工程地质课件

Chapter2Theformationofsoil

anditsengineeringproperties

土的形成和土的工程性質1theimportanceSoilsaretheresultsofnaturalgeologicalhistory,atthesametimesoilsarealsothemostcommonmaterialsdistributedonthegroundsurfaceoftheearthcrust.Theengineeringpropertiesofsoilshavecloselyrelationswiththeengineeringactivitiesofhumanbeing.Becauseofcomplexitiesofsoils,manyengineershavebeenpaidmuchattentiontothestudyonsoils.Insomesense,thecomplexitiesofsoilsaremainlyfromthecomplexityofformationprocessofsoilsandthecomplexitiesofsoilsconstitution.Inthischapter,Wearemainlyconcernedwiththeformation,constitutionofsoils,theclassificationofsoilsbasedonthedifferentformation,sinceothersaspectsaboutsoilswillbediscussedinsoilsmechanics§2-1

Soilformation2thesoilsdefinition

Soilsareporousnaturalmaterialscomposedofinorganicandorganicmatter,soilsaretheendproductfromweatheringrocks.(Alsowecanmerelytakeitasastageinthegiganticcycleofmineralrecyclingbythemovementoftectonicplates)3theinfluencingfactorsofsoilsformationparentmaterial

time

climate

atmosphericcomposition

topography

organisms§4-2Themaintypesofsoils

basedontheformationprocess

Generallyspeaking,theengineeringpropertiesofsoilsaremuchinfluencedbythevarietiesofformationprocess.Sointhisaspect,itisimportantforacivilengineertoknowthesoilstypesbasedonformationprocess.1Eluvialsoils(殘積土)

Theeluvialsoils（residualsoils）arethedirectproductsof

weathering,theyareformedintheplacewheretheirmotherrocksarelocated.Features:

●solublematerialshavebeencarriedaway

●thecompositionhastherelationwiththemotherrock●differentparticlesize

●obviousedgeandcorner

●thicknesschangegreatlylowerpsephicity[si’fisiti]motherrockeluvialsoils2Slopedeposits(坡積物)Qdl

Theslopedepositsareformedfromerosionofsurfaceflowalongthemountainslopesurface.afterbeingcarriedtothefootofhillbysurfaceflow(面流),wherethespeedofflow（流速）

willslowdownandtheslacksedimentswilldepositthere.沖溝形成過程圖Features:

●slackcondition

●thecompositionhasnorelationwiththebadrock●

fineparticlesize

●obviousedgeandcorner

●thinthickness

●lowerpsephicity[si’fisiti]

Thepluvialdepositsaremorecommonlydistributedalongtheconnectionzonesbetweenthemountainousareasandplainareas.Thefloodwatercausedbyheavyrainorsnowdissolvedwhentemperatureriseupisthedynamicresource.3Pluvialdeposits(洪積物)QplABCAthezoneforgroundwaterleveldeeplyburied

◆largegrainsize

◆lowercompressivefactor

◆Higherbearingcapacity

◆

lowerpsephicityBZoneforgroundwateroverflowing

◆

sandysoilsandclayaredepositedalternatively

◆thegroundwatershallowlyburiedCZoneforperiodicdryanddampcondition◆clay◆engineeringpropertiesdependsondampcondition洪積扇地形4.Alluvialsoil沖積物

(Qal)（1）thedefinitionofAlluvialsoilAlluvialsoilsaretheresultsofrivergeologicalAction.(includingrivererosion;carrying;sedimentation)

CuterosionV字型河谷（上游）SideerosionandsedimentationU字型河谷（中游）Sedimentation成形型河谷地上河（下游）（2）rivergeologicalaction河流側蝕作用牛軛湖的形成Theresultofsideerosion侵蝕階地階座基地（侵蝕堆積）堆積階地（內迭階地）Theformationofriverterrace階地的形成河床河漫灘河谷斜坡一級階地二級階地三級階地（3）FacesofRiverdeposits

◈riverbedfaces（河床相）:

coarsesand,gravel,boulderwellpsephicity

◈

terracefaces（階地相）:

upperpart→finesand

lowerpart→riverbedfaces◈oxbowlakefaces（牛軛湖相）:

swampd<0.005mm

ooze:highwatercontenthighporosity,lowerstrength,highcompressive5.Lakedeposits(QL)6

