Rock mechanics and engineering: prediction and control of landslides and geological disasters helin

and

https://ebookmass.com/product/rock-mechanics-andengineering-prediction-and-control-of-landslides-andgeological-disasters-helin-fu/

Instant digital products (PDF, ePub, MOBI) ready for you

Download now and discover formats that fit your needs...

Reaction Mechanisms in Environmental Engineering. Analysis and Prediction James G. Speight

https://ebookmass.com/product/reaction-mechanisms-in-environmentalengineering-analysis-and-prediction-james-g-speight/

ebookmass.com

Soil Mechanics and Foundation Engineering: Fundamentals and Applications Nagaratnam Sivakugan

https://ebookmass.com/product/soil-mechanics-and-foundationengineering-fundamentals-and-applications-nagaratnam-sivakugan/

ebookmass.com

The Mechanics of Threaded Fasteners and Bolted Joints for Engineering and Design Toshimichi Fukuoka

https://ebookmass.com/product/the-mechanics-of-threaded-fasteners-andbolted-joints-for-engineering-and-design-toshimichi-fukuoka/

ebookmass.com

Clinical

Reasoning Cases in Nursing E Book 7th Edition, (Ebook PDF)

https://ebookmass.com/product/clinical-reasoning-cases-in-nursing-ebook-7th-edition-ebook-pdf/

ebookmass.com

Personality Psychology, Ideology, and Voting Behavior: Beyond the Ballot Ben F. Cotterill

https://ebookmass.com/product/personality-psychology-ideology-andvoting-behavior-beyond-the-ballot-ben-f-cotterill/

ebookmass.com

Clinical Anesthesia Fundamentals: Ebook without Multimedia First Edition, (Ebook PDF)

https://ebookmass.com/product/clinical-anesthesia-fundamentals-ebookwithout-multimedia-first-edition-ebook-pdf/

ebookmass.com

Organic Nanochemistry: From Fundamental Concepts to Experimental Practice Yuming Zhao

https://ebookmass.com/product/organic-nanochemistry-from-fundamentalconcepts-to-experimental-practice-yuming-zhao/

ebookmass.com

A Trail so Lonesome (Wagon Train Matches Book 1) Lacy Williams

https://ebookmass.com/product/a-trail-so-lonesome-wagon-train-matchesbook-1-lacy-williams/

ebookmass.com

CT and MR in Cardiology 1st Edition Suhny Abbara

https://ebookmass.com/product/ct-and-mr-in-cardiology-1st-editionsuhny-abbara/

ebookmass.com

Microbiological Analysis of Foods and Food Processing

Environments Osman Erkmen

https://ebookmass.com/product/microbiological-analysis-of-foods-andfood-processing-environments-osman-erkmen/

ebookmass.com

RockMechanicsandEngineering PredictionandControlofLandslides andGeologicalDisasters

WeiChen JiajunFu

HelinFu

Elsevier

Radarweg29,POBox211,1000AEAmsterdam,Netherlands

TheBoulevard,LangfordLane,Kidlington,OxfordOX51GB,UnitedKingdom

50HampshireStreet,5thFloor,Cambridge,MA02139,UnitedStates

©2021CentralSouthUniversityPress.PublishedbyElsevierLtd.Allrightsreserved.

Nopartofthispublicationmaybereproducedortransmittedinanyformorbyanymeans,electronicor mechanical,includingphotocopying,recording,oranyinformationstorageandretrievalsystem,without permissioninwritingfromthepublisher.Detailsonhowtoseekpermission,furtherinformationaboutthe Publisher’spermissionspoliciesandourarrangementswithorganizationssuchastheCopyrightClearance CenterandtheCopyrightLicensingAgency,canbefoundatourwebsite: www.elsevier.com/permissions.

ThisbookandtheindividualcontributionscontainedinitareprotectedundercopyrightbythePublisher (otherthanasmaybenotedherein).

Notices

Knowledgeandbestpracticeinthisfieldareconstantlychanging.Asnewresearchandexperiencebroadenour understanding,changesinresearchmethods,professionalpractices,ormedicaltreatmentmaybecome necessary.

Practitionersandresearchersmustalwaysrelyontheirownexperienceandknowledgeinevaluatingandusing anyinformation,methods,compounds,orexperimentsdescribedherein.Inusingsuchinformationormethods theyshouldbemindfuloftheirownsafetyandthesafetyofothers,includingpartiesforwhomtheyhavea professionalresponsibility.

Tothefullestextentofthelaw,neitherthePublishernortheauthors,contributors,oreditors,assumeanyliability foranyinjuryand/ordamagetopersonsorpropertyasamatterofproductsliability,negligenceorotherwise,or fromanyuseoroperationofanymethods,products,instructions,orideascontainedinthematerialherein.

LibraryofCongressCataloging-in-PublicationData

AcatalogrecordforthisbookisavailablefromtheLibraryofCongress

BritishLibraryCataloguing-in-PublicationData AcataloguerecordforthisbookisavailablefromtheBritishLibrary

ISBN:978-0-12-822424-3

ForinformationonallElsevierpublications visitourwebsiteat https://www.elsevier.com/books-and-journals

Publisher: MatthewDeans

AcquisitionsEditor: GlynJones

EditorialProjectManager: NaomiRobertson

ProductionProjectManager: VijayarajPurushothaman

CoverDesigner: MarkRogers

TypesetbySPiGlobal,India

Acknowledgments

ThestudiesinthisbookweresupportedbytheNationalNaturalScienceFoundationofChina, andasaprojectoftheRailwayCorporation(theformerMinistryofRailway)inChina,the WesternProjectoftheManagementCenteroftheMinistryofCommunicationsinChina,the DepartmentofCommunicationsofGuizhouProvinceinChina,theDepartmentof CommunicationsofHunanProvinceinChina,theScienceandTechnologyDepartmentof GuizhouProvinceinChina,theCommitteeoftheGuangzhouRailinChina,andtheCentral SouthUniversityinChina.Intheprocessofwritingthisbook,Mr.JiajunFu,Mr.HuiDong, Mr.WeiChen,Mr.ZhongZhou,Mr.NingZhou,Ms.QingyanTian,Ms.FenChen, Ms.CuisongBu,Mr.WeiguoZhang,Mr.JiangfengGuo,Mr.ChunlongNie,Mr.XinTan, Mr.YunsiLiu,Mr.WeizhiHou,Mr.LongChen,Mr.QibingHuang,andotherteammembers havecontributedagreatdealofmodelverificationandotherwork.Theteammembersas mentionedhavemadeothersimilarcontributionstothisbook.Prof.LiangLi,Dr.QiangLuo, Dr.HanuaTan,Mr.WangXueLong,Prof.JianbingLv,Ms.YingweiLiuandotherfriends, includingWuzhuangLuo,providedtheirphotosandsuggestionsforuseinthisbookfor demonstration.MuchappreciationalsogoestotheSchoolofCivilEngineeringCentralSouth University,NationalEngineeringLaboratoryofhigh-speedrailwayconstruction.Theauthor expresseshisheartfeltthankstothem.

