A numerical analysis of the shear behavior of granular soil with fines--颗粒学报PARTICUOLOGY

Dai, B., Yang, J., & Luo, X. (2015). A numerical analysis of the shear behavior of granular soil with fines. Particuology, 21, 160-172. https://doi.org/10.1016/j.partic.2014.08.010

A numerical analysis of the shear behavior of granular soil with fines

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

a Research Centre of Geotechnical Engineering and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
b Department of Civil Engineering, The University of Hong Kong, Hong Kong, China

10.1016/j.partic.2014.08.010

Volume 21, August 2015, Pages 160-172

Received 28 May 2014, Revised 7 August 2014, Accepted 14 August 2014, Available online 30 December 2014, Version of Record 6 June 2015.

E-mail: beibing_dai@yahoo.com

Highlights

• Fine particles played a vital role in the overall response of granular soil to shearing.

• Liquefaction of silty sand resulted mainly from the removal of fine particles from soil skeleton.

• Interim contraction was followed by fines migrating back to soil skeleton, resulting in dilation.

• Shear loads were mainly carried by large particles through force chains formed at S–L and L–L contacts.

• Fine particles tended to roll and rotate and large particles were prone to slide in soil skeleton.

Abstract

Shear behavior of granular soil with fines is investigated using the discrete element method (DEM) and particle arrangements and inter-particle contacts during shear are examined. The DEM simulation reveals that fine particles play a vital role in the overall response of granular soil to shearing. The occurrence of liquefaction and temporary reduction of strength is ascribed mainly to the loss of support from the fine particle contacts (S–S) and fine particle-to-large particle contacts (S–L) as a consequence of the removal of fine particles from the load-carrying skeleton. The dilative strain-hardening response following the strain-softening response is associated with the migration of fine particles back into the load-carrying skeleton, which is thought to enhance the stiffness of the soil skeleton. During shear, the unit normal vector of the large particle-to-large particle (L–L) contact has the strongest fabric anisotropy, and the S–S contact unit normal vector possesses the weakest anisotropy, suggesting that the large particles play a dominant role in carrying the shear load. It is also found that, during shear, fine particles are prone to rolling at contacts while the large particles are prone to sliding, mainly at the S–L and L–L contacts.

Graphical abstract

Keywords

Granular soil; Fine particle; Shear behavior; Discrete element method; Fabric anisotropy; Coordination number

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