Seadeposits(Qm)海積物7

Winddeposits(Qeol)風積物windsand（風積砂）wind-loess（風積黃土）

collapsiblesoil

uniform,homogeneous

porous,scatteredstructure8

Glacialdeposits(Qgl)冰積物河谷橫斷面及各部位名稱§4-3Mineralcompositioninsoils1Primaryminerals（原生礦物）

2Secondaryminerals(unsolvablewithwater)

次生礦物

3Solublesaltanddecomposedminerals

可溶鹽類

4Organicmaterials（有機物質）階地的類型1Primaryminerals（原生礦物）

◈Primarymineralsarefrommagmarock,theyaremainlyquartz,feldspar,ice,amphibole

◈

generalfeatureofPrimaryminerals:

--Stableinchemicalproperties--weatheringresistance--GoodperformanceofengineeringProperties河谷的形態階地的類型2secondaryminerals

（次生礦物）

◈Primarymineralsarefromtheprocessofsoilsformation,theyare

①

clayminerals（黏土礦物）

Kaolinite，montomorillonite，watermica

②SiO2,Al2O3,Fe2O3:colloidalstate

③

Oxidizedmaterial（）

Themineraldescribedaboveisveryimportanttotheengineeringpropertiesofsoil.Reasonare：

mineralparticlesurface→surfacepowerabsorbingwateraffinity(親和力)

3Solublesaltanddecomposedminerals

可溶鹽類

solublesalt:NaCl,Caso4.2H2O(石膏),

CaCO3(calciumcarbonate)

salinizedsoil(鹽

土)

Usually,solublesaltinsoildon’thavemuchinfluencetosoilengineeringproperties,becauseitslittlecontent(indroughtarea,saltcanbeaccumulatedintheupperpartsofgroundsurface),Butifsoilcontainingmuchsaltreactwithwater,theconnectionbetweensoilgrainwilldisappear,sothesoil’sstrengthandstabilitywillbedecreased.4Organicmaterials（有機物質）

Whichusuallyexitsintheooze.Whencontentofoozeismorethan5%.Theinfluencewillbeobvious.§4-4Thestructureandtectonicsofsoils

(土的結構與構造)一、soilsstructuretype(土的結構類型)Whichmeanthecharacteristicsofsoilgrainandtherelationshipsamonggrains.

thesizeofgrain

Shapeandroughnessofgrain

arrangementofgrainand

connectionbetweendifferentgrain

1.

SingleParticleStructure(SPS)(crushedstone,gravel,sand)

--d>0.074mm

--nocohesion,nocapillarywater

--permeabilityisobvious

--highstrengthandlowdeformatio

2honeycombstructure

d<0.075mm

--siltgrain(粉粒

d=0.075-0.005mm)

--claygrain(粘粒

d<0.005mm)

--sandgrain(砂粒

d=2-0.074mm)

3cottonstructure

whichinsomesenselikehoneycombstructureTheclayusuallyhavethehoneycombandcottonstructureandhavetheengineeringpropertiesasbelow：

d<0.005mm

bigporosity(50%-98%)

easytobedeformed

watercontent(w)>75%

unstablewhenencounterwater二.Thetectonicsofsoil（土的構造）

soil’stectonicsmeanthespaceshapeofsoillayer.♦Innorth-westarealoess—verticalcracks

♦Incoastarea,softclayhaveusuallydistributed,stratifiedstructure,isotropicsoil§4-5Theindexofphysicalpropertiesofsoils(土的物理性質指標)soils’sthree-phasecomposition

liquidsolidairV：

totalvolumeofsoilsW:totalweight(KN)Vs:solidvolume

Ws:solidweightVw:watervolumeWw:waterweightVa:airvolumeVv:porevolumeVWV=Vs+Vw+Va=Vv+VsW=Ws+Ww(1)

relativeunitweight(G)土的相對密度unitweightofsolidmineralparticleunitweightofwater(10KN/m3)

