The stress-strain relations tend to the characteristic of strain softening or hyperbola for the intact loess. The stress-strain relations tend to the characteristic of hyperbola and strain hardening for the remolded or saturated loess. The soil structure reduces gradually with the increasing of shear deformation and water content. The consolidation pressure ? c and intermediate principal stress patameter b are the influential factors for soil structure. The simulation formula can accurately reflect the theory and experimentation. It is convenient for application in projects.

Key words: theory of comprehensive structure potential, structure parameter, true triaxial, stress path