工程地质课件

Chapter2Theformationofsoil

anditsengineeringproperties

第二章土的形成和土的工程性质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(残积土)

Theeluvialsoils（residualsoils）arethedirectproductsof

weathering,theyareformedintheplacewheretheirmotherrocksarelocated.Features:

●solublematerialshavebeencarriedaway

●thecompositionhastherelationwiththemotherrock●differentparticlesize

●obviousedgeandcorner

●thicknesschangegreatlylowerpsephicity[si’fisiti]motherrockeluvialsoils2Slopedeposits(坡积物)Qdl

Theslopedepositsareformedfromerosionofsurfaceflowalongthemountainslopesurface.afterbeingcarriedtothefootofhillbysurfaceflow(面流),wherethespeedofflow（流速）

willslowdownandtheslacksedimentswilldepositthere.冲沟形成过程图Features:

●slackcondition

●thecompositionhasnorelationwiththebadrock●

fineparticlesize

●obviousedgeandcorner

●thinthickness

●lowerpsephicity[si’fisiti]

Thepluvialdepositsaremorecommonlydistributedalongtheconnectionzonesbetweenthemountainousareasandplainareas.Thefloodwatercausedbyheavyrainorsnowdissolvedwhentemperatureriseupisthedynamicresource.3Pluvialdeposits(洪积物)QplABCAthezoneforgroundwaterleveldeeplyburied

◆largegrainsize

◆lowercompressivefactor

◆Higherbearingcapacity

◆

lowerpsephicityBZoneforgroundwateroverflowing

◆

sandysoilsandclayaredepositedalternatively

◆thegroundwatershallowlyburiedCZoneforperiodicdryanddampcondition◆clay◆engineeringpropertiesdependsondampcondition洪积扇地形4.Alluvialsoil冲积物

(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河流侧蚀作用牛轭湖的形成Theresultofsideerosion侵蚀阶地阶座基地（侵蚀堆积）堆积阶地（内迭阶地）Theformationofriverterrace阶地的形成河床河漫滩河谷斜坡一级阶地二级阶地三级阶地（3）FacesofRiverdeposits

◈riverbedfaces（河床相）:

coarsesand,gravel,boulderwellpsephicity

◈

terracefaces（阶地相）:

upperpart→finesand

lowerpart→riverbedfaces◈oxbowlakefaces（牛轭湖相）:

swampd<0.005mm

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

Seadeposits(Qm)海积物7

Winddeposits(Qeol)风积物windsand（风积砂）wind-loess（风积黄土）

collapsiblesoil

uniform,homogeneous

porous,scatteredstructure8

Glacialdeposits(Qgl)冰积物河谷横断面及各部位名称§4-3Mineralcompositioninsoils1Primaryminerals（原生矿物）

2Secondaryminerals(unsolvablewithwater)

次生矿物

3Solublesaltanddecomposedminerals

可溶盐类

4Organicmaterials（有机物质）阶地的类型1Primaryminerals（原生矿物）

◈Primarymineralsarefrommagmarock,theyaremainlyquartz,feldspar,ice,amphibole

◈

generalfeatureofPrimaryminerals:

--Stableinchemicalproperties--weatheringresistance--GoodperformanceofengineeringProperties河谷的形态阶地的类型2secondaryminerals

（次生矿物）

◈Primarymineralsarefromtheprocessofsoilsformation,theyare

①

clayminerals（黏土矿物）

Kaolinite，montomorillonite，watermica

②SiO2,Al2O3,Fe2O3:colloidalstate

③

Oxidizedmaterial（）

Themineraldescribedaboveisveryimportanttotheengineeringpropertiesofsoil.Reasonare：

mineralparticlesurface→surfacepowerabsorbingwateraffinity(亲和力)

3Solublesaltanddecomposedminerals

可溶盐类

solublesalt:NaCl,Caso4.2H2O(石膏),

CaCO3(calciumcarbonate)

salinizedsoil(盐

土)

Usually,solublesaltinsoildon’thavemuchinfluencetosoilengineeringproperties,becauseitslittlecontent(indroughtarea,saltcanbeaccumulatedintheupperpartsofgroundsurface),Butifsoilcontainingmuchsaltreactwithwater,theconnectionbetweensoilgrainwilldisappear,sothesoil’sstrengthandstabilitywillbedecreased.4Organicmaterials（有机物质）

