UseUse ofof LaunchedLaunched SoilSoil NailsNails toto StabilizeStabilize LandslidesLandslides inin SummitSummit County,County, OhioOhio MitchellMitchell W.W. Weber,Weber, P.G.P.G. Gannett Fleming Engineers & Architects, P.C.

GregGreg Bachman,Bachman, P.E.,P.E., P.S.P.S. County of Summit Engineer

RobertRobert K.K. BarrettBarrett Soil Nail Launcher, Inc. ProjectProject LocationLocation

I-77 IR-271 IR-480

SR-8 IR-80 GeologicGeologic SettingSetting ƒƒ NWNW partpart ofof SummitSummit CountyCounty lieslies withinwithin thethe GlaciatedGlaciated AlleghenyAllegheny Plateau.Plateau. –– UplandsUplands andand manymany slopesslopes composedcomposed ofof EndEnd oror GroundGround Moraine.Moraine. ƒ 33% Sand, 34% Silt, 32% Clay –– CuyahogaCuyahoga RiverRiver valleyvalley andand basebase ofof slopesslopes composedcomposed ofof glacialglacial--lacustrinelacustrine deposits.deposits. ƒ 0% Sand, 39% Silt, 60% Clay OhioOhio LandslideLandslide AreasAreas

Ref: ODNR GeoFacts No. 8 LandslidesLandslides AffectingAffecting NWNW SummitSummit CountyCounty RoadwaysRoadways NN TypicalTypical SlideSlide CharacteristicsCharacteristics

OBSERVED SLIDE TYPES • Earth Slumps • Earth Flows 10 – 12 ft. • Earth Block Slides 2 1 Glacial Till (SM-SC) ± 46 ft.

Glacial-Lacustrine (ML-CL) BasalBasal LacustrineLacustrine DepositDeposit EngineeringEngineering PropertiesProperties

(Ref: ODNR GB-2, Field Trip 3, Table 2) SlideSlide TriggersTriggers

ƒƒ IncreasedIncreased DrivingDriving ForcesForces (IDF)(IDF) –– Saturation.Saturation. ((above average rainfall in 2003 & 2004)) –– ToeToe undercuttingundercutting byby streamstream erosion.erosion. –– LateralLateral ‘‘squeezesqueeze’’ ofof basalbasal lakelake deposit.deposit.

ƒƒ DecreasedDecreased ResistingResisting ForcesForces (DRF)(DRF) –– SofteningSoftening ofof basalbasal clayclay throughthrough desiccationdesiccation andand wettingwetting cycles.cycles. Rain,Rain, Rain,Rain, GoGo AwayAway……

ƒƒ TheThe MemorialMemorial DayDay (2004)(2004) weekendweekend rainsrains triggeredtriggered severalseveral landslideslandslides withinwithin thethe County,County, twotwo resultedresulted inin immediateimmediate roadroad oror lanelane closures.closures. ƒƒ ByBy JuneJune 2004,2004, SummitSummit CountyCounty hadhad 99 slidesslides thatthat requiredrequired ““immediateimmediate”” attentionattention ƒƒ CountyCounty forcesforces werewere occupiedoccupied withwith otherother stormstorm damagedamage cleanclean up.up. ƒƒ CountyCounty EngineerEngineer soughtsought aa ““good,good, fast,fast, cheapcheap”” solution.solution. SelectionSelection ofof LaunchedLaunched SoilSoil NailsNails ƒƒ InIn consultationconsultation withwith GFGF andand SNL,SNL, ninenine ““emergencyemergency”” landslideslandslides sitesite werewere selectedselected forfor remediationremediation withwith launchedlaunched soilsoil nails.nails. SoilSoil NailingNailing

ƒƒ ConsistsConsists ofof reinforcingreinforcing thethe groundground withwith closelyclosely spaced,spaced, passivepassive inclusionsinclusions (nails),(nails), toto createcreate inin--situsitu aa coherentcoherent gravitygravity structurestructure whichwhich resultsresults inin anan increaseincrease ofof thethe overalloverall shearshear strengthstrength ofof thethe inin--situsitu soil.soil. ƒƒ BasicBasic designdesign conceptconcept -- transfertransfer thethe resistingresisting tensiletensile forcesforces generatedgenerated inin thethe nailsnails intointo thethe groundground throughthrough thethe frictionfriction mobilizedmobilized atat thethe interfaces.interfaces. Ref: FHwA –SA-96-069R SoilSoil NailsNails ƒƒ NailsNails typicallytypically consistconsist ofof :: –– SteelSteel barsbars oror otherother metallicmetallic elementselements thatthat resistresist tensiletensile && shearshear stressesstresses andand bendingbending moments.moments.

