Table Of Content

Fell MacGregor Stapledon Bell Foster Geotechnical Engineering of Dams, 2nd edition provides a comprehensive text on the geotechnical and geological aspects of the investigations for and the design and construction of new dams and the review and assessment of existing dams. The main emphasis of this work is on embankment dams, but much of the text, particularly those parts related to geology, can be used for concrete gravity and arch dams. EG All phases of investigation, design and construction are covered. Detailed descriptions ne go are given from the initial site assessment and site investigation program through to the it preliminary and detailed design phases and, ultimately, the construction phase. The ne ec assessment of existing dams, including the analysis of risks posed by those dams, is eh also discussed. This wholly revised and significantly expanded 2nd edition includes rn i a lengthy new appendix on the assessment of the likelihood of failure of dams by ni c internal erosion and piping. ga ol This valuable source on dam engineering incorporates the 200+ years of collective f experience of the authors in the subject area. Design methods are presented in D combination with their theoretical basis, to enable the reader to develop a proper a m understanding of the possibilities and limitations of a method. For its practical, well-founded approach, this work can serve as a useful guide for professional dam s engineers and engineering geologists and as a textbook for university students. Photograph front: Hinze Dam at completion of Stage 3 construction. Courtesy of The Hinze Dam Alliance (comprising Seqwater, SKM, Thiess and URS). Geotechnical Engineering of Dams 2nd edition 2nd Robin Fell edition Patrick MacGregor David Stapledon Graeme Bell Mark Foster an informa business Geotechnical Engineering of Dams, 2nd edition TThhiiss ppaaggee iinntteennttiioonnaallllyy lleefftt bbllaannkk Geotechnical Engineering of Dams, 2nd edition Robin Fell Emeritus Professor,School of Civil and Environmental Engineering, University of New SouthWales,Sydney,Australia Patrick MacGregor Consulting Engineering Geologist,Australia David Stapledon Consulting Engineering Geologist,Australia Graeme Bell Consulting Dams Engineer,Australia Mark Foster Senior Principal Dams Engineer,URSAustralia,Sydney, Australia Coverillustration:HinzeDamatcompletionofStage3construction.CourtesyofTheHinze DamAlliance(comprisingSeqwater, SKM,ThiessandURS). CRCPress/BalkemaisanimprintoftheTaylor&FrancisGroup,aninformabusiness ©2015Taylor&FrancisGroup,London,UK TypesetbyMPSLimited,Chennai,India PrintedandBoundbyCPIGroup(UK)Ltd,Croydon,CR04YY. Allrightsreserved.Nopartofthispublicationortheinformationcontained hereinmaybereproduced,storedinaretrievalsystem,ortransmittedinany formorbyanymeans,electronic,mechanical,byphotocopying,recordingor otherwise,withoutwrittenpriorpermissionfromthepublisher. Althoughallcareistakentoensureintegrityandthequalityofthispublication andtheinformationherein,noresponsibilityisassumedbythepublishersnor