0 123456
- 5
- 0
- 5
- 0
- 0
- 5
- 0
- 5
- 0
Experimental data
SimulationShear strain (%)Tilting angle90
or bedding angle0Shearstressratio(f)yShearstressratio(f)y(a)Tilting angle60
or bedding angle300 1 234 5 6
- 5
- 0
- 5
- 0
- 0
- 5
- 0
- 5
- 0
Experimental data
SimulationShear strain (%)Shearstressratio(f)yShearstressratio(f)y(b)Tilting angle30
or bedding angle600 123456
- 5
- 0
- 5
- 0
- 0
- 5
- 0
- 5
- 0
Experimental data
SimulationShear strain (%)Shearstressratio(f)yShearstressratio(f)y(c)0 1234 56
- 5
- 0
- 5
- 0
- 0
- 5
- 0
- 5
- 0
Experimental data
SimulationShear strain (%)Tilting angle0
or bedding angle90Shearstressratio(f)yShearstressratio(f)y(d)Figure 2: Comparison between experimental data and simulation by using ( 16 ) for the confining pressure 0.5 kg/cm^2.friction angle,휙휇mob. This parameter is obtained from the
following equation:
tan−1(휏
푝
)=
휃휎−휃푓
푧
+휆(
휀V̇
휀푞̇
)+휙휇mob, (22)where푧and휆are material constants. Kuhn [ 28 ] and Shaverdi
et al. [ 29 ] showed that the variation of훼with the shear strain
is similar to the variation of shear to normal stress ratio with
shear strain.
7. Verification of( 16 )with Experimental Data
Oda et al. [ 17 ] conducted some experimental tests on Toyoura
sand with an initial void ratio 0.67-0.68 and the confining
pressures 0.5 kg/cm^2 and 2 kg/cm^2 to study the effect of
bedding angle with tilting angles훿= 0 ∘,30∘,60∘,and 90 ∘.For
better modeling, the constant푐for the plastic shear strain less
than 1% must be modified as follows:푐 = 0.001 + 0.001⟨1 − 푚耠휀푝푞⟩, (23)
where푚耠is a constant which depends on confining pres-
sure and⟨⋅⋅⋅⟩stands for the positive values only. In this
simulation,푚耠 =1is taken into account for the confining
pressure 0.5 kg/cm^2 ,and푚耠=6.5for the confining pressure
2.0 kg/cm^2.
Equation ( 17 ) can model the different behavior of the
granular soils with the same confining pressure and initial
void ratio (density) in which the only difference is due to the
fabric and its evolution, as shown in Figures 2 and 3.