Mathematical Model for Shear Stress-strain Relationship of Unsaturated Soil

Shear stress-strain model of unsaturated soil plays an important role in its constitutive law, and it is very interesting and not well solved. In this paper, deficiency of traditional hyperbolic model for unsaturated soil shear stress-strain relationship is analyzed by employing half-value-strength index (HVSI). A new model with 3 parameters for unsaturated soil shear stress-strain relationship is established based on coupled energy dissipation theory and differential governing equation. Mathematic analysis shows that the 3-parameter model can overcome the deficiency of traditional hyperbolic model and has more extensive applications. Finally, comparisons between the traditional hyperbolic model, the new established model and laboratory tests are conducted, and the results show that the new model is more accurate than the hyperbolic model.