Abstract: The influence of granular fabric on mechanic properties and microscopic parameters of sandy soil was investigated in this research via numerical simulation of triaxial compression test in association with Labenne's laboratory test of sandy soil. The numerical model which could determine the initial porosity and gradation of materials in consideration of rolling resistance was developed based on discrete element open source system Yade. According to the results of numerical tests, the variation laws of particle force chain, displacement field, and strain field with triaxial model deformation were analyzed. The numerical test involved five groups of particle gradation and three groups of porosity, and were compared with Labenne's laboratory test of sandy soil. Results conclude that: 1) the nonuniform coefficient and porosity have obvious influences on the peak strength of sandy soil; 2) the nonuniform coefficient has great influence on the coordination number of particles and the local stress; (3) the failure of sandy soil follows the pattern extending from the interior to the exterior along the shear plane.

Key words: sandy soil, triaxial compression, granular fabric characteristics, Yade, rolling resistance