Civil Engineering Reference
In-Depth Information
Intense shear zone
Figure 10.17
UDEC model for Profile P3 with lithology, discontinuities and annual pit geometries.
Moderate shear zone
Figure 10.18
UDEC model of Profile P5 with lithology, discontinuities and annual pit geometries
(see Figure 10.15 for location of Profile P5).
where
ε
cr
is the creep rate,
σ
ij
is the deviatoric
part of
σ
ij
, and
A
and
n
are material properties
that were found by calibration.
Modeling was performed for conditions repres-
entative of the years 1996 through 2002. Initially,
the model was brought to equilibrium under con-
ditions representative of January 1996. At this
point, the creep model was turned on and run for
one year of simulated time. For each subsequent
year, new water pressures and slope geometry
were introduced, and the model was run for
another year of simulated time.
Calibration was performed by adjusting the
power law parameters until reasonable agree-
ment was reached between the prism records and
Creep behavior was believed to be concentrated
within the sheared zone located just to the
west of the West Fault. In the model discussed
here, the behavior of the sheared rock was
represented using a viscoplastic model that
combined the behavior of the viscoelastic two-
component Norton Power Law model and
the Mohr-Coulomb elasto-plastic model. The
standard form of the Norton Power Law (Norton,
1929) is
Aσ
n
ε
cr
=
(10.8)
3
2
1
/
2
σ
ij
σ
ij
1
/
2
σ
=
(10.9)