theauthorforanydamagetothepropertyorpersonsasaresultofoperation oruseofthispublicationand/ortheinformationcontainedherein. LibraryofCongressCataloging-in-PublicationData Fell,Robin. Geotechnicalengineeringofdams/RobinFell,Emeritus,Professor,SchoolofCivilandEnvironmental Engineering,UniversityofNewSouthWales,Sydney,Australia,PatrickMacGregor,Consulting EngineeringGeologist,Australia,DavidStapledon,ConsultingEngineeringGeologist,Australia, GraemeBell,ConsultingDamsEngineer,Australia,MarkFoster,SeniorPrincipalDamsEngineer, URSAustralia,Sydney,Australia.–2ndedition. pagescm Includesbibliographicalreferencesandindex. ISBN978-1-138-00008-7(hardback)–ISBN978-0-203-38731-3(ebook) 1. Dams–Designandconstruction. I.Title. TC540.F45 2014 627’.8–dc23 2014040176 Publishedby: CRCPress/Balkema P.O.Box11320,2301EHLeiden,TheNetherlands e-mail:[email protected] www.crcpress.com–www.taylorandfrancis.com ISBN:978-1-138-00008-7(Hbk) ISBN:978-0-203-38731-3(eBookPDF) Table of contents AuthorBiographies xxxiii 1 Introduction 1 1.1 Outlineofthebook 1 1.2 Typesofembankmentdamsandtheirmainfeatures 2 1.3 Typesofconcretedamsandtheirmainfeatures 6 2 Keygeologicalissues 11 2.1 Basicdefinitions 11 2.2 Typesofanisotropicfabrics 12 2.3 Defectsinrockmasses 12 2.3.1 Joints 14 2.3.2 Shearedandcrushedzones(faults) 14 2.3.3 Soilinfillseams(orjustinfillseams) 15 2.3.4 Extremelyweathered(oraltered)seams 15 2.3.5 Theimportanceofusingtheabovetermstodescribedefects inrock 15 2.4 Defectsinsoilmasses 16 2.5 Stressesinrockmasses 17 2.5.1 Probablesourceofhighhorizontalstresses 18 2.5.2 Stressreliefeffectsinnaturalrockexposures 20 2.5.3 Effectsinclaystonesandshales 20 2.5.4 Specialeffectsinvalleys 21 2.5.5 Rockmovementsinexcavations 24 2.6 Weatheringofrocks 26 2.6.1 Mechanicalweathering 26 2.6.2 Chemicaldecomposition 26 2.6.3 Chemicalweathering 27 2.6.3.1 Susceptibilityofcommonmineralsto chemicalweathering 29 2.6.3.2 Susceptibilityofrocksubstancesto chemicalweathering 30 2.6.4 Weatheredrockprofilesandtheirdevelopment 31 2.6.4.1 Climateandvegetation 32 2.6.4.2 Rocksubstancetypesanddefecttypesand pattern 32 vi Table of contents 2.6.4.3 Timeanderosion 38 2.6.4.4 Groundwaterandtopography 39 2.6.4.5 Featuresofweatheredprofilesnear valleyfloors 40 2.6.5 Complicationsduetocementation 42 2.7 Chemicalalteration 43 2.8 Classificationofweatheredrock 43 2.8.1 Recommendedsystemforclassificationofweathered rocksubstance 44 2.8.2 Limitationsonclassificationsystemsforweatheredrock 46 2.9 Rapidweathering 47 2.9.1 Slakingofmudrocks 47 2.9.2 Crystalgrowthinpores 48 2.9.3 Expansionofsecondaryminerals 48 2.9.4 Oxidationofsulphideminerals 48 2.9.4.1 Sulphideoxidationeffectsinrockfill dams–someexamples 49 2.9.4.2 Possibleeffectsofsulphideoxidationin rockfilldams 50 2.9.4.3 Sulphideoxidation–implicationsforsitestudies 51 2.9.5 Rapidsolution 51 2.9.6 Surfacefrettingduetoelectro-staticmoistureabsorption 51 2.10 Landslidingatdamsites 51 2.10.1 First-timeand“reactivated’’slides 53 2.10.1.1 Reactivatedslides 53 2.10.1.2 First-timeslides 53 2.10.2 Importanceofearlyrecognitionofevidenceofpastslope instabilityatdamsites 53 2.10.3 Damsandlandslides:Someexperiences 54 2.10.3.1 TalbingoDam 54 2.10.3.2 ToomaDam 54 2.10.3.3 WungongDam 60 2.10.3.4 SugarloafDam 62 2.10.3.5 ThomsonDam 66 2.11 Stabilityofslopesaroundstorages 70 2.11.1 Vitalslopestabilityquestionsforthefeasibilityandsite selectionstages 73 2.11.1.1 Mostvulnerableexistingorproposedproject features,andpartsofstoragearea?