国际课件公路工程地质章

Chapter2GeologicalStructure第二章地质构造contentsSection1GeologicaltimeSection2GeologicalstructureSection3ReadinggeologicalmapsSection4ActivefaultsSection5EarthquakeCrust(地壳)movement(structurechanges)—mechanicalmovementoftheearth’scrust,movementofcrustrocksdeformationcausedbytheinsidedynamic.CrustmovementHorizontalmovementVerticalmotion—Differencefluctuation(差异升降)Tension(拉伸)Geologicalstructurearetheresultsofrockdeformation.Horizontalmovement

ThetheoryofcontinentaldriftadvancedbyWegener(魏格纳)in1912Evidences:Bendingshapeofcoastlines,Paleontologyfossils(古生物化石),geologicalstructure,ancientclimate.compression（挤压）

Shearing（剪切）VerticalmotionThetheoryofGeosyncline—Platform(地槽-地台）Thechangeofdepositionthickness(沉积厚度)andsedimentaryenvironmental(沉积环境).Stratigraphiccontact(地层接触)relationsTheevidenceofverticalmovement整合接触conformity角度不整合angularunconformity平行不整合parallelunconformity(假整合）disconformity意大利HorizontalmovementContinentaldriftSection1GeologicaltimeExpressionmethodofgeologicaltime（地质年代的表示方法）：1).Relativeage(相对年代):Relativeageanswerswhichoneisyoungerandwhichoneisolder.Itisdeterminedbytherelativelayers’relationshipbetweenthelithostratigraphic（岩石层位）unitsandadjacentknownlithostratigraphicunit.Weonlyknowtheorder(产生顺序),donotknowthespecifictime.2).Absoluteage(绝对年代):Itisexpressedbyhowmanyyearsagodidthelithostratigraphicunitfromtodayanddeterminedthroughthedecayofradioactiveelementsofstrata(地层中的放射性元素).RelativetimeSedimentaryrocks

(沉积岩)StratigraphicSequence(地层层序)Lithologycontrast（岩性对比）Stratigraphiccontactrelationship(地层接触关系)

Paleontologyfossils(古生物化石)

Magmaticrocks

Thecontactrelationwiththeknownsurroundingrocks.(与周围已知围岩的接触关系)

Cross-cuttingtheory(穿插切割定律)StratigraphicSequence(地层层序)

：地层形成时是水平或近于水平的，先形成的位于下部，后形成的位于其上部。注意：原始产出的下老上新，并非现在野外见到的地层都是下老上新，其中又有后期地壳运动的改造。对于后期地壳运动使地层变动（倾斜、倒转）的地层层序可用沉积构造中的层面构造（波痕、泥裂、雨痕等）作为“示底构造”恢复顶底后，判断先后顺序。

Lithologycontrast（岩性对比）

：在一定的区域内，同一时期形成的岩层，其岩性特征（成分、结构、构造）基本上一致或近似。Stratigraphiccontactrelationship(地层接触关系)整合接触conformity:新老的层产状一致，地质年代连续，无缺失；说明地层形成过程中基本保持稳定的沉积环境，构造运动为地壳缓慢的下沉，即使有上升，也未将沉积面上升到水面之上而遭受剥蚀。平行不整合parallelunconformity不整合面上、下地层产状基本一致，地质年代有缺失，新地层之下常有底砾岩；说明老地层沉积后有明显的均衡抬升，遭受剥蚀后又均衡下降，接受新的地层沉积。角度不整合angularunconformity不整合面上、下地层产状不一致，有缺失，新地层之下常有底砾岩；说明老地层形成后构造运动强烈，形成断层、褶皱等构造，长期遭受外力剥蚀，而后下降接受新的地层沉积不整合接触为划分地层相对地质年代的重要依据。沉积间断形不整合面，不整合面以下先形成，较老；不整合面以上岩层晚形成，较新平行不整合形成示意图

parallelunconformity(假整合）disconformity角度不整合形成示意图angularunconformity古生物化石：生物的演化从古到今，由低级到高级，由简单到复杂（无可逆性）；某一时代的地层中只能含有该时代生存的生物化石(间断性)；具有相同标准化石或化石群的地层为同一时代形成（全球性）Paleontologyfossils(古生物化石)生物进化岩浆岩相对地质年代确定

它的相对年代的确定主要依据它与已知时代围岩的接触关系及不同岩浆体的穿插切割关系确定接触(contactrelation)1）侵入接触：岩浆体晚于其侵入其中地层，一般由烘烤、变质现象。2）沉积接触：岩浆岩体早于覆盖其上的地层（为一不整合面）。侵入者年代新，被侵入者年代老；切割者年代新，被切割者年代老。

Cross-cuttingtheory(穿插切割定律)接触关系穿插关系contactrelationCross-cuttingTimestratigraphicunits(时间地层单位):theformationofgeologicalstratacorrespondingtoeachgeologicaltimeingeologicalhistory.