Foreword

Undertheactionofvariousgeologicalforcesorabnormalchangesinthegeological environment,geologicaldisastersoftenoccur.Asthemaintypeofgeologicalhazards, collapses,slips,anddebrisflowsarecharacterizedbysuddenoccurrence,widedistribution,and certainconcealment,thesecancausemajordamagetotrafficinfrastructure.Geologicalhazards poseapotentialthreattotheconstructionandoperationofthehigh-speedrailwayinfrastructure andrestrictthesustainableandstabledevelopmentofhigh-speedrailwaytransportation. Althoughscientificandtechnologicalprogresshasbroughtimprovementstothelevelof high-speedrailwaysurvey,design,constructionandoperationsmanagement,technologystill cannotfullyadapttothegeologicalenvironmentofcomplexareasofrailwayconstruction.For example,theSichuan-TibetrailwayandtheYunnan-Tibetrailway,whichwillbebuiltsoon, willhavemoreintensiveenvironmentaltransformations.Inordertoensurethesmooth completionoftheseprojects,itisnecessarytostudytheenvironmentalandphysicallawsof geologicalhazards,themutualfeedbackeffectsbetweenstructuresandthegeological environment,thegradingandpredictionofgeologicalhazards,andthedigitalgeological hazardpredictionsystems.Strengtheningthemonitoringandpredictionofgeologicalhazards inordertoreduceandpreventgeologicalhazardsofhigh-speedrailwaysarekeydirectionsfor railwayconstruction.

Ahigh-speedrailwayhasitsowncharacteristics,suchasacompletemaintenancesystemand longrailwayline;inadditiontoroadbedslopes,bridgefoundationslopes,tunnelentranceand exitslopes,thegeologicalbodyisnotonlysubjectedtostaticloads,butalsotocyclictrain dynamicloads.Thedamageofthegeologicalbodyisnotonlycloselyrelatedtorockandsoil strengthandhydrologybutisalsoaffectedbyfatigueload.Therefore,itiscomplicatedtostudy thephysicallawsofdisaster-causingactivitiesaswellasthemonitoringandpredictionof geologicalhazardsonhigh-speedrailways;itisnecessarytostudytheregularityof disaster-causingactivities,themonitoringandforecastingtechnologyofrock(soil)slope collapse,andlandslideanddebrisflowdisastersinducedbyrainfallandhumanactivitieson high-speedrailways.Intheexperienceofdepartmentsoftherailway,waterconservancy, mining,landandresources,urbanconstruction,etc.,basedonthecharacteristicsofthe high-speedrailwayproject,researchonmonitoringandforecastingtechnologysuitableforthe characteristicsofhigh-speedrailwaygeologicalhazardshasbecomearesearchhotspot.

Thisbookmainlystudiesthemonitoringandforecastingofgeologicalhazardsinthesurveyand designstage,constructionstage,andoperationsstageofhigh-speedrailways,optimizesthe technologyofgeologicalhazardsremediation,ensuresthatthedesignschemeinthesurveyand designstageiseconomicalandreasonableandthatthepreventionandcontrolmeasuresinthe constructionstagearesafeandeffective,andfinallyachievesthegoaloftrafficsafety,which hasfar-reachingsignificanceforrailwayconstructioninChina.

Themaincontentandinnovationsofthisbookareasfollows:

1.Themechanismofrainfall-typelandslideisstudied,andtheinfluenceoftriggeringfactors onthemechanismoflandslidehazardsandmovementlawisrevealedthroughthestudyof residualslopesediment.Thisprovidesareliabletheoreticalbasisforthetime,space,and strengthpredictionoflandslides,andisofgreatsignificanceforguidingengineering practice.

2.Fromlaboratorytestsoflandslides,itisfoundthroughanalysisthattheoccurrenceof collapseofasoilslopeisaffectedbythreefactors:slope,soilquality,andrainfall,and theinteractionrelationshipamongthethreefactorsisrevealed.

3.Throughthestudyofthecollapseprocessofarockslope,therelationshipbetweenenergy rate(frequencyofmajorevents)andcollapseprobabilityisobtained.Energyrateisrelated tothestateofrockmass:whenenergyrateishigh,thefrequencyofmajoreventsishigh, andtheprobabilityofcollapseishigh.Thisbookputsforwardhowtousethecurveof acousticemissioneventsandenergyrateofrockmassstructuralplanewithtimetoguide themonitoringworkofacousticemissioninacollapsesite,andprovidesastrongbasisfor collapseprediction.

4.Theprincipleofslopemonitoringisestablished:theslopeinastablestate(K > 1.25) doesn’tneedtobemonitored;theslopeinarelativelystablestate(1.05 < K < 1.25) shouldbeinspectedonthesurface;theslopeinapotentiallyunstablestate(0.95 < K <1.05) andtheslopeinanunstablestate(K < 0.95)shouldbemonitoredprofessionally.

5.Anautomaticmonitoringsystemwasdeveloped.Thedataacquisitioninstrument automaticallycollectsthedataofthesensorofthemonitoringinstrumentandstoresit inthestorageunitofthedataacquisitioninstrument.Afterthedataacquisitioninstrument isconnectedwiththeDTUtransmissionunit,themonitoringdatainthestorageunitis transmittedtothedataprocessingcenterremotelythroughtheinternetandstoredinthe computerwiththehelpoftheGPRSfunctionoftheGSMcard.Inthecomputer,real-time monitoringisrealized.

6.Researchandformulationofalandslidecollapsepredictionmodelandjudgmentprinciples weredevelopedandcarriedout.Comprehensiveresearchinthisareashouldbecarriedout withfullawarenessofactualgeologicalenvironmentalconditions,maintriggerfactors, deformationandfailuremechanisms,deformationandfailurestages,multimodeland multicriteriapredictions,andcomprehensiveanalysisandselectionofanappropriateand effectivemonitoringandpredictionmodel,notjustasingletheoreticalpredictionmodel.

Themethodsusedtoobtainthecriterionwerethesimilarsimulationtestandengineering analogyanalysis.

7.Basedonthemonitoringdataofactuallandslides,thepredictionaccuracyofvarious modelswastestedandanalyzedandtheiradvantagesanddisadvantagesandapplicable conditionswereanalyzedaswell.Theconstructionschemesofgeologicalhazard monitoringandforecastingsystems,theimplementationrulesofearlywarningsystems, andinformationfeedbackmechanismswerealsostudied.

8.Basedontheirdifferentstages,themonitoringschemesandpreventionmeasuresfor geologicalhazardswerestudiedandformulated.Throughthestudyofthehydraulic mechanismofslate,themechanicalcharacteristicsofcollapseandinstabilityofslateafter excavationwerestudied,layingatechnicalfoundationforthepredictionandcontrolofthe instabilityofslateslopes.

ThisbookwascompletedbyHelinFu,WeiChen,andJiajunFu(BeijingUniversityofPosts andTelecommunications).ItquotesfromresearchresultsofHelinFu,LiangLi,andChangyou Li,anditalsoquotesfromsomeresearchresultsfromacademicdissertationsbydoctoraland postgraduatestudents,includingHuiDong,ZhongZhou,QingyanTian,NingZhou,Jianfeng Guo,WeiguoZhang,CuishongBu,FenChen,andChunlongNie.Mastersstudents,including WeizhiHou,LongChen,andQibingHuang,havecontributedtotheprocessofreorganizingthe literatureandtotheworkofproofreading,drawing,andprinting.

Withtherapiddevelopmentsinhigh-speedrailwayconstruction,thestudyofgeological hazardsisalsochangingwitheachpassingday,asthesehazardsinvolveawiderange,rich content,profoundtechnology,andrapiddevelopment.Inaddition,theauthor’slevelof knowledgeisunavoidablylimited,andthereareinevitablysomeerrorsorinconsistenciesin thisbook.Isincerelyhopethatcolleaguesfromallwalksoflifewillassistinfindingand correctingthem.

Foreword(2)fortheBeltandRoadSeries

Geologicaldisastersoftenoccurundertheactionofvariousgeologicalforcesorabnormal changesinthegeologicalenvironment.Asthemaintypesofgeologicaldisaster,collapses, slips,anddebrisflowsarecharacterizedbysuddenoccurrence,widedistribution,andcertain concealment,andcancausemajordamagetothetransportationinfrastructure.Geological hazardsposeapotentialthreattotheconstructionandoperationofthehigh-speedrailway infrastructureandrestrictthesustainableandstabledevelopmentofhigh-speedrailway transportation.Themonitoringandforecastingofhigh-speedrailwaygeologicaldisastersand themitigationandpreventionofsuchgeologicaldisastersisoneofthekeyconcernsofrailway construction.

Ahigh-speedrailwayhasitsowncharacteristics,suchasacompletemaintenancesystemand longrailwaylines;inadditiontoroadbedslopes,bridgefoundationslopes,andtunnelentrance andexitslopes,thegeologicalbodyisnotonlyaffectedbystaticloads,butalsobydynamic loadsofthereciprocatingtrain.Thedestructionofthegeologicalbodyiscloselyrelatedtothe strengthandhydrologyoftherockmassandisalsoaffectedbythefatigueload.Therefore, researchonthelawsofdisasteroccurrenceandmonitoringandforecastingofhigh-speed railwaygeologicaldisastersisquitecomplicated.Itisnecessarytoinvestigatethephysicallaws affectingdisasterscausedbycollapse,landslides,andmudslidescausedbyrainfallandhuman activitiesonhigh-speedrailwayrock(soil)slopes.Basedontheexperienceofthedepartments ofrailways,waterconservancy,mining,landandresources,urbanconstruction,etc.,according tothecharacteristicsofhigh-speedrailwayprojects,monitoringandforecastingtechnology suitableforthecharacteristicsofhigh-speedrailwaygeologicalhazardshasbecomearesearch hotspot.

Thisbookmainlystudiesthemonitoringandforecastingofgeologicaldisastersinthe high-speedrailwaysurveyanddesignstage,constructionstage,andoperationsstage;optimizes thegeologicaldisasterremediationtechnology;ensuresthatthedesignplaninthesurveyand designstageiseconomicalandreasonableandthatthepreventionandcontrolmeasuresinthe constructionstagearesafeandeffective;andfinallyachievesthepurposeoftrafficsafety, whichhasfar-reachingsignificanceforrailwayconstructioninChina.

ThisbookwascompletedbyHelinFu,WeiChen,andJiajunFu(BeijingUniversityofPosts andTelecommunications).ItquotesfromresearchresultsofHelinFu,LiangLi,andChangyou

Li,anditalsoquotesfromsomeresearchresultsfromacademicdissertationsbydoctoraland postgraduatestudents,includingHuiDong,ZhongZhou,QingyanTian,NingZhou,Jianfeng Guo,WeiguoZhang,CuishongBu,FenChen,andChunlongNie.Mastersstudents,including WeizhiHou,LongChen,andQibingHuang,havecontributedtotheprocessofreorganizingthe literatureandtotheworkofproofreading,drawing,andprinting.

Withtherapiddevelopmentsinhigh-speedrailwayconstruction,thestudyofgeological hazardsisalsochangingwitheachpassingday.Geologicalhazardsinvolveawiderange,rich content,profoundtechnology,andrapiddevelopment.Inaddition,theauthor’slevelislimited. Thereareinevitablysomeerrorsandinconsistenciesinthisbook.Isincerelyhopethat colleaguesfromallwalksoflifewillassistinfindingandcorrectingthem.

Overviewofresearch

Geologicaldisastersareacommonenemyofallmankind;theycauseseriouseconomiclosses andarecloselywatchedbygovernments.Establishingageologicaldisasterforecastingand earlywarningsystemisthecommonresponsibilityofgovernmentdepartments,scienceand technologyworkers,andthebroadmassesofthepopulation.Theestablishmentofsucha systemisofgreatpracticalsignificanceforappropriatedecision-makingandmitigationof losses.Chinaisoneofthecountrieshavingsomeofthemostseriousgeologicaldisasters,with annuallosseshavingreachedover100billionyuan.Thecurrentdomesticandinternational researchstatusofgeologicalhazardwarningsystemsissummarizedintheremainderofthis chapter.

(1)Statusofforeignresearch

① UnitedStates

TheUSNOAAWeatherRadioAllHazardsandtheFederalCommunicationsCommission (FCC)hostanemergencywarningsystemthatincludesaradionetworkforbroadcasting“all disasterwarninginformation.”Thissourcecanbeusedtoaccesscomprehensiveweatherand emergencywarninginformation.Throughcontactswiththefederalgovernment,state,local emergencymanagers,andotherpublicserviceofficials,theseweatherstationscanbroadcast almostalltypesofdisasterwarningsalongwithpostprocessinginformation,includingnatural disasters(earthquakes,avalanches),environmentaldisasters(chemicalspills,oilspills, emergencysituationsatnuclearpowerplants),publicsafetyinformation(emergency broadcastsofmissingpersonsintheUnitedStates,911telephoneoutageinformation),national emergency(terroristattacks)information,etc.