（2）unitweight土的重度（3）dryunitweight土的幹重度

whichindicatethedensityofsoilsgrain（4）saturatedunitweight飽和重度

（5）effectveunitweight土的有效重度（6）watercontent(w)土的含水量

Thewatercontentinsoils,especiallyincohesivesoils,hasmuchinfluenceontheengineeringpropertiesofsoils.Sothedeterminationofwatercontentisnecessary(7)saturationdegree飽和度（8）porosity(n)空隙度(9)relativeporosity(voidratio)孔隙比Chapter2Rock第二章岩石Sincemineralsarethebuildingblocksofrocks,itisimportantthatyoulearntoidentifythemostcommonvarieties.Mineralscanbedistinguishedusingvariousphysicaland/orchemicalcharacteristics,but,sincechemistrycannotbedeterminedreadilyinthefield,thephysicalpropertiesofmineralsareusedtoidentifythem.§2-1:Themainmineralsintherock(造岩礦物)♥

Crystalform（晶形）

♥

Hardness（硬度）

(relativetoasteelbladeoryoufingernail),♥

colour(真色，假色，它色)

♥

Luster（光澤）

♥

Streak(條痕)

(thecolourwhenamineralisgroundtoapowder).

♥cleavage（解理）Physicalpropertiesofmineralsincludefeaturessuchas：Quartzishard-itcaneasilyscratchasteelknifeblade.Inmanyrocks,quartzgrainsareirregularinshapebecausecrystalfacesarerareandquartzdoesnothaveacleavage(ie,itdoesnotbreakonregularflatfaces).1Quartz(石英):Quartzisaglassylooking,transparentortranslucentmineralwhichvariesincolourfromwhiteandgreytosmoky.Whenthereareindividualcrystalstheyaregenerallyclear,whileinlargermassesquartzlooksmoremilkywhite.油脂光澤

Feldsparisalsohardbutcanbescratchedbyquartz.Feldsparinigneousrocks（火成岩）formswelldevelopedcrystalswhichareroughlyrectangularinshape,andtheycleaveorbreakalongflatfaces.Thegrains,incontrasttoquartz,oftenhavestraightedgesandflatrectangularfaces,someofwhichmeetatrightangles.2Feldspar（長石）:Feldsparistheothercommon,light-colouredrock-formingmineral.Insteadofbeingglassylikequartz,itisgenerallydulltoopaque（不透明）

withaporcelain-likeappearance.Colourvariesfromred,pink(orthoclase正長石),andwhitetogreen,grey(plagioclase斜長石).Plagioclase斜長石Orthoclase正長石Themostcommonamphiboleishornblende（角閃石）.Hornblendeisquitesimilartoaugite（普通輝石）

inthatbotharedarkminerals,howeverhornblendecrystalsaregenerallylonger,thinnerandshinierthanaugiteandthemineralcross-sectionsarediamond-shaped.hornblende（角閃石）3Amphibole（閃石）Themostcommonpyroxenemineralisaugite.Augiteisgenerallydarkgreentoblackincolourandformsshort,stubby（短而粗）

crystalswhich,ifyoulookatanend-onsection,havesquareorrectangularcross-sections.Pyroxene（輝石）4Pyroxene輝石Talcoccursingranular（粒狀的）

orfoliated（片狀的）

massessometimesknownassoapstone（皂石）.Itiswhitetogreen,sometimesgreyorbrownish.Itisverysoftandwillbescratchedbyafingernail.Ithasagreasyfeel（滑感）5Talc（滑石）Olivineinthejewellerytrade,isyellow-green,translucent（半透明的）

andglassylooking.Crystalsarenotcommon;itusuallyoccursasroundedgrainsinigneous（火成的）

rocksorasgranularmasses.Olivineisalmostashardasquartz;itdoesnothaveawell-developedcleavage.6Olivine橄欖石Micaiseasilydistinguishedbyitscharacteristicofpeelingintomanythinflatsmoothsheetsorflakes（薄片）.Thisissimilartothecleavageinfeldsparexceptthatinthecaseofmicathecleavageplanesareinonlyonedirectionandnorightanglefacejoinsoccur.Micamaybewhiteandpearlyordarkandshiny.7Mica雲母8Gypsum(plasterstone,石膏)9Kaolinite(高嶺石)10Montmorillonite（蒙脫石）11Watermica（伊利石）§2-2:Rock(岩石)(一種或多種礦物組成的集合體)

一、Theclassificationofrockaccordingto

thecauseofformation

igneousrock（岩漿岩）

(magmarock)

sedimentaryrock（沉積岩）

metamophicrock（變質岩）

岩石二、

Igneousrock1theformationofigneousrock:DeepwithintheEarth,rockiskeptinamolten（融熔的）

stateduetoextremetemperatureandpressure.