地质年代单位(thetimeunit)宙(eon)代(era)纪(period)世(epoch)期(stage)时间地层单位(thestrataunit)宇(eonothem)界(erathem)系(system)统(series)阶(stage)Accordingtothefeaturesofcrustmovementandbiologicalevolution(生物演化),geologichistorywillbedividedintoseveraldifferentsizeslevelperiods.Eon(宙)Phanerozoic(显生宙)Cenozoic(新生代)Mesozoic(中生代)Paleozoic(古生代)Cryptozoic(隐生宙)ProterozoicEra(元古代)ArcheozoicEra(太古代)QuaternaryPeriod(第四纪)TertiaryPeriod(第三纪)

GretaceousK(白垩纪)JurassicJ(侏罗纪)TriassicT(三叠纪)LatePaleozoic(晚古生代)EarlyPaleozoic(早古生代)PermianP(二叠纪)CarboniferousC(石炭纪)DevonianD(泥盆纪)SilurianS(志留纪)OrdovicianO(奥陶纪)Cambrian(寒武纪)Section2GeologicalstructureDefinition:resultsofrockdeformationleavedbythecrustmovement.TypesStrataoccurrence(岩层的产状)Definitionofoccurrence:Occurrenceistheorientationofastructuralplaneorastructuralline.Itcanbedescribedbystrike,dipanddipangle.Definitionofthestrata’sshape:Thestrata’sspacelocationcalledstrata’sshape.Itisusuallyexpressedbystrata’sstrike(岩层的走向),dip

direction(倾向)anddipangel(倾角).Horizontalstructure(水平构造)Tiltstructure(倾斜构造)Fold(褶皱)Fracture(断裂)Threeelementsofstrataoccurrences(岩层产状的三要素)：1).strikeline(走向线):

theintersectionofrocklevelandanyhorizontal.Strikeisthedirectionortrendthatastructuralsurface(suchasbeddingorfaultplane)takesasitintersectswithahorizontalsurface.Thedirectionisexpressedwithtwoazimuthvaluesintheoppositedirections.2).Dipdirection

isthedirectionwhichpointstothelowersideofastructuralplaneandisperpendiculartothestrikeofthesurface.Thedipismeasuredatrightanglestothestrikeinahorizontalsurface,pointingtothelowersideoftheinclinedplane.Ifadipdirectionismeasured,thestrikeofthesurfacecanbecalculatedbecausestrikeisperpendiculartodipdirection.However,ifthestrikeismeasured,thedipisstillnotdeterminedbecausedipisaradialline.3).Dipangle

istheanglethatastructuralsurfacemakeswiththehorizontal,measuredperpendiculartothestrikeofthestructure(foreigngeologistsoftenusethetermdipasdipangle).Therearetruedipandapparentdip,amongalltheanglesthetruedipisthelargestone.Strike,dipdirectionanddipanglearethethreekeyelementsofoccurrencesofgeologicalstructures.Representationmethodofstrataoccurrences(岩层产状的表示方法):1).Azimuthrepresentation

(方位角表示法)Determinedpointtreatedasthecenter.Northdirectionrepresent0degreesazimuthangle,accordingtothedirectionofrotation,rotateawhirl(一周)is360degree,andeast,south,illicitaffairrepresent90,180,270degree.Azimuthonlyrecordsdipdirectionanddipangle.2).QuadrantAnglerepresentation