– Question1 73 2.11.1.2 Currentlyactiveorolddormantlandslides?– Questions2and4to7 73 2.11.1.3 Areaswherefirst-timelandslidingmaybe induced(Questions3to7) 75 2.11.1.4 Whatisthelikelypostfailurevelocityand traveldistance? 76 2.11.1.5 Whatisthesizeofimpulsewaveswhich maybecreated? 80 Table of contents vii 2.12 Watertightnessofstorages 80 2.12.1 Modelsforwatertightnessofstoragesinmanyareasof non-solublerocks 80 2.12.2 Watertightnessofstorageareasformedbysolublerocks 83 2.12.3 Featureswhichmayformlocalzonesofhighleakage,from anystoragearea 84 2.12.4 Watertightnessofstoragesunderlainbysoils 85 2.12.5 Assessmentofwatertightness 85 2.12.5.1 Storagesinnon-solublerockareas–assessment ofwatertightness 85 2.12.5.2 Storagesinsolublerockareas–assessment ofwatertightness 86 2.12.5.3 Storagesformedinsoils–assessment ofwatertightness 87 2.12.6 Methodsusedtopreventorlimitleakagesfromstorages 88 3 Geotechnicalquestionsassociatedwithvarious geologicalenvironments 89 3.1 Graniticrocks 89 3.1.1 Freshgraniticrocks,propertiesanduses 89 3.1.2 Weatheredgraniticrocks,properties,usesandprofiles 90 3.1.3 Stabilityofslopesingraniticrocks 91 3.1.4 Graniticrocks:checklist 91 3.2 Volcanicrocks(intrusiveandflow) 91 3.2.1 Intrusiveplugs,dykesandsills 92 3.2.2 Flows 93 3.2.2.1 Flowsonland 93 3.2.2.2 Underseaflows 96 3.2.3 Alterationofvolcanicrocks 97 3.2.4 Weatheringofvolcanicrocks 98 3.2.5 Landslidingonslopesunderlainbyweatheredbasalt 98 3.2.6 Alkali-aggregatereaction 99 3.2.7 Volcanicrocks(intrusiveandflow)checklistofquestions 99 3.3 Pyroclastics 100 3.3.1 Variabilityofpyroclasticmaterialsandmasses 100 3.3.2 Particularconstructionissuesinpyroclastics 102 3.3.3 Pyroclasticmaterials–checklistofquestions 105 3.4 Schistoserocks 105 3.4.1 Propertiesoffreshschistoserocksubstances 106 3.4.2 Weatheredproductsandprofilesdevelopedin schistoserock 106 3.4.3 Suitabilityofschistoserocksforuseasfiltermaterials, concreteaggregatesandpavementmaterials 108 3.4.4 Suitabilityofschistoserocksforuseasrockfill 108 3.4.5 Structuraldefectsofparticularsignificancein schistoserocks 110 3.4.5.1 Minorfaultsdevelopedparallelandatacute anglestothefoliation 110 viii Table of contents 3.4.5.2 Kinkbands 111 3.4.5.3 Mica-richlayers 113 3.4.6 Stabilityofslopesformedbyschistoserocks 114 3.4.7 Schistoserocks–checklistofquestions 114 3.5 Mudrocks 114 3.5.1 Engineeringpropertiesofmudrocks 115 3.5.2 Bedding-surfacefaultsinmudrocks 116 3.5.3 Slickensidedjointsorfissures 117 3.5.4 Weatheredproductsandprofilesinmudrocks 117 3.5.5 Stabilityofslopesunderlainbymudrocks 117 3.5.6 Developmentofunusuallyhighporepressures 118 3.5.7 Suitabilityofmudrocksforuseasconstructionmaterials 118 3.5.8 Mudrocks–checklistofquestions 120 3.6 Sandstonesandrelatedsedimentaryrocks 121 3.6.1 Propertiesoftherocksubstances 122 3.6.2 Suitabilityforuseasconstructionmaterials 122 3.6.3 Weatheringproducts 123 3.6.4 Weatheredprofileandstabilityofslopes 123 3.6.5 Sandstonesandsimilarrocks–listofquestions 126 3.7 Carbonaterocks 126 3.7.1 Effectsofsolution 127 3.7.1.1 Rockmassescomposedofdense,finegrained rocksubstancescomprisingmorethan90%of carbonate(usuallyCategoryO) 128 3.7.1.2 Rockmassescomposedofdensefinegrainedrock substancecontaining10%to90%ofcarbonate (usuallyCategoryO) 130 3.7.1.3 Rockmassescomposedofporous,lowdensity carbonaterocksubstance(usuallyCategoryY) 131 3.7.2 Watertightnessofdamfoundations 132 3.7.2.1 Damswhichhaveexperiencedsignificant leakageproblems 133 3.7.3 Potentialforsinkholestodevelopbeneathadam,reservoir orassociatedworks 135 3.7.4 Potentialforcontinuingdissolutionofjointedcarbonate rockindamfoundations 137 3.7.5 Potentialforcontinuingdissolutionofaggregatesof carbonaterockparticlesandofpermeablecarbonate substances(CategoryOcarbonate,ineachcase) 140 3.7.6 Discussion–potentialforcontinuingdissolutionof carbonaterocksinfoundations 141 3.7.6.1 CategoryOcarbonaterocks 141 3.7.6.2 CategoryYcarbonaterocks 143 3.7.7 Potentialproblemswithfilters’composedof carbonaterocks 143 3.7.7.1 CategoryOcarbonaterocks 143 3.7.7.2 CategoryYcarbonatematerials 145 Table of contents ix 3.7.8 Suitabilityofcarbonaterocksforembankmentmaterials 147 3.7.9 Suitabilityofcarbonaterocksforconcreteand pavementmaterials 148 3.7.10 Stabilityofslopesunderlainbycarbonaterocks 148 3.7.11 Dewateringofexcavationsincarbonaterocks 151 3.7.12 Carbonaterocks–checklistofquestions 151 3.8 Evaporites 151 3.8.1 Performanceofdamsbuiltonrockscontaining evaporites 152 3.8.2 Guidelinesfordamconstructionatsiteswhich containevaporites 152 3.8.3 Evaporites–checklistofquestions 153 3.9 Alluvialsoils 154 3.9.1 Riverchanneldeposits 156 3.9.2 Open-workgravels 156 3.9.3 Oxbowlakedeposits 156 3.9.4 Floodplain,lacustrineandestuarinedeposits 157 3.9.5 Useofalluvialsoilsforconstruction 157 3.9.6 Alluvialsoils,listofquestions 157 3.10 Colluvialsoils 158 3.10.1 Occurrenceanddescription 158 3.10.1.1 Screeandtalus 158 3.10.1.2 Slopewashsoils 159 3.10.1.3 Landslidedebris 159 3.10.2 Propertiesofcolluvialsoils 160 3.10.2.1 Screeandtalus 160 3.10.2.2 Slopewash 160 3.10.2.3 Landslidedebris 160 3.10.3 Useasconstructionmaterials 161 3.10.4 Colluvialsoil–listofquestions 161 3.11 Lateritesandlateriticweatheringprofiles 162 3.11.1 Composition,thicknessesandoriginoflateritic weatheringprofiles 162 3.11.2 Propertiesoflateriticsoils 163 3.11.3 Useoflateriticsoilsforconstruction 164 3.11.4 Karsticfeaturesdevelopedinlateriteterrain 164 3.11.5 Recognitionandinterpretationofsilcretelayer 165 3.11.6 Lateriticsoilsandprofiles–listofquestions 166 3.12 Glacialdepositsandlandforms 166 3.12.1 Glaciatedvalleys 167 3.12.2 Materialsdepositedbyglaciers 170 3.12.2.1 Propertiesoftillmaterials 174 3.12.2.2 Disruptedbedrocksurface beneathglaciers 176 3.12.3 Glaciofluvialdeposits 177 3.12.4 Periglacialfeatures 179 3.12.5 Glacialenvironment–listofquestions 182