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Stability analysis and monitoring study of Jijia River landslide based on WebGIS

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Stability analysis and monitoring study of Jijia River landslide based on WebGISof,on,On,and,study,Jijia,River,based,Study

    Stability analysis and monitoring study of

    Jijia River landslide based on WebGIS JoURNAL0FCoALSCIENCE&ENGINEERING

    (CHINA)DOIl0.1007s1240401001087

    PP4146VO1.16No.1Mar.2010

    StabilityanalysisandmonitoringstudyofJijiaRixerlandslide

    basedonWebGIS

    LIXiaogen',

    WANGAnming,WANGZong.min'

    (1.SchoolofWaterConservancyandEnvironmentEngineering,ZhengzhouUniversity,Zhengzhou450001,China;

    2.NorthChinaInstituteofWaterConservancyandHydroelectricPower,Zhengzhou450011,China)

    TheEditorialOfficeofJournalofCoalScienceandEngineering(China)andSpringer

    VerlagBerlinHeidelberg2010

    AbstractOnthebasisofInsituinvestigationanddeformationmonitoringoftheJijiaRiver landslide(JJRL),therigidbodyIimitequilibriummethodandfiniteelementmethod(FEM) wereusedtoanalyzethestabilityoftheJJRL:thegreysystemtheorymethodwasapplied toforecastthedeformationtrendoftheJJRL:andthejnformationsystemabouttheIand. slidedeformationandmonitoring,andforecastingsystemsbasedontheplatformofthe WebGeographicallnformationSystem(WebGIS)weredeveloped,whichcanbeusedto analyzeinsitumonitoringdataandpredictthedeformationoftheIandslide.Thestudyre- sultscanbesummarizedasfoIlows:(1)theJJRLisstableasawhole;thewatercontent intheIandslidehasagreateffectonitsstability;(thedevelopedWebGeographicalln. formationSystemhasrealizedmanyfunctions,includinginputting,computing,inquiry, analyzing.andthefunctionoffcIrecasting;ithasalsorealizedthefunctionsofdistance datamanagement,analysis,andforecastingbasedontheWebGIS;(thejnformation

    resourcecanbesharedbytheWebGlSdevelopedalIovertheworld. Keywordslandslide,stability,WebGIS,rigidbodyIimitequilibriummethod,finiteelement

    method(FEM).

    Inrecentyears.withtheinitiationofChina's WesternDevelopmentandtheaccelerationofanex

    presswayconstruction.alOtOfgeologicalhazards weretriggered,ofwhichlandslidewasoneofthemost severehazards(Fig.1).Atpresent,thestudyofinter

    nationallandslidesrangesfromtrendsinhazardas

    sessmenttohazardmanagement(Yineta1.,2000).The GISplatform,togetherwiththehelpofanexpertsys

    temandcombinedquantitativeandqualitativefore

    castingresultsinaneffectivemeansofcarryingout anintegrativeforecastingandriskassessmentofa landslidefYineta1..2000;Xueta1..2004).Some scholarsstudiedtheproblemoneafteranother,suchas: YipingWuandKunlongYin(1997).Da'anLiuand XiaojiaLiu(1997),XinliHuandHuimingTang r2002).ZhenjunWueta1.f2004).AshisK.Sahaeta1. (2005),etc.:theyhavedevelopeddifferentGIS.based landslideforecastinginformationsystems.However, seenfromthepresentstudy,oneobviousdisadvantage thatexistsisthatrealforecastingsystemswitheasy operationandhighpopularityarenotestablished (Zhangeta1.,1998;Zhangeta1.,2005).

