Numerical and experimental direct shear tests for coarse-grained soils--颗粒学报PARTICUOLOGY

Bagherzadeh-Khalkhali, A., & Mirghasemi, A. A. (2009). Numerical and experimental direct shear tests for coarse-grained soils. Particuology, 7(1), 83–91. https://doi.org/10.1016/j.partic.2008.11.006

Numerical and experimental direct shear tests for coarse-grained soils

Ahad Bagherzadeh-Khalkhali^*, Ali Asghar Mirghasemi

School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran

10.1016/j.partic.2008.11.006

Volume 7, Issue 1, 18 February 2009, Pages 83-91

Received 15 February 2008, Accepted 18 November 2008, Available online 15 January 2009.

E-mail: aghasemi@ut.ac.ir

Highlights

Abstract

The presence of particles larger than the permissible dimensions of conventional laboratory specimens causes difficulty in the determination of shear strength of coarse-grained soils. In this research, the influence of particle size on shear strength of coarse-grained soils was investigated by resorting to experimental tests in different scale and numerical simulations based on discrete element method (DEM). Experimental tests on such soil specimens were based on using the techniques designated as “parallel” and “scalping” to prepare gradation of samples in view of the limitation of laboratory specimen size. As a second approach, the direct shear test was numerically simulated on assemblies of elliptical particles. The behaviors of samples under experimental and numerical tests are presented and compared, indicating that the modification of sample gradation has a significant influence on the mechanical properties of coarse-grained soils. It is noted that the shear strengths of samples produced by the scalping method are higher than samples by the parallel method. The scalping method for preparing specimens for direct shear test is therefore recommended. The micromechanical behavior of assemblies under direct shear test is also discussed and the effects of stress level on sample behavior are investigated.

Graphical abstract

Keywords

Discrete element method; Direct shear test; Micromechanics; Coarse-grained soil; Shear strength

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