slopes analyses and stabilization

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GL DATAAPN-AAJ-282 1 TCOO-0000-0000.BEI IS u nCHii (USLTi NDAlnSlTs( !. , .;(M)Transportationtechnologysupportfordevelopingcountries.Compendium13: Slopes: analysis andstabilization 4.TERSONALAOlS1 (1W).

.CORPORATEAUHORS(101)National Research Council,TransportationResearchBoard

6.DOCUMENT DATE(110) , N1JM *7.FPAGIS (L20) I. ARCN (170)1980 273p. 625.74.N277b9.REFERENCEORGAiIZATION (130}NAS .10.SUPPLEMENTARY NOTES(500)

11. ABSTRACT (950) .''~ "

1LDESCREPTORS (920) I. PRJECr UMIR(150)Highwayplanning 931111600Engineering Landslides

mechanicsStabilization]Erosion control Soil analysisSoil erosion I4.oDraACFNo4)AID/otr-C-1591 RC (or

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PROJECT STEERING COMMITTEE KERMIT L.BERGSTRALH, BergstralhAssociates, Inc., chairmanG.A. EDMONDS, International Labor Office (ILOliaison) CLELLG.HARRAL, International Bank for Reconstruction and Development (IBRDliaison)WILLIAM G.HARRINGTON, MaricopaCounty HighwayDepartment,Arizona R.G.HICKS, Oregon State UniversityW. RONALD HUDSON,.Universityof Texas at AustinLYNNE H.IRWIN, Cornell UniversityWILLIAM C.LaBAUGH, JR.,-DanielMann,JohnsonandMendenhallMELVIN B.LARSEN, IllinoisDepartmentof TransportationVOYCE J.MACK, U.S.Department of Transportation (DOTliaison)RAY MILLARD, intc-nationalBankfor ReconstructionandDevelopment (PIARCliaison)WILBUR J.MORIN, _yon Associates, Inc.CLARKSON H OGLESBY, Stanford,CaliforniaADR IAN PE LZINER, U.S. ForestService GEORGE W. RING, III, FederalHighwayAdministration (FHWA liaison) EDWARD C.SULLIVAN, Instituteof TransportationStudies,Universityof California,Berkeley PETER H.THORMANN;U.S.Agencyfor International Development (AID liaison) W.G.WILSON, International Road Federation (IRF liaison)ELDON J.YODER, Purdue University JOHN P.ZEDALIS,U.S.Agencyfor InternationalDevelopment (AIDliaison)

PROJECT STAFF AND LIAISON STAFFPAULE.IRICK,AssistantDirectorfor SpecialTechnical Activities,TRBLLOYD R.CROWTHER,ProjectEngineer, TRBH.STANLEY SCHOFER, Manager, Information SystemsDevelopmentand'Operations, TRBOJOHNW.GUINNEE, Engineer of Soils,Geology,andFoundations, TRB (DivisionA liaison)THOMAS L. COPAS,ProjectEngineer, TRB(NCHRP liaison)JANICE BAIN, Librarian, TRBVICTOR RABINOWITCH, Commission on International Relations,NationalResearchCouncil (NRCliaison)MARY SECOY, AdministrativeAssistant,TRBJUDITH L. FAULS,ProjectSecretary, TRBBRENDA CUTRELL (Spanish)SUZANNE D.CROWTHER(French),TRRUKMINISEEVARATNAM Index), TRBNANCY RODINOAcquisitions), TRB

TheTransportation Research Board is anagency oftheNationalResearchCouncil,which servestheNational AcademyofSciencesandthe NationalAcademy ofEngineering. The Board'spurposeis tostimulate researchconcerning thenature andperformanceoftransportation systems, todisseminate information thatthere-searchproduces, andtoencourage theapplicationofappropriateresearch findings. TheBoard's program iscarried outby morethan 150committeesand task forcescomposedofmorethan1800administrators, engineers, social scientists,andeducatorswhoservewithout compensation. Theprogrmm issupported bystatetransportationand highwaydepartments, theU.S. Depart-mentofTransportation,andotherorganizations interested in thedevelopmentoftransportation,The Transportation Research Boardoperates withintheCom-mission on -iclotechnicalSystems of the NationalResearchCouncil. TheCouncil wasorganized in 1916at therequest ofPresidentWoodrowWilw-nasanagencyof theNationalAcademyofSciencestoenable .le broadcommunity ofscientistsandengi-neers toassociate theirefform withthose ofthe Academymem-bership. MembersoftheCouncil areappointed by thepresidentof theAcademyandaredrawn from academic, industili, and

governmental organizationsthroughouttheUnitedStates.TheNationalAcademyof Scienceswas establishedby acongressional actof incorporationsigned byPridntAbrahamLincolnon March 3, 1863,tofurtherscienceand itsuseforthegeneral welfareby bringingtogetherthemost qualified individualstodealwithscientificand technologicalproblemsofbroadsignifIcance. It Isaprivate,honorary organizationof more than 1000scientists electedon the basisofoutstandingcontributionstoknowledgeandissupported by privateandpublicfundt. Undertheterm- ofitscongressionalcharter, theAcademy iscalledupontoactasan official-yetindependent-advisorto thefederalgoveminent in any matterofscienceand technology,although it isnotagovernment agencyand itsactivitiesare not limitedtothoseon behalfof thegovernment.To dhare in thetaskoffurtheringsciencoandengineeringandofadvising the federalgovernment, theNationalAcademyof Engineringwasestablished onDecember5,1964,under theauthorityof theactof incorporationofthe NationalAcademyofSciences. Itsadvisoryactivitiesoerclosely coordinatedwiththoseoftheNationalAcademyofSciences, butit is l'.lpenlentandautonomous in itsorganizationandelectionofnembers.


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TRANSPORTATION TECHNOLOGY SUPPORTFOR DEVELOPING COUNTRIESCOMPENDIUM 13Slopes:Analyses andStabilizationTaludes: Analisisy estabilpzacinonTalus: Analyseset stabilisation

prepared 'under-coniract AID/OTR-C-1591, project931-1116,iU.S. Agency for International Devolopment -'

Transportation Research BoardCommission on SociotechnicalSystemsNational Research'Council

NATIONAL,:ACADEMYO0F SCIENCES WASHINGTON. D.C. 1980


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LibraryofCongressCatloging InPublicationDataNational Resarch Council. TransportationResearchBoard.Slopes: analysesandstabilization- Taludes.(Transportation technologysupportfordevelopingcountries:Compendium; 13)"Prepared undercontractAlD/OTR-C-1591,project931-1116,U.S. Agency for InternatiunalDevelopment."Bibliography: p.Includes index.1. Underdeveloped areas-Slopes (Soil mechanics)-Addresses, essays, lectures. 2. Underdeveloped areas-Landslides-Addresses, essays, lectures. 3. Underdevelopedareas-roll stabili-zation-Addresses, essays,lectures. 4. Underdevelopedareas-Roadsubgrades-Addresses, essays, lectures. I. National ResearchCouncil. Transportation Research Board. II. Title: Taludes.

III. Title: Talus. IV. Series.TA71O.$554 C25.7'3 80-23057ISBN0-309-03064-1

NoticeTheprojecttha Ishe subjectofthisreport wasapproved by theGoverning Board ofthe National ResearchCouncil,whosemembersare drawn from thecouncilsoftheNationalAcademy ofSciences,the National AcademyofEngineering, andtheInstituteofMedicina. The membersofthecommittee responsibleforthereportwere chosenfortheirspecialcompetenceandwith regardforap propriatebalance.ThisreportI beenreviewed bV agroupother thantheauthorsaccording topr,.edures approvedby aReport ReviewCommitteeconsistingofmembersoftheNationalAcademy ofSciences,theNationalAcademy ofEngineering,and theInstitute ofMedicine.

Coverphoto: Slide-proneareas cause maintenanceproblems in Bolivia.

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ContentsTabla de materiasTable des matibresPROJECT DESCRIPTION ..................... ...DESCRIPCION DEL PROYECTODESCRIPTION DU PROJETFOREWORD ANDACKNOWLEDGMENTS ...............,...,*......PREFACIO YAGRADECIMIENTOS AVANT-PROPOS ET REMERCIEMENTS OVERVIEW ................ ..... ..... ...........ISTA GENERAL :, - i , ... , ,......., . , " ' " '

EXPOSESELECTED TEXTS "...... ....TEXTOS SELECCIONADOSTEXTES CHOISIS

1. Landslides:.AnalysisandControl,Chapter2,SlopeMovementTypesandProcesses ....(Deslizamienics: Anclisis y control, Capltulo 2- Tipos y procesos de movimiento detaludes)(Glissementsde terrain: Analyse et contr6le, Chapitre2- Types etd6veloppement demouvements detalus)TransportationResarch Board, 1978 2. SoilMechanics inEngineeringPractice,Article35,Stabilityof Slopes ............ ..(Mecdnicade suelosen la ingenierlapractica,Art.35- Estabilidad detaludos)(M6canique desscisappliqude,Art.35- Stabilitddestalus)JohnWileyandSons, Inc., 1967 3. ChartSolutionsforAnalysisofEarth Slopes ..............................(Solucionesgr~ficas parael andlisisdetaludesde tierra)(Tablesdecalculpour I'analysedetalusen terre)HighwayResearch Board, 1971 4. TransportationEngineering Handbook,SlopeDesign Guide ..... ...... ..(Manualpara ingenierfadetransporte, Gufaparaeldiseriode taludes)(Manuel du genie destransports, Manuel de dimensionnement des talus)U.S. ForestService, 19735. Determining CorrectiveActionforHghwayLandslideProblems .......................(Determinaci6n dela operaci6n correctivaparaproblemas de deslizamientovial)(D6termination des mesures correctives pour rdsoudre les problbmes deglissements deterrain en construction routibre)Highway Research Board, 19556. Handbookon LandslideAnalysisandCorrection ....................................(Manual sobre el andlisisycorrecci6nde deslizamientos)(Manuel d'analyse etcorrection deglissementsde terrain)Central Road Research Institute,New Delhi, 1966

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7. ConstructionofEmbankments ..................................................... 199 (Construcci6ndeterraplenes) (Construction deremblais) Highway Research Board, 1971 8. LocatingGroundWaterforDesignof SubsurfaceDrainageinRoadwaysandEmbankments 219(Localizaci6ndeaguafrecticaparael disethodedrenajesubdlveoencaminosyterraplenes)

(LocalisationdeI'eauphr6atiquepour ledimensionnementd'undispositifdedrainagesouterrain pour routes et remblais)Tennessee HighwayConference, UniversityofTennessee, 1963BIBLIOGRAPHY ......................................................................... 229BIBLIOGRAFIABIBLIOGRAPHIEINDEX ................ ... 237..... ....... ..... ...........INDICEINDEX


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Project DescriptionThedevelopmentofagriculture,thedistributionof food, the provisionof healthservices, and theaccess to information through educationalser-vicesandotherformsofcommunication inruralregions of developing countries a!l heavilyde-pend on transport facilities.Although railandwater facilities mayplayimportant roles incer-tain areas,adominantand universal need isforroadsystems thatprovidean assuredandyetrelativelyinexpensivemeans forthemovementofpeopleandgoods.Thebulkofthisneed is forlow-volume roadsthatgenerallycarryonly5to10 vehiclesadayand thatseldomcarryas manyas400vehiclesaday.

Descripci6ndel proyecto En las regiones rurales deparsesen desarrollo,eldesarrollodela agricultura, la distribuci6ndeviveres, la provisi6n deserviciosde sanidad,yelaccesoainformaci6n pormediodeservicioseducacionalesyotrasformas de comunicaci6n,dependen en granpartede losmedios detrans-porte.Aunqueen ciertas Areas losmediosde fe-rrocarrilyaguadesempehan unpapel impor-tante,existeuna necesidad universalydomi-nantedecrearsistemasvialesqueproveanunmedio aseguradopero relativamente pococos-tosoparaelmovimiento degenteymercanclas.La mayorpartedeestanecesidad se soluciona-ria conla construcci6ndecaminosdebajovo-lImen quegene'almente moverlanOnicamentede5a 10vehfculos pordiayquepocasvecesmoverfan tantocomo400vehfculos pordia.

