PERMFILE56512

• Permit No: C1981038
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: Volume 6 PHASE II Stability Analysis - Phase II Geotechnical Studies
• Media Type: D
• Archive: No

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3.1.2 Cuts
Cuts have been made during development of the benches
at the site in both colluvial soils and in bedrock. The
stability of all cuts was evaluated during our geotechnical
review phase of this investigation.
The stability of slopes cut into bedrock was evaluated
based on the character of the exposed rock, the orientation
of the cut slopes, and the orientations of geologic dis-
continuities within the rock mass. They are generally consi-
dered to be stable overall, although some local problems of
rockfall may occur.
The diversion channel cut, which lies at the back of
the Fan level fill, has been cut into both colluvial soils
and bedrock at ankles between about 45 and 50 degrees. While
the cut generally appears stable where it has been made into
bedrock, several slides have developed where the cut is in
soil. These indicate that the safety factor of the cut in
soils is close to unity.
While other soil cuts have been excavated at similar
slopes to the diversion channel cut, they are generally of
lesser heights than the diversion channel cut. No signs of
instability were observed in any of these cuts, and it was
noted that all these slopes had been successfully revegetated.
Their stability is attributed to tfTe favorable physical pro-
perties of the colluvial soils and the revegetation of the
slopes. These slopes .are considered to be steep for unce-
mented sediments. However, it is considered tha[ no addi-
tional stabilizing procedures should be undertaken in view of
their pas[ and current performance, even though there is some
risk that local failures may occur in tlTese cuts.
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