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Researchonthenumericalsimulationoftwo - stagelandslidedam
breachprocessandcharacterizationofbreachflowevolution
1,2,3
1
1,4
CHENLingchun,ZHONGQiming ,MEIShengyao ,ZHANGLucheng 1
(1.DepartmentofGeotechnicalEngineering,NanjingHydraulicResearchInstitute,Nanjing 210024,China;
2.TheNationalKeyLaboratoryofWaterDisasterPrevention,Nanjing 210098,China;
3.KeyLaboratoryofDamReservoirSafetyoftheMinistryofWaterResources,Nanjing 210029,China;
4.CollegeofCibilandTransportationEngineering,HohaiUniversity,Nanjing 210098,China)
Abstract:Undertheinfluenceofstrongearthquakes,mountainouscanyonregionsarepronetoexperiencingland
slidesthatblockriversandformingcascadinglandslidedams.Oncetheoneoftheselandslidedamsbreaches,itcan
triggerachainreaction ,leadingtothesuccessivefailureofcascadinglandslidedamswhichposesasignificantthreat
tothelives,property,andinfrastructuredownstream.Basedonthethree - dimensionalReynolds - averagedNavier -
Stokesequations ,turbulentrenormalizationgroupmodeling,suspendedandbedloadtransportequations,andcon
sideringtheunstablecollapseofthedambreachslope ,byusingtheFiniteVolumeMethod,anumericalsimulation
methodforcalculatingthecascadingdambreachprocesshasbeendeveloped.Thisnumericalmethodcanbeusedto
simulatethehydrauliccharacteristicsandthedambreachmorphologyevolutionduringthecascadingfailureprocess.
Atypicalgeneralizedmodeltestonthebreachesoftwocascadinglandslidedamsischosenasthevalidationcase.The
comparisonofmeasuredandcalculatedresultsindicatesthat ,thebreachhydrographandbreachmorphologyevolution
processoftheupstreamanddownstreamdamsaregenerallyconsistent,andtherelativeerrorsofkeybreachingpa
rameters,suchaspeakbreachflowsoftheupstreamanddownstreamdams,andfloodroutingtimebetweentheinter
zone ,arelessthan±5%.Further,thecomparisonofthebreachhydrographsoftheupstreamanddownstreamdams
showsthat ,thereisanamplificationeffectofbreachfloodonthecascadinglandslidedamfailures.Threekeyparam
eters ,suchasdistancebetweenupstreamanddownstreamdams,riverchannelslope,anddownstreamdamheight,
areselectedtostudythefloodamplificationeffect.Theparametersensitivityanalysisshowsthat,thepeakbreach
flowatthedownstream dam decreaseswiththeincreasesofdistancebetweenthetwodamsanddownstream dam
height ,anditfollowsatrendofincreasingatfirstandthendecreasingwiththeincreaseofriverchannelslope.When
thefloodcausedbytheupstreamdamfailureflowedtothedownstreamdam ,itmayproducesurgethatovertopsand
erodesthedamcrest ,resultinginadecreaseinthedamcrestelevation.Thishasacertainimpactonthefailureoc
currencetimeandpeakbreachflowofthedownstreamdam ,andtheinfluenceofsurgeonthedownstreamdamfailure
processisrelatedtotheamountofwaterovertopsthedamcrestandtheerosioncharacteristicsofdammaterials.The
cascadingdamfailurecasesofXiaogangjian - upperandXiaogangjian - lowerareselectedastherepresentativesforthe
validation.Bycomparingthecalculatedandmeasuredbreachhydrographsandfinalbreachmorphologies ,therelative
errorsofthekeydambreachingparametersareallwithin±10%,whichverifytherationalityofthemodel’sapplica
tioninreal - wordcases.Theproposednumericalsimulationmethodcanprovideimportanttechnicalsupportforcasca
dinglandslidedamfailureriskassessmentandemergencytreatment.
Keywords:cascadinglandslidedams;cascadingbreaching;detailednumericalsimulationmethod;amplification
effect ;parametersensitivityanalysis
(责任编辑:耿庆斋)
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