TheUSFCC’sEmergencyAlertSystemwasestablishedinNovember1994.Thesystemis connectedtothousandsofradioandtelevisionstations,cableoperators,andsatellitecompanies intheUnitedStatestotransmitearlywarningmessagestothepublicinemergencysituations acrossthecountry.TheUnitedStatesgovernmentandtheradioandtelevisionsystemsusean emergencyalarmtesteveryweektoensurethesystemisoperatingnormally.Thesystemis usedonceamonthinstatesandareasbelowthestate,andtheinformationisreleasedaccording tothelocalactualsituation. RockMechanicsandEngineering. https://doi.org/10.1016/B978-0-12-822424-3.00001-3 # 2021CentralSouthUniversityPress.PublishedbyElsevierLtd.Allrightsreserved.

Inaddition,manystatesintheUnitedStatesalsouseairraidsirenstoissuealertsfortornadoes andmajorfloods.Peoplelivingnearcertainnuclearfacilitieshavespecialradiosathomethat areusedtoreceivebroadcastwarningsignalsinemergencysituations,suchasradiationleaks.

② Canada

AsofJanuary2007,Canadastilldoesnothaveanationalemergencyalertsystem.But Pelmorex,aprivatecompanywithtwomajorweathernetworksinCanada,hasproposeda relatednationalearlywarningsystem,calledACA(AllChannelAlert),similartoEASinthe UnitedStates.

Canada’sweatherchannelTWN(TheWeatherNetwork)isthenation’sonlyprofessional channelforweatherservices.Itnotonlyprovides24-hourweatherinformationtoviewers,but alsotomorethanhalfofTVstationsinCanada,morethan70%ofnewspapers,andmost websites.About1in6CanadiansobtaintheirweatherschedulesfromTWNregularly.When therelevantgovernmentdepartmentsissuenaturaldisasterwarnings,TWN’sACAcan promptlydisplaysubtitlesorsignsinallTVchannelsintherelevantregions,andalsosuggest thatuserswatchthemintimetounderstandthedetailsofthealertandhowtorespond.

Alberta,CanadahaditsownearlywarningsystemcalledtheEmergencyPublicEarlyWarning System(EPWS).In2011itwasreplacedbyAlbertaEmergencyAlerttorespondtochangesin technology.

③ Japan

JapanislocatedintheNorthwestPacificOcean,atopaspotwherefourmajortectonicplates grindtogetherandinanareasubjecttotyphoons.Asaresult,earthquakes,tsunami,typhoons andothernaturaldisastersoccurfrequently.Inviewofitsgeographicalenvironment,Japan attachesgreatimportancetodisasterpreventionwork.Therefore,itsearlywarningsystemalso focusesonmitigatingnaturaldisasterssuchasearthquakesandtyphoons.Intermsofearly warningrelease,theEarthquakeEarlyWarningSystem(EEW)builtbyJMA(Japan MeteorologicalAgency)waslaunchedinOctober2007andpromotedthroughoutJapan.The EEWcanissueitsearlywarningsmainlyduetodenselydistributedseismicstationsinJapan (aboutoneevery20km)andtotheabilityofcomputerstoquicklycalculatethelocationof earthquakesandthedirectionofseismicwaves.Whenanearthquakeoccurs,seismicwaves withdifferentdestructiveforcesaregeneratedintime.Generally,seismicwaveswithless destructivepowerbutfasterspeed(Pwaves)actfirst,followedbyseismicwaveswithlarger destructivepowerbutslowerspeed(referredtoasSwaves).Thereareonlyafewsecondsto tensofsecondsoftimedifferencebetweenthetwoseismicwaves.Japaneseresearchershave usedthistimedifferencetoquicklyissueanearlywarningafterusingtheinstrumenttodetect Pwaves.BeforethearrivaloftheSwave,peopleareallowedvaluableescapetime,fromafew secondstotensofseconds.Moreover,byusingthewarningtimeofseveralseconds,the

operationofgas,electricity,water,nuclearpowerplants,chemicalplants,etc.canbesuspended byautomaticdevicestoavoidsecondarydisasters.

④ Othercountries

Thereal-timeseismicinformationservicesysteminEuropeisaEuropean-widereal-time earthquakeearlywarningsystemestablishedbytheEarthObservationandResearch OrganizationoftheMediterraneanregionofEurope.Thesystemcollectionisbasedon informationfeedback.Thedatasupplypointsareautomaticallytransmittedwithinashorttime aftertheearthquake.Theinformationispassedthroughadecision-makinglayertodetermine whethertobroadcastthereportedseismicinformation.Ifabroadcastisrequired,theprocessed resultswillincorporatesomeperipheralauxiliaryinformation.Themeansofdistributionis mainlythroughanetwork.

TheearthquakeearlywarningsysteminMexicoissimilartotheearthquakeearlywarning systeminJapan.ThewarningsystemusesthearrivaltimedifferenceofthePwaveandthe Swaveandissuesanearthquakewarningtothepublictoreducelossoflifeandproperty.Its uniquefeatureisthatifanearthquakewithamagnitudegreaterthan5occurs,theradio communicationsystemsendsasignaltothecontrolcenter.Whenthecontrolcenterreceives thissignalsentbytheearlywarningstation,theradioalarmsystemissuesasiren.Thesound warningistransmittedtotheMexicancitizensthroughthegeneralAM/FMradiostationandthe alarmreceiverisinstalledinapublicplace.

InOctober2001,Germanybegantooperateanewtypeofearlywarningsystem.Through satellites,officialwarningnoticescouldbetransmittedthroughradioandtelevisionstationsin justafewseconds.

SouthKoreahasestablishedamobilephone-basedearlywarningsystem.Duetothedense coverageofmobilephonebasestations,theKoreaFirePreventionandDisasterPrevention Officecanimplementthepracticeofusingmobilephonetextandvoicemessagestoissue disasterwarningstoresidentsindisaster-proneareas.Inordertoreducelossestoresidentsdue totheinabilitytoreceivedisasterinformationinareaswherecellphonesignalshavelow coverage,anautomaticalarmfacilitywasadded.Thisfacilitycanautomaticallymeasure rainfall.Onceadangerouswaterlevelisexceeded,thetweeterwilladviselocalresidentsto movetoasafezoneassoonaspossible.

(2)ResearchstatusinChina

① Monitoringandearlywarningstatusofgeologicaldisasters

WithChina’seconomicprogressandthegreateruseofscienceandtechnology,thefieldof naturaldisasterpredictionandearlywarninghasachievedbeneficialresults.Forexample,the predictionofthe7.3-magnitudeearthquakeinHaicheng,LiaoningprovinceonFebruary4, 1975wasthefirstsuccessfulearthquakepredictionintheworld,andhadanobviousdisaster

reductioneffect.ThesuccessfulpredictionoftheXintanlandslidein1985wasalsoamodelof disasterforecasting,whichsavedhundredsoflives.

ShandongMeteorologicalBureauhasdevelopedanoceanalarmsystemandsetupanalarm launchsysteminShidao,Weihai.ThetransmissiondistanceoftheShidaomarine meteorologicalwarningsystemhasreached1000km,andthenumberofusershasreached morethan500,initiallysolvingtheproblemoflong-distancedisseminationofmarineearly warninginformationandplayinganimportantroleinreducingmarinedisasterlosses.