Descriptiondu projetDans lesregions ruralesdes paysen voleded6veloppement, 'exploitationagricole, la distri-butiondesproduitsalimentaires, I'accbs auxservicesm~dicauxiI'accbsauxmat~riauxetauxmarchandises,A l'informationetauxautresser-vices,dependentengrande partiedesmoyensdetransport. Bien que lestransportsparvoieferrme etparvoienavigablejouentun r6le impor-tantdanscertaines r6gions,un besoindominantetuniversel6xisted'unr6seau routierquipuisse

Theplanning, design,construction, andmaintenanceof low-volume roadsfor rural regions ofdeveloping countriescan be greatlyenhancedwith respecttoeconomics, quality,andperformance by theuseof low-volume roadtechnologythat isavailable inmanyparts oftheworld. Much ofthis technologyhas been producedduring the developmental phasesofwhatarenow themoredeveloped countries,andsome iscontinually produced in both the lessand the more developedcountries. Someofthetechnologyhasbeen documented inpapers, articles,and reports thathavebeenwritten byexperts inthe field.Butmuchof the technologyis

El planeamiento, diseho,construcci6nymantenimientodecaminosdebajovolOmen pararegiones rurales depaisesen desarrollo puedensermejorados, con respectoalcosto,calidad,yrendimiento,porel usodela tecnologfadecaminos debajovolmenqueseencuentra disponibleen muchaspartes delmundo. Muchadeestatecnologfaha sidoproducidadurante lasdpocasdedesarrollode loqueahora son lospalsesmcs desarrollados,yalgunase producecontinuamente enestos palsesasfcomo en lospaisesmenosdesarrollados. Partede latecnologfaseha documentadoendisertaciones,artfculos,e informes quehan sidoescritosporexpertos enelcampo. Pero muchadela tecnologlanoestddocumentadayexisteprincipalmenteen lamemoria deaquellosque handesa

assureraveccertitudeetd'une fagonrelativementbonmarch6, led~placement deshabitants,et letransport desmarchandises. La plusgrandepartiedecebesoinpeut6tresatisfaitepar la constructionde routesAfaiblecapacit6,capablesd'accommoder un traficde5a 10v6hiculesparjour,ou plusrarement,jusqu'A400v6hiculesparjour.L'utilisationdesconnaissancesactuellesentechnologie,qui sontaccLssiblesdansbeau


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vi

undocumentedandexistsmainly in the mindsofthosewhohavedeveloped andappliedthetechnology through necessity. Ineithercase,existing knowledgeabout low-volume roadtechnology iswidely dispersed geographically,isquitevaried inthelanguageand theformof itsexistence,and isnot readiyavailable forappli-cation to theneedsofdeveloping countries,InOctober1977 theTransportation ResearchBoard (TRB) began this 3-yParspecial projectunder thesponsorship of the U.S. Agencyfor In-ternational Development (AID) toenhance ruraltransportation indevelopingcountries byprovid-ing improvedaccesstoexisting informationon

rrolladoyaplicado latecnologlapornecesidad.En cualquiercaso, losconocimientosen exis-tenciasobre la tecnologfadecaminos de bajovolmenestingrandemente esparcidosgeogr6-ficamente,varianbastante con respectoal idio-ma ysu forma,y nose encuentranf~cilmentedisponiblesparasu aplicaci6nalasnecesida-desde lospalsesen desarrollo.En octubrede 1977elTransportation Re-searchBoard (TRB) comenz6esteproyectoes-pecialde tresarnos de duraci6n bajoel patroci-niodela U.S.Agencyfor International Develop-ment(AID) paramejorarel transporteruralenlospafsesen desarrolloacrecentando la dispo-

coupdepays,peutfaciliterI'tudedesprojetsdeconstruction,traceetentretien,de routes&faiblecapacit6 dansles regionsrurales despaysen volededeveloppement,surtouten cequi concerne I'Mconomie, la qualit6,et la perfor-mancedeces routes. Lamajeure partiedecettetechnologiea te produitedurant la phasededeveloppement despaysque l'on appellemain-tenantdeveloppes,etellecontinueA6tre pro-duiteAla foisdanscespaysetdansles paysen..voiededeveloppement.Certains aspectsde ,"cettetech.nologieont6t6documentesdansdesarticlesou rapports 6crits pardesexperts. Maisune grande partiedesconnaissances n'existeque dansI'esprit de ceuxqui onteubesoin ded6velopperetappliquercettetechnologie. Deplus, ,danscesdeuxcas, les6critsetconnais-sancessur la technologiedes routesAfaiblecapacit6,sontdisperses g~ographiquement,sontdcrits dansdes languesdifferentes,etnesontpasassezais6ment accessiblespourOtre

theplanning,design, construction, andmaintenanceof low-volume roads. Withadviceandguidancefromaproject steeringcommittee,TRBdefines,produces,andtransmits informationproducts throughanetworkofcorrespondents indevelopingcountries.Broad goalsfor theultimate impactofthe projectworkareto promoteeffectiveuseofexisting information intheeconomicdevelopmentoftransportation infrastructureandtherebyto enhanceotheraspectsof rural development throughouttheworld.Inaddition to thepackaginganddistributionoftechnicalinformation, personal interactionswithusersare provided through fieldvisits,con

nibilidadde la informaci6nen existenciasobreel planeamiento, diseio,construcci6n,ymantenimiento decaminosdebajovoltlmen.Conelconsejoydirecci6n de uncomitdde iniciativasparael proyecto, elTRB define,produce,ytransmite productos informativos atravesdeunareddecorresponsalesenpafses en desarrollo.Lasmetasgeneralesparael impactofinaldeltrabajodel proyectoson la promoci6n delusoefectivodela informaci6n en existenciaeneldesarrollo econ6micodela infraestructurade transporte ydeestaformamejorar otrosaspectosdel desarrollorural atrav6sdelmundo.

Ademds de la recolecci6nydistribuci6ndela

appliqu6saux besoinsdes paysenvoieded6veloppement ..En octobre 1977, leTransportation ResearchBoard (TRB) initiaceprojet,d'unedur6de3ans,souslepatronage de 'U.S. Agencyfor InternationalDevelopment (AID), pourameliorer le trari-.sportruraldans lespays envoieded6veloppement,en rendantplusaccessiblela documentationexistantesur la conception, le trace,la construction, et I'entretien desroutesAfaiblecapacit6.Avec le conseil,etsous laconduited'un comit6de direction,TRBd6finit,produit, ettransmetcettedocumentationAI'aide d'un r6seauJecorrespondants dans lespaysenvoiededeveloppement.Nousesperonsqueleresultatfinal deceprojetseradefavoriser l'utilisationdecettedocumentation, pouraiderau developpement6conomique del'infrastructuredestransports,etdecettefa(on mettreenvaleurd'autresaspectsd'exploitation ruraleAtravers lemonde.


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ferences inthe UnitedStatesandabroad,andotherformsof communication,ShteringCommitteeThe Steering Committee iscomposedofexpertswhohave knowledgeof thephysicalandsocialcharacteristicsofdevelopingcountries, knowl-edgeof theneedsof developingcountriesfordgetransportation, knowledgeofexistingtransporta-tion technology,andexperience ints use.Majorfunctionsof the SteeringCommittee aretoassist in thedefinition ofusersand theirneeds, thedefinition of information productsthatmatchuserneeds, andthe identificationofin-formatibnalandhuman resources fordevelop-mentoftheinformation-products.Through itsinformaci6n t6cnica,seproveeaccionesrecf-procaspersonales conlos usuariospormediodevisitasdecampo, conferenciasen losEsta-dosUnidosde NorteAmericayenelextranjero,yotras formasdecomunicaci6n.ComIt6 de IniciativasEl comit6de iniciativasse componedeexper-tosquetienenconocimiento de lascaracterfsti-casftsicas ysociales de lospalses en desarro-l, conocimiento de las necesidadesde trans-portede lospaisesendesarrollo,conocimientode la tecnologfadetransporteen existencia,yexperienciaen suuso.Lasfunciones importantes delcomitdde ini-ciativassonlasdeayudaren la definici6nde4usuarios ysusnecesidades,de productosin-formativos queseasemejanalasnecesidadesdelusuario,yla identificaci6nderecursos de

En plusde la dissemination decettedocu-mentation technique,desvisites,desconferen-cesauxEtats Uniset AI'6tranger,etd'autresformesdecommunicationpermettront une inte-ractionconstanteavec lesusagers.Comit6 dedirection

LeNotrequiontAla foisdes connaissancessurlesca-ractdristiquesphysiquesetsocialesdespaysenvoed6veloppeentpoint e vuetransports, sur la technobogie ac-tuelledes transports,etontausside I'exp6-rencequantAI'utilisation pratiquedecette,technologie.Les fonctionsmajeuresdececomitdsontd'abordd'aider Adefinir lesusagersetleurs be-soins,puisdedefinir leurs besoinsen matiere

membership thecommittee provides liaison withproject-related activitiesand providesguidanceforinteractionswith users. Ingeneral theSteeringCommittee givesoverview adviceanddirection forallaspectsof theprojectwork.Theproject staffhasresponsibility forthe preparationand transmittal ofinformationproducts,thedevelopment ofacorrespondence networkhroughout theuser community, and interactionswith users.InformationProductsThree typesof informationproducts areprepared: compendiums ofdocumented informationon relativelynarrow topics,synthesesofknowledgeandpracticeonsomewhat broaderconocimientosyhumanosparael desarrollo delosproductos informativos. A travesdesusmiembros elcomit6provee vfnculosconactividades relacionadascon elproyectoytambi6nunagufa parala interacci6ncon losusuarios.Engeneralelcomit6 de iniciativasproporcionaconsejosy direcci6ngeneral paratodos losaspectosdel trabajodeproyecto.El personalde proyecto es responsablede lapreparaci'n ytransmisi6nde losproductos in- Vi iformativos,el desarrollo deuna red decorresponsalesa traves dela comunidad deusuarios,yla interacci6n con los usuarios.ProductosinformativosSepreparan trestiposdeproductosinformati-,vos: loscompendiosde la informaci6n documentada sobretemas relativamente limitados, lasfntesisdelconocimiento yprlcticasobre temasde documentation, etd'identifier les ressourcesdocumentairesethumainesnecessairespour led6veloppementde cettedocumentation. Par I'interm6diaire des sesmembres, lecomitd pourvoitAla liaison entre lesdiff6rentes fonctions relativesau projet,etdirige l'interaction avec lesusagers. En g~n~ral, le comit6dedirectionconseilleetdirigetoutes les phasesdu projet.personnel est responsablede aprpadisseminationrationet d'unaau de cue ntsd'un rseaudecorrespondantsprisdansla communaut6 d'usagers, etde I'interaction avac lesusagers.

ration et de la edocuments, du

La documentationTroisgenresdedocuments sontprepares:desrecueilsdont lesujetest relativement limitd,des


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subjects,and proceedingsof low-volume roadconferencesthat aretotallyor partiallysup-ported bytheproject. Compendiums atepre-paredbyproject staffat the rate ofabout6peryear;consultantsare employedtopreparesynthesesat the rateof2peryear.At leastoneconference proceedingswill be publisheddur-ingthe3-yearperiod. Insummary, thisprojectaims to produceanddistributebetween 20and30 publicationsthatcover muchofwhatisknown about low-volume road technology,InteractionsWithUsersAnumberof mechanismsareused to providein-teractionsbetween theprojectand theuser

un pocomc.s amplios,y losexpedientes deconferenciasde caminosde bajovoli~menqueestcntotalmente oparcialmenteamparados porel proyecto.El personal de proyectoprepara loscompendiosa raz6ndeunos 6porafio;seutili-zanconsultorespara preparar lassfntesisaraz6n de2porario.Se publicar, porlo menosun expedientedeconferenciaduranteelpe-riodo detresarios. En breve,esteproyectopre-tendeproducirydistribuirentre20y30publica-viii clones quecubren muchode lo queseconocedela tecnologladecaminos de bajovolmen.Interaccibncon los usuarlosSeutilizanvarios mecanismosparaproveerlasinteraccionesentreelproyectoy lacomunidaddeusuarios.Sepublican lasnoticiasdelpro-

synthesesdeconnaissancesetdepratiquesurdessujetsbeaucoupplusg6neraux, etfinale-mentdescomptes-rendus deconferencessurlesroutes Afaiblecapacit6,quiserontorgani-seescompletementou en partieparnotreprojet.Environ 6recueils paran sontprepar6s par no-tre personnel. Deuxsynthesesparansont6cri-tespardesexperts prisAI'exterieur. Lescomptes-rendusd'au moins uneconferencese-ront6critsdansuneperiodede 3ans. En rd-sum6, I'objet de ceprojetestdeproduire etdis-seminer entre20 et30documents quicouvrirontI'essentiel desconnaissancessur latechnologiedes routes&faiblecapacit6.Interactionavec les usagersUncertain nombredemecanismessontutilisdspourassurer l'interactionentre lepersonnel du

community. Project newsis published ineachissueofTransoortatlonResearchNews. Feedbackformsare transmittedwith the informationproductsso that recipients have anopportunityto sayhow the productsarebeneficial and howtheymaybe improved.Through semiannual visits todeveloping countries, theproject staffacquires first-hand suggestions fortheprojectwork andcanassistdirectly inspecifictechnicalproblems.Additional opportunitiesfor interactionwith usersarise through internationaland incountry conferences inwhich thereisprojectparticipation. Finally,annual colloquiumsareheld forstudents from developing countrieswhoareenrolledat U.S.universities.

