Gordon R. Keller, PE, GEGordon R. Keller, PE, GEGeotechnical EngineerGeotechnical Engineergrkeller@fs.fed.usgrkeller@fs.fed.us

ororgordonrkeller@gmail.comgordonrkeller@gmail.com

Slope StabilizationSlope Stabilization

Rural Roads Educational Webinar SeriesRural Roads Educational Webinar Series

Slopes and SlopeSlopes and Slope StabilizationStabilization

• Avoiding Unstable AreasAvoiding Unstable Areas• Preventing InstabilityPreventing Instability• Stabilizing SlidesStabilizing Slides

• Stabilization AlternativesStabilization Alternatives

Mike Long

Slide Recognition and Avoidance Slide Recognition and Avoidance

Slide PreventionSlide Prevention

Cut SlopesCut Slopes

Fill SlopesFill Slopes

Nearly Vertical CutsNearly Vertical Cuts

Slope Stabilization AlternativesSlope Stabilization Alternatives

Assessment of Risks Involved•Hazard, or Likelihood of Failure•Consequences of Failure/Values at Risk (Infrastructure and Environment)

Range of Management Options•Do Nothing or Adapting to Slide•Move Facilities, Protection Measures•Stabilization Measures

Stabilization Measures(What is adequate and cost-effective)

•Maintenance--Slide Removal•Use of Vegetation, Drainage•Slope Modification•Gabions, Small Walls, Buttresses•Reinforced Fills, Deep Patch Repairs•Designed Retaining Structures•Piles, Anchors, Soil Nails, Etc.

Use of Vegetation for Slide Prevention Use of Vegetation for Slide Prevention and Slope Stabilizationand Slope Stabilization

D. Gray

R. Sotir

Soil bioengineering Soil bioengineering andand

biotechnical slope biotechnical slope stabilizationstabilization

R. Sotir

J. McCullah

R. Sotir

Surface andSurface and subsurface subsurface

drainagedrainage

C. Gillies

Rock Cuts & Rock Fall Problems

CDOT

Flattening or reshaping over-steep Flattening or reshaping over-steep failing failing slopesslopes;

Fill Slope StabilizationFill Slope Stabilization

Placement of Waste Material

Bad Disposal Sites

OK Disposal AreasOK Disposal Areas

ReinforcedReinforced FillsFills

Deep PatchDeep Patch

Retaining WallRetaining Wall

MSE WallsMSE Walls(MechanicallyStabilized Earth)(MechanicallyStabilized Earth)

MSE WallsMSE Walls

Soil Nail LauncherSoil Nail Launcher

Bob Barrett

GRS Bridge AbutmentsGRS Bridge Abutments

FHWA GRS Integrated Abutment Design(Bowman Road Bridge, Defiance Co. Ohio)

-TRB SR 247- Landslides- Investigation and Mitigation

-USFS- Slope StabilityReference Guide

Walls Need Good Foundations!!Walls Need Good Foundations!!

Ed Rose

Ed Rose

SummarySummary• Use commonly stable cut and fill slope angles

• For failures, assess why a site failed

• Find the least expensive, effective stabilization measure

• Consider use of drainage and vegetation

• Use structures where necessary. Analyze and design significant structures!

• Place structures on a solid foundation

Gordon Keller, PE, GEGordon Keller, PE, GEGeotechnical EngineerGeotechnical Engineergrkeller@fs.fed.usgordonrkeller@gmail.com