Takingtheearthquakeandgeologicaldisasterforecastandearlywarningsystemasan example,Chinahasestablishedamultilevelforecastandearlywarningnetworkatthelevels ofstate,province,city,andcounty,basedonearthquakemonitoringstations,andhasformed aregularconsultationsystemformajoreart hquakeinformation.First,themonitoringdata fromeachseismicnetworkareregularlysenttothesuperiornetworkofthestate seismologicalbureau.Second,thestateseis mologicalbureauorganizesregularmeetings withearthquakeexpertstoidentifykeyareaswhereearthquakesarelikelytooccur.Finally, thekeyareasstrengthentheirmonitoring,increasetheirirregularconsultation,andfeedback informationtothehigherwarningnetwork.AccordingtoArticle16ofthelawofthePeople’s RepublicofChinaonpreventingandmitig atingearthquakes,thefinalearthquake informationforecastshallbeissueduniformlybythestate – thatistosay,theadministrative departmentforearthquakeworkintheStateCouncilortheadministrativedepartmentfor earthquakeworkinthelocalgovernmentatorabovethecountylevelshalldealwithitin accordancewiththeprovisionssetforth.

Geologicaldisastersmainlyincludelandslides,debrisflow,androckfalls.Duetothelarge mountainousareasinChina,geologicaldisastersseriouslythreatenthesafetyofpeopleand property.Forthisreason,thestateorganizedexpertstomeetandstudytheissues,andlaunched ageologicaldisasterforecast.SinceJune1,2013,thecentraltelevisionhasreleaseddaily geologicaldisasterinformationintheweatherforecastprogram.Preliminaryresultshavebeen achieved.Bytheendof2013,697geologicaldisasters,nearly30,000casualties,andeconomic lossesexceeding400millionyuanhadbeenavoided.

Since1997,researchinstitutesrepresentedbyChengduUniversityofTechnology [1–7] have activelyadvocatedinthefieldofregionalgeologicalenvironmentevaluationandgeological hazardpredictionforall-roundintroductionofGIStechnology,combiningwiththeMinistryof LandandNaturalResourcesintheprojects“mountainouswatershedgeologicalenvironment evaluationandpredictionofgeologicaldisastersofGISsystem”and“theYangtzeRiverThree Gorgesgeologicaldisastermonitoringtest(demonstration).”Ageologicalhazardsynthesis databasebasedonGISwasconstructedandasetofriskassessmentindexsystemssuitablefor mountainbasinandwaterreservoirbankswasestablished,usingmultivariatestatistics, informationmethods,fuzzycomprehensiveevaluationmathematicalmodels,andneuralnetworks forriskassessmentandprediction.BasedonGIS,“GHGIS”wasdevelopedatthisuniversity.

② Currentsituationofgeologicaldisasterforecasting

Landslidesareatypicalgeologicaldisaster.Theresearchonlandslidepredictionhasahistory goingbackmorethan50years,sincetheempiricalformulaoflandslidepredictionwasput forwardbytheJapanesescholarSaitointhe1960s.Duringthisperiod,manyexpertshave studiedandexplored,andhaveputforwardavarietyoftheoreticalmodelsandmethodsfor landslideprediction.Theseforecastingmodelsandmethodscanbedividedintofourcategories: deterministicforecastingmodel,statisticalforecastingmodel,nonlinearforecastingmodel,and macroforecastingmodel.

Althoughmanylandslidepredictionmodelsandmethodshavebeenputforwardbyexperts,and therearesomesuccessfulexamples(suchastheXintanlandslide,Huangzilandslide,and Jimingsilandslide),thesetheoriesandmethodsaregenerallydeficient.Forthosebasedon creeptheory,itisdifficulttodeterminetheacceleratedcreepstageofthecreepcurve.The statisticalpredictionmodelmostlystaysatthemathematicalprocessingandstatisticalfittingof slopedeformationtimedisplacementcurve,andhasinsufficientunderstandingofsomebasic problemscloselyrelatedtolandslideprediction,suchasanalysisandprocessingofobservation data,selectionofforecasttimeseriesdata,eliminationofinterferenceinformation,and enhancementofusefulinformation.Mostofthenonlinearpredictionmodelsdemonstratetheir feasibilitybythetestpredictionoflandslideoccurrence,whichhassomeadvantagesintheory andhasnotbeentestedinengineeringpractice.Duetothecomplexity,randomness,and uncertaintyoflandslideevolutionprocess,aswellastheapplicabilitylimitationsofthese theoriesandmethods,sometheoreticalmodelsareusuallyonlyapplicabletolandslide predictionofacertaintypeoracertainstage.Atpresent,thereisnomaturemodel,whichneeds tobeimprovedinpractice.

Atpresent,scholarsathomeandabroadhaveputforwardmorethan10kindsofprediction criteriaforjudgingthecriticalinstabilitystateofaslope,suchas:stabilitycoefficient,reliable probability,deformationrate,anddisplacementacceleration.Thepredictionofslopeinstability timeusingapredictioncriterionhasitsownadvantagesanddisadvantages.Thesafetyfactor andthereliableprobabilitycriterioncanonlyjudgewhethertheslopeisstableornot.The criterionofdeformationrateisintuitive,butitisdifficulttodeterminethecriticaldeformation rateofaslope.Themacroinformationforecastcriterionismoreaccurate,butithasstrong personality.Somestudiessuggestthatsomelandslideshavebeensuccessfullypredicted accordingtothephenomenonofthe“warpingtail”ofthedisplacementtimerelationcurveor theoccurrenceofanabrupttransitionsectionandasharpincreaseofdeformationrate.The XujiahelandslideintheBaochengrailwaylinewaspredictedsuccessfullybyusingthe macroscopicinformationforecastcriterion.However,foralllandslides,therearenoreasonable andclearphysicalcriteria,andalmostalloftheproposedcriteriaareimperfect.These predictioncriteriahavesomeapplicability,buttheyaregenerallynotsufficientanduniversal, sosomecasesofmiscalculationandfalsealarmoccur.Theincompletenessofthelandslide predictioncriterionmainlyliesinthedifferentdeformationmechanismsofsloperockmass,

andthereisnounifiedmovementbehaviorbeforeslidingofdifferentslopebodies,norcanitbe characterizedbyaunifiedcurve.Itisdifficulttogiveanobjectivestandardtoforecast quantitativeindexorthresholdvalue,andsubjectivefactorsareinevitablyinvolved.Therefore forecastinglandslidesonlybyalandslidepredictioncriterionisnotcomprehensiveenough.

