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8.4 Test and Application Examples of the Particle Simulation Method 207

1.60E–01

1.20E–01
CS = 10MPa
CS = 1MPa
CS = 0.1MPa
8.00E–02
Volumetric Strain 4.00E–02

0.00E+00
0.00 0.04 0.08 0.12 0.16

–4.00E–02

–8.00E–02
Axial Strain
(A) 1×2 m sample

2.80E–01

2.40E–01
CS = 10MPa
2.00E–01 CS = 1MPa
CS = 0.1MPa
Volumetric Strain 1.20E–01
1.60E–01

8.00E–02
4.00E–02
0.00E+00
0.00 0.04 0.08 0.12 0.16
–4.00E–02
–8.00E–02
Axial Strain
(B) 1× km sample
2
Fig. 8.11 Effects of confining stress on the curve of volumetric strain versus axial strain

simulation, the dilation of the particle sample is negative, implying that the total
volume of the particle sample decreases with an increase of the axial strain. This
phenomenon continues until the mechanical response of the particle sample reaches
a critical stage, at which a major failure takes place within the particle sample so
that there is a remarkable increase in the volumetric strain of the particle sample.
After this major failure, the volumetric strain of the particle sample becomes posi-
tive, implying that the volume expansion takes place within the particle sample. The
dilation phenomenon of the particle sample is consistent with what was observed in