Thismoltenrockiscalledmagma（岩漿）.

Themagmaisconstantlymovingandsometimesmovesitswaytothesurfacethroughthecracks（裂縫）inthesolidrock.

Onceitreachesthesurface,itiscalledlava（熔岩）.

Thelocationitpushesthroughtothesurfaceiscalledavolcano（火山）.

Theopeninginthevolcanothatthelavaeruptsoutofiscalledavent(出口).

Formanyvolcanos,thereismorethanonevent.

Oftenvolcanoshaveafunnel（漏斗）shapewithapitatthetop.

Thispitiscalledavolcaniccrater（火山口）.

Ifthiscraterbecomesverylarge,thewallsofthecratermightcollapsetoproduceafeaturecalledacaldera（噴火山口）HowIgneousrockrockIsFormedPyroclasticash(火山灰)Batholith岩基Captivemass俘虜體laccolith岩盤岩牆Rockwall岩株Volcanoneck火山頸Lavaflow岩流theformationstateofigneousrock（岩漿岩的產狀）Sill岩床3theclasscificationofigneousrock（岩漿岩的分類）

（1）Accordingtotheformationstate(按產狀)

◈IntrusiveIgneousRocks（侵入岩）

-usuallymediumtocoarsegrainedtextureduetoslowcooling.

Typicallylightcoloured.

◈

ExtrusiveIgneousRocks（噴出岩）

-glassyorfine-grainedduetorapidcooling.Mayhavevoidsduetodegassingofthemagma.Typicallydarkcoloured.

(2)AccordingtotheSilicaContentandMineralComposition(根據二氧化矽含量)

◈

AcidIgneousRocks(酸性岩)-silicarich(>65%byweight)composedmainlyoflight

colouredminerals(eg.feldspars,quartz)

◈IntermediateIgneousRocks（中性岩）

silica50-65%byweight,composedmainlyoffeldspars,

some

mafic（鐵鎂質的

minerals,withsomequartz.

◈BasicIgneousRocks（基性岩）

-silicapoor(<50%byweight)containsignificantamountsofmaficordarkcolouredferromagnesianminerals(eg.olivines,pyroxenes,

amphiboles,micas).Nofreequartz.thedescriptionofmainigneousrock

（岩漿岩描述）

◈

granite（花崗岩）

Graniteisanigneousrockthatiscomposedoffourminerals.

Thesemineralsarequartz,feldspar,mica,andusuallyhornblende.Graniteformsasmagmacoolsfarundertheearth'ssurface.Becauseithardensdeepunderground，itcoolsveryslowly.Thisallowscrystalsofthefourmineralstogrowlargeenoughtobeeasilyseenbythenakedeye.Graniteisanexcellentmaterialforbuildingbridgesandbuildingsbecauseitcanwithstandthousandsofpoundsofpressure.Itisalsousedformonumentsbecauseitweathersslowly.Engravingsinthegranitecanbereadforhundredsofyears,makingtherockmorevaluable.GraniteisquarriedinmanyplacesintheworldincludingtheUnitedStates.TheStateofNewHampshirehasthenickname"GraniteState"becauseoftheamountofgraniteinthemountainsofthatbeautifulstate.TheCanadianShieldofNorthAmericacontainshugeoutcroppings(surfacerocks)ofgranite.

