1. Retaining Wall Design Slope Stability on US-189 MAQuiGr Engineering
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Retaining Wall Design
Slope Stability on US-189
MAQuiGr Engineering
greg
Matthew Hakes, Quinton Taylor, Greg Hanks

2. Site Evaluation Site 1 is featured on top Site 2 on bottom Notice:
Water location
Temporary solutions
Loads caused by road
Site 1
Site 2
greg

3. Considered Solutions Sheet pile Pros Rapid Construction Cons
Shallow rock makes it impossible to dig in deep enough to get moment
Quinton matt greg
Gabion
Tieback
Sheetpile
Tieback
Shotcrete
Soil Nail

4. Analysis with SnailPlus
Assumptions made:
Two different soil types
Gravel/Sand
Bedrock
Loading
Temporary Max: 700 psf from construction
Permanent Max: 200 psf from traffic
Morgenstern-Price
General limit equilibrium (Moment-force)
FHWA factors of safety used
mat

5. Analysis with SnailPlus
Under construction loading conditions
Under normal traffic loads
Design section
Calculation
FS Slope
Fmax Nails (k)
Fmax Nails at Head (k)
STR Check Nails
STR Check Plates
STR Check Facing
No. 4
Calculation successful
1.347
17.3
0.296
0.89
0.286
No. 3
2.155
6.8
0.117
0.353
0.113
Design section
Calculation
FS Slope
Fmax Nails (k)
Fmax Nails at Head (k)
STR Check Nails
STR Check Plates
STR Check Facing
No. 4
Calculation successful
1.579
14.9
0.257
0.856
0.275
No. 3
3.07
5.5
0.094
0.331
0.09
matt

6. Final Design Initial conception of wall shape
Created slope in AUTO cad
Unified design 1/2 the distance Follow slope or what
Optimized for construction
greg
10ft from road edge
120ft in length
17 Total Soil Nails
Average height, 6ft
Max height, 13ft

7. Phase 1 Site Preparation Conducted during low traffic flow
Conducted during low traffic flow
Close southbound lane
Flaggers to direct flow of traffic
through single lane
Environmental Impact Reduction
(3 lines of defense)
Excavated 5ft bench
1ft silt fence installed 20ft below excavation line
Exposed Shoreline
quiton

8. Excavation Slope Preparation
Phase 2
Excavation Slope Preparation
5ft bench approximately 10ft out from edge of the road
Excavation of 1,000 cubic feet
Soil relocated to holding site
Quinton

9. Soil Nail Installation
Phase 3
Soil Nail Installation
Williams Geo-Drill Injection Anchor System with rotary percussive drilling
In case of hitting hard rock, a Polyester Resin Rock Anchor System may be used
matt

10. Prefabrication of Rebar Cages
Phase 4
Prefabrication of Rebar Cages
Phase 4:
Constructed offsite due to limited space
75 year design life, hot-dip galvanizing
Matt – geosynthetic fabrics have excellent water flow levels, prevents clogging by stopping soil from entering molded plastic core allows for high in-plane water flow and far more effective than the old gravel and perforated pipe system

11. Installing Rebar Cages
Phase 5
Installing Rebar Cages
Challenge will be mobility and visibility of excavator
Guided into place by multiple workers located on bench
The key to the project was contstruction speed
8 in mat
Number 6 rebar
Tied together
Bring in on flat bead and then drop in excavator secure them in place
greg

12. Phase 6
Shotcrete
Two step process using wire mesh as backstop for shotcrete
First day application spraying towards the road, second day other side is applied
A problem (wall needs concrete)
solution we could pump it with shotcrete
Bench was created for workers to stand on
No wall – wire mesh 2 sided
greg

13. Installing Drainage System Phase 7
Composite Drainage system
Drainage system includes: geosythetic filtered fabric and molded plastic core
Quinton – geosynthetic fabrics have excellent waterf flow levels, prevents clogging by stopping soil from entering molded plastic core allows for high in-plane water flow and far more effective than the old gravel and perforated pipe system

14. Anchor to wall Attachments
Phase 8
Anchor to wall Attachments
Bearing plate, hardened washers, hex nut, and Geo-Drill Injection Anchor
75 year design life, galvanizing bearing plate and hardened washers and capped with a steel tube filled with cement grout
Quinton

15. Phase 9
Backfill
Using the soil from the excavation, backfill at 8-12in lifts
Compact soil with plate compactor attachment while avoiding soil nails
Increased bar size to improve bending strength in the case of accidental contact with compactor
matt

16. Phase 10 Capping Phase 11 Cleanup Phase 10:
Last 4-6in of backfill will be filled with cement to cap off the retaining system
Reduce permeability of surface and prevent corrosion
Phase 11:
Remove silt fencing and any loose material
Add soil to bench to create a more natural slope
Application of hydroseed to slope to promote vegetation growth
matt

17. Time and Cost Estimates
The Federal Highway administration
Charcteristics that cost $$$
Location, material, night time ect
Schedule
How we came up
Integrating phases to opomize time
greg
Cost estimates are based on the FHWA pricing graph and scheduling was created in 11 phases

18. Conclusion
A soil nail retaining system is the best option for this project
Adaptable – Depending on what is encountered during construction this design can easily be modified to meet the needs of the project
Cost Effective – With little excavation near the road, a temporary wall will be unnecessary
75 Design Life – Simple methods that can be implicated to increase design life
quinton