DEM investigation on the effect of sample preparation on the shear behavior of granular soil--颗粒学报PARTICUOLOGY

Dai, B., Yang, J., Zhou, C., & Luo, X. (2016). DEM investigation on the effect of sample preparation on the shear behavior of granular soil. Particuology, 25, 111-121. https://doi.org/10.1016/j.partic.2015.03.010

DEM investigation on the effect of sample preparation on the shear behavior of granular soil

Beibing Dai ^a *, Jun Yang ^b, Cuiying Zhou ^a, Xiaodong Luo ^b

a Research Institute of Geotechnical Engineering and Information Technology, Sun Yat-sen University, China
b Department of Civil Engineering, The University of Hong Kong, Hong Kong, China

10.1016/j.partic.2015.03.010

Volume 25, April 2016, Pages 111-121

Received 17 September 2014, Revised 3 March 2015, Accepted 16 March 2015, Available online 8 September 2015, Version of Record 18 February 2016.

E-mail: beibing_dai@yahoo.com; daibb@mail.sysu.edu.cn

Highlights

• Effect of initial fabric anisotropy on the shear behavior of granular soil was investigated.

• The stress–dilatancy relationship was less affected by the initial fabric anisotropy.

• Various anisotropy indices tended to reach a common steady state at large shear strains.

• Fabric and force anisotropy accounted for the main contribution to the mobilized friction angle.

• A unique critical state line could be identified in both e–log p′ and q–p′ plots.

Abstract

The effect of initial fabric anisotropy produced by sample preparation on the shear behavior of granular soil is investigated by performing discrete element method (DEM) simulations of fourteen biaxial tests in drained conditions. Numerical test specimens are prepared by three means: gravitational deposition, multi-layer compression, and isotropic compression, such that different initial inherent soil fabrics are created. The DEM simulation results show that initial fabric anisotropy exerts a considerable effect on the shear behavior of granular soil, and that the peak stress ratio and peak dilatancy increase with an increase in the fabric index an that is estimated from the contact orientations. The stress–dilatancy relationship is found to be independent of the initial fabric anisotropy. The anisotropy related to the contact orientation and contact normal force accounts for the main contribution to the mobilized friction angle. Also, the occurrence of contractive shear response in an initial shearing stage is accompanied by the most intense particle rearrangement and microstructural reorganization, regardless of the sample preparation method. Furthermore, the uniqueness of the critical state line in e–log p′ and q–p′ plots is observed, suggesting that the influence of initial fabric anisotropy is erased at large shear strains.

Graphical abstract

Keywords

Initial fabric anisotropy; Stress–dilatancy relationship; Shear strength; Critical state line; Particle motion

文章导读