◈

porphyriticgranite

(花崗斑岩)

shallowintrusiverock（淺成侵入岩）

moderatecrystallization（中等結晶）

porphyriticstructure斑狀結構

quartz-feldspar-blackmica花崗斑岩

◈

rhyolite（流紋岩）

Rhyoliteisverycloselyrelatedtogranite.Thedifferenceisrhyolitehasmuchfinercrystals.Thesecrystalsaresosmallthattheycannotbeseenbythenakedeye.Rhyoliteisanextrusiveigneousrockhavingcooledmuchmorerapidlythangranite,givingitaglassyappearance.Themineralsthatmakeuprhyolitearequartz,feldspar,mica,andhornblende.Rhyolite流紋岩

◈

Diorite(閃長岩)

1abyssalintrusiverock2wellcrystallization3feldspar,quartz,amphibole◈Dioriteporphyrite（閃長玢岩）1shallowintrusiverock,2mediancrystallization3feldspar,quartzamphiboleDaciteisanextrusiveigneousrock.Theprinciplemineralsthatmakeupdaciteareplagioclase,quartz,pyroxene,orhornblende.Dacite安山岩◈Dacite（安山岩）Andesite

◈

pyroxenire(輝岩)

1abyssalintrusiverock2wellcrystallization3amphibole,phyroxenefeldsparBasaltsaredarkcolored,fine-grainedextrusiverock.Themineralgrainsaresofinethattheyareimpossibletodistinguishwiththenakedeyeorevenamagnifyingglass（放大鏡）.Theyarethemostwidespreadofalltheigneousrocks.Mostbasaltsarevolcanicinoriginandwereformedbytherapidcoolingandhardeningofthelavaflows.SomebasaltsareintrusivehavingcooledinsidetheEarth'sinterior.◈basalt玄武岩1ultrabasicrock（超基性岩石）(sio2<45%)2abyssalintrusiverock（深成岩）

3wellcrystallization（結晶好）

4olivine；pgroxene◈

olivinerock(橄欖岩)◈Obsidian黑耀岩Obsidianisaveryshinynaturalvolcanicglass.Whenobsidianbreaksitfractureswithadistinctconchoidal（貝殼狀的）fracture.Noticeinthephototothelefthowitfractures.Obsidianisproducedwhenlavacoolsveryquickly.Thelavacoolssoquicklythatnocrystalscanform.Whenpeoplemakeglasstheymeltsilicarockslikesandandquartzthencoolitrapidlybyplacingitinwater.Obsidianisproducedinnatureinasimilarway.Obsidianisusuallyblackoraverydarkgreen,butitcanalsobefoundinanalmostclearform.Pumiceisaverylightcolored,frothy（起泡的）volcanicrock.Pumiceisformedfromlavathatisfullofgas.Thelavaisejectedandshotthroughtheairduringaneruption.Asthelavahurtles（急飛）throughtheairitcoolsandthegasesescapeleavingtherockfullofholes.◈Pumice（浮石）Pumiceissolightthatitactuallyfloatsonwater.Hugepumiceblockshavebeenseenfloatingontheoceanafterlargeeruptions.Somelavablocksarelargeenoughtocarrysmallanimals.三、sedimentaryrock（沉積岩）

1theformationofsedimentaryrock:

Forthousands,evenmillionsofyears,littlepiecesofourearthhavebeeneroded--brokendownandwornawaybywindandwater.Theselittlebitsofoureartharewasheddownstreamwheretheysettletothebottomoftherivers,lakes,andoceans.Layerafterlayeroferodedearthisdepositedontopofeach.Theselayersarepresseddownmoreandmorethroughtime,untilthebottomlayersslowlyturnintorock.HowSedimentaryRockIsFormedSedimentsaresubdividedintothreetypes:

▦1Clasticordetritalsediments（碎屑岩）

Comprisingparticlesofvarioussizescarriedinsuspensionbywind,waterorice.Sand(砂岩)isanexampleofaclasticsediment.Silt（粉砂岩）andsand

sizeparticlesarecarriedinsuspensionbywind,waterandice.

