Numerical and Experimental Investigations of the Effect of Gradation and Shape of Particles on the Mechanical Behavior of Granular soils

Authors

Faculty of Civil, Water and Environmental Engineering, Shahid Beheshti University, Tehran, Iran

Abstract

Because testing on different materials often requires a lot of time and money, numerical simulation can be an acceptable method to avoid conducting several tests. One of the most effective methods to investigate the behavior of granular materials is discrete element method. This method, as a new approach, can simulate the behavior of material realistically, without implementing complex constitutive models (Wang et al, 2007; Shamsi and Mirghasemi, 2012; Tian et al, 2018). We know that the behavior of the particle assembly is influenced by the experimental test conditions, particle size distribution, particle shapes, etc. Previous researches show that particle shape has a significant effect on the mechanical behavior of granular soil (Tian et al, 2018). Therefore, to properly model the behavior of granules, it is better to simulate the particle shape as close to reality as possible. The main objective of this paper is to evaluate the effect of gradation and realistic particle shape on the mechanical behavior of granular soil in three dimensional discrete element method modeling in order to increase accuracy and precision of the simulation results. In this regard, in this study, irregular particles are modeled using a set of spheres that have different radii, overlap with each other and form a rigid object (clump) as shown in Fig. 1. Then, a series of consolidated drained triaxial compression tests have been performed on the specimens containing particles with various shapes. Finally, the results of the modeling were compared qualitatively with the experimental results.

Keywords

Main Subjects


اسلامی فیض آبادی ا، بررسی اثر دانه ­بندی بر نتایج آزمایش سه محوری زهکشی شده بر روی مصالح دانه ­ای توسط روش المان منفصل، پایان­نامه کارشناسی ارشد، دانشکده عمران و محیط‌زیست، دانشگاه صنعتی شیراز، 1393.
Asadi M, Mahboubi A, Thoeni K, “Discrete modeling of sand-tire mixture considering grain-scale deformability”, Granular Matter, 2018, 20 (2), 18-32.
Cundall PA, “A computer model for simulating progressive, large scale movements in blocky rock systems”, The International Symposium on Rock Fracture, 1971.
Cundall PA, Strack OD, “A discrete numerical model for granular assemblies”, Geotechnique, 1979, 29 (1), 47-65.
Gong G, Lin P, Qin Y, Wei J, “DEM simulation of liquefaction for granular media under undrained axisymmetric compression and plane strain conditions”, Acta Mechanica Solida Sinica, 2012, 25 (6), 562-570.
Gong J, Liu J, “Effect of aspect ratio on triaxial compression of multi-sphere ellipsoid assemblies simulated using a discrete element method”, Particuology, 2017, 32, 49-62.
Gong J, Liu J, Cui L, “Shear behaviors of granular mixtures of gravel-shaped coarse and spherical fine particles investigated via discrete element method”, Powder Technology, 2019, 353, 178-194.
Hart R, Cundall PA, Lemos J, “Formulation of a three-dimensional distinct element model-Part II. Mechanical calculations for motion and interaction of a system composed of many polyhedral blocks”, International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1988, 25 (3), 117-125, Pergamon.
“Particle Flow Code in Three Dimensions (PFC3D), Version 6.00”, Itasca Consulting group Inc., Minneapolis, USA, 2018.
Jiang MD, Yang ZX, Barreto D, Xie YH, “The influence of particle-size distribution on critical state behavior of spherical and non-spherical particle assemblies”, Granular Matter, 2018, 20 (4), 80-94.
Lee SJ, Hashash YM, Nezami EG, “Simulation of triaxial compression tests with polyhedral discrete elements”, Computers and Geotechnics, 2012, 43, 92-100.
Manne A, Satyam N, “A review on the discrete element modeling of dynamic laboratory tests for liquefaction assessment”, Electronic Journal of Geotechnical Engineering, 2015, 20 (1), 21-46.
Matsushima T, Saomoto H, “Discrete element modeling for irregularly Y-shaped sand grains”, 5th European Conference Numerical Methods in Geotechnical Engineering, Mestat (ed.), 2002, 239-246.
Nouguier-Lehon C, Cambou B, Vincens E, “Influence of particle shape and angularity on the behaviour of granular materials: a numerical analysis”, International Journal for Numerical and Analytical Methods Geomechanic, 2003, 27 (14), 1207-1226.
Shamsi MM, Mirghasemi AA, “Numerical simulation of 3D semi-real-shaped granular particle assembly”, Powder Technology, 2012, 221, 431-446.
Tian J, Liu E, Jiang L, Jiang X, Sun Y, Xu R, “Influence of particle shape on the microstructure evolution and the mechanical properties of granular materials”, Comptes Rendus Mécanique, 2018, 346 (6), 460-476.
Wang L, Park JY, Fu Y, “Representation of real particles for DEM simulation using X-ray tomography”, Construction and Building Materials, 2007, 21 (2), 338-346.
Xie YH, Yang ZX, Barreto D, Jiang MD, “The influence of particle geometry and the intermediate stress ratio on the shear behavior of granular materials”, Granular Matter, 2017, 19 (2), 35-49.