PERMFILE55017

• Permit No: C1996083
• IBM Index Class Name: Permit File
• Doc Date: 3/24/2004
• Doc Name: Section 11
• Section_Exhibit Name: Volume VII Geotechnical Studies
• Media Type: D
• Archive: No

determined by calculating the ratio of resisting forces to driving
forces along discontinuities. Safety factors less than 1.0
indicate that driving farces are greater than resisting forces.
A safety factor of 1.0 would
theoretically indicate
equilibrium. Safety factors
of 1.2 to 1.3 are typically
considered the minimum
acceptable.
5. Remediation
Possible recommendations for
remediation include: do
nothing (for safe slopes or
impossible slopes); provide
drainage for excess water;
redesign the rock slope to a
more stable geometry; provide
artificial support, netting,
or catchment areas; or,
relocate the project and/or
affected people.
B. STEREONET BASICS
For analytical purposes,
discontinuities are assumed to
be planar. There are three
possible representations of a
plane in space on stereonets.
They are poles, dip vectors,
and great circles, as
illustrated in Figure 2.
Geologists have traditionally
used poles to represent
planes. A pole is formed by
passing a line perpendicular
to the plane through the
center of the reference
sphere. The point where the
line intersects the lower
hemisphere is the pole and is
projected upward to the
stereonet (Figure 2.).
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A
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B
C
A great circle is formed by
the intersection of the plane
in space with the lower half
of the reference sphere. The
stereonet projection of this
intersection is an arc called
a cyclographic trace of the

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Figure 2. (a) Perspective view
illustrating strike and dip of
bedding surfaces. (b) Lower
hemisphere illustration of poles,
dip vectors, and great circles.
(c) stereonet projection of the
representations frog Zb (modified
from Bassarab, 1979.)
Stereonet Analyses 4 Appendix A
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