Landslidestriggeredbyartificialrainfallhavebeenthesubjectofresearch:inordertostudythe mechanismandprocessofrainfall-inducedlandslides,researchershavecarriedoutsomefield slopeartificialrainfallexperiments.Inthe1990s,Limetal.conductedanartificialrainfalltest onaresidualsoilslopeonthecampusofNanyangTechnologicalUniversityinSingapore,and obtaineddetaileddataonthechangeprocessofmatricsuctioninsoil,andcomparedthe influencesofvegetationprotectionandartificialantiseepagecover.

ZhangJiafaconductedrainfallinfiltrationexperimentsonstronglyweatheredgraniteslopes.

Sincethe21stcentury,professorBaoChenggangoftheYangtzeRiverAcademyofSciences,in cooperationwithDr.WuHongweioftheHongKongUniversityofScienceandTechnology, hascarriedoutlong-termmonitoringonthechangeprocessofthecharacteristicsbeforeand afterartificialrainfallonanexpansiveearthcanalslopeinZaoyang,Hubeiprovince.

ChenShanxiongetal.fromWuhanInstituteofRockandSoil,ChineseAcademyofSciences, carriedoutrainfall-inducedlandslidetestsinthetestsectionofXiangjingexpresswayinHubei province.

HuMingjianetal.conductedfieldrainfallexperimentsongravellysoilslopeswhilestudyingthe debrisflowformationmechanismoftheJiangjiagoulandslideinDongchuan,Yunnan,andfound thattherewasobvioussymbiosisbetweenlandslideanddebrisflowundertestconditions.

Someuniversitiesandscientificresearchinstitutionshavereportedontheliteratureofartificial rainfallexperiments,butthemainpurposeoftheresearchisnotthemechanismandprocessof rainfall-inducedlandslides.

Uptonow,therehavebeenfewreportsintheliteratureonmechanicalexcavationexperiments athomeandabroad,whichreflectsthegreatdifficultyofthiskindofexperiment.In1993, HuangRunqiuetal.fromChengduUniversityofTechnologyconductedsometheoretical discussionsonmechanicalexcavationexperiments.

Beforethe1970s,thestudyofgeologicaldisastersinChinawasmainlylimitedtotheanalysis ofdistributionlaw,formationmechanism,andtrendpredictionofdisasters,whichbasically belongedtothecategoryofhydrogeologicalengineeringgeology.Sincethe1970s,geological disastershaveinvolvedlandandresources,waterconservancyandhydropower,mines, railways,urbanconstruction,andotherfields.Inordertoreduceeconomiclossescausedby geologicaldisasters,variousdepartmentsinChinahavecarriedoutextensiveresearchandhave achievedaseriesofresearchgoalsinthebasictheoryofgeologicaldisasters,survey technology,evaluationtechnology,monitoringandforecastingtechnology,andpreventionand remediationtechnologyofgeologicaldisastersandotheraspects.

FuHelinandZhouZhongcarriedoutlarge-scalemechanicalexcavationandlarge-scale experimentsofinducedslipcausedbyartificialrainfallintheconstructionoftheproject, revealingthelandslidemechanismofslopeaccumulationandproposingcorrespondingcontrol measures,whichpointedouttheresearchdirectionfordisasterpreventionandreduction.

Inviewofthecharacteristicsoflonghigh-speedrailwaylines,thegeologicalbodyisaffected notonlybystaticload,butalsobycyclicdynamicloadsoftrainsandsuddenearthquakeload.In addition,thedestructionofageologicalbodyisnotonlycloselyrelatedtothestrengthofthe rockandsoilmassandhydrology,butalsotofatigueload.Thereforetheresearchonmonitoring andforecastingofgeologicaldisastersinhigh-speedrailwaysismorecomplicated.Atpresent, thenaturaldisasterforecastsystemisstillintheexplorationstageandhasnotfullygraspedthe physicallawsofdisasterbreedinganddevelopment.Thatistosay,duetotheuncertaintyof naturaldisastercarriersandthecomplexityofdisasterformation,theresearchonthe mechanismandevolutionlawsofnaturaldisastersneedsfurtherbreakthroughs.

Withthefundingofthewesterntransportationproject,FuHelinhascarriedoutalargenumber ofresearchstudies,consideringgeologicaldisastertypes,size,differentaffectingfactors, monitoringandpredictioncriterion,models,andtheregularityofrockfallsandlandslides inducedbyrainfallandhumanactivities,andhasaimedatkeyscientificandtechnological problemsinmonitoring,forecasting,andcontrol,leadingtoaseriesofinnovative achievements.Thetypes,genesismechanism,basiccharacteristics,distribution,andevolution ofgeologicaldisastersalongtherailwaywerecomprehensivelyanalyzed.Thereliability analysistheoryofmulticomponentmultistatesystemswasintroducedandthereliability calculationmodelofmultistatesystemsforhighwaygeologicalhazardassessmentwas established.Accordingtothebasictheoryandmethodofgeologicalhazardzoningand segmentation,thecorrespondingcomputersoftwarewascompiledandtwonationalsoftware copyrightswereobtained.Fieldartificialrain-inducedlandslidetests,excavation-induced landslidetests,rockacousticemissioncharacteristictests,laboratoryrockfalltests,slate hydraulictests,andTDRlaboratorytestswerecarriedouttorevealthecollapsingandsoftening propertiesofslateaswellastherockfallandlandslidemechanismsofslate.

Basedonthecharacteristicsofrailwaygeologicalhazards,automaticlandslidemonitoring, remotetransmission,andgeologicalhazardpredictionandcontrolsystemsweredeveloped.In otherwords,aregionalrailwaygeologicalhazarddatageodatabase,geographicdatamodel, regionalizationdatamodel,andgeologicalhazardprojectdatamodelwereconstructed,andthe RegionalRailwayGeologicalHazardcenterdatabasebasedonthegeodatabasewasgradually created,accordingtotheconceptualmodel,logicalmodel,andphysicalmodel.AGIS geologicaldisasterpredictionandcontrolsystembasedonmultisourceinformationacquisition, updateandoutputplatformwasconstructed,andaWebGIS-basedrailwaygeologicaldisaster monitoring,analysis,evaluation,forecastandcontrolmanagementsystemwasformed.The landslideandrockfallmonitoringandpredictiontechnologyandcontrolmethodwereput

forward,andatechnicalguideforrailwayrockfallandlandslidepredictionandcontrolwas compiled.Theapplicationoftheresearchhasproducedamajorcomprehensiveeffectofsocial economyandtechnology.Throughprediction,theoccurrenceofgeologicaldisasterson railwayshasbeengreatlyreduced,andtheunblockedanddrivingsafetyofrailwaysinareas withfrequentgeologicaldisastershasbeenguaranteed.Incomplexgeologicaldisasterareas, theGISgeologicaldisasterpredictionandcontrolsystemwasadoptedwithfunctionsof automaticmonitoring,remotetransmission,multisourceinformationcollection,updateand outputplatform,whichhasimprovedtheworkingenvironmentandsafetyandgreatlyreduced themonitoringlaborintensity.TheresearchresultshavebeenappliedinHunan,Guizhou, Sichuan,andGuangdongprovinces,generatinghugesocioeconomicandenvironmental benefits.

