Investigation on the effect of intermediate principal stress on shear behaviour of unsaturated soils




Investigation on the effect of intermediate principal stress on shear behaviour of unsaturated soils


Directional-dependent properties of the soil, like shear strength, stiffness and hydraulic conductivity, are known as anisotropy in soils. The shape and size of the soil particles and void distribution as microstructure characteristics and external factors such as stress history, environmental and geological conditions, and present stress condition can be the causes of the anisotropy in soils. In this paper, the behaviour of soil has been studied in a stress-strain plain under monotonic anisotropic loading to investigate the effect of induced anisotropy on the brittleness index of the soil sample. The brittleness index of the soil is defined as the difference between the ultimate and peak shear strength divided by the peak shear strength of the soil. The two major parameters describing induced anisotropy or anisotropic loading are intermediate principal stress (b) and principal stress direction () which are representative of the difference between intermediate, maximum and minimum principal stresses and the rotation angle of the principal stresses axis, respectively. This paper only takes the effect of intermediate principal stress with values of 0.25, 0.5, and 0.75. In addition, the soil is in an unsaturated state with a saturation degree of 80% using the constant water (C.W.) method.



F. Jafarzadeh; Amirsajjad Poorakbar; Mahdi Moghayad


8th International Symposium on Deformation Characteristics of Geomaterials (ISDCG2023)



I.1) Advances in laboratory testing techniques (equipment and procedures)