(象限角表示法):Treatnorthorsouthasthedatum(基准)（0º），planeisdividedintofourquadrantstorepresentoccurrences.Generallywerecordstrike,dipdirectionanddipangle.3)SpecialoccurrenceHorizontalstrata:dipangle=0°dipdirection——strike∞Verticalstrata:dipangle=90°dipdirection——strikeα°2.HorizontalstructureSedimentaryrocksthatwithoutstructurechange,theiroriginaloccurrencesarehorizontalwhentheywereformed.Theoldstrataisbelowthenewone.2.TiltstructureBecauseofthecrustmovement,theoriginalcrusthaseinclined.Thecrustwhichhasaanglebetweenthelayerandthehorizoniscalledinclinedstructure.Itisalwaysapartofthefoldingorthefractureanditsformationalsocanbeaccordingtotheunevenliftingordroppinginthebigarea.Tiltstructurecanbeexpressedbythreeelementsincludingstrike,dipdirectionanddipangleofthecrustlayer.3.FoldDefinition:Foldisabentorwarpedstratumorsequenceofstrata,whichwasoriginallyhorizontal,ornearlyso,andwassubsequentlydeformed.Thegeometryofafoldincludescore(核),limb(翼),crest(弧尖),hinge(枢纽)orfoldaxis(褶皱轴),axisplane(轴面),axialtrace(轴迹),foldlength,widthandheight.core(核),limb(翼),crest(弧尖),hinge(枢纽)orfoldaxis(褶皱轴),axisplane(轴面),axialtrace(轴迹),Thebasictypesoffoldareanticline(背斜)andsyncline(向斜).Foldswhichhavebothlimbsdippingawayfromthefoldaxisarecalledanticlines.Whenananticlineisupliftedanderoded,olderrocksareexposednearthefoldaxisandyoungerrocksareexposedawayfromtheaxis.Foldswhichhavebothlimbsdippingtowardsthefoldaxisarecalledsynclines.Whenasynclineisupliftedanderoded,youngerrocksareexposednearthefoldaxisandolderrocksareexposedawayfromtheaxis.Eachtypeoffoldcanbefurtherclassifiedbytherelationshipoftheaxialplanetothelimbs.symmetricalfold(对称褶皱)orverticalfold(直立褶皱)hasaverticalaxialplaneandthetwolimbsfromamirrorimageofeachotherwithoutbeingoverturnedinanyside.

Asymmetricalfold(非对称褶皱)orinclinedfold(倾斜褶皱)hasaninclinedaxiswithonelimbdippingsteeperthantheother.

Overturnedfold(倒转褶皱)alsohasaninclinedaxiswithbothlimbsdippingtothesamedirection.

Arecumbentfold(平卧褶皱)hasanalmosthorizonaxiswithbothlimbsbeingnearlyhorizontaltoo.Obviously,inarecumbentfold,onelimbisoverturnedandtheotherisnormal.Overturnedfold(倒转褶皱)：Figureexample:Recumbentfold(平卧褶皱):b).Foldscanalsobeclassifiedintonon-plungingfoldandplungingfoldaccordingtotheorientationofhinges.

non-plunging(非倾伏褶皱)oruprightfold(平轴褶皱/水平褶皱),

plungingfold(倾伏褶皱)

：plungeorpitch(倾伏角)

；Plungingdirection(倾伏向)Accordingtotheirrelativelengthandwidth,foldscanalsobeclassifiedintolinearfold(线状褶皱),inwhichtheratiooflengthtowidth(L/W)isgreaterthan10,brachy-fold(短轴褶皱),inwhichtheratioisbetween3and10,anddome(穹隆)orbasin(盆地),inwhichtheratioislessthan3.DomeBasinDomeBasin倾伏的褶皱长宽比小于1：3时，背斜称为穹窿，向斜称为盆地野外对大型褶皱的研究方法穿越法：垂直岩层走向观测，了解岩层的产状、层序、新老关系；根据岩层出露的层序及新老关系，判断背斜还是向斜；根据两翼岩层的产状及与轴面的关系，判断褶皱的形态。追索法：平行于岩层走向进行观测，查明褶皱的延伸方向及其构造变化，判断为倾伏褶皱还是水平褶皱。在实践中一般以穿越法为主，追索法为辅。褶皱构造的野外鉴别

顺或逆着倾向方向，地层重复出现，倾角变化有规律；anticline（背斜）：新—

老—

新syncline(向斜)：老—

新—

老褶皱构造的野外鉴别正地形：向斜成谷（synclinalvalleys)、背斜成山(anticlinalhill)；逆地形：向斜成山、背斜成谷（地形倒置）anticlinalvalleys（背斜谷）；Synclinalhill(向斜山)

；。褶皱的工程地质评价

转折端(crest)岩石破碎严重，完整性差、强度低、稳定性差，抗风化的能力较弱，透水、储水能力强.道路、桥梁、隧道等工程建筑物，可能遇到岩层坍塌、涌水等问题。翼部(limb)岩体的完整性较好，岩层的抗风化能力较强，透水、储水能力弱；如开挖边坡走向近于岩层走向，边坡坡角大于岩层倾角时，易造成顺层滑动；如边坡坡角小于岩层倾角或倾向相反时，有利于边坡稳定；如开挖边坡走向与岩层走向斜交，交角越大越稳定。隧道等地下工程，一般布置在翼部，隧道方向与岩层走向交角越大越好。断裂构造