    Recently,thisstudyhasmadenewprogressdue toastudybyZhang(2005)andYin(2005).Combin- ingrealtimerainfa11information.theytooktheintemet asatopicandestablishedaforecastingsystemforre

    Received:lDecember2008

SupportedbytheInnovativeProminentTalentsProjectFundationforHenanUniversitiesin2

    005;HenanInnovationProjectforUniversiyProminent ResearchTalentsin2005(HAIPURT)f2005KYCX015)ImportantScience&Technol

    ogyFundationofHenanProvince

    Tel:86371-69127361,E-mail:lixiaogen@ncwu.edu.cn 42OHl'I]L/[L,f((,llScience&}n~inccting(Chilla) gionalgeologicalhazardsforthefirsttime.Because thesystemsoftwarewasdevelopedwiththehelpofa network,jthasthecharacteristicofeasieroperation, whichreflectsthetrendofinternet.orientedforecast

    ingsystemsforregionalgeologicalhazards(Yineta1., 2000).

    ??胁.Fig.1SketchmapofJJRL

    ThispaperconsideredtheJijiaRiverIandslide (JJRL)(Huangeta1.,2003)astheobjectofstudy. CombininglandslideforecastingwiththeWebGIS (WebGeographicalInformationSystem)andonthe basisofinsituinvestigationandmonitoring.thede. formationtrendofthe1andslidewasforecastedand analyzedwiththegreysystemtheoryandtheengi- neeringgeologymechanismprinciple.Softwareabout landslidedeformationandmonitoring.andforecasting informationsystemsbasedontheplatfornlof WIND0WSandtheWebGISweredeveloped.realiz

    ingthefunctionsofdatamanagement,realtimeanaly

    sis.andforecastingbasedontheWebinterfaceofthe internet.

    1Engineeiinggeologicalsetting

    TheJJRLliesonthesouthbankoftheJiiiaRiver

betweenK105+75andK106+410oftheLuoy

    angSanmenxiaexpresswayfLSE)inHenanProvince. China.Itconsistsofthreesmalllandslides.ofwhich landslideNo.1isthebiggestpart.Itbelongstoadeep, thick.giantlandslidewithaIengthof230mfrom southtonorth;thewidthfromeasttowestis280m, themaximumthicknessis32m.andthemeanthick. nessis17-20m.Itresemblesahorseshoeshape.with atotalcapacityof10O.0billionmandamainaxial orientationOfNE5..TheLSEpassesthroughthe JJRLwithahighroadcutslope.andtheJJRLthreat. ensthesafetyoftheLSEveryseriously.

    Theloess.withabout7Omthicknessandfiveto sixcalciumsotlandancientsoil.arecontinuouslydis

    tributedonthesouthoftheJijiaRiver.Belowtheloess. thereare8-10mofsandandgravelstrata,andasteep cliff;andthenthereare10-30mofredclayandpeb. bles.whichconstitutesasteepIandslide.Yhecutting depthofthevalleyisabout140m,whilethelocal perpendicularityandmeangradientofthelandformis 35-40..withameanlandslidegradientOf3540..A

    widevalleyexistsbelowthedeepslope.Thesefea

    turesmaketheconditionandsitefavorableforthe JJRL.

    2Monitol'ingoflandslide

    Theforecastingofalandslidehasalwaysbeena dimcultproblem.inwhichmonitoringisanimportant basis(Zhao,2000).Inordertograspthedeformation endoftheJJRL.theResearchGroupbegantomark

thedangerouszoneoftheJJRL(Fig.1,HlH9toob

    serveitsinnerdeformation.HuangZhiquaneta1. (2003)andWangAnmingeta1.(2006)presentedthe projectandproductsindetail.whichjndicatedthatthe JJRLwasstableasawholeandthatthemaximum displacementfromsouthtoeastwascloseto50mm ontheupperpartoftheJJRL.Therockandsot1mass hadlittledeforlTlationintheJJRLmass.anditsdeep parthadnobiggerdeformation.

