國際課件公路工程地質(zhì)章

Chapter2GeologicalStructure第二章地質(zhì)構(gòu)造contentsSection1GeologicaltimeSection2GeologicalstructureSection3ReadinggeologicalmapsSection4ActivefaultsSection5EarthquakeCrust(地殼)movement(structurechanges)—mechanicalmovementoftheearth’scrust,movementofcrustrocksdeformationcausedbytheinsidedynamic.CrustmovementHorizontalmovementVerticalmotion—Differencefluctuation(差異升降)Tension(拉伸)Geologicalstructurearetheresultsofrockdeformation.Horizontalmovement

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

Shearing（剪切）VerticalmotionThetheoryofGeosyncline—Platform(地槽-地臺）Thechangeofdepositionthickness(沉積厚度)andsedimentaryenvironmental(沉積環(huán)境).Stratigraphiccontact(地層接觸)relationsTheevidenceofverticalmovement整合接觸conformity角度不整合angularunconformity平行不整合parallelunconformity(假整合）disconformity意大利HorizontalmovementContinentaldriftSection1GeologicaltimeExpressionmethodofgeologicaltime（地質(zhì)年代的表示方法）：1).Relativeage(相對年代):Relativeageanswerswhichoneisyoungerandwhichoneisolder.Itisdeterminedbytherelativelayers’relationshipbetweenthelithostratigraphic（巖石層位）unitsandadjacentknownlithostratigraphicunit.Weonlyknowtheorder(產(chǎn)生順序),donotknowthespecifictime.2).Absoluteage(絕對年代):Itisexpressedbyhowmanyyearsagodidthelithostