Discrete simulation and micromechanical analysis of two-dimensional saturated granular media--颗粒学报PARTICUOLOGY

Khalili, Y., & Mahboubi, A. (2014). Discrete simulation and micromechanical analysis of two-dimensional saturated granular media. Particuology, 15, 138–150. https://doi.org/10.1016/j.partic.2013.07.005

Discrete simulation and micromechanical analysis of two-dimensional saturated granular media

Younes Khalili, Ahmad Mahboubi^*

Department of Civil and Environmental Engineering, Power and Water University of Technology, Tehran, Iran

10.1016/j.partic.2013.07.005

Volume 15, August 2014, Pages 138-150

Received 19 June 2012, Revised 20 May 2013, Accepted 18 July 2013, Available online 21 September 2013.

E-mail: mahboubi@pwut.ac.ir; ar_mahboubi@yahoo.com

Highlights

• Undrained behavior of saturated granular media was simulated in DEM using the coupled method.

• At high axial strains the behavior predicted by coupled and constant volume methods was different.

• Increasing void ratio increased the positive pore pressure and decreased negative pressure values.

• Micromechanical behavior and anisotropy of undrained particles were studied using the two methods.

Abstract

In this study, a novel approach to incorporate the pore water pressure in the discrete element method (DEM) to comprehensively model saturated granular media was developed. A numerical model was constructed based on the DEM by implanting additional routines in the basic DEM code; pore water pressure calculations were used with a two-dimensional (2D) model to simulate the undrained behavior of saturated granular media. This model coupled the interaction of solid particles and the pore fluid in saturated granular media. Finally, several 2D undrained shear tests were simulated. The test results showed that the model could predict the response of the saturated granular soil to shear loading. The effect of initial compaction was investigated. Biaxial tests on dense and loose specimens were conducted, and the effect of the initial density on the change in shear strength and the volume change of the system was investigated. The overall behavior of loose and dense specimens was phenomenologically similar to the real granular material. Constant volume tests were simulated, and the results were compared to those from the coupled model. Induced anisotropy was micromechanically investigated by studying the contact force orientation. The change in anisotropy depended on the modeling scheme. However, the overall responses of the media obtained using the coupled and constant volume methods were similar.

Graphical abstract

Keywords

DEM; Saturated granular media; Numerical simulation; Micromechanical investigation

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