定义：构成地壳的岩石受地应力作用后变形，当变形达到一定程度，岩石地连续性和完整性遭到破坏，产生各种大小不同的断裂，称为断裂构造。

类型裂隙(节理)：岩层沿断裂面没有明显的位移，称为裂隙或节理；断层：岩层沿破裂面（一个或一组）两侧发生了明显位移或较大错动，称为断层。

Fracture(断裂构造)Definition:Fracturesincludefaults(断层)andjoints/fissure(节理、裂隙).Ajoint/fissureisacrackalongwhichtherehasbeennoappreciablemovement.Afaultisafracturewithrelativemovementoftherocksonbothsidesofit,paralleltothefracture.Joints/fissure（节理、裂隙）

tectonicjoints/fissure:

non-tectonicjoints/fissure:构造裂隙tectonicjoints/fissure（一）剪裂隙shearfissure

定义:岩石受到剪（扭）应力的作用形成的破裂面特征产状稳定，在平面和剖面上的延伸距离较长节理面光滑，常具有擦痕、镜面等现象，紧密闭合常成对呈X状出现，又称共轭裂隙或X裂隙一般发育密实，裂隙间距小，在软弱薄层岩石中常密集成带，剪裂隙交叉切割岩体，破坏岩体完整性，故剪裂隙常是易于滑动的软弱面构造裂隙（二）tectonicjoints/fissure

张裂隙(tensionfissure)定义：岩层受到张应力作用而形成的破裂面；特征裂隙产状不稳定，延伸距离短；裂隙面弯曲、粗糙，裂缝较宽，常被岩脉充填；一般发育较稀，裂隙间距大，很少密集成带；张裂隙往往是地下水渗透的良好通道。裂隙形成示意图非构造裂隙non-tectonicjoints/fissure定义：由于成岩作用、外动力和重力等非构造因素所形成的裂缝.类型原生裂隙风化裂隙卸荷裂隙裂隙的工程地质评价

岩体中的裂隙虽有利于开挖，但岩体的强度和稳定性均有不利影响；裂隙破坏了岩石的整体性，促使风化速度加快；增加了岩体的透水性，强度和稳定性降低；裂隙的主要发育方向与路线的走向平行，倾向与边坡一致，不论岩体的产状如何，路堑边坡都易发生崩塌和碎落；影响爆破作业的效果。Faults(断层构造)faultplaneorfault

surface(断面层).hangingwallblock(上盘）footwallblock(下盘）Upliftside(上升盘）Downthrownside(下降盘）Thefaultscanbeclassifiedintothreebasictypes:normalfaults(正断层）：thehangingwallmoveddownwardandthefootwallmovedupwardalongthefaultplane.Anormalfaultisgenerallyinducedbyhorizontalextensioninthecrust.reversefaults(逆断层)：isoneinwhichtherocksabovethefaultplanemoveupwardinrelationtotherockbelow,causingashorteningofthesection.Thatistosay,reversefaultingresultsfromcompression.strike-slipfaults(走滑断层，平移断层).：isoneinwhichthemovementishorizontal,paralleltothestrikeoffaultplane.normalfaults(正断层）

reverse

faults(逆断层)strike-slipfault(走滑断层,平推断层)sinistralfault(左旋断层).dextralfault(右旋断层);断层的组合形式正断层：阶梯状：由一组走向大致平行，倾向相同的正断层组成。地堑：由两走向近平行，倾向相对的正断层组成地垒：由两走向近平行，倾向相背的正断层组成。逆断层迭瓦状：由一组大致平行的倾向相同的逆断层组成。地堑与地垒断层的工程地质评价断层构造破坏了岩体的完整性，加速风化作用和地下水活动，降低了岩石的强度和稳定性，对工程产生不利的影响.（1）对于道路：路基的稳定性差（2）对于隧道：应避开或大角度通过影响隧道的稳定性和衬砌开挖出现涌水的现象（3）桥梁：基础及临近活动断层是否存在桥基的稳定性桥基的过量沉降和不均匀沉降断层的野外识别地貌特征：

断层崖；

断层三角面地形；

沟谷或峡谷地形；

山脊错断、错开；

河谷跌水瀑布；

河谷方向发生突然转折等。地层特征：

岩层发生重复或缺失，

岩脉被错断，

岩层沿走向突然发生中断，与不同性质的岩层突然接触等。

断层的伴生构造现象：岩层牵引弯曲、断层角砾、糜棱岩、断层泥和断层擦痕等。断层的野外识别——断层崖断层的野外识别——地层缺失或重复地层重复地层缺失断层的野外识别——构造岩断层角砾岩断层的野外识别——擦痕、镜面、阶步擦痕阶步Engineeringgeologicalevaluationoffaults(断层的工程地质评价)Faultdestroytheintegrity(整体性)ofrockmass,accelerateweatheringandgroundwateractivities,reducetherockofstrengthandstabilityandcausesomeadverseeffectstotheengineering.Faultfracturezonewhichreducefoundationbearingcapacityandstabilityofrockmassandeasytocauselargersettlementofbuildingproduce,evencausetiltedorfault;haslowintensity,poorstability,largecompressibility.Faultcausesomeimportantimpacttothestabilityofslopeandfoundation(边坡和桥基).Suchasthebridgebuildingswhichcrossthefracturedzones,maycauseunevensubsidencebecauseofdifferentlithologic(岩性)oftwoplates.Itiseasytoproduceroofcollapsewhenthetunnelcrossthefaultzone,weshouldavoidlarge-scalefaultfracturezonewhendeterminingthetunnelplaneposition.Whenthetunnelaxisandfaultstrikeparallels,weshouldavoidcontactbetweentunnelandfracturezone.Whenthetunnelacrossthefault,faultcausesmallaffectontunnelengineering,westillshalltakereasonableprotectivemeasuresandengineeringmeasurestoensureconstructionsafety.Faultwildidentification(断层野外识别)Faultscarp(断层崖)Stratamissingorrepeated(地层缺失或重复)Tectonicrock(构造岩)Faultbreccia(断层角砾岩)Slickensides(擦痕、摩擦镜面),step(阶步)Tractionfold(牵引褶皱)1)Faultoftenassociateddensejoints(密集的节理)whichparallelwithfaultplane.2)Asuddeninterruptionalongthestrikeofrockororebed(矿层).3)Negativeterrain(负地形),faulttriangleface(断层三角面).4)Alongtherockfaultfracturezone,springislinearexposed(呈线状出露).Section3ReadinggeologicalmapsLocalgeologicalconditionsshouldbeconsideredintheconstructionofroads,bridgesandtunnelsinordertoensurethesafety,stableandreasonableeconomyoftheprojects.Geologicalmapsclearlyshowthetopography,landformsandhydrogeological(水文地质)conditionsofthecoveredareasandtheyalsoshowtherockstrata,thegeologicaltectonicconditionsandthedevelopmentprocessofthegeologicalhistory.Itisnecessaryforthebuilderstoobtaincorrespondinggeologicalinformationingeologicalmaps.GeologicalmapsAgeologicalmapisadrawingthatexpressesthegeologicalconditionofaregiontoreflectstrata,lithologyandthedistributionofgeologicalstructurewithacertaincolormaps,symbols,codes.Awholegeologicalmapincludesplan(平面图),profile(剖面图)andhistogram(柱状图).Geologicalmaps’content1)Topographycharacteristic:Usingcontourstoexpress.2)Lithology(岩性):Usingrockssymbol.3)StrataSedimentarystratigraphicalInternationalcurrentstandardcolorreflectsthestrata.RefillgeologicaltimesymbolsandlithologicsymbolsMagmaticrocksDifferentcolorormonochromestripeorrockpatternsymbols.Refillgeologicaltimesymbols.4)conformablecontact--StratigraphiccontactrelationshipPlan-Accordingtothegeologicaltimeandrockoccurrencetomakeanclassification.Profileparallelunconformitycontact--angleunconformity--5)Hydrologicalgeologycharacteristics(partly)—rivers,stream,springsandsoon.6)GeologicalstructureNormalfaults:ReversefaultsStrike-slipfaultsAnticline:SynclineThetypesofgeologicalmaps1)Ordinarygeologicalmap:Reflectstrata,lithologyandgeologicalstructure.2)Tectonicgeologymap:Reflectgeologicalstructureswhichincludesfold,faultandothers.3)Quaternaryperiodgeologymap:Reflectthecauses,time,compositionanddistributionoftheloosesediments.4)Bedrockgeologicalmap:Reflectthetime,lithologyanddistributionoftheloosesedimentsbeforequaternaryperiod.5)Hydrologicalgeologymap(水文地质图):Reflectaregion’shydrogeologicalconditions6)Engineeringgeologicalmap:ReflectregionalengineeringgeologicalconditionsorfieldgeologicalconditionsThestepsofreadinggeologicalmaps1)Readmapname,scale,understandmap’spositionandprecision.2)Readillustrations,establishinitialconceptofstrata,lithology,geologicalstructureofthegraph.3)Analysistheterrainandtheriversystemdistribution.4)Readingstratadistribution,oldandyoungrelationship,occurrence,anditsrelationshipwiththeterrain;analysisgeologicalstructure.Theperformanceformofgeologicalstructureing