    3Numericalana1)sisO11stabilit3ofJJRL

    Atpresent.thenumericalanalysismethodof landslidestabilitymainlyincludestwocategories rZhangandTian.2004)oneisthelimitequilibrium method(SARMA)basedonthetheoryofIimitequi

    librium;theotheristhefiniteelementmethodfFEM1. InthisPaDer'thetwomethodswereusedtoanalyze thestabilityofthelandslideundertwoconditions:that therewasnowaterinthelandslideandthattheland. slidewasfullofwater.Fourtypicalsectionsinthe JJRLwerecomputedinthisstudy.Thefollowingtext presentsthesolutionsbytakingsectionKl06+025as anexample.

    3.1LimitequilibriummethodanalysisrSARMA1 Manyimportantfactorsaffectingthestabilityofa landslidecanbetakenintoaccountintheSARMA method.ToimproveaccuracV.theparametersofthe K106+025sectionwereadopted;theheightis230m. thelengthis150m.andthedistancebetweenthesur- faceandthebackpartoftheJJRLisabout16m.From theresultsofchissection.thesafetyfactorisabout

    1.97whenthereisnowaterintheJJRL.whileitis only1.19whentheJJRLisfullofwater.Furthermore. fromtheresultsofthefoursections,thesafetyfactor is1.74-2.14whenthereisnowaterinJJRL.anditis 1.10-1.20whentheJJRLfulofwater.Fromthe

    above.mentioned.theJJRLisstablewhenthereisno waterinthelandslide.andwatercontenthasanim

    portanteffectonthestabilitytheofJJRL_

    l_\?"l.c{a1Smbilit5allal\,lulldli1()Iaitot'ingstudyof.1i, iiaRi\Cl'landslidebased01]WcbGIS43

    3.2Finiteelementanalysisoflandslidestability rFEM)

    ANSYSsoftwarewasadoptedinthisstudy;

    nonlinearanalysis,4nodeelement,andtheDrucker-

    Pragermodelwereused.Gridpointswith13l1ele. mentsand1344nodeswereplottedinthelandslide; thebacksideandbottomboundaryofthesectionwere fixedinthevertica1andhorizontaldirection.1'ab1e1 presentsthephysicalandmechanicalparameters. Table1Physicalandmechanicalparametersundertwo conditionsintheK106+025section(theparametersinthe blankfornowaterinthelandslide)

    ThefinalanalysisontheK106+025sectionand thethreeothersectionsindicatesthatthereismainly smallcompressivestressdownwardalongtheland. slideundertheabovementionedtwoconditions.

    Thereexistslittletensilestressinthebackyardofthe 1andslideandonthesurfaeeofthelandslide. Generallyspeaking,thetensilestressusuallyex

    istsinthebackyardofthelandslide.onthesurfaceof

    the1andslide.ontheupsideofthelandslide.andinthe iointbetweenthefillingandundisturbedsoil,sothese sitesshouldbeconsideredimportant.Ontheother hand,therearebiggerdownwarddisplacementsmore obviousalongthelandslidecomparedtotheothersites (Fig.21:thesevariedfrom5cmto12cm.

    00544680.1634040.2723400-3812750.490211 O0.1O89360.2178720.3268080.435743

    Fig.2VectorgraphofdisplacementofK106+025with water-filiedsectioninthelandslide

    4Gre)systemforecastingoflandslidede

    tormation

    Thegreysystemmethod,startedbyDengJulong (1988a,1988b),isbroadlyappliedtomanyaspectsof dataprocessing.Thistheorycanalsobeusedtofore

    castdeformationinthefieldofengineeringgeology, suchasthedeformationoflandslidesandhostrockin thecavity.Themethodwasusedtoforecastthetrend ofdeformationoftheJJRLinthispaper(Fig_3,.The modelGM(1,1),oneofthegreymodels,isused widely.

    Fig.3GM(1,1)forecastingcurveofaccumulation ofdisplacement

    Supposingtheoriginalobservationdatacomprise theseries.(f)composedofnmeasureddata(i=1,2, 3,,).Then'()canbeobtainedbyamethod

    calledoneorderaddinggenerationoperation(AGO) (DengJulong,1988):

    (.)={(.(1),(.(2),.

