REP43039

• Permit No: M1992069
• IBM Index Class Name: Report
• Doc Date: 2/22/1993
• Doc Name: LETTER OF TRANSMITTAL
• From: TUTTEL APPLEGATE INC
• To: DMG
• Media Type: D
• Archive: No

Soil properties used for this analysis are as follows:
Description Design Parameter
Top layer - Silty Sands
Soil~Classification SM
Plasticity Index 5
Liquid Limit 20
Plastic Limit 15
Cohesion 0
Internal Angle of Friction 15deg (40~
Layer 2 - Sandy Gravels
Soil Classification GM
Plasticity Index 7
Liquid Limit 29
Plastic Limit 22
Cohesion 0
Internal Angle of Friction 35deg oi~
Layer 3 - Sandstone Bedrock
Solid impermeable Layer
Design Analysi
The embankment was analyzed using the UTEXA52 Slope Stability
program developed by the Army Corp of Engineers and the University
of Texas, Department of Civil Engineering. This program performs
the analysis of an earth embankment with custom input parameters to
model the critical parameters and conditions that may occur during
a given condition such as this one. The analysis performed is
based on the conditions listed above.
l~lethodology Used in Analysis
The computer analysis that was run used the Spencer's procedure
(].967). The first run performed a circular shear failure search to
find the shear plane with the lowest factor of safety. Because of
the stable nature of the embankment only minor failures on the
surface of the side slope resulted in this analysis. To check
these results another procedure - Simplified Bishop's procedure
(1.955) - was used with different X-Y coordinates. The convergence
of'.these two procedures supported the stable embankment assumption.
TYie second approach was to manually search for the center
coordinates and radius with the lowest factor of safety. This
method entailed forcing a failure in the area most likely to have
a major failure then moving the center coordinates slightly and
comparing the factors of safety (FOS). This procedure was repeated
until the lowest FOS was determined. The results are shown in the
appendix.