MICROMECHANICS ANALYSIS FOR UNSATURATED GRANULAR SOILS  

作　　者：Weihua Zhang Chenggang Zhao 

机构地区：[1]School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China

出　　处：《Acta Mechanica Solida Sinica》2011年第3期273-281,共9页固体力学学报（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (No. 50778013);the National Basic Research Program (973) of China (No. 2010CB732100)

摘　　要：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 con- tact 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.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 con- tact 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.

关 键 词：unsaturated granular soils pendular state average stress FABRIC capillary stress anisotropy 

分 类 号：O343.8[理学—固体力学] TU375[理学—力学]