–– SoilSoil nailsnails areare notnot prestressedprestressed butbut areare closelyclosely spacedspaced (e.g.,(e.g., oneone drivendriven nailnail perper 2.52.5 ftft²²,, oneone groutedgrouted nailnail perper 1010--5050 ftft²²)) toto provideprovide anan anisotropicanisotropic apparentapparent cohesioncohesion toto thethe nativenative ground.ground. Ref: FHwA –SA-96-069R SuitableSuitable GroundGround ConditionsConditions

ƒƒ FavorableFavorable ConditionsConditions – Clays – Sandy soils – Weathered rock; talus slope deposits – Heterogeneous and stratified soils

ƒƒ SoilSoil nailingnailing isis generallygenerally notnot practicalpractical in:in: – Soft, plastic clays – Organics/Peat – Loose (N<10), low density and/or saturated soils LaunchedLaunched SoilSoil NailsNails LaunchedLaunched NailNail AdvantagesAdvantages

ƒƒ EffectiveEffective –– IncreasesIncreases shearshear resistanceresistance whilewhile decreasingdecreasing shearshear stresses.stresses. ƒƒ UnobtrusiveUnobtrusive –– EquipmentEquipment cancan reachreach ±± 2020 -- 2525 feetfeet downslope.downslope. –– ArticulatingArticulating headhead facilitatesfacilitates workingworking aroundaround treestrees andand utilityutility poles.poles. –– UsuallyUsually onlyonly shouldershoulder oror singlesingle lanelane closureclosure required.required. LaunchedLaunched NailNail AdvantagesAdvantages

ƒƒ FastFast InstallationInstallation –– 1010 nails/hour,nails/hour, 100100 nails/day.nails/day. ƒƒ ImmediateImmediate ResultsResults –– NoNo waitingwaiting forfor groutgrout set.set. ƒƒ SingleSingle ProcessProcess withwith smallsmall crewcrew –– PerformedPerformed byby aa laborerlaborer andand aa operator.operator. ƒƒ CostCost--effectiveeffective –– AverageAverage rangerange ofof $200$200 $400/lf$400/lf ofof crowncrown length.length. LaunchedLaunched SoilSoil NailsNails

ƒƒ SoilSoil ReinforcingReinforcing ElementsElements –– 11--inchinch diameter,diameter, hollowhollow steelsteel tubes.tubes. –– 2020--footfoot long.long. –– PerforatedPerforated forfor drainage.drainage. ƒƒ InstalledInstalled byby aa ProprietaryProprietary LauncherLauncher –– LauncherLauncher mountedmounted onon anan excavator.excavator. –– HasHas 360360ºº mobility.mobility. TheThe LauncherLauncher TypicalTypical LaunchedLaunched SoilSoil NailNail ApplicationApplication

Launched Soil Nails 3 or 4-foot c-c 2-3 rows

Slide Mass

Failure Surface TypicalTypical LaunchedLaunched SoilSoil NailNail ApplicationApplication

Launched Soil Nails 3 or 4-foot c-c 2-3 rows

Slide Mass

Failure Surface LauncherLauncher inin ActionAction RevereRevere RoadRoad SlipSlip -- BeforeBefore RevereRevere RoadRoad SlipSlip –– AfterAfter HighlandHighland RoadRoad LandslipLandslip –– BeforeBefore HighlandHighland RoadRoad LandslipLandslip –– AfterAfter BostonBoston MillsMills RoadRoad -- BeforeBefore BostonBoston MillsMills RoadRoad -- AfterAfter ColumbiaColumbia RoadRoad -- BeforeBefore ColumbiaColumbia RoadRoad -- BeforeBefore ColumbiaColumbia RoadRoad -- AfterAfter EverettEverett RoadRoad -- BeforeBefore EverettEverett RoadRoad -- AfterAfter SlideSlide TooToo LargeLarge SummitSummit CountyCounty’’ss LaunchedLaunched SoilSoil NailNail StatisticsStatistics ƒƒ 1111 sitessites havehave beenbeen nailed,nailed, repairingrepairing 1,0001,000 lflf ofof roadwayroadway .. ƒƒ AboutAbout 1,2001,200 launchedlaunched soilsoil nailsnails installedinstalled inin lessless thanthan aa 44 weekweek timetime frame.frame. ƒƒ CostCost ofof ±± $480,000.$480,000. ƒƒ CountyCounty crewscrews monitormonitor repairedrepaired sitessites onon monthlymonthly schedule,schedule, nono renewedrenewed movementmovement toto date.date. DesignDesign ResourcesResources

ƒƒ FHwAFHwA--SASA--9696--069R069R ƒƒ USFSUSFS EMEM--71707170--13,13, VolumesVolumes II –– III.III. QQ && AA