Acta Mechanica Solida Sinica

, Volume 24, Issue 3, pp 273–281 | Cite as

Micromechanics analysis for unsaturated granular soils

  • Weihua Zhang
  • Chenggang Zhao


This paper aims at establishing an anisotropic stress expression for unsaturated pendular-state granular soils. Using the second-order fabric tensor, we formulate a micromechanics scheme of soils with statistically averaging method, and reveal that the macroscopic average stress of unsaturated granular soils in pendular-state is not isotropic. Not only is the stress from contact forces anisotropic due to the fabric, but also the capillary stress is directional dependent, which is different from the common point that the capillary stress is isotropic. The capillary stress of unsaturated pendular-state granular soils is determined by the orientation distribution of contact normals, so it is closely related to the initial and induced anisotropy of soils. Finally, DEM numerical simulations of triaxial compression tests of pendular-state soils at different degrees of saturation are used to verify the existence of above anisotropy of stresses.

Key words

unsaturated granular soils pendular state average stress fabric capillary stress anisotropy 


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Copyright information

© The Chinese Society of Theoretical and Applied Mechanics and Technology 2011

Authors and Affiliations

  1. 1.School of Civil EngineeringBeijing Jiaotong UniversityBeijingChina

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