analyses of de-confinement mechanisms of unstable failures ... · fric@on angle and dilaon angle...
TRANSCRIPT
![Page 1: Analyses of De-confinement Mechanisms of Unstable Failures ... · fric@on angle and dilaon angle in the MCSS model. • Con@nuously Yielding (CY) joint model Joint and Block Model](https://reader034.vdocuments.us/reader034/viewer/2022051913/60040a8507df00242211d6a2/html5/thumbnails/1.jpg)
AnalysesofDe-confinementMechanismsofUnstableFailuresinUndergroundMiningCondi<ons
RuixiangGuandUgurOzbayColoradoSchoolofMines
Preparedforthe33rdInterna@onalConferenceonGroundControlinMining
July29-31,2014,Morgantown,WV
PresentedbyRyanGarvey
![Page 2: Analyses of De-confinement Mechanisms of Unstable Failures ... · fric@on angle and dilaon angle in the MCSS model. • Con@nuously Yielding (CY) joint model Joint and Block Model](https://reader034.vdocuments.us/reader034/viewer/2022051913/60040a8507df00242211d6a2/html5/thumbnails/2.jpg)
• Unstablefailure• S@ffnesscriteria• Jointandblockcons@tu@vemodels
§ Con@nuouslyYielding(CY)jointmodel
§ Mohr-CoulombstrainsoTening(MCSS)model
• De-confinementmechanismsandsimula@onresults§ Unstableshearfailureatinterface§ Weakregionsalonginterface
• Conclusions
Contents
![Page 3: Analyses of De-confinement Mechanisms of Unstable Failures ... · fric@on angle and dilaon angle in the MCSS model. • Con@nuously Yielding (CY) joint model Joint and Block Model](https://reader034.vdocuments.us/reader034/viewer/2022051913/60040a8507df00242211d6a2/html5/thumbnails/3.jpg)
UnstableFailures–RockBurstsandCoalBumps
Stablefailure Unstablefailure
![Page 4: Analyses of De-confinement Mechanisms of Unstable Failures ... · fric@on angle and dilaon angle in the MCSS model. • Con@nuously Yielding (CY) joint model Joint and Block Model](https://reader034.vdocuments.us/reader034/viewer/2022051913/60040a8507df00242211d6a2/html5/thumbnails/4.jpg)
Stablefailures(b)andunstablefailure(c)inshearalongdiscon@nuity(Rice,1983)
Unstableandstablefailuresincompression,modifiedfromCook(1965)
S<ffnessCriteria
§ Cook,N.G.W.1965.Anoteonrockburstsconsideredasaproblemofstability.JournaloftheSouthAfricanIns3tuteofMiningandMetallurgy65:437-446.
§ Rice,J.R.1983.Cons@tu@verela@[email protected](3):443-475.
DynamicEjec@on
SeismicEnergy
![Page 5: Analyses of De-confinement Mechanisms of Unstable Failures ... · fric@on angle and dilaon angle in the MCSS model. • Con@nuously Yielding (CY) joint model Joint and Block Model](https://reader034.vdocuments.us/reader034/viewer/2022051913/60040a8507df00242211d6a2/html5/thumbnails/5.jpg)
JointandBlockModel
• Mohr-CoulombstrainsoTening(MCSS)model
Anexamplestress-straincurveofsoTeningmodel. Aconceptualrepresenta@onofvaria@onsofcohesion,fric@onangleanddila@onangleintheMCSSmodel.
