Fig 1.
Soft-contact vs hard-contact approach.
Fig 2.
Sample contact between two objects (a) and the corresponding Signorini’s complementarity relation (b).
Fig 3.
A cluster of objects in contact: Schematic diagram of the contact forces (a); and the nested relation between the contact forces (b).
Table 1.
Characteristics of chrome steel beads.
Fig 4.
First row of metal beads placed in the direct shear box.
Fig 5.
Velocity of different collision shapes in Bullet with regard to the rotation of tilting plane for interface friction angle of 35° (friction ratio of 0.7).
Fig 6.
Input friction ratio vs the friction ratio at which slid occurs.
Fig 7.
The modeled sample in Bullet.
Fig 8.
Magnified view of the edge of shear box: The effect of gap on the formation of failure plane.
Fig 9.
Shear strength envelope from the laboratory experiments.
Fig 10.
Stress-strain curve for the laboratory tests under normal stress of 50 kPa.
Fig 11.
Stress-strain curve for the laboratory tests under normal stress of 150 and 300 kPa.
Fig 12.
Dilative response of the samples for the laboratory tests under normal stress of 150 and 300 kPa.
Fig 13.
Movement of a bead subjected to horizontal and normal load.
Fig 14.
Comparison of shear envelopes obtained from numerical results and laboratory experiments.
Fig 15.
Comparison of stress-strain curves for numerical and laboratory results.
Fig 16.
Comparison of dilation curves for numerical and laboratory results.
Fig 17.
Rotation of metal beads: Prior to shearing(a); at shearing of s/d = 1(b); total rotation of beads located in the proximity of failure plane(c).
Fig 18.
Displacement vectors of metal beads during shearing for the sample under 150 kPa.
Fig 19.
2D projected view of the normal chain forces at different stages of shearing (left) and the corresponding accumulated normal forces.
Fig 20.
Angle of mobilized friction and dilation curves for dense and loose samples.
Fig 21.
Displacement vector field of the sand grains for dense and loose samples (only the vectors larger than 0.06 mm are visualized).
Fig 22.
Chain force network of the sand grains for dense (left) and loose (right) samples (only the forces larger than 1.7 N are visualized).