2theclassificationofsedimentaryrock:

▦2

Chemicalorprecipitatedsediments（化學岩）

whicharecarriedinaqueoussolution.Salt(halite)isanexampleofachemicalprecipitate.·

▦3

Organicorbiogenicsediments（有機岩）

precipitatedoraccumulatedbybiologicalagents.Manyorganismspromotetheprecipitationofcalcitetoformbiogenicallyprecipitatedcalcareous（含鈣的）

muds.3Thetextureandstructureofsedimentaryrock

沉積岩的結構和構造沉積岩的層理構造平行層理斜層理波狀層理印模粒序層理交叉層理沉積岩的結構特徵砂粒孔隙膠結物砂粒粘粒粉粒鐵餅形的Sphericity球形度[sfe’risiti]4thedescriptionofsedimentaryrockConglomeraterocksaresedimentaryrocks.Theyaremadeupoflargesedimentslikesandandpebbles（鵝卵石）.Thesedimentissolargethatpressurealonecannotholdtherocktogether;itisalsocementedtogetherwithdissolvedminerals.◈gravelstone(conglomerate)礫岩(clasticrock)◈

sandstone(d=2-0.05mm)砂岩Sandstonerocksaresedimentaryrocksmadefromsmallgrainsofthemineralsquartzandfeldspar.Theyoftenforminlayersasseeninthispicture.Theyareoftenusedasbuildingstones.◈siltstone(d=0.05-0.005mm)粉砂岩◈mudstone(d<0.005mm)泥岩

kaolinite(高嶺石)

montorillonite（蒙脫石）

watermica（伊利石）MineralCompositionShalerockisatypeofsedimentaryrockformedfromclaythatiscompactedtogetherbypressure.Theyareusedtomakebricks◈shalestone(d<0.005mm)葉岩Limestonerocksaresedimentaryrocksthataremadefromthemineralcalcitewhichcamefromthebedsofevaporatedseasandlakesandfromseaanimalshells.Thisrockisusedinconcreteandisanexcellentbuildingstoneforhumidregions.colorgrey◈limestone石灰岩◈

dolomiterock白雲岩color:white-greymineral:dolomit◈

Gypsum石膏Gypsumrocksaresedimentaryrocksmadeupofsulfatemineralandformedastheresultofevaporatingseawaterinmassiveprehistoricbasins.ItisverysoftandisusedtomakePlasterofParis,casts,molds,andwallboards.四、Metamorphicrock（變質岩）

Metamorphicrocksaregeneratedbyrecrystallizationofeitherigneousorsedimentaryrocksbytheactionofanyorallofthefollowing:Pressure,Temperature,PoreFluids.

Thetypeofmetamorphicrockisdeterminedbytheparentrock（母岩）

andtheP/Tconditions.Ingeneral,metamorphismcauses:

Growthofnewminerals

Deformationandrotationofmineralgrains

Recrystallizationofmineralsaslargergrains1theformationandclassificationofMetamorphicrocks變質岩的形成接觸變質岩的形成區域變質岩的形成2thedescriptionofMetamorphicrocks

◈Marble

（大理岩）Marbleismetamorphosedlimestoneordolomite.Bothlimestoneanddolomitehavealargeconcentrationofcalciumcarbonate(CaCO3).Marblehasmanydifferentsizesofcrystals.

Marblehasmanycolorvariancesduetotheimpurities(雜質)presentatformation.Someofthedifferentcolorsofmarblearewhite,red,black,mottledandbanded,gray,pink,andgreen.Marbleismuchharderthanitsparentrock.Thisallowsittotakeapolishwhichmakesitagoodmaterialforuseasabuildingmaterial,makingsinktops,bathtubs,andacarvingstoneforartists.Today,headstonesaremadefrommarbleandgranitebecausebothoftheserocksweatherveryslowlyandcarvewellwithsharpedges.◈

Quartzite（石英岩）Quartziteiscomposedofsandstonethathasbeenmetamorphosed.Quartziteismuchharderthantheparentrock,sandstone.Itformsfromsandstonethathascomeintocontactwithdeeplyburiedmagmas.Quartzitelookssimilartoitsparentrock.Thebestwaytotellquartzitefromsandstoneistobreaktherocks.Sandstonewillshatterintomanyindividualgrainsofsandwhilequartzitewillbreakacrossthegrains.Chapter6

Themainengineeringgeology

problemsincivilengineering

第六章工程地质问题分析Themaintopicsofchapter6:

§6-1Theerosionofriver(河流的侵蝕)§6-2landslide（滑坡）

§6-3Collapse（崩塌）

§6-4mudflow（泥石流）

§6-5KarstandEarthcave（岩溶和土洞）

§6-6Theengineeringproblemsinundergroundengineering

（地下工程地質問題）§6-1Theerosionofriver(河流的侵蝕)

一、Whatisrivererosion

Whichmeanthedamagetotheriverbedorriverbank,therivererosionisthemostactive,vigorousfactortothechangeoftopography.Norivererosion,nocomplicatedsurface.二、Therivererosion’stype

Whichcanbedividedinto：

sideerosive（側蝕）

cuterosion（下蝕）cuterosion(下蝕)→meansthatthemovingwateranditsmaterialscarriedbywaterhavemotivepowerthatmakesriverbeddeepenedcontinuously.Cuterosionareusuallyobviousinupstreamofriver.