Atpresent,thepreventionandcontrolofgeologicaldisastersaremainlybasedonprediction. Whennecessary,activemeasuresaretakentoreinforceandcooperatewithmonitoringmeans torealizeearlywarningofgeologicaldisasters.Themainmonitoringinformationincludes surfacedisplacement,deepdisplacement,atmosphericrainfall,porewaterpressure,and acousticemissionofstressgaugesinrockmassessubjectedtosupportstructures.

Thedevelopmentdirectionofthepreventionandcontrolofgeologicaldisastersistochangethe passiveintotheactive:thatis,torealizethemonitoringandearlywarningofgeological disasters,andthentodealwiththem,soastohaveadefinitetargetofsavingmanpower, materialresourcesandfinancialresources,andeliminatingthepotentialsafetyrisksof geologicaldisasterstohigh-speedrailways.Atthesametime,man-machineexchangescan realizetheinstrumentingofmonitoringandscientificdecision-making.Onthisbasis,itisof far-reachingsignificanceforChina’srailwaysandrailwayconstructiontooptimizegeological disastermanagementtechnologytoensurethesafeconstructionandsafeoperationofhighspeedrailways.

References

[1] ShenF,HuangRQ.GIStechnologyforregionalgeologicalenvironmentassessmentanddisasterprediction. JMountRes1999;04:3–5.

[2] ShenF,HuangRQ.Geographicinformationsystemandgeologicalenvironmentassessment.GeolHazards EnvironProtect2000;01:6–10.

[3] XuQ,HuangRQ.Predictionandpredictionofthetimeandspaceofgeologicaldisasters.JMountRes 2000;S1:112–7.

[4] XiangXQ,HuangRQ.Geologicalhazardriskassessmentandriskmanagement.GeolHazardsEnvironProtect 2000;01:38–41.

[5] RuanSY,HuangRQ.ApplicationofGIS-basedinformationmethodmodelingeologicaldisasterriskzoning. JChengduUnivTechnol2001;01:89–92.

[6] XiangXQ,HuangRQ.Preliminarystudyonecologicalgeologicalenvironmentriskassessmentand management,In:EngineeringgeologyprofessionalcommitteeofthegeologicalsocietyofChina.Proceedings ofthe2002forumonmajorengineeringgeologicalissuesinNorthwestChina.Engineeringgeologyprofessional

committeeofthegeologicalsocietyofChina:EditorialOfficeofJournalofEngineeringGeology;2002. p.195–8.

[7] WangWJ,XiangXQ.Evaluationofthesusceptibilityofregionalcollapseandlandslides:takingGongxian County,SichuanProvinceasanexample.ChineseJGeolHazardControl2003;(02)33–36+40.

Furtherreading

LimTT,RahardjoH,ChangMF,etal.Effectofrainfallonmatricsuctioninaresidualsoilslope.CanGeotechJ 1996;33(2):618–28.

ZhangJF,XuCM.ResearchonseepageparametersofgranitefullyweatheredzoneintheThreeGorgesdamsite. ChinJRockMechEng2001;05:705–9.

BaoCG.StabilityproblemsandcountermeasuresofexpansivesoilcanalslopeinthemiddlerouteofSouth-to-North WaterTransferProject.YangtzeRiver2003;(05)4–6+53.

ChenSX,XuXC.Characteristicsandstabilityanalysisofrainfall-typeaccumulationlayerlandslide.RockSoil Mech2005;26(S2):6–10.

HuMJ,WangR.ExperimentalstudyonsymbiosisrelationshipoflandslideanddebrisflowinJiangjiagou watershed.ChinJRockMechEng2003;05:824–8.

FuHL,LiCY.In-situtestsonlandslidetriggeringfactorsandtheireffects.JCentralSouthUniv(NatSciEd) 2009;40(03):781–5.

ZhouZ,FuHL.Experimentalstudyonin-situmonitoringofartificialrainfall-inducedslippageofaccumulation layerslopes.ChinaRailwaySci2006;04:11–6.

Similarsimulationtestsoflandslides

2.1Purposeandsignificance

Landslideandrockfallpredictionisanextremelycomplicatedprocess.Itisimportantto achieveaccurateforecasting,alongwithaccuracyandrepresentativenessofthemonitoring data,forecastingmodel,andtheory,aswellastheinternalmechanismsandphysicallawsofthe disasters.Tothisgoal,ourresearchteamcarriedouton-sitesimulationtestsofartificialrainfall andmechanicalexcavation-inducedslippageontheQinglonglandslidebodynearthe Shanghai-Kunminghigh-speedrailwayinGuizhouProvince,andsystematicallyinvestigated themechanismsandphysicallawsofrepresentativeresidualslopelandslidesinthewestern region.Theresultsaresummarizedasfollows:

(1)Thecriterionwasdirectlyappliedtotheforecastingpracticeofthelandslide,ensuringthe rationalityofthelandslidedesignandconstructionsafety.

(2)Thecriterioncanbeusedasareferenceforothersimilarlandslides.

(3)Thistestprovesthatitisfeasibleandnecessarytoobtainthelandslidecriterionthrough similarsimulationtestsinthelandslidemonitoringandforecasting,providing demonstrationsforengineeringpracticeandapplication.

(4)Themechanismsoflandslidesduringrainfallandexcavationconditionswerestudied.

(5)Afocuswasplacedonobtainingthespatialshapeoftheslidingsurfacebymonitoring,so thattheshearstrengthindexoftheslidingsurfacecouldbeaccuratelycalculatedand directlyappliedtothelandslidedesign(Fig.2.1).

2.2Simulatedtestsite

2.2.1Projectprofile

ThetestareawastheZhengning_ShengguansectionoftheShanghai-Kunminghigh-speed railwaypassingthroughGuizhouProvince,whichis544kmlong.Inthissection,construction wasstartedin2012onatotallengthof198kmoftherailwaylinewithaverageelevationat 900–1200m.

2.2.2Geologicalsurvey

Thesitesoftheartificialrainfalltestsandmechanicalexcavationtestswerelocatedinthe YK85+650 +690sectionofthe18thcontractsectionneartheShanghai-Kunminghigh-speed railwayinGuizhouProvince(Qinglonglandslide),whichwereabout10mapart(see Fig.2.2). Tomeettheneedsoftheresearch,adetailedengineeringgeologicalsurvey(see Table2.1 for physicalandmechanicalproperties)andastudyofthepermeabilitywerecarriedout.Onthis basis,relevantexperimentalresearchworkwasalsoconducted.

Thetestareawastheareathroughwhichthehigh-speedrailwaysubgradewouldpass.The overlyingstratumwasmainlyaQuaternaryresidualslope(Qdl+el).Thegravelsoillayerwitha thicknessof10–30mandanaveragedepthof20mwaspartiallysubclay,andthestructurewas looseandslightlywet.ThebedrockwasanUpperPermianLongtanFormation(P2l)coalseam

Fig.2.1 Thetestarea.

Fig.2.2 Fieldtestlayout(units:m).

Table2.1:Basicphysicalandmechanicalproperties.

Geologicalprofileofthetestarea. ①—Originalgroundline; ②—Groundlineafterbrushingslope(test area); ③—Strongweatheringzonelowerlimit;Qdl+el—Quaternaryresidualslope;P2l—UpperPermian LongtanFormationcoalseamstratum.

stratum.Itconsistedofargillaceoussiltstone,carbonaceousmudstone,andsiltymudstone.The testareawaslocatedinthemiddleofamountain.Thehydrogeologicalconditionsweresimple, mainlyrelyingonatmosphericprecipitation,whichwasgreatlyaffectedbytheseason.The groundwaterinthetestareawasmainlybedrockfissurewater,anditwasburieddeeply.During thesurvey,nogroundwaterwasfoundintheborehole.Theengineeringgeologicalsectionof thetestareaisshownin Fig.2.3.

Atotalof15samplesweretestedforparticleanalysis.Theaveragegradingcharacteristics were:cosmid(<0.005mm)contentof0.95%,powder(0.05–0.005mm)contentof8.88%,and gravel(>5mm)contentof47.49%.Theunevennesscoefficient Cu was12.31,whichindicated thatthesoilsamplecontainedmoreparticlesizegrades,withalargedifferencebetweenthe coarseandfineparticlediameters.Thecurvaturecoefficient Cc oftheparticlegradationcurve was1.59,andthegradationwasexcellent.Itcouldbeseenthatthesoilmaterialhashighgravel content,lowclaycontent,largepermeabilitycoefficient,andpoorplasticity.Theengineering geologicalsectionofthetestareaisshownin Fig.2.4.

2.3Fieldsimulationtestoflandslidestriggeredbyartificialrainfall

2.3.1Purpose

Thepurposesofthelandslidefieldsimulationtestwere:

(1)Obtaininga Vcr (criteria)valueoftheslopeslidingunderrainfallconditions.

(2)Invertinganalysisforthelandslide c and φ valuesthroughanaccurateslidingsurface.

(3)Findingthestabilitycoefficientoftheslopeunderthejointactionofhydrostaticpressure andhydrodynamicpressure.

Fig.2.3

Similarsimulationtestsoflandslides15

Fig.2.4 Topographicmapoftestarea.

(4)Providingabasisforrelyingonengineeringdesign.

(5)Providingabasisforresearchonmonitoringandforecastingtechnologyofthesubject.

2.3.2Implementationprocessandcontent

Themonitoringcontentincludedslopecrackmonitoring,deepsoildisplacementmonitoring, porewaterpressuremonitoring,rainfallintensity,andsurfacerunoff.Theprocessandthe contentareshownin Fig.2.5.

2.3.3Monitoringmethodsandinstruments

Thissectiondiscussesthemonitoringmethodsand thevariousinstrumentsusedtoimplementthem.

1)Slopecrackmonitoring.

Whenconductingsurfaceinspection,themaincrackwidthofthelandslidebodywasmeasured usingasteeltapemeasure.

2)Deepdisplacementmonitoringofslope.

Thedeepdisplacementoftheslopewasmonitoredusinganinclinometer.Theinclinometer consistedofthreeparts:theinclinometerpipe,theinclinometeritself,andthedigitalreading

Fig.2.5 Implementationprocessandcontent.

instrument.Theinclinometerwasembeddedinthelandslide.Aschematicdiagramofthe inclinometerisshownin Fig.2.6

3)Porewaterpressuremonitoring.

Theporewaterpressurewasmonitoredbyaporewaterpressuregauge(Fig.2.7).Theporewater pressureprobecanbecategorizedintothreetypes:steelstringtype,resistivetype,and pneumatictype.Theprobeconsistedofametalshellandapermeablestone.Theporewater pressuregaugeworkedbyplacingaporouselement(suchasapermeablestone)inthesoil,the waterinthesoilcontinuouslypassedthroughtheporesoftheelement(afterpermeable),andthe soilparticleswereisolatedfromtheoutsideoftheelementtoallowonlywatertoenterthe induction.Theporepressurecouldbemeasuredbymeasuringthewaterpressureinthecontainer ofthemembrane.Themeasuringrangeoftheporewaterpressuregaugecouldbedetermined accordingtothedepthoftheburiedpositionandthevariationrangeoftheporewaterpressure.

ThesoilporewaterpressuresensorwasaKYJ-30vibratingwiretypeporewaterpressure sensorproducedbyJintanCivilEngineeringInstrumentFactory.Themeasuringrangewas 0–200kPa,andaZXY-2vibratingwirefrequencymeasuringinstrumentwasalsoused. Measuringrange:frequency f ¼ 500–5000Hz;frequencymodulusdisplayvalue F ¼ f2 10 3 ; measurementaccuracy: 0.008Hz;resolution: 0.1Hz;sensitivity:acceptssignal 300 μV, duration 500ms.Thecontinuousoscillationmodeofoperationwasused,thepower consumptionwasextremelysmall,andtheusewassimple.

Inthistest,avibratingwireporewaterpressuregaugewasused.Underthemicrovibration,the relationshipbetweenthenaturalfrequencyandthestressofthesteelstringwas:

Fig.2.6 Inclinometer.

Intheformula: L isthelengthofthevibratingportionofthestring,unitscm; σ istheforceto whichthestringissubjected,unitsMPa;and ρ isthemassdensityofstringmaterial.

Whenthepressuregaugewaspressed,thenaturalfrequencyofthesteelstringchanged accordingly,andthesquareofthefrequencywaslinearwiththeforce(f2 P).Eachpressure gaugewasshippedwithreliableforce-frequencycalibrationdata.Basedonthecalibrationdata, thefollowingformulawascompiledbytheleast-squaresmethod:

Intheformula: Pi istheporewaterpressuremeasured i times, i ¼ 1,2,3,…; f0 istheinitial frequency; fi isthemeasuredfrequency; b istheintercept;and k istheporewaterpressuregauge coefficient.

Ifthezerofrequencyofthepressuregaugedrifted,thezerofrequencyafterthedriftshouldbe directlysubstitutedintotheprecedingformulaas f0.

4)Rainfallintensityandsurfacerunoffmonitoring.

Thetotalrainfallinthetestareawasrecordedbytheflowmeteronthemainwatersupply pipeoftheartificialrainfallsimulationdevice,andtherainfallperunittimeperiodwas dividedbythetestareaof100m2 todeterminetherainfallintensityperunittime.Thesurface runoffwascollectedintothesumpbythecollectingchannelbelowthetestarea,andthen

Fig.2.7 Porewaterpressuregauge.