Discrete element modeling of the effect of particle size distribution on the small strain stiffness of granular soils--颗粒学报PARTICUOLOGY

Gu, X., Lu, L., & Qian, J. (2017). Discrete element modeling of the effect of particle size distribution on the small strain stiffness of granular soils. Particuology, 32, 21-29. https://doi.org/10.1016/j.partic.2016.08.002

Discrete element modeling of the effect of particle size distribution on the small strain stiffness of granular soils

Xiaoqiang Gu ^{a b}, Lutong Lu ^a, Jiangu Qian ^a *

a Department of Geotechnical Engineering & Key Laboratory of Geotechnical and Engineering of the Ministry of Education, Tongji University, Shanghai 200092, China
b State Key Laboratory of Hydrology-Water Resource and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210098, China

10.1016/j.partic.2016.08.002

Volume 32, June 2017, Pages 21-29

Received 12 May 2016, Revised 15 July 2016, Accepted 2 August 2016, Available online 21 December 2016, Version of Record 20 April 2017.

E-mail: qianjiangu@tongji.edu.cn

Highlights

• The effect of particle size distribution on the small strain stiffness was investigated by DEM.

• The observed “size effect” was mainly caused by the sample size effect.

• The small strain stiffness of soil decreased with increasing coefficient of uniformity.

• Coordination number determined the small strain stiffness of granular soil at a particle level.

• The Poisson’s ratio decreased with decreasing void ratio and increasing confining pressure.

Abstract

Discrete element modeling was used to investigate the effect of particle size distribution on the small strain shear stiffness of granular soils and explore the fundamental mechanism controlling this small strain shear stiffness at the particle level. The results indicate that the mean particle size has a negligible effect on the small strain shear modulus. The observed increase of the shear modulus with increasing particle size is caused by a scale effect. It is suggested that the ratio of sample size to the mean particle size should be larger than 11.5 to avoid this possible scale effect. At the same confining pressure and void ratio, the small strain shear modulus decreases as the coefficient of uniformity of the soil increases. The Poisson’s ratio decreases with decreasing void ratio and increasing confining pressure instead of being constant as is commonly assumed. Microscopic analyses indicate that the small strain shear stiffness and Poisson’s ratio depend uniquely on the soil’s coordination number.

Graphical abstract

Keywords

Discrete element method; Particle size distribution; Small strain stiffness; Poisson’s ratio; Coordination number

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