Inbridgeengineering,thelocationoffoundationmustbeconsideredcarefully.Thatistheelevationofbottomsurfaceoffoundationmustwillbelowerthantheerosionbaseline(侵蝕基準面).Erosionline1Erosionline2sideerosiveSideerosionarecausedbytraversecirculationofriver.Theresultsofsideerosionisthatrivervalleyisbroaden.Thesideerosionisobviousinmiddleordownstreamofriver.Preventingmethod:stonecage,changingofriverrouteDirectionofsideerosionDirectionofsideerosionBuildingisnotingoodpositiontraversecirculationofriver

§6-2landslide（滑坡）

一.Thedefinitionoflandslide

Thesoilorrockbodyslidedownalongthefixedslidingsurfaceontheactionofgravity.

Thehappeningoflandslidemaycausethedamageofbuilding,endangerhumanlife,alsocausetheartificalearthquake.

滑坡形態描述滑坡體Slidingbody滑坡床Slidingbed滑坡壁cliff滑坡面Slidingsurface扇形張裂縫Fan-hapedtensivecracks滑坡舌鼓脹裂縫Swellingcracks

剪裂縫Shearcracks

滑坡周界滑坡臺階二.ThefeatureofdifferentpartoflandslideTensioncracks三.Theclassificationoflandslide1.

Accordingtothematerialsdifferenceofslidingbody

■soillandsliding(土體滑坡)

■rocklandsliding(bedrocklandslide)岩層滑坡

■speciallandslides(frozenandthaw、collapeslide)

特殊滑坡■soillandsliding(土體滑坡)

cohesivesoilslandslides（黏土滑坡）

loesslandslides（黃土滑坡）eluvialsoilslandslides（殘積層滑坡）Eluvialsoillandslide

cohesivesoilslandslides■rocklandsliding(bedrocklandslide)岩層滑坡順層滑坡切層滑坡滑動面滑動面movementparalleltoplanesofeaknessandoccasionallyparalleltoslope.■speciallandslides(frozenandthaw、collapeslide)

特殊滑坡凍融層Flow:

viscoustofluid-likemotionofdebris.

2

Accordingtothemechanicscondition

RivererosionArtificialcuttingtractivestylePushingstyle3accordingtothelandslidescalesize四、thedevelopingprocessoflandslide

step1creepdeformationstagenofixedslidingplane

Softrock岩質邊坡的破壞形式：鬆動蠕動剝落4滑坡5崩塌深層蠕動表層蠕動step2failurestage

Thepenetratingfailureplanehasformed;theslidingmassslowlyorquicklyslidesalongthecrackplane，

drunken-liketrees;sabre-liketreesdevelopsinthisstagestep3stablestage

Theslidingmasshasbeeninbalancedpositiondrunkentreeshavebecometogrowvertically五、Themechanicsanalysisandinfluencingfactor土層均勻時：Theanalysis

influencefactorsofsliding

Theinfluencefactorcanbeconsideredasthefactorswhichhavethecontributiontothechangeofsafetyfactor(K)

①

slopeappearance

slophigh;slopeangle,slopeshape②

rockandsoilsproperties

softrock(shale,sandrock)

soilwithmontmorillonitewhichiseasytoabsorb

waterandexpanding.③

structure

theconditionofstrataplane,joint,fault,(dipangle,dipdirection)

④

water

tosoftrockandsoil

⑤

earthquakes

tostimulatetheliquefaction(液化)

toproducetheinertiaforcetorockorsoilbody

⑥

artificialfactors

impropercuttingslope

puttingon(piling)(overlapping)soilorbuildingstructure六、thecontrol(harness)oflandslippingCon