yectoen cadaedici6nde laTransportationResearchNews. Setransmiten,con losproductosinformativos,formulariosde retroacci6n paraque los recipientes tenganoportunidadde decirc6mo benefician losproductosyc6mopuedensermejorados.Atravesde visitassemianualesalosparsesen desarrollo, el personal delproyectoadquieredirectamentede fuentesoriginalessugerenciasparael trabajodelproyecto ypuedeasistirdirectamente en problemas tecnicosespecfficos.Surgen oportunidadesadicionalesparala interacci6ncon losusuariosa trav6sdeconferencias internacionales y nacionalesendonde participaelproyecto.Finalmente,seorganizan diclogosconestudiantes depalsesendesarrollo queest~n inscriptosen universidades norteamericanas.

projetet la communautdd'usagers.Un bulletind'information estpubli6danschaquenumdro deTransportationResearchNews.Des formulairessontjointsauxdocuments,afinque lesusagersaient l'opportunitddejugerdelavaleurdecesdocumentsetde donner leuravissur lesmoyens de lesameliorer.Au coursdevisitessemi-annuelles dans lespaysenvoiededoveloppementnotrepersonnel obtientdepremieremain dessuggestionssur le bonfonctionnementdu projetet peutaiderAr6soudre surplacecertainsprobImes techniques specifiques.En outre,desconferences tenuessoitauxEtats Unis,soitAI'tranger,sont 'occasiond'un dchanged'id6esentre notrepersonnel et lesusagers.Finalement, descolloquesannuels sontorganis6spourlesLtudiants despaysenvoieded~veloppement qui6tudient dans lesuniversit&samdricaines.


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Foreword and Acknowledgments This bookis the fifteenthproductof the Acknowledgment ismadeto the followingTransportation Research Board's projecton publishers fortheir kindpermission to reprinttheTransportation TechnologySupport forDevelop- selected text portionsof thiscompendium:ing Countriesunder thesponsorshipof the U.S. Central Road Research Institute,NewDelhi;Agency for International Development. Theob- John Wileyand Sons, Inc., New York; U.S.jectiveofthisbookis that itprovideuseful and ForestService,Region 6,Portland, Oregon; andpractical information for those indeveloping University ofTennessee, Engineering Expericountrieswho have direct responsibility for mentStation,Knoxville. slope analysisandstabilization. Feedback fromcorrespondents indevelopingcountrieswill be solicitedand usedto assess thedegree towhich thisobjectivehas beenattained andto influence thenatureof later products.

PrefacioyagradecimentosEste libro esel d6cimoquinto productodelpro- Se reconocea lossiguientes editoresI'orelyectodelTransportation Research Board sobre permiso dado para reimprimir lasporciones deApoyo de TecnologfadeTransporte para Parses textoseleccionadaspara estecompendio:en Desarrollobajoel patrociniode laU.S. Central Road Research Institute,NewDelhi; IxAgencyfor InternationalDevelopment. El obje- John WileyandSons, Inc., New York;U.S.tivodeeste libroeselde proveer informaci6n ForestService,Region 6,Portland,Oregon; ytil yprcticaparaaquellosenparsesendesa- UniversityofTennessee,Engineering Experirrolloquienestienen responsabilidad directa mentStation, Knoxville.parael andlisisy laestabilizacfonde suelos. Se pedirda loscorresponsales en lospafsesen desarrollo informaci6n sobre los resultados,parautilizarseen el asesoramiento del gradoal cual seha obtenidoeseobjectivoyparainfluenciar lanaturalezadeproductos subsequentes.

Avant-propos et remerciementsCe livre repr~sente lequinzirne volumedu a6t atteint, etpourinfluencer lanaturedesprojetduTransportation Research Board surla ouvragesAvenir.Technologiedes transportsA l'usagedespays Nous remercions les 6diteursquiontgracieuen voiede d6veloppoment. Ceprojetestplac6 sement donn6 leurpermissionde reproduire lessous le patronage de U.S. Agency for Interna- textess~lectionn6s pour ce recueil:tional Development. L'objetdecerecueil estde Central Road Research Institute, New Delhi;r6unirunedocumentation pratiqueet utilequi John WileyandSons, Inc., New York;U.S.puisse aider lespersonnes responsables ForestService,Region 6,Portland, Oregon;etde I'analyse et de lastabilisation des'sols. La UniversityofTennessee,Engineering Experireaction descorrespondants des paysenvoie mentStation, Knoxville.de d6veloppementserasollicit6eet utilis6epour6valuer Aquelpoint le butpropos6de ceprojet


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Appreciation is alsoexpressedto librariesandinformation services thatprovided references.anddocuments fromwhich finalselectionsweremade fortheselected textsand bibliographyofthiscompendium.Special acknowledgment ismadeto the U.S. Department ofTransportationLibraryServices Division and to theLibrary andInformation Serviceof the U.K.TransportandRoad ResearchLaboratory (TRRL).

Tambl6n sereconocea lasbibliotecas yser-viciosdeinformaci6n queproveen lasreferen-clasydocumentosde loscualesse hacen lasseleccionesfinalespara lostextos selecciona-dosy labibliograffaen estecompendio.Sehaceunespecialreconocimiento a laLibraryServices Divisiondel U.S. Department ofTrans-portationyel Libraryand Information ServicedelU.K.Transport andRoad ResearchLaboratory(TRRL).

Nosremerciements aussiauxbibliothbquesetbureauxde documentation quinousontfournilesdocumentset les r6f6rences utilis6sdanslestexteschoisisetbibliographie de ce recueil.Nous remercions sp6cialementla U.S. Depart-ment ofTransportation LibraryServices Divisionet les Libraryand Information Serviceof the U.K.Transportand Road ResearchLaboratory(TRRL).

Finally,theTransportation Research Boardacknowledgesthevaluableadviceanddirectionthat have been provided bytheproject SteeringCommittee and isespeciallygrateful to VoyceJ.Mack,U.S. Department ofTransportation, WilburJ. Morin, LyonAssociates, Inc.,andGeorgeW.Ring Ill, Federal HighwayAdministration, whoprovided specialassistanceonthis particularcompendium.

Finalmente,elTransportation Research Boardagradece elconsejoy direcci6nvaliosos provistospor el comit6de iniciativas,con especial reconocimientoa lossen'oresVoyce J. Mack,U.S.Department ofTransportation, WilburJ.Morin,Lyon Associates, Inc.,y GeorgeW.Ring Ill,FederalHighwayAdministration, que prestaronayudaespecial paraestecompendio en particular.

Finalement, le Transportation Research BoardreconnaltlagrandevaleurdeladirectionetdeI'assistancedesmembres ducomitddedirectionet lesremerciede leurconcoursetdelafagondont ils dirigent le projet,sp6cialementVoyceJ.Mack,U.S. Department ofTransportation,WilburJ. Morin, Lyon Associates,Inc.,etGeorgeW.Ring 111,ederal HighwayAdministration,quiont bien vouluprdter leurassistance'Ala pr6parationdecer6cueil.


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OverviewBackground and ScopeSlopestabilizationisthepreventionofslopemovement. Compendium 13 considersthreetypes ofslopes- natural slopes,cutslopes,andfillslopes.Landslideis theterm most commonlyusedtodescribe the failure ofanatural slope.A land-slideishe downward andoutward movement oftheslope-formingmaterials-natural rock,soils,artificial fills, orcombinations ofthese materials,In fact,theterm landslide isgenericandisusedtodescribedifferenttypesofmovements, suchasslides, flows, andfalls,byvarioustypesofmaterials.The stabilizationofslopes,eithernatu-ralor man-made, first requiresthe identification

Vista GeneralAntecedentes yalcanceLa estabilizaci6ndetaludeses la prevenci6ndesusmovimientos. El Cornpendio 13 conslderatrestiposdetaludes- naturales, de corteyderelleno.El t6rmino deslizamiento esel quecom~n-mente seutilizapara describir la falladeuntaludnatural. Un deslizamientoes el de-splazamientohaciaabajoyhaciaafueradelosmateriales queforman el talud- piedra natural,suelos, rellenosartificiales,ocombinaciones delas mismas. Se podrfadcirqueel tdrrnino de-

Expos6HistoriqueetdescriptionLa stabilisationdes talusest lapreventiondeleursd~placements.Dans lerecueil no. 13,troissortesdetalussontexamindes, lesversants na-turels, lesd~blaiset les remblais."Glissement deterrain" est le terme couram-mentutilisdpourd6crire la rupture d'un versantnaturel. Un glissementdeterrainestle mouve-mentvers le basetversI'ext6rieurdes mat6-riaux qui composent le versant-soient-ilsdesroches,dessols,desremblaisdeterrains d'ap-port,ou certainescombinaisons de cesmat6-Fiaux. En fait, le terme "glissementde terrain" estun terrne g6n~rique,etestutilis6pourlades-criptiondediff6rentessortesdemouvements:glissoments,fluagesetchOtes de diff~rentsty-

of(a)the typeof material involved,(b)thetypeofmovement thathas occurredor isanticipated,and(c)thecause(s) forthe lossof stabilitythat precedesactual failure. The cutslopethat remains aftersomeexistingmaterial has beenremoved isthesecond typeof slopeconsidered.These slopesfail forthesame technicalreasons as donatural slopes.These failurescanalso be broadlytermed landslides. Cut-slope failures are much more common thanthoseof natural slopesbecausethe physicalact ofremoval ofmaterial tendsto upset theequilibriumof the soil in itsnatural state. The embankmentor fillslope, the third typeof

slizamientoes gen6rlco,yqueseutilizaparadescribir distintostiposdedesplazamientos,talescomo deslizamientos, flujos,ycardas, porparte devarios tiposdemateriales.En la es-tabilizaci6ndetaludesnaturalesohechosporel hombre, lo queprimero se necesitaes la identificaci6nde(a)el tipodematerial dequese trata, (b)el tipo demovimiento quehaocurrido oquese anticipa,y(c)la causaocausasdela p6rdida deestabilizaci6nqueprecede la falla misma.

pesdematdriaux. Lastabilisationdes talus,na turelsou artificiels,demandetoutd'abord l'identification:(a)du typedematdriauen question,(b)dutypede mouvementquial ieuouquiestanticip6,et (c)de la ou lescauses de la pertede stabilit6quiprecede la rupture m~me.Le talus ded~blaiquiresteapr~squeI'onaenlev6unecertainepartiedumat~riau, est lesecondtypede talusque nousallonsconsiddrer.Lesm~mes raisonstechniquessontlacausedela rupturede cestaluset de la rupturedesversarnis naturels. Ces ruptures,d'unefagong~n~rale,peuventdtre design~escommeglissements deterrain.Les ruptures destalusded6blai sontbeaucouppluscommunes quecel

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slopeconsidered, is man-made. Undernormalconditions(i.e., using suitablematerials andproperplacementandcompaction of that mate-riai), fillslopesexperiencefewer failuresthan docut slopes. Fillsor embank nentsmost com-monly fail becauseof(a)erosion,(b) the naturaldrainage isblocked whenan impermeable fill isconstructedon asidehillwithout underdrainage,(c)thesoftmaterial onwhich the fillhasbeenconstructed fails, displacingthe filldownward,or(d) the fill itselfstarts tomove downanaturalslope.Fill-slope failuresand fillfailuresare dueto thesame technical reasons as those fornatu-ralor cutslopes.Thesesametechnical reasonscontribute tothecollapseof trenchexcavations(i.e., thewallsfail)-either in fills,natural ground,or acombi-nationof both.

El segundo tipode taludque seconsideraesel decorte,quequedadespuesdeque sehayaquitadoalg~n material. Estos taludes fallan porlas mismas razones t6cnicasque losnaturales.En terminosgeneralesestasfallastambienpueden ilamarsedeslizamientos. Ocurrenmds amenudoqueaquellos de taludes naturales,yaque la acci6ndequitarmaterial tiendea trastor-nar el equilibriodelsueloen suestado natural.El tercer tipode talud aconsiderar,el de re -Ileno,eshechopor el hombre. Bajocondicionesnormales (es decir,si seutilizanmaterialesadecuadosyse loscoloca ycompacta bien)talestaludessufren menos fallasque losccr-tados. Generalmente fallan acausa de (a)aro-si6n, (b)eldrenaje natural obstrufdo porun re-Ileno impermeablecolocadosobreun taluddedeslizamiento sinsubdrenaje, (c)la falladelma-terialblando sobreel quese construy6el terrap-In desplazandoAste haciaabajo, o(d)el re-lesdesversantsnaturels,car lesimpleacted'enlever dumateriauatendanceAbouleverserI'quilibredusoldansson tat naturel.Letalusde remblai, le troisiemegenredeta-lusquenousallonsexaminer, estartificiel.Quand lesconditionssontnormales (c'estAdirequand onutilisedesmateriaux addquatsplacesetcompactescorrectement), ilyamoinsderup-turesdanscestalusquedans lestalusdedA -blai. Lesruptures detalusde remblai sontcau-sees, laplupartdu temps, par(a)I'rosion, (b) ledrainagenaturel quiestbloqudquand oncons-truitun remblai impezainablesurunversantdezollinesansdrainagesouterrain, (c) ilyarup-turedumatdriau mou sur lequelonaconstruitleremblai, cequi cause leglissementpar lebas

Theconsideration ofslopestability, therefore,encompassesall rockand soil found inor nearalow-volumeroad. Gravityisthe driving force foralllandslides;allmaterial is inastate ofunsiableequilibriumwhen itliescn aslope.An understanding of thebasicmechanicso analyzingthe materials at handwill assistthe low-volumeroadengineer indetermining what preventiveorcorrective measuresare necessarytocounterchanges in soil equilibriumdueto reductions inresistancevaluesor increases inshearingstresses.This typeofanalysisshouldbeusedforproper routeand materials selectionandfordetermining proper constructionmethods. Itwillassurethattheroad isconstructedat aminimumcost,or thatthemost economic solutionwill befoundforslopesthat fail duringor after construction.Ileno mismo,que empiezaadeslizarse sobreuntalud natural.Las fallasde taludes de rellenoyde rellenosson debidasalas mismasrazonest6cnicas que aquellasdetaludes naturalesocortados.Estasmismas razones tecnicascontribuyenalcolapsodeexcavaciones dezanjas(donde fal-Ian lasparedes)- en rellenos,suelonatural,ounacombinaci6n de ambos.Por lo tanto, laconsideraci6n de la estabilidaddetaludesincluye todaroca ysueloque seencuentredentroocerca deun caminodebajovolumen. Lagravedad es la fuerzade impulsopara tododeslizamiento; todomaterialseencuentraenestadodeequilibrio inestablecuandoestdsobreunapendiente. Unentendimiento dela meccinicab~sicapara analizarlosmaterialesa manoayudarcial ingenierodecaminosdebajovolumenadeterminar qudmedidas correctivaso preventivassondecelui-ci,ou (d)le remblai lui-memecommence Aglisser le longd'unepentenaturelle. Les rupturesdes talusde rernblai, et desremblais eux-mdmes,sontdOesauxmimesconditionstechniquesquecellesdestalusded6blaietdesversants naturels.Ces memes raisonscontribuentAI'effondrementdestranchees (lesmurss'effondrent)soitde remblais,desolnaturel,ou de la combinaisondesdeux.L'tudedela stabilitA destalusdonc inc!uttouslessolset rochesquise trouventsuruneroute conomique,ouAsesalentours. La gravitdest la forcedominante detouslesglissementsdeterrain; lematdriau estdansun,tat d'6quilibre instablequandilestplacdsurune pente.La


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Water isoneofthemajor causesofslopefail-ures. The entiresubjectof erosioncontrol isanintegralpartofslopestabilizationasaremanyfacetsof drainage design.Texts thatare relatedto theproblem ofslopestabilization6ppear inCompendium 2,Drainage andGeolojicalCon-siderations inHighwayLocation; Compendium3,SmallDrainage Structures; Compendium 5,Roadside Drainage; Compendium6, Investiga-tionandDevelopment ofMaterialResources;andCompendium 9,ControlofErosion. Thus,Compendium 13 stressesotherslopestabilityproblemsand solutionsrather thandetailedmethods ofpreventingsurfaceerosion.Althoughthiscompendium does notattempt torepeat soilnecesarias paracombatircambiosen elequilib-riodelsuelo,debidosareduccionesenlosval-oresderesistenciaoaumentos enelesfuerzocortante. Estetipodeandlisisse deberdutilizarparaunacorrecta ubicaci6ndel trazado yselecci6n de losmateriales ypara determinarelmdtodocorrecto deconstrucci6n.AsegurarAqueelcamino seconstruir, acostomfnimo, oquesepodrc encontrarlasoluci6nmds eco-n6micapara lostaludesque fallanduranteodespuesdelaconstrucci6n.Unadelascausasprincipalesdefallaeselagua.El temacompletode controlde laerosi6nesunaparteIntegra de laestabilizaci6ndetaludes, al igualquemuchos de losaspectosdeldisefio dedrenaje.Por lo tanto,el Compen-dio2:Cons/deraciones de drenajeygeol6gicasen/a ubicaci6n delcamino,el Compendio 3: comprehensiondu mecanismedebasede 'ana-lysedesmatdriauxqu'ilasousla main,aideral'ingdnieur routierderoutes AfaiblecapacitdAd6terminer quellesactions, preventivesoucor-rectives, sontn6cessairespour parerauxchan-gementsd'dquilibredusol dOsauxr6ductionsdesvaleursde r6sistance,ouauxaugmenta-tionsdestensionsdecisaillement.Cegenred'analyse devrait6treutilis6pour lechoixdutrac6de laroute etdesmat~riaux,et pour ladd-terminationdemethodesdeconstruction correc-tes.OnauraainsiI'assurance que larouteseraconstruiteAuncoOtminimal, ou qu'ontrouveralasolution laplus6conomique Alarupturedestalus,pendantouaprbslaconstruction.L'eauest l'une desraisons majeuresderup-turede talus.Toutcequi comprend lecontr6lede I'6rosion etbeaucoupd'aspects du drainage,fontpartie int~gralede lastabilisationdestalus.C'estpourquoi les recueils no.2, Considerationssurlesfacteurs dedrainageet deg ologiequi

information introduced inpreviouscompendiums, such information isalsocritical to theanalysisof slopestability.Thiscompendium isdirectedtothegeneralhighwayengineer.Slope movement isacomplexphenomenon that isoften poorlyunderstood by thenonspecialist.The textswereselected topresentthe basicprinciplesofslopestabilization andtoprovidegeneral approachestothecorrection ofthe more commonslopestabilization problems. The proper solutionforcomplex stabilization problems requires adepthofknowledgeandexperiencethat isbeyond thescope ofthiscompendium. The prudent high.way engineerwill callonan expertforassis-Pequehasestructurasde drenaje, el Compendio5: Drenajedelbordedela carretera,elCompendio 6: Investigaci6nydesarrollo derecursosdemateriales, y Compendlo 9: Controlde eros/6n, contienentextosque serelacionanconel problema de estabilizaci6ndetaludes.Porlotanto,el Compendio 13 subrayaotrosproblemasysolucionesen la estabilizaci6ndetaludes, envezde presentar metodos detalladospara laprevenci6ndelaerosi6n delasuperficie.Aunqueestecompendiono intentarepetirla informaci6nsobresuelospresentadaen compendios previos,estainformaci6n tambi6nes importantepara el andlisis delaes.tabilizaci6n detaludes.

Este compendiose dirige al ingenierovialgeneral. El desplazamiento detaludeses unfen6meno complejoymuchasveces elque noinfluencentle choxde 'emplacementd'uneroute;no.3, Petitsouvragesdedrainage;no.5,Drainage desbas-cOt sdela route; no.6,Investigation etdeveloppementdesgisementsdematbrlauxroutiers; etno. 9,Contrble de/'erosioncontiennentdestextesquisontapparentdsauproblemede lastabilisationdestalus. Danscerecueil no.13,on porteuneattentionspecialeAd'autres probl~mes destabilit6 destalusetAleurssolutions,plut6tquedes'6tendreendetailsur lesm6thodes depr6ventionde I'6rosion desurface. Dans cerecueil nousn'allons pasnonplusessayerd'enseigner denouveau certainsaspectsde lap~dologie,ainsiquenous I'avonsfaitdensdesrecueils prec6dents, maisnousinsistonssur le faitqu'une bonneconnaissancede ceux-ciest crucialepouranalysercorrectement lastabilit6 destalus.Ce recueil est6crit& l'intention deI'ingdnieurroutier g~n~raliste.Le d~placementdestalusestun ph6nombne tr~scomplexe,qui n'estsouvent


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tancewhenanalyzingslopestabilization prob-lems thatareunusual, expensive,or dangeroustohumanlife.Rationale forThisCompendiumSlopestabilization isaproblem that is inherentthroughoutall phasesofhighwaywork.Thesolu-tion to slopestabilization problemsbeginswiththeabilitytoidentifythe typesofmaterials in-volvedand theassociatedmodes of failurethatcan occurin thesematerials. Oncethe mechan-icsofevaluatingslopestabilizationproblemsareunderstood, thesolution ofpossibleor actual in-dividualslopefailures becomes a matterofeco-nomics. Slopestabilityevaluations should takeplacenot onlyduring preliminaryroad locationbutalsoduring actualdesign, duringconstruc-tion of the road,and,as necessary,during thelifeof theroad.

Thefirstevaluationofslopestabilizationprob-seaespecialistano locomprende perfec-tamente.Los textosfueron seleccionadosparapresentar losprincipios bdsicosdeestabilizaci6ndetaludesyparaproveer m(todos

AV generalespara lacorrecci6nde losproblemasvmds comunes de estabilizaci6n. Lacorrecta so luci6npara losproblemas deestabilizaci6n m~scomplejos requiereun conocimientoprofundoyexperiencia extensaque estcnmc.s all del al-cancedeestecompendio.El ingenierovialprudente,al enfrentarseconelanclisisdeunproblemadeestabilizaci6n que escaro, peli-

pastr(sbiencomprisdeceuxquin'ontpasregu despecialisationencesujet.Nostextesontdtdchoisispour presenter les principesdebasedelastabilisation destalus,etpourfourniruneapprocheg6n6raleAla correctiondespro-blbmes les pluscommun(ment rencontr6s. Lasolution correctedeprobl(mes complexesdestabilisationdemande uneconnaissancepro-fondedecesujet,conjugu(e avecune longueexpdriencepratique-etcecid(passe I'enver-guredenotrerecueil. L'ing(nieur routierprudentdemandera I'aided'un experten la matieres'ildoitanalyserdes problbmes destabilisationdetalusqui sont inhabituels, treson(reux,ou quirisquent de metreendangerdes vieshumaines.Objectifdece recuellLastabilisationdestalusestun probl(me quiseposeAtoutes les phasesde laconstruction rou-

lems shouldoccuraspart ofthe initialroad locationdecision. (See Compendium 2,SelectedText9-Landslide Investigations:AFieldHandbookforUse inHighwayLocationandDesign.)Itisinhisphasethat theeconomicsofavoidance ofunstableareasis most attractive.Avoidancemayalso bethemosteconomic alternative during later phases (i.e., during designor becauseof faluresduring or afterconstruction).However,the highesteconomicbenefitwillobviouslyoccur iftheavoidancesolution isevaluated andselectedassoonaspossible.Thesecondevaluation ofslopestabilizationproblems should occurduring the detaileddesignof theroad. Atthis time, localizedslopestabilityevaluationscan be made.The propersideslopescan bedetermined forthematerialsonsite,and controlmeasuressuchasretainingwalls can be most economicallyplanned. Notethat furthereconomic benefits can be realizedduring thisdesign evaluationperiod by thegroso,opococomon, consultarAconunexperto en la materia.Exposlclibnrazonada para estecompendioLaestabilizaci6n detaludesesun problemainherenteatodas lasetapasdetrabajo vial.Lasoluci6nparaestos problemascomienzaconlahabilidadde identificar lostiposde materialesinvolucradosylosmodosasociadosde fallaquelosacompaflan. Unavezque seha compren

ti(re.Pour pouvoirr(soudreceprobl(me ilfautd'abord trecapabled'identifier les typesdemat6riauxavec lesquelsonvadevoir travailleretleursmodesde rupture. Une foisque 'onabiensaisi latechniqued'6valuationdes probl(mesde stabilisationdes talus, la r6solutiondecesprobl(mes, potentielsouactuels, devientunequestion6conomique. Les6valuationsdelastabilit6 des talusdevraient6treenvisag(es, nonseulement austade du trace pr(liminaire delaroute,maisaussiauxstadesdela conceptionetde laconstruction et, le cas6cheant,pendanttoute lavie dela route.Lapremiere 6valuation du probleme devraitprendre placeau moment oO I'onvadeciderletrac6 initialde la route (voirRecueilno.2,Textechoisi9: Etudes deglissementsde terrain: Unmanuelpour ledimensionnementet I'emplacementdes routes). C'estAcestagequeladecisiond'dviterlesendroitsinstablesestlaplus


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properdetermination of sideslope anglesbasedon stabilitycriteriarather thanon the ac-ceptanceofarbitrary"standard" sideslopesoften indicatedon"typical crosssections."Thethirdevaluationofslopestabilizationprob-lemsshouldoccurduringtheconstructionphase.Material typesmay provetobedifferentthan anticipated, andsigns ofseasonal tinder-ground water flows orfluctuating water tablesmay be uncovered.These conditionsshould beevaluated assoon astheyare identified be-causethecost tosolvesuch potentialslopesta-bilityproblems before theyoccurwill bemuchless than thattocorrectsubsequent failures.The fourthevaluationofslopestabilizationproblemsoccurs afterconstruction is finished-dido la mecdnicadeevaluaci6n delosprob-lemas deestabilizaci6n, la soluci6n defallas in-dividuales, potencialesoactuales, sevuelveasunto decosto. Nos6losedeber~n Ilevaracabo evaluacionesde estabilidad, detaludesdurante la ubicaci6n preliminardel camino,sinotambidn durante el disenioactual, durantelaconstrucci6ndel camino,ycuandoseanecesariodurante la vidaOtil delcamino.Laprimeraevaluaci6nde problemas deesta-bilizaci6n deber6ocurrircomoparte dela deci-si6n inicialde ubicaci6ndelcamino (veaseCompendio 2,TextoSeleccionado9, Investiga-clonesdederrumbes: Un manualde campahaparausoeneldisehoyubicacibndecarrete-ras).Es en estaetapa que lasensatezecon6-micadeevitardreas inestablesesmdsatractiva.attrayantedu pointdevue6conomique. Cetted6cisionpeut6treaussi I'alternative la plus6co-nomique durant lesphases ulterieuresdu projet'(conception,dimensionnement, ou au momentderupturespendantouapres la construction.Cependant leplus t6ton evalueleproblbme etlad6cisionest prise, leplus importantseraI'avantage 6conomique.Lasecondeevaluation duprobleme devraprendre placeaumoment du dimensionnernentdetaill dela route.C'est eneffetccette p6riodequel'on peut6valuer localement la stabilit6destalus.Les pentescorrectespeuventdtredeter-.mincesenfonctiondesmateriauxen place,etdesmesuresdecontr6le,tellesque les mursdesoutenement parexemple, peuvent6tre proje-t6esbeaucoupplus6conomiquement. IIfautbien remarquer aussique leprixde revientpeutdtreencoreplusdiminu6si 'on asoin,pendantcetteevaluation, decalculerlesanglesdespen-tesen sebasant sur lescrithres destabilit6, plu-

wheneithersignsofdistress appearoraslopeactuallyfails.Again, itismore economicandsafertosolvetheseproblems whenthe firstsignsappear rather than afterthesubsequentfailure.The evaluationofslopestability ismade bydetermining the factorofsafetyofaslope (i.e.,the ratiooftheshearing resistanceto theweightoftheslidingmass). The factorofsafetyis1 justbeforeslope failure.Slopesmay therefore bestabilized by increasing shearing resistanceorreducing shearstress. Mostcutslopesareleaststableimmediately afterthe cutis madebutmayfailatany time ifmoistureconditions becomemoresevere thananticipated. Fillslopes normallyfailquite awl ileafterthe fillhas beenEvitaci6ntambi6n podrfa ser la alternativamdsecon6mica durante fasesposteriores (esdecir,duranteeldisehooporfallasduranteodespuesde la construcci6n). Es obvioqueelbeneficioecon6mico mcs grandeocurrirdcuando la soluci6ndeevitaci6nseevalayselecciona lomclsprontoposible.Lasegundaevaluaci6nde losproblemas deestabilizaci6n detaludesdeberdocurrirduranteel disefiodetallado delcamino.Es enestaetapaquesepuedenIlevaracabo lasevaluacioneslocalesdeestabilidad detaludes.Se puedendeterminar loscorrectos taludes lateralesparalosmateriales ensitu,y lasmedidasdecontrol,talescomo murosdecontenci6n, puedenserplaneadasen formamdsecon6mica.Debercnotarsequesepueden realizarmsbeneficiost6tqu'enacceptantdes "normes" arbitrairesbas6essurdes "sections transversalestypiques".Latroisieme6valuationdes problemesdestabilisationdestalusdevraitavoir lieu lorsdelaconstruction elle-mdme. Lesmat6riaux peuvent8trediffdrents deceuxqui6taientanticipes,etl'onpeutdecouvrirdesmarques indiquant lapresencedecourantssaissonniers d'eausouterraineou defluctuations dela nappephr6atique.On devrait6valuercesconditionsaussit6t quepossibleapresleuridentification,carilestbeaucoupmoinson6reuxde resoudrecesproblemes potentielsavantque ledommage nesoitfait,quede r6parer lesruptures.Laquatriemeevaluation desproblemesdestabilit6destalus,alieuquand laconstructionestterminee- s'ilestapparentqu'il vay avoirrupture ou s'ilya rupture. Denouveau, ilestbeaucoupplus6conomique derdsoudre cesprobImesdesI'apparence despremiers


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completedunlessthecause is foundationfail-ure, inwhich casethe fillsubsidessoonafter itiscompleted. Fill slopesnormally failfrom theirownweight rather thanfrom theweightof thevehicles usingthe road.Slopestabilizationproblems inengineeringsoilscanbedivided intotwo basictypes,de-pendingon theinfluence oftheheightoftheslopeon itsstability.Cohesionlessmaterial de-pendson mechanicalstrengththatincreaseswiththenormal component of theweight (onereason forthecompactionofgranularfills).Therefore, anyslope ofcohesionlessmaterialthat isataflatteranglethantheangle ofinternalfrictionwill bestable regardlessof theheightoftheslope.However, ifhighgroundwater ispresent incoarse-grained material, one-half theangleof internal frictionisnormallyconsideredecon6micosduranteesteper'ododeevaluaci6ndeldisenio,determinando correctamente losdn-gulosdetalud lateral basadosen criteriosdees-tabilidad,en vezdetaludeslaterales "norma"recomendadosamenudoen "secciones trans-versalestfpicas".La tercera evaluaci6ndeproblemas deestabi-lizaci6ndetalud sedeberA Ilevaracabodu-rantela etapadeconstrucci6n.Podr. ocurrirquelostiposdematerialessondistintos deloanticipado,yquesedescubren flujosestaciona-lesdeagua subterrdneao fluctuacionesdelnivelfredtico. Estascondicionesdeberdn eva-luarsetan prontocomose identifiquen porqueel costode resolvertalesproblemaspotencialesdeestabilidad detaludantes queocurranserfamuchomenosqueelde corregirla fallasubse-cuente.signes,plut6tquede diffdrer lesr6parationsjusqu'A la rupture complete.L'6valuation de la stabilit6destalussecalculeen d6terminant leco6fficientdesecuritdd'unepente(c'estAdire le rapport de la r6sistanceaucisaillementau poiddela masse interessdeparleglissement).Lefacteurdesecurit6est6galA1 justeavantla rupture.On peutdoncstabiliserlespentessoitenaugmentant la resistanceaucisaillement, soiten reduisantla tensiondeci-saillement. La plupartdestalusdedeblaisontstables justeapres led6blaiementmais peuventserompre d'unmoment AI'autre si lescondi-tionsd'humidit6deviennent plusseveresquel'onavaitanticip6. Lestalusde remblai, d'ordi-naire,n'onttendance Ala rupture qu'apresuncertain temps,saufsi lacauseenest la rupturede lafondation et,danscecas, le remblai s'af-

asthestability limit.Cohesive soil,ontheotherhand,dependson attractionbetweensoil particles and moisture,whichare independent ofthesoil'sweight.Stability incohesivesoil isdependentmainlyon thesteepnessand heightof theslopeandtheshearstrengthof the soil.Cohesivesoilmay suffer (a) slopefailurewhere thebottom of thecurved failure plane islocatedatorabovethe toeofthe slopeor (b)base failurewherethe faceof thecurved failure plane is tangenttosome less-yieldingsurface belowthetoeoftheslope, inwhichcasethe intersectionof thefailureplanewith thesurface occursbeyond thetoeoftheslope. (These typesof failure areillustratedon SelectedTextpage 36.)Slopes inmixed soils, i.e., soilsthatareneither purelycohesionless nortotallycohesivesuchassomemixed claysand gravels,are alsodependent on

La cuartaevaluaci6ndeproblemasdeestabilizaci6ndetalud ocurredespu6sdeterminarselaconstrucci6n -cuando aparecen serialesdetensi6no realrnente fallael talud.Se reitera quees m~sec6nomicoyseguroresolverestosproblemascuandoaparezcan lasprimerassenalesen lugardedespuesde lafallasubsecuente.Sehace la evaluaci6ndeestabilidad determinandoel factordeseguridad deun talud (esdecir, laraz6n de la resistenciaalesfuerzo cortantealpesode lam"saquese desliza).El factordeseguridad es1enelmomento antesde lafalladel talud. Porlo tanto lostaludespuedenestabilizarseaumentando la resistenciaal esfuerzocortante oreduciendoelesfuerzocortante.El perfododemds inestabilidad paracasitodotaludes inmediatamente despudsdequesehayarealizadoelcorte,peropuedefallarenfaissetrest6tapresqu'ilsoitconstruit.Normalement, la rupture des talusde remblaiestcauseeparleurproprepoids,plut6tquepar lepoidsdesvehicules circulantssur la route.IIyafondamentalement deuxsortesdeproblbmesdestabilisationdetalusen sols routiers, selon rinfluencedela hauteur dutalussur sastabilit6. Unsolsanscohesiond6pend dela r6sistancem6caniquequiaugmenteavec la composantenormaledu poids (unedes raisonspour lesquelleson compacte les remblaisen solsgranuleux).Donc touttalusensolnon-coherentquiestAunangleplusplatqueI'anglede frottementinterne serastablequellequesoitsahauteur.Toutefoissidansun materiaugrossierI'eauphrdatiqueestLlev6e, lamoitiLde I'angledefrottement interneestnormalementconsiderecomme la limitedestabilit6. Lessolscohdrents,


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thesteepnessandheightof theslope.Both surfacewaterandground waterare im-portant factors inslopestability,notonlybe-causeof thesurface erosion problemsdis-cussed inprevious texts butalsobecause of(a) internal erosionproblems (i.e., piping),(b)thehydrostatic pressure introducedwithinthesoil mass itselfthat reducesshear strength,(c)theadditionalweight of thewater in thesoilmassthat increasesshearstress, and (d)the reduction in strengthofcohesivesoilswith in-creasing moisturecontent. Slopestabilityanalysesare best madebyspecialists becausethere are somanyun-knowns involved that requiresubjectiveevalu-ations. Inmanycases,however, theavailabilityorthecostofsuchspecialists makes theiruseimpractical inthe location, design,andconstruc-tionof low-volume roads.Although thiscompen-cualquiermomento silascondicionesde hume-dadsevuelven mdsgravesde loanticipado.Lostaludesderellenonormalmente fallanuntiempodespu6sde quese hayacompletadoel relleno,almenos quehayaunafllapor la base,en cuyocasoel rellenosehundepocodespuesdecompletarse. Estostaludes normalmente fa-Ilan porraz6nde supropio peso,en vezdeporelpesode losvehfculosqueutilizan elcamino.Los problemasdeestabilizaci6n en suelos in-genierilespuedendividirseendos tiposbdsi-cos,dependiendodela influenciade la alturadeltaludsobre suestabilidad. El material nocohesivodependede resistenciamec~nicaqueaumentaconelcomponente normal delpeso(una de lasrazones para la compactaci6nde re-Ilenosgranulares). Porlo tanto,un taluddema-terial no cohesivoesestable,cualquiera seasu altura,siempre queel dngulo deltalud seamenorqueeldngulo de fricci6n interna.Sin em-bargo, sihayaguafredtica cercade lasuperfi-d'un autrec6t6,dependent deI'attractionentrelesparticulesdesol et 'humidit6, independam-mentdu poidsdusol. Lastabilit6dessolscoh6-rentsestfonction principalement dela hauteuretdel'inclinaisondela pente,etde la resistanceau cisaillementdu sol.Dans unsolcoh6rentonpeutavoir: (a) rupture du talusquand la basedelasurfacecourbe deglissementestsitueeaupiedou au dessusdu pieddu talus;ou (b) rup-tureparla base,quand la surfacecourbedeglissement esttangenteAunesurface r6sistanteau dessous du pieddu talus,danscecasla sur-facedeglissementcoupele talusau-delAdeson pied.Ces sortesderupture sontillustreesdans lestexteschoisis,Ala page 36.Lestalus

dium presents information thatshouldbeofas:sistancetothegeneralhighwayengineer,someofthemore theoretical aspectsofslope stabilizationhavebeen omitted toallow the inclusionofsome generalized, simplified approaches toacomplex problem. Whenever an improper slopestabilizationanalysismay lead to thepossibilityof thelossoflifeorhigh economiclossesto thecommunity, aspecialistshouldbe consulted.DiscussionofSelectedTextsThefirsttext, Chapter2- SlopeMovement TypesandProcesses, isexcerpted from Landslides:Analysisand Control (Special Report 176,Transportation Research Board, 1978). Itre viewsafairlycompleterangeofslopemovement processes. it identifiesandclassifiesthem according to features that arealsotosomecieenmaterial degranulaci6ngruesa,la mitaddel dngulo defricci6n interna normalmente seconsidera comoel Ilmite deestabilidad. Porotraparte, el suelocohusivodependedela atracci6nentre laspartfculasde sueloy la humedad,quesonindependientes del pesodel suelo.En tonces la estabilidad delsuelocohesivodependeprincipalmente de la pendienteyalturadel taludyla resistenciaalesfuerzocortantedelsuelo.En sueloscohesivos,puedeproducirse(a)fallade talud donde la parteinferior delpianocurvodedeslizamientoseencuentra alpiedeltalud o rmds arriba o(b) fallaporla basedonde la car&del pianocurvodedeslizamientoes tangentecon unasuperficiemenos movedizaque seencuentra debajodelpie deltalud,encuyocaso la intersecci6ndel pianodedeslizamientoconla superficieocurre mds allc dedichopie.Estostiposde fallade taludhansidoilustradosen la p~gina36de lostextos seleccionados.Los taludesen suelosmixtos,esdeensolsmixtes,c'est Adireensolsquinesontpascomplitement non-coherents,nicompletementcohdrents,commecertaines argilesetcertainsgranulats, d6pendentaussidela penteetdela hauteurdu talus.L'eau phr6atiqueet I'eau de surfacesontdesfacteursimportants dela stabilit6destalus,nonseulementAcausedesproblemesd'6rosion superficiellequenous avonsdiscut6sdansdestextespr6c6den;.3, mais aussiAcausede:(a)problomesd'6rosion interne (renards); (b) lapressionhydrostatiqueintroduitedansla massedesol,quiabaisse la r6sistanceaucisaillement,(c) lepoidsadditionnelde I'eaudansla massedesol,quiaugmente lacontrainte decisaille


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degree relevant totheir recognition,avoidance,control,or correction.Thechiefcriterion used intheclassification is typeof movement. The typeof material isasecondarycriterion.The typesofmovement include(a)falls; (b) topples;(c)slides,eitherrotational or translational;(d)spreads;(e) flows; and(f)complexslopemovementsthat includecombinations of twoormoreof the first fivetypes.Materials are dividedcir,suelosquenosonpuramenteno cohesivosni totalmente cohesivos,talescomoalgunasar-cillasygravasmixtas, tambien dependen de lapendienteyalturadeltalud,El agua desuperficiey el aguasubterraneason factores importantes en laestabilidadde ta-ludes, nos6loporlosproblemas deerosi6n de la superficiesobre losquese habl6entextosprevios,sinotambienpor'(a)problemas deero-si6n interna (esdecir,tubificaci6n), (b) la pre-si6nhidrost~tica introducida dentrodela masadesuelomisma quereduce la resistenciaales-fuerzo cortante,(c) elpesoadicionaldelaguaen la masa delsuelo queaumenta elesfuerzocortante,y (d) ladisminuci6n de la resistenciaen sueloscohesivos cuandova aumentando elcontenido dehumedad.xvliI Es mejor queunespecialista realiceelanclisisdeestabilidadde taludes,yaqueexistenmu-chas inc6gnitas querequierenevaluacionessubjetivas. Sinembargo,haymuchoscasos

donde ladisponibilidadocostodetalespecia-listahaceimpracticablesu participaci6nen lamentet (d) lamoindre resistancedessolscoh6-rentsAmesure queleurteneureneauaugmente.On devrait laisserauxspecialistes lesoind'analyserla stabilitddestalus,carcesanalysesdemandentune evaluation subjectived'un bonnombred'inconnues.En maintes occasionstoutefois,on estobligedesepasserdeleurex-pertise,car ilsne sontpasdisponibleset leuremploiest tropon6reuxpour6tre justifi6dans laconception, locationetconstruction deroutesdconomiques. Bienquedans cerecueil nousprdsentons un ensemblededocuments quide-vraitdtre utile6 l'ingenieurroutier g6neraliste,nousavonsomiscertains desc6tss les plusth6oriques de la stabilisationdestalus,afindenouspermettre d'inclurequelquessolutionssimpleset g6n6rales6 ceprobl~me complexe.Maisaussit6tqu'il ya le moindrerisquequ'uneanalyse incorrectede la stabilit6d'untaluspuisse mettreen periluneviehumaine,ou

mdmecauserdegrosdommages 6conomiques

intotwoclasses- rockand engineering soil.Soil isfurther divided into debrisandearth.(Some of thevariouscombinations of movementsandmaterials areshown inFigure2.1,which is includedas an insertwith thiscompendium.)Thistextalsointroduces the causesofslidingslope movements (slope instability). Thesecauses includeboth factorsthatcontribute-to anubicaci6n,diseio,yconstrucci6ndecaminosdebajovolumen.Aunque estecompendiopresenta informaci6n quepuede ayudaral ingenierovialgeneral, sehanomitido algunosde losaspectos mcste6ricos deestabilizaci6nparapermitir quese incluyanalgunos m6todos generalizadosy simplificadospara resolverun problemacomplejo. Cuando unandlisis incorrectodeestabilizaci6nde talud puede provocarposibles p6rdidasdevidaode grandes cantidadesde dinero parala comunidad,se deberc consultarconun especialista.Presentaci6n de lostextosseleccionadosEl primertexto, Chapter2- SlopeMovementTypesandProcesses(Capftulo2-Tiposyprocesosdemovimiento detaiudes), fueextraldodeLandslides:AnalysisandControl(Deslizamientos:andlisisycontrol, SpecialReport 176,TransportationResearch Board, 1978). Repasaunagama bastantecompletadeprocesos demovimiento detaludes. Los identificayclasificaA[a communaut6, on devraitconsulterun expert. Discussiondes textescholsisLepremier texteestledeuxibmechapitre,SlopeMovementTypesandProcesses(Typeset ddveloppement demouvementsdetalus)du rapportLandslides:AnalysisandControl(Glissementsdeterrain: Analyseetcontr6le,SpecialReport 176,Transportation Research Board,1978).On y passeen revueune grandevariet6demouvementsde terrainet leprocessusdeleur6volution.Onles identifieet on lesclasseselon leselements caracteristiquesquipermettentde lesidentifier,les6viter, lescontr6leroulescorriger. Lecritbre principaldecetteclassificationestle typedemouvementde terrain.Legenredemateriau est lecrit~resecondaire. Lestypesde mouvements deterrainsont: (a)leschtes,(b) les basculements,(c)lesglisse--:.

ments rotationnels outranslationnels;(d) les


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increased shearstress andfactorsthatcontrib-ute to low orreduced shearstrength. Theanalyses ofslope failuresand corrective mea-suresnecessary topreventor repairthesefail-ures (i.e., slopestabilization),which are includedintheothertexts,areall basedon (a)reducingshear stressalong apotential planeof failureor(b) increasing shearstrength in thematerial sub-jecttoslope movement,The second text,Art.35,StabilityofSlopes, isexcerpted from SoilMechanics inEngineeringPractice (2nd ed.,John Wiley andSons, Inc.,1967). It introduces theconcept thatslopefail-de acuerdoconcaracteristicasquetambi~naciertogradosonaplicablesasureconocimiento,evasi6n,control,ocorrecci6n. El criterioprinci-palutilizadoen la clasificaci6nesel tipodemo-vimiento. El tipode materialesuncriteriose-cundario.Los tiposde movimiento incluyen(a)calda; (b)derribo,(c)deslizamiento, rotatorioodetraslaci6n;(d) desparramo; (e) flujo;y(f)movimientos detaludcomplejosque incluyencombinacionesde dosomcsde losprimeroscincotipos.Losmaterialessedividenen dosclases- rocaysuelo ingenieril.Ademdselsuelosedivideen detritosytierra.(Se presen-tan algunasde lasdiversascombinacionesdemovimientos ymateriales en la Figura2.1 in-clufda enestecompendio.)Estetextotambi~n hablasobre lascausasdelosmovimientos dedeslizamiento detaludes(inestabilidaddetaludes). Estascausasinclu-yen factoresqueaumentan la acci6ndel es-fuerzocortantey factoresquedisminuyen lare-sistenciaal esfuerzocortante.Losandlisisdefa-Ilasdetaludesy lasmedidascorrectivas nece-sariasparaimpedir orepararestasfallas (es6talements; (e) le fluage;et (f)lesmouvementscomplexesqui comprennentdescombinaisonsdedeuxou plusdescinq premiersd~sordresd6crits ci-dessus.Lesmat6riauxsontdivis6sendeux classes- rochesetsols routiers.Lessolssontsubdivis~sendebris etterre.(Quelquescombinaisonsdemouvements etdemat6riauxsontillustr6esdans la figure 2.1 de I'encartdece recueil).Lescausesdes mouvements glissantsdespentes (instabilit6destalus)sontintroduites.Cescausescomprennent lesfacteurscontri-buantsAune augmentation de latension decisaillement,et ceuxquicontribuentAuner6sistanceaucisaillement basseou r6duite.Lesanalyses desrupturesdetalusetdesmesurescorrectivesn~cessairesAla preventionou la r6-paration deces ruptures(c'estAdire la stabilisa-

ureoccursatthattimewhentheshear stress.,causedby theweightof theslidingmassovercomes the shearstrengthor resistance toslidingof thematerial involved.Justpriorto failure, theweightandshearing resistance areequal.Theratioof the shearingresistancetotheweightofthesliding mass is termed the factorofsafetyF;therefore, atthe instant before failure,F=1.Aslopeis considered stablewhen Fisdeterminedtobegreater than 1andunstablewhen Fslessthan 1.Slopes ofcohesionlessmaterial dependoninternal frictionforstability.Theangleof internaldecir, la estabilizaci6ndetaludes),inclufdosenotros textos, todossebasan en (a) reducci6ndelesfuerzo cortantesobreel pianodedeslizamiento potencial, o(b)aumentodela resistenciaalesfuerzocprtanteen el material sujetoalmovimientodel talud.El segundotexto,Art.35,StabilityofSlopes(Art.35,Estabilidaddetaludes),fueextraidodeSoilMechanics inEngineering Practice (Mec6nicadesuelosen la ingenierla pr~ctica,2d. ed.,John Wileyand Sons, Inc., 1967). Proponeelconceptodequela falladel taludocurreenelmomento cuando el esfuerzocortante producidoporel pesode la masaen deslizamientovencela resistenciaal esfuerzo cortante,esdeciral deslizamientodel material involucrado. Justoantesdeldeslizamientoel pesoyla resistenciaal esfuerzocortanteson iguales.Laraz6n delaresistencia alesfuerzocortanteal pesodelamasa endeslizamiento sellamael factorde seguridad F; por lo tanto,en elmomento antesdelafalla,F=1.Un taludseconsidera establecuandosedetermina queFesmayorque1einestablecuandoFes menorque 1.tiondestalus),quisont inclusesdanslesautrestextessonttoutesbas~essur(a)la reduction delatension docisaillementsurune surfacedeglissement potentielleou (b) I'augmentation deIardsistanceau cisaillementdu matdriau sujetau mouvementdetalus.Ledeuxi~metexte,Art.35,StabilityofSlopes(Stabilit6des talus), estextrait deSoilMechanicsinEngineeringPractice (M6caniquedessolsappliqu6e,2eme 6dition, JohnWileyandSons, Inc.,1967). On introduit leconceptquelaruptured'un talusseproduit au momentprecisou latensionde cisaillementcaus~epar le poidsde la masse interess~epar le glissement I'emportesur la r6sistanceaucisaillement, ourdsistanceau glissementdu mat~riau dont ilestquestion.Justeavant la rupture lepoidset la r6 sistanceaucisaillementsont6gaux.Le rapport

x


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friction 0 is the angleabovethe horizontalatwhich the loosecohesionlessmaterial will juststand. (This isthe angleat which F= 1.) Foranygivenslope in cohesionless material, the factorof safetyis found bydividing the tangentof theangle of internal friction by thetangent off3, theangle of the slope under investigation(theanglebeing measured from a horizontalplane). Theheight of slopes in cohesionlesssoil is not a fac-tor in the stabilityof the slope,The stabilityof slopes in cohesivesoils is morecomplicated and is based on Rankine's earth-pressuretheory. In general, a homogeneouscohesive soil willfail alonga curvedsurface. TheLostaludescompuestosde material nocohe-sivodependendela fricci6n interna parasues-tabilidad. El Angulo de fricci6n interna0es el,ngulo sobreel horizontalen el queel material

suelto,nocohesivopuedesoportarse. (Este esel dngulo dondeF= 1.) Dado cualquier taluddematerial nocohesivo,seencuentra el factorde seguridad dividiendola tangentedel dngulodefricci6n internapor la tangentede/P, el Angulodeltaludque seestd investigando(se deberdmediresteAngulo en un pianohorizontal). Laal-turade lostaludesde suelo nocohesivonoes: un factoren suestabilidad.Laestabilidaddetaludes ensuelos cohesivosesmds complicadayse basaen la teorlade Rankine delempujedetierras. Por logeneral,unsuelohomog6neo cohesivofallarA sobreunasuperficiecurva. El textodescribe lascaracterfs-ticasgeneralesde losdeslizamientosenestede la r6sistanceau cisaillementau poidsde lamasse interessdepar le glissement,estappeldle coefficientdes6curit6F; donc,A l'instantavantla rupture,F=1.Un talusestconsid6r6stablequand Festplusgrand que1,et instablequand Festpluspetitque 1.Lestalus construitsen mat~riaux non-coh~rents dependent du frottement interne pourleurstabilit6.L'anglede frottement interne0estI'angle audessusdeI'horizontale auquel le ma-t6riauxnon-coh6rentet non-compact6 reste sta-tionnaire(l'angle auquelF= 1). Pour trouver leco6fficientde sdcurit d'untalusde matdriaunon-coherent,ondivise la tangentede I'anglede frottement interne par la tangentedep,I'angle du talusen question (l'anglequeforme letalusavec I'horizontale). La hauteurd'untalusenmatdriau non-coherentn'a aucuneffetsursastabilit6.La stabilit6des talusde mat~riaucoherentestpluscompliqu~e,etestbas~esur la thdoriede

textdescribes the general characterofslides inhomogeneous cohesivesoil. The mathematicaljustification forthis is not excerpted for thiscompendium; the final information is reduced tocharts thatare included in thetext.The centerofthe curved surfacealongwhich a homogeneouscohesivesoil will fail can be located from information shown on the charts. By usingthe slopeangle,8 and the relation between the slopeheightand depth toa firm basebeneath thecohesivesoil, thetypeof possible failure(slopeor base)and the locationof the centerofthe criticalcircleforslope failure can be graphically located. The safetyofslopes in cohesivesoils istipodesuelo.Nose ha incluldoenel compendiosu justificaci6nmatemAtica; la informaci6nfinalse ha reducido a diagramasquesehan incluldoen el texto. Se puede localizarel centrode lasuperficiecurva pordonde fallar6 un suelohomog6neo cohesivo,utilizando la informaci6npresentadaen losdiagramas. Se puedeaveriguarpormedio de gr~ficos el tipode fallapotencial(detalud o por labase) yelcentrodelcfrculo crfticode fallade talud,si seutilizaelangulo de taludPy la relaci6nentre la alturadeltaludyel espesorhastauna basefirmedebajodelsuelocohesivo. La seguridad de los taludesensueloscohesivosdepende dela pendienteyaltura.El textotambi6n evalialos taludesde sueloscon cohesi6nyfricci6n interna.Laseguridaddelostaludesendichos suelostambi6ndependede supendientey altura.lapoussde desterresde Rankine. Eng~n~ral larupture d'unmatdriau coherenthomog~ne serale longd'une surfacecourbe. Dans le texteond6crit lescaractdristiques gdn~ralesdesglissementsde sol coh6renthomog6ne.Lajustificationmath~matique dececin'estpas inclusedans le texte reproduit pourcerecueil; nousavons inclus le r6sultatfinal,en formede tablesdecalcul. Le centre dela surfacecourbederuptured'unsolcoherenthomog~ne peut6tred6termin6en seservant destablesdecalcul.Enutilisant I'angledu talus8et le rapportentre lahauteur et la profondeurdutalusetunebase rdsistanteau dessousdusol coh6rent, letypedorupture potentielle(par la baseou de talus)et lecentreducerclecritique,peuvent6trecalcul6sgraphiquement. Las~curit6 des talusdesolscohdrents depend de leur inclinaisonetde leurhauteur.Ondvalue aussi les talusdesolscoh~rentsAfrottement interne. Las~curit6 destalusdans


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dependent on both steepnessandheight.The textalso evaluatesslopes on soilswithbothcohesionand internalfriction. Thesafetyofslopeson thesesoils isalsodependentonsteepnessand height.Achartsolution thatusestheslope angle8 and theangleof internal fric-tion0 ispresented. Failures in soilswith bothcohesionand internal frictionwill occuralongtoe.circlesunless0 issmallerthan approximately30Afurtherdescriptionof the useofthechartsmentionedabove is included inthenextselected text.Amethod ofinvestigating irregular slopesonnonuniform soil isdescribed inthetextas is theinvestigation ofacompositesurfaceofsliding (anoncircular slipplane). Both these investigationsuse themethod of slices.This textpresents thetheoryof themethod of slices.Apractical solu-tion usingthe methodofslices is included inthefifthselected text.

Sepresenta unasoluci6nen diagrama queutilizaeldngulo detaludpyeldngulodefric-ci6n interna0. Lasfallasen lossueloscohesivosyconfricci6n internaocurrirc.nalo largodeloscirculos que pasanporel piedetalud al menosque0sea menorque aproximadamente30.En elpr6ximotexto seleccionadose han incluldo mdsexplicacionesdelusode losdiagramasmen-cionadosarriba.Sedescribeen el textounm~todo deinvesti-gar lostaludesirregula,-esen suelonouniforme,

comotambi~n lainvestigaci6n de una superficiededeslizamientocompuesta (un pianodedesli-zamiento nocircular). Ambas investigacionesutilizanel m~tododetajadas, lateorfadel cualespresentada en estetexto.Una soluQi6n prdc-ticautilizandoestem6todose incluyeen elquinto textoseleccionado.cessolsdepend ausside leurhauteuretdeleurinclinaison. Unesolutionpartabledecalcul,quiutiliseI'angle du taluspetI'angle defrottementinterne 0est prdsentde. La rupturedesmat6-riauxd~critsci-dessus seproduiraaupieddutalus,Amoins que0soitplus petitqu'Apeupros30.Unedescriptionplus dlabor~e de I'emploides tablesdecalculdontnous venonsdefairemention, est incluse dansle textechoisisuivant.Unem~thoded'investigation destalus irr~gu-liersde solsnon-uniformes estd6critedansletexte,ainsique I'investigation d'unesurfacedeglissementcomplexe (plandeglissementnon-circulaire). Ces deuxenqu~tesutilisent lamd-thodedes tranches,et danscetexteonex-pliquelath6oriedecette m6thode. Uneappi-

The third text, ChartSolutionsforAnalysisofEarth Slopes, appeared inHighwayResearchRecord345 (HighwayResearch Board, 1971). Itcompiles practicalchartsolutionsfortheslopestabilityproblemand isconcerned with theuseofthesolutions ratherthan with theirderivations.Theprevious tex'.:described thedevelopmentforthefigures presentedunder theTaylorSolutionsection of thistext.Also included in this paperare (a)the Bishop and Morgenstern Solution,which isbasedon an adaptationof theSwedishslicemethod; (b) theMorgenstern Solution,which canbeusedfor highwayembankmentsthatattimesactasdams; (c)theSpencerSolution,which isamore generalized solution ofBishop'sadaptationof theSwedish slicemethod; (d)the HunterSolution,which accountsforvariations in thewatertable;and (e)th .Hunterand SchusterSolution,which isaspecialcaseoftheHunterSolution.

El tercertexto,ChartSolutions forAnalysisofEarth Slopes (Solucionesgr~ficasparaelandlisisdetaludesde tierra), apareci6enelHighwayResearchRecord345(Registrode investigaci6n vial345,HighwayResearch Board,1971). Compilasoluciones factibles en diagrama para el problema deestabilidad detalud xy seconciernecon el usode lassoluciones,mAs queconsusderivaciones.El texto previodescribecomose desarrollaron las figuraspresentadas en lasecci6nde laSoluci6ndeTaylorenestetexto.Tambi~n se incluyenenestearticulo (a) laSoluci6nde BishopyMorgenstern, quesebasa enunaadaptaci6ndelm~todo suecodetajadas; (b) laSoluci6ndeMorgenstern, quesepuede utilizarpara losterraplenesdecarreteras que avecesact0ancomo presas; (c)laSoluci6n deSpencer,quecation pratiquede lam~thodedes tranches estinclusedans le textechoisino. 5.Letroisi6metexte, ChartSolutionsforAnalysisofEarth Slopes(TablesdecalculpourI'analysedetalusen terre) a6t6publiddans I'HighwayResearchRecord 345 (HighwayResearchBoard, 1971). On y pr~sentedessolutionsauprobl~medelastabilit6des talusA'aidedetablesdecalcul,eton met I'emphasesurI'application pratiquede cessolutionsplut6tquesurleurs d6rivations.Dans letexte precedentonad~crit led~veloppementdesfigures utilis~esdanslasolutiondite deTaylorpr~sent~e danscetexte.On inclutaussi danscetexte(a) lasolutiondeBishopet Morgenstern, bas6esuruneadaptationsu6doisede lam6thode destran


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This textprovides asampling of the chartsdeveloped forthe solutionsofanumber of typesofslopestabilityanalyses.For more completesetsofcharts foranyofthese solutions, thereader is referred to the references accompany-ingthis text.The fourth text,Slope DesignGuide, isex-cerpted from TransportationEngineering Hand-book(Region6, U.S. Foreign Service,1973). Itwas prepared for engineers andtechnicianswho are required todesign roads butare notskilledsoilsengineersor engineeringgeologists.Itrepresents an attempttoreflectsoils-engineering principlesduring the routine designesuna soluci6nmds generalizadade laadapta-ci6nde Bishopdel m6todo suecodetajadas;(d) laSoluci6n deHunter,quetoma enconsid-eraci6n fluctuacionesdel nivel fre~tico; y (e) laSoluci6n deHuntery Schuster,quees un casoespecial de laSoluci6nde Hunter.Este textopresentaunmuestreo de los dia-gramas desarrollados paralas solucionesdevarios tiposde an~lisisdeestabilidad detaludes.Si el lectordeseaun juegode dia-gramas mds completopara cualquierade estassoluciones, deberci referirsea las referencias in-clurdos al final deestetexto.El cuarto texto,SlopeDesignGuide (Gulaparael disefiodetaludes), fueextrardo deTransportationEngineeringHandbook(Manualparalaingenierfa detransporte, Region 6,U.S.ForestService, 1973).Fue preparadopara losingenierosy t~cnicosqueson encargadosdelches, (b)lasolution de Morgenstern qui peut treutilisdepourdes remblais routiersdevantservirdedigueAI'occasion, (c)lasolutiondeSpencerquiestune solutiong6ndralisdede I'adaptationdeBishopdelam~thode suddoisedestran-ches,(d)lasoldtion deHunterqui prend encompte leschangements deniveaudelanappephr6atique,et (e) lasolutiondeHunteretSchus-terquis'appliqueAun casspecialde lasolutiondeHunter.Dans cetexte ontrouvera unaperqudestablesdecalculd~velopp~es poureffectuerplusieurssortesd'analyse destabilit6 detalus.Pourunes~rie pluscompletedetablesdecal-culpourchacunede cessolutions, le lecteurestinvit6Alirelesr6f~rences quisuiventcetexte.Lequatri~me texte, SlopeDesignGuide (Ma-nuel'de dimensionnementdestalus), estextraitdeTransportationEngineeringHandbook (Re-gion 6,U.S. Forest Service, 1973).Ce livreadtLdcritAl'intentiondes ing6nieurset techniciens

ofhighwaycut-and-fill slopesand,assuch, re quiresmanyassumptions and simplifications.Theprocedures are notintended toreplacethetypesof investigationsandanalyses describedintheprevioustwotextsor inthenexttext.Rather, they aremeantto be anaid whenmoredetailed investigationsarenotpractical becauseoffactors suchascost,value of theroad involved, manpower, and availableskilllevels.Thisguide isbased on soilproperties thatareidentified by theUnified classification system.(See Compendium 6,Selected Text 1, forcomparisonsofvarious soilclassification systems.) Itisusablewithout conducting laboratorysoilsdiseiodecaminos,peroque nosonespecialistasen la ingenierfadesuelos ni en lageologfaingenieril. Tratadeutilizar losprincipicsdelaingenierfade suelosduranteel diseho rutinariodetaludesdecorteyde rellenoy, por lotanto,requiere muchas suposicionesysimplificaciones.Estos procesosnointentanreemplazar los tiposdeinvestigaci6nyan.lisisdescritos en losdostextos previosni el textosiguiente. Se handiseiadoparaayudar cuandoinvestigaciones m~s detalladas noserfan factiblespor raz6n defactores comocosto,valordelcamino involucrado,mano deobra,ylos nivelesde habilidad disponibles.Lagufasebasaen propiedades de sueloquese identifican porel sistemadeclasificaci6nunificadadesuelos. (Vedse Compendio 6, TextoSeleccionado1,para comparacionesentrevariossistemas declasificaci6n desuelos.) Sequidoiventconcevoiretdimensionnerdesroutes, maisnesontni specialistesdelatechni-'que dessols,nigdologues.Onessaiedetraiterdesprincipesdelatechniquedessolspour ledimensionrement normal destalus routiers deremblaiou ded6blai,etdece fait,le texteassumeetsimplifie beaucoupdechoses.Cesproc~dsnedevraient pas remplacer les investigationset lesanalyses d6critesdanslesdeuxtextesant6rieurset danscelui quivasuivre.Nouslesavons incluses pour lescasoti iln'estpaspossibledefairedes analysesplusapprofondies, Acausedeconsiderations 6conomiques ou de main d'oeuvre,deniveaud'expertisedisponible,ou d'importancede la routeenquestion.Cemanuel estbas6sur lescaract6ristiquesdessols selon lesyst~medela ClassificationUnifi6e (voir le recueil no.6,textechoisi no.1,pourlacomparaisondediffdrentssyst~mes declassification dessols).On peutremployersans


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shearstrengthtestsbecause itisbased inpartonsoilidentification asdescribed inCompen-dium 2,SelectedText 6,and the simplified testsdescribed inCompendium 7,SelectedText3.Theguidewasdevelopea irom typicalsoilstrength valuesbyusing chartsolutions forslopestability,studiesthatuse theconventionalmethod ofslices,publishedempirical relations,andtheauthors' experiences.The followingdatawere used todevelopthisguide:1.Theeffectofseepage incoarse-grainedmaterials wasdetermined byusingone-half theangleof internalfriction(/2) astheeffectiveangleof internal friction forthehighground-watercondition.

porquese basaenparte en laidentificaci6ndesuelos,comose describeen el Compendio2.TextoSeleccionado4; identificaci6nde rocas,comose describe enel Compendio2. TextoSeleccionado6; y laspruebassimplificadasdescritasenel Compendio 7,TextoSeleccionado3.Lagufasedesarroll6 devalores tfpicos de resistenciadelsueloutilizandosolucionesgrdficas paralaestabilidaddetaludes,estudiosen quese utilizael m~todoconvencionaldetajadas, relacionesemplricaspublicadas,y las experiencias delos autores.Seutilizaron lossiguientes datosparadesar-rollar estagula:

1.El efectodefiltraci6nen losmaterialesdegranulaci6n gruesafuedeterminado utilizandolamitad deldngulo de fricci6n interna (0/2)comoel Anguloefectivode fricci6ninternaparalacondici6nde aguasubterrcnea cercade lasuperficie.

puede utilizarsin realizarpruebas de laboratoriode resistenciade suelosal esfuerzocortantefaired'essais en laboratoirepour d6terminer lar6sistanceau cisaillementdessols,carilestbasden partiesur l'identificationdessolstellequ'elleestd6critedans le recueilno.2, textechoisino.4-Identification desroches- d6-critedansle texteno. 6dum~merecueil;et le sessaissimplifi6sd6critsdans le texte no. 3durecueil no. 7.Le manuela 6t6 d6velopp6 Apartirdevaleurstypiquesderesistancedes solsenutilisantdes tablesdecalculpour lastabilit destalus,d'6tudesqui utilisent lam6thodeconven-

2. Theanglesof internal frictionused for thedevelopment ofthemaximum slope ratios inTableli:andsandGravelswithNonplasticFines (page 90)areas follows:Soil SoilType AngleofInternalFrIctionNumber (degrees)1 Sandygravels 34 502 Well-gradedsands, 32 45Iangulargrains3 Siltygravels 27 34-,andsands,uniform sands.,

3. The soil strength valuesusedforthedevelopmentof ChartsIandIh.andsandGravelswithPlasticFinesareas follows:

2. Loscngulosde fricci6ninterna utilizadospara eldesarrollode las razonesmdimasde...talud en la TablaIhArenasyGravas conFinosNoPlbsticos (pdgina90)soncomo sigue:No Angulode fdccl6nlnteme(grados) T podesuelo desuelo Suelto Densa1 gravesarenosas . -34; -23

arenasblengraduadas,granosangularesgravesyarenas

:32j27

.. 4534fangosas,arenasuniformes 3:,-3. LosValores deResistenciadelSueloquese utilizaronenel desarrollode losDiagramasIyIh:renasy GravasconFinosPldst/cossoncomosigue:

tionnelledestranches,derapports empiriquesquiontdtdpublids,et deI'expdrience personnelledes auteurs.Ons'estservidesdonndesci-dessouspourd6velopper ceguide:1. L'infiuencedelapercolation sur lesmat6riauxd&granuleuxgrossiersa6tscalculeen utili-santlamoiti6 de 'anglede frottement interne(0/2)comme anglede frottementinterne reel, quandleniveaude 'eauphr~atiqueest6lev6.

2. Les anglesdefrottement interneutilisdspourcalculer lescoefficientsmaximaux desta


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Soil Sol AngleofInternal CohesionNumber Type Friction(degrees) (ib0)1 (Seepage 93 20 1oo2 fordescription 15 750,3 of thesesoils.) 13 5004 15 2505 10 .250

4. Thesoilstrengthvalues used forthede-velopmentof Charts Ill andIV: FineGralnedSoilsareasfollows:Sil Soi Angle ofInternal -CohesionNumber Type Frition(degrees) (efti )Num er 96-97pees) 03000r 2

1 *(See pages 96-97 0 ;3;.2 fordescription 0 15003 of thesesoils.) 0", - 750,4 0 4005 0 200

No 77po Angulodefrccl6n oheslonde suelo de suelo Interna(grados) (ibraspl62)1 vWase la pdgina 93 20 1000,2 paraIadescripcl6n 15 7503 deestossuelos 13 5004 15 2505 10 250

4. Los ValoresdeResistencia delSueloutilizadosen el desarrollodelos Diagramas IlyIV- SuelosdeGrano Fino soncomosigue:

lusde latableI1:ablesetgraviersavecfinesnonplastiques p.90sontlessuivants:NO Type AngledefrottementInternedusol desol (endegr6s)nontass6 dense1 gravierssableux 34 502 sableAbonne 32 45granulomdtrie,grainsangulaires3 graviers limoneux 27 34at sables,sableuniforme

3. Lesvaleurs derdsistancedessolsutllisdespourled6veloppementdestables Iet.II:.Sablesetgraviersavecfinesplastiques sont lessuivan-tes: .I-, " " :,....lNo., Type . Angl1edefrottement eo Cohesion- dusol 1 'interne (endegrs) (lvresIpled2)desol,

1 voirpage93, 20. 10002 pour Ia3 ,. description. . 13 5004 15 2505 10 250

Itmust be emphasizedthat thisguide mustnotbe followed indiscriminatelyas a preciseanswer toall situations. Itmust be used inconnectionwith localexperiencetoarrive at reasonablevalues forslope ratios. v Thefifth text, Determining CorrectiveActionforHighwayLandslideProblems, taken fromHighwayResearchBoardBulletin49 (HighwayResearch Board, 1955), presentsthe basicfundamentals of landslideanalysesand classifiesthecorrective measures commonly used incontrollingoravoiding highway landslide problems.Itdescribes thepreliminaryanalysisof a landslide,thedetailedfieldstudy of thelandslidearea,and astabilityanalysisofan actual landslide insilty-claysoil overlying bedrock.

Thestabilityanalysisdescribed is a compositeofnumerous methods thathave appeared in the

Nodesuelo Tipodesuelo AngulodefriccibnInterna (grados) Cohesi6n(lbraslpl62)1 vWaselas 0 300023 p~ginas96-97paraIadescripcidn 00 "15007504 deestossuelos 0 4005 .0 200

Deberd subrayarse queestagulano deberdseguirseindistintamente como respuestaprecisapara todasituaci6n.DeberA utilizarseenconexi6ncon laexperiencia localpara Ilegara

4. LesvaleursderesistancedessolsutilisdesdanslestablesIIIt IV:Sols&grainsfinssontlessuivantes:No. Type Angledefrottement oh6slondusol desol Interne (endegr6as) (livres/pled2)1 voirpages96-97 0 30002 pourla description 0 .15003 decessols 0 7504 0 4005 0 200

slopes analyses and stabilization

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