![Page 6: Analyses of De-confinement Mechanisms of Unstable Failures ... · fric@on angle and dilaon angle in the MCSS model. • Con@nuously Yielding (CY) joint model Joint and Block Model](https://reader034.vdocuments.us/reader034/viewer/2022051913/60040a8507df00242211d6a2/html5/thumbnails/6.jpg)
• Con@nuouslyYielding(CY)jointmodel
JointandBlockModel
Thetypicalshearstress-sheardisplacementcurveoftheCYjointmodel(ItascaConsul@ngGroup,2010)
Shearstress-sheardisplacementcurveoftheCYjointmodelunderincreasednormalloading(GuandOzbay,2014)
§ [email protected],version4.0.Minneapolis,MN,USA.§ Gu,RandOzbay,U.2014.Dis@nctelementanalysisofunstableshearfailureofrockdiscon@nui@esinundergroundminingcondi@ons.
Interna3onalJournalofRockMechanicsandMiningSciences,68:44-54.
![Page 7: Analyses of De-confinement Mechanisms of Unstable Failures ... · fric@on angle and dilaon angle in the MCSS model. • Con@nuously Yielding (CY) joint model Joint and Block Model](https://reader034.vdocuments.us/reader034/viewer/2022051913/60040a8507df00242211d6a2/html5/thumbnails/7.jpg)
De-confinementMechanism
Mininggeometryusedformodelingde-confinementinducedunstablecompressivefailuresinsidewalls(miningadvancesperpendiculartotheplanecausingshearstressincreasesattheinterfacesclosetothesidewalls).
![Page 8: Analyses of De-confinement Mechanisms of Unstable Failures ... · fric@on angle and dilaon angle in the MCSS model. • Con@nuously Yielding (CY) joint model Joint and Block Model](https://reader034.vdocuments.us/reader034/viewer/2022051913/60040a8507df00242211d6a2/html5/thumbnails/8.jpg)
NumericalModelandResults
Modelforthestudiesofde-confinementresultedfromunstableshearfailuresattheinterfaces.
![Page 9: Analyses of De-confinement Mechanisms of Unstable Failures ... · fric@on angle and dilaon angle in the MCSS model. • Con@nuously Yielding (CY) joint model Joint and Block Model](https://reader034.vdocuments.us/reader034/viewer/2022051913/60040a8507df00242211d6a2/html5/thumbnails/9.jpg)
NumericalModelandResults
Shearstress-@mecurveoftheinterfacemeasurementpoints
Ver@calstress-@mecurveofthecoalmeasurementregions
MCinterface(stable)
CYinterface(unstable)
![Page 10: Analyses of De-confinement Mechanisms of Unstable Failures ... · fric@on angle and dilaon angle in the MCSS model. • Con@nuously Yielding (CY) joint model Joint and Block Model](https://reader034.vdocuments.us/reader034/viewer/2022051913/60040a8507df00242211d6a2/html5/thumbnails/10.jpg)
De-confinementMechanismandModel
Modelforthestudiesofde-confinementresultedfromtheexistenceofweakregionsattheinterfaces.
![Page 11: Analyses of De-confinement Mechanisms of Unstable Failures ... · fric@on angle and dilaon angle in the MCSS model. • Con@nuously Yielding (CY) joint model Joint and Block Model](https://reader034.vdocuments.us/reader034/viewer/2022051913/60040a8507df00242211d6a2/html5/thumbnails/11.jpg)
NumericalModelResults
Ver@calstress-@mecurvesofthemeasurementregionsinthesimula@on.
![Page 12: Analyses of De-confinement Mechanisms of Unstable Failures ... · fric@on angle and dilaon angle in the MCSS model. • Con@nuously Yielding (CY) joint model Joint and Block Model](https://reader034.vdocuments.us/reader034/viewer/2022051913/60040a8507df00242211d6a2/html5/thumbnails/12.jpg)
• Unstablefailuressignifiedbysuddenlossesofloadwhilestablefailuresfollowarela@velysmoothandgradualreduc@oninload.
• Suddenslipalonginterfaceledtorapidde-confinementandstrengthreduc@onofcoal->coalbumpcondi@ons
• Weakpor@onsinrock-coalinterfacecouldleadtogreatervolumesofaffectedcoalandlargermagnitudecompressivefailures
Conclusions