On the role of particle breakage in the shear failure behavior of granular soils by DEM

Abstract

SUMMARYThis article presents a fundamental study on the role of particle breakage on the shear behavior of granular soils using the three-dimensional (3-D) discrete element method. The effects of particle breakage on the stress ratio, volumetric strain, plastic deformation, and shear failure behavior of dense crushable specimens undergoing plane strain shearing conditions are thoroughly investigated through a variety of micromechanical analyses and mechanism demonstrations. The simulation of a granular specimen is based on the effective modeling of realistic fracture behavior of single soil particles, which is demonstrated by the qualitative agreement between the results from platen compression simulations and those from physical laboratory tests.The simulation results show that the major effects of particle breakage include the reduction of volumetric dilation and peak stress ratio and more importantly the plastic deformation mechanisms and the shear failure modes vary as a function of soil crushability. Consistent macro-and micromechanical evidence demonstrates that shear banding and massive volumetric contraction depict the two end failure modes of a dense specimen, which is dominated by particle rearrangement-induced dilation and particle crushing-induced compression, respectively, with a more general case being the combination and competition of the two failure modes in the medium range of soil crushability and confining stress. However, it is further shown that a highly crushable specimen will eventually develop a shear band at a large strain because of the continuous decay of particle breakage.

Bonded-cell model for particle fracture

“…Numerical simulations by the molecular dynamics (MD) method or discrete element method (DEM) have been increasingly employed in order to get a better understanding of the particle-scale mechanisms of the comminution process [1,9,[27][28][29][30][31]. Such methods combine the general framework of the DEM, based on rigid-body dynamics and frictional contact interactions, with a particle fracture model.…”

Discrete-continuum analysis of monotonic pile penetration in crushable sands

“…However, the PSD does not seem to converge towards a stable grading in either case. It should be noted that, although the current numerical study is conducted in 2D, the particle-cluster technique employed for the breakage simulation is fully effective in producing a meaningful result of PSD evolution that is comparable to that from a previous 3D DEM study employing the same technique (Wang and Yan 2013).…”

“…The full-field shear and volumetric strain distributions will be generated using the meshless strain calculation method proposed and used by the first author in his previous studies (Wang et al 2007a(Wang et al , 2007bWang and Gutierrez 2010;Wang and Yan 2013). The full-field stress distributions can be calculated using a grid-based method similar to the strain-calculation method.…”

3D Modeling of Sand Particle Fracture Using Discrete Element Method and Synchrotron Micro-Tomography Images

“…Generally, the crushable nature of particles is represented either by bonding spherical particles as agglomerate (Cheng et al 2003, Wang andYan 2013) or replacing the particle with a group of small particles based on a specific failure criterion (Lobo-Guerrero andVallejo 2007, Ben-Nun et al 2010). These studies provide valuable information about the deformation characteristics of granular materials; however, the primary limitation of the published literature is the lack of representing 3D physical shape of particles.…”