2013-08-01_PERMIT FILE - C1980007A

• Permit No: C1980007A
• IBM Index Class Name: Permit File
• Doc Date: 8/1/2013
• Doc Name: Refuse Pile Expansion East
• Section_Exhibit Name: Exhibit 82 Refuse Pile Expansion East
• Media Type: D
• Archive: Yes

.i
Retaining Wall Design
RPEE Haul Road Switchback, Gunnison County
Based on the provided information, the estimated soil parameters used in the retaining
wall design are summarized below, and must be verified prior to and during the wall
construction.
It should be noted that the cohesion of soils could be significantly reduced if the soils
become wet. Therefore, properly constructed surface drainage and a wall drain system
should be included in the retaining wall. The areas surrounding the retaining wall should
be carefully graded to provide positive surface drainage away from the walls. Irrigation
(including haul road watering for dust control) around the retaining walls should be
reduced to a minimum throughout the life of the retaining walls.
Retaining Wall Design
Retaining wall design was performed on a typical wall section of the proposed retaining
wall with a maximum design height of 10.5 feet (including exposed wall height and
required toe embedment) and surcharge load(s) where applicable. The wall design
calculations were performed in general accordance with NCMA Design Procedures by
using the SRWallo computer program. The wall design calculations evaluate the
external stability (including base sliding, overturning, bearing capacity, and base
eccentricity), internal stability (including geogrid length, over stress, pullout resistance,
and internal sliding), and facing stability (including facing overturning, shear, and
connection stress) to determine the required geogrid strengths, number of layers, and
reinforcement lengths. Results of the wall design calculations are presented in Appendix
A. Recommendations for retaining wall construction are presented in Appendix C.
Global stability analysis was performed on a typical wall section with maximum total wall
height of 10.5 feet. Global stability analysis was performed by using the Slope -W®
computer program. The Morgenstern -Price Method was used to calculate the factors of
safety. The lowest factor of safety is above the typically accepted value of 1.3. Results
of the global stability analysis are also presented in Appendix B.
Job No. 13 -3605 GROUND Engineering Consultants, Inc. Page 2 of 4
Unit
Friction
Material Type
Weight
Angle
Cohesion
Wo
(degree)
(pso
Existing Fill
130
18
350
Native
130
18
600
Import Backfill
135
34
0
Bedrock
130
18
1,000
It should be noted that the cohesion of soils could be significantly reduced if the soils
become wet. Therefore, properly constructed surface drainage and a wall drain system
should be included in the retaining wall. The areas surrounding the retaining wall should
be carefully graded to provide positive surface drainage away from the walls. Irrigation
(including haul road watering for dust control) around the retaining walls should be
reduced to a minimum throughout the life of the retaining walls.
Retaining Wall Design
Retaining wall design was performed on a typical wall section of the proposed retaining
wall with a maximum design height of 10.5 feet (including exposed wall height and
required toe embedment) and surcharge load(s) where applicable. The wall design
calculations were performed in general accordance with NCMA Design Procedures by
using the SRWallo computer program. The wall design calculations evaluate the
external stability (including base sliding, overturning, bearing capacity, and base
eccentricity), internal stability (including geogrid length, over stress, pullout resistance,
and internal sliding), and facing stability (including facing overturning, shear, and
connection stress) to determine the required geogrid strengths, number of layers, and
reinforcement lengths. Results of the wall design calculations are presented in Appendix
A. Recommendations for retaining wall construction are presented in Appendix C.
Global stability analysis was performed on a typical wall section with maximum total wall
height of 10.5 feet. Global stability analysis was performed by using the Slope -W®
computer program. The Morgenstern -Price Method was used to calculate the factors of
safety. The lowest factor of safety is above the typically accepted value of 1.3. Results
of the global stability analysis are also presented in Appendix B.
Job No. 13 -3605 GROUND Engineering Consultants, Inc. Page 2 of 4