    ()={((1),((2),..

'(f)=?'.().k=1

    

    ,'.()l,

    ?

    ,'()l,(1)

    Thecorrespondingdifferentialequationisestab

    lishedasfollows:

    

    dx

    

    (1)

    +axax(1):6,f21——:D,IZ)

    dt

    InEq.(2),aandbareunknownconstantsthatcan bedeterminedbytheleastsquaremethod. SolvingmeEq.(1),"(f)canbeobtainedbythe correspondingmethodpresentedinrelevantpapers. Thepredicteddatacanbederivedfromtheprocessing oftheinvertedAGO(IAGO).

    '.(k+1)=''(k+1)''(),

    thevalue(k+1)isthepredicteddisplacement whenk>n.

    Inordertoverifythevalidityandsuitabilityof theadoptedgreymodel,amethodcalledposterror

    test(DengJulong,1989)isperformed;furtherdetails onthismethodarepresentedinrelevantliterature.For theoriginal.(f)andcorrespondingpredictedval

    ues()(i=1,2,3,,),theresidualerrorisde?

    Olll'llalt1rCoaIScience&Engincc~l1g((,1fina)

    finedas

()='.(k)'.(k)(k=1,2,,n)

    SupposingS1andare,respectively,thevari

    ancesoftheoriginalmeasureddataandtheresidual errorsdefinedasfollows:

    I2.n],

    o2

    1

    L):——

    

    ],

    where,'.and~-arethemeanscorrespondingto(.(f) and(),respectively.

    Theposterrorratioofto1,markedasC,is

    givenby:

    C=IS,,

    andtheprobabilityoferrorisdefinedas: P={『占()l<0.6745Sl}.

    Thecriterionforverifyingtheprecisionofthe predictingmodelisconstrainedbyPandCsimulta

    neously,andthetestgradesofprecisioncanbeclassi

    fledinto4categories(Huangeta1.,2003).Theeffec

    tivemodelwiththehighergradeisthenappliedto predictthetendencyofdeformationoftheJJRL. 5Delopmentoflandslidedeformation.

    monitoring,andfoi'ecastinginfm'mation systemsbased011GlS

    Agreatamountofdatawasobtainedduringthe courseofobservation.Inordertoanalyzeandcleanup theinformationseriously,quickentheutilizationand feedbackofinformationandevaluatethestateofthe

landslideandforecasttheslidingtimeintime.there

    searchgroupdevelopeddeformation,monitoring,and forecastinginformationsystemsbasedontheWebGIS. 5.1DevelopmentofWebGISbaseddeformation.

    monitoring,andforecastinginformationsys- tems

    5.1.1Approachofdevelopment

    Thesystemwasdevelopedbasedontheplatform ofanetwork.whichcanbesharedbyeveryonewithin thenetwork,sothattherearemanymorepeoplewho canusethesystemandinformationresourcecompared tothecommonforecastinginformationsystems.The IIS+SQLServer2000wasdesignedastheapplication environmentofthesystem.andtheASP+XML+ JavaScript+HTMLwasdesignedastheimplementing meansofthesystem.

    5.1.2Structureofsystem

    Thewidelyusedthree.tierstructurewasadopted inthissoftwaresystem:thatistosay,theapplication functionofthesystemwasdividedintothreeparts, includingthepresentationtier,theapplicationtier,and thedatatierfFig.4).Theplanofsolutionwasthatthe threetierswouldbemarkedlydetachedandseparated fromeachotherlogically.Thewholestructurewasthe C/Sstructure.TheoriginaldatatierasDBMShasbeen detached.Accordingly,akeyproblemishowtomake theapplicationtierandthepresentationtierbecome unattachedprogramsindividuallyandsimplifythe jnterfacebetweenthetwotiers.

    Presentation

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