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

(土的结构与构造)一、soilsstructuretype(土的结构类型)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（土的构造）

soil’stectonicsmeanthespaceshapeofsoillayer.♦Innorth-westarealoess—verticalcracks

♦Incoastarea,softclayhaveusuallydistributed,stratifiedstructure,isotropicsoil§4-5Theindexofphysicalpropertiesofsoils(土的物理性质指标)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)土的相对密度unitweightofsolidmineralparticleunitweightofwater(10KN/m3)

（2）unitweight土的重度（3）dryunitweight土的干重度

whichindicatethedensityofsoilsgrain（4）saturatedunitweight饱和重度

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

Thewatercontentinsoils,especiallyincohesivesoils,hasmuchinfluenceontheengineeringpropertiesofsoils.Sothedeterminationofwatercontentisnecessary(7)saturationdegree饱和度（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(造岩矿物)♥

Crystalform（晶形）

♥

Hardness（硬度）

(relativetoasteelbladeoryoufingernail),♥

colour(真色，假色，它色)

♥

Luster（光泽）

♥

Streak(条痕)

(thecolourwhenamineralisgroundtoapowder).

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

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

withaporcelain-likeappearance.Colourvariesfromred,pink(orthoclase正长石),andwhitetogreen,grey(plagioclase斜长石).Plagioclase斜长石Orthoclase正长石Themostcommonamphiboleishornblende（角闪石）.Hornblendeisquitesimilartoaugite（普通辉石）

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

crystalswhich,ifyoulookatanend-onsection,havesquareorrectangularcross-sections.Pyroxene（辉石）4Pyroxene辉石Talcoccursingranular（粒状的）

orfoliated（片状的）

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橄榄石Micaiseasilydistinguishedbyitscharacteristicofpeelingintomanythinflatsmoothsheetsorflakes（薄片）.Thisissimilartothecleavageinfeldsparexceptthatinthecaseofmicathecleavageplanesareinonlyonedirectionandnorightanglefacejoinsoccur.Micamaybewhiteandpearlyordarkandshiny.7Mica云母8Gypsum(plasterstone,石膏)9Kaolinite(高岭石)10Montmorillonite（蒙脱石）11Watermica（伊利石）§2-2:Rock(岩石)(一种或多种矿物组成的集合体)

一、Theclassificationofrockaccordingto

thecauseofformation

igneousrock（岩浆岩）

(magmarock)

sedimentaryrock（沉积岩）

metamophicrock（变质岩）

岩石二、

Igneousrock1theformationofigneousrock:DeepwithintheEarth,rockiskeptinamolten（融熔的）

stateduetoextremetemperatureandpressure.

Thismoltenrockiscalledmagma（岩浆）.

Themagmaisconstantlymovingandsometimesmovesitswaytothesurfacethroughthecracks（裂缝）inthesolidrock.

Onceitreachesthesurface,itiscalledlava（熔岩）.

Thelocationitpushesthroughtothesurfaceiscalledavolcano（火山）.

Theopeninginthevolcanothatthelavaeruptsoutofiscalledavent(出口).

Formanyvolcanos,thereismorethanonevent.

Oftenvolcanoshaveafunnel（漏斗）shapewithapitatthetop.

Thispitiscalledavolcaniccrater（火山口）.

Ifthiscraterbecomesverylarge,thewallsofthecratermightcollapsetoproduceafeaturecalledacaldera（喷火山口）HowIgneousrockrockIsFormedPyroclasticash(火山灰)Batholith岩基Captivemass俘虏体laccolith岩盘岩墙Rockwall岩株Volcanoneck火山颈Lavaflow岩流theformationstateofigneousrock（岩浆岩的产状）Sill岩床3theclasscificationofigneousrock（岩浆岩的分类）

（1）Accordingtotheformationstate(按产状)

◈IntrusiveIgneousRocks（侵入岩）

-usuallymediumtocoarsegrainedtextureduetoslowcooling.

Typicallylightcoloured.

◈

ExtrusiveIgneousRocks（喷出岩）

-glassyorfine-grainedduetorapidcooling.Mayhavevoidsduetodegassingofthemagma.Typicallydarkcoloured.

(2)AccordingtotheSilicaContentandMineralComposition(根据二氧化硅含量)

◈

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

colouredminerals(eg.feldspars,quartz)

◈IntermediateIgneousRocks（中性岩）

silica50-65%byweight,composedmainlyoffeldspars,

some

mafic（铁镁质的

minerals,withsomequartz.

◈BasicIgneousRocks（基性岩）

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

amphiboles,micas).Nofreequartz.thedescriptionofmainigneousrock

（岩浆岩描述）

◈

granite（花岗岩）

Graniteisanigneousrockthatiscomposedoffourminerals.

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

◈

porphyriticgranite

(花岗斑岩)

shallowintrusiverock（浅成侵入岩）

moderatecrystallization（中等结晶）

porphyriticstructure斑状结构

quartz-feldspar-blackmica花岗斑岩

◈

rhyolite（流纹岩）

Rhyoliteisverycloselyrelatedtogranite.Thedifferenceisrhyolitehasmuchfinercrystals.Thesecrystalsaresosmallthattheycannotbeseenbythenakedeye.Rhyoliteisanextrusiveigneousrockhavingcooledmuchmorerapidlythangranite,givingitaglassyappearance.Themineralsthatmakeuprhyolitearequartz,feldspar,mica,andhornblende.Rhyolite流纹岩

◈

Diorite(闪长岩)

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

◈

pyroxenire(辉岩)

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

3wellcrystallization（结晶好）

4olivine；pgroxene◈

olivinerock(橄榄岩)◈Obsidian黑耀岩Obsidianisaveryshinynaturalvolcanicglass.Whenobsidianbreaksitfractureswithadistinctconchoidal（贝壳状的）fracture.Noticeinthephototothelefthowitfractures.Obsidianisproducedwhenlavacoolsveryquickly.Thelavacoolssoquicklythatnocrystalscanform.Whenpeoplemakeglasstheymeltsilicarockslikesandandquartzthencoolitrapidlybyplacingitinwater.Obsidianisproducedinnatureinasimilarway.Obsidianisusuallyblackoraverydarkgreen,butitcanalsobefoundinanalmostclearform.Pumiceisaverylightcolored,frothy（起泡的）volcanicrock.Pumiceisformedfromlavathatisfullofgas.Thelavaisejectedandshotthroughtheairduringaneruption.Asthelavahurtles（急飞）throughtheairitcoolsandthegasesescapeleavingtherockfullofholes.◈Pumice（浮石）Pumiceissolightthatitactuallyfloatsonwater.Hugepumiceblockshavebeenseenfloatingontheoceanafterlargeeruptions.Somelavablocksarelargeenoughtocarrysmallanimals.三、sedimentaryrock（沉积岩）

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（化学岩）

whicharecarriedinaqueoussolution.Salt(halite)isanexampleofachemicalprecipitate.·

▦3

Organicorbiogenicsediments（有机岩）

precipitatedoraccumulatedbybiologicalagents.Manyorganismspromotetheprecipitationofcalcitetoformbiogenicallyprecipitatedcalcareous（含钙的）

muds.3Thetextureandstructureofsedimentaryrock

沉积岩的结构和构造沉积岩的层理构造平行层理斜层理波状层理印模粒序层理交叉层理沉积岩的结构特征砂粒孔隙胶结物砂粒粘粒粉粒铁饼形的Sphericity球形度[sfe’risiti]4thedescriptionofsedimentaryrockConglomeraterocksaresedimentaryrocks.Theyaremadeupoflargesedimentslikesandandpebbles（鹅卵石）.Thesedimentissolargethatpressurealonecannotholdtherocktogether;itisalsocementedtogetherwithdissolvedminerals.◈gravelstone(conglomerate)砾岩(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(高岭石)

montorillonite（蒙脱石）

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

dolomiterock白云岩color:white-greymineral:dolomit◈

Gypsum石膏Gypsumrocksaresedimentaryrocksmadeupofsulfatemineralandformedastheresultofevaporatingseawaterinmassiveprehistoricbasins.ItisverysoftandisusedtomakePlasterofParis,casts,molds,andwallboards.四、Metamorphicrock（变质岩）

Metamorphicrocksaregeneratedbyrecrystallizationofeitherigneousorsedimentaryrocksbytheactionofanyorallofthefollowing:Pressure,Temperature,PoreFluids.

Thetypeofmetamorphicrockisdeterminedbytheparentrock（母岩）

andtheP/Tconditions.Ingeneral,metamorphismcauses:

Growthofnewminerals

Deformationandrotationofmineralgrains

Recrystallizationofmineralsaslargergrains1theformationandclassificationofMetamorphicrocks变质岩的形成接触变质岩的形成区域变质岩的形成2thedescriptionofMetamorphicrocks

◈Marble

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

Marblehasmanycolorvariancesduetotheimpurities(杂质)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(河流的侵蚀)§6-2landslide（滑坡）

§6-3Collapse（崩塌）

§6-4mudflow（泥石流）

§6-5KarstandEarthcave（岩溶和土洞）

§6-6Theengineeringproblemsinundergroundengineering

（地下工程地质问题）§6-1Theerosionofriver(河流的侵蚀)

一、Whatisrivererosion

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

Whichcanbedividedinto：

sideerosive（侧蚀）

cuterosion（下蚀）cuterosion(下蚀)→meansthatthemovingwateranditsmaterialscarriedbywaterhavemotivepowerthatmakesriverbeddeepenedcontinuously.Cuterosionareusuallyobviousinupstreamofriver.

Inbridgeengineering,thelocationoffoundationmustbeconsideredcarefully.Thatistheelevationofbottomsurfaceoffoundationmustwillbelowerthantheerosionbaseline(侵蚀基准面).Erosionline1Erosionline2sideerosiveSideerosionarecausedbytraversecirculationofriver.Theresultsofsideerosionisthatrivervalleyisbroaden.Thesideerosionisobviousinmiddleordownstreamofriver.Preventingmethod:stonecage,changingofriverrouteDirectionofsideerosionDirectionofsideerosionBuildingisnotingoodpositiontraversecirculationofriver

§6-2landslide（滑坡）

一.Thedefinitionoflandslide

Thesoilorrockbodyslidedownalongthefixedslidingsurfaceontheactionofgravity.

Thehappeningoflandslidemaycausethedamageofbuilding,endangerhumanlife,alsocausetheartificalearthquake.

滑坡形态描述滑坡体Slidingbody滑坡床Slidingbed滑坡壁cliff滑坡面Slidingsurface扇形张裂缝Fan-hapedtensivecracks滑坡舌鼓胀裂缝Swellingcracks

剪裂缝Shearcracks

滑坡周界滑坡台阶二.ThefeatureofdifferentpartoflandslideTensioncracks三.Theclassificationoflandslide1.

Accordingtothematerialsdifferenceofslidingbody

■soillandsliding(土体滑坡)

■rocklandsliding(bedrocklandslide)岩层滑坡

■speciallandslides(frozenandthaw、collapeslide)

特殊滑坡■soillandsliding(土体滑坡)

cohesivesoilslandslides（黏土滑坡）

loesslandslides（黄土滑坡）eluvialsoilslandslides（残积层滑坡）Eluvialsoillandslide

cohesivesoilslandslides■rocklandsliding(bedrocklandslide)岩层滑坡顺层滑坡切层滑坡滑动面滑动面movementparalleltoplanesofeaknessandoccasionallyparalleltoslope.■speciallandslides(frozenandthaw、collapeslide)

特殊滑坡冻融层Flow:

viscoustofluid-likemotionofdebris.

2

Accordingtothemechanicscondition

RivererosionArtificialcuttingtractivestylePushingstyle3accordingtothelandslidescalesize四、thedevelopingprocessoflandslide

step1creepdeformationstagenofixedslidingplane

Softrock岩质边坡的破坏形式：松动蠕动剥落4滑坡5崩塌深层蠕动表层蠕动step2failurestage

Thepenetratingfailureplanehasformed;theslidingmassslowlyorquicklyslidesalongthecrackplane，

drunken-liketrees;sabre-liketreesdevelopsinthisstagestep3stablestage

Theslidingmasshasbeeninbalancedpositiondrunkentreeshavebecometogrowvertically五、Themechanicsanalysisandinfluencingfactor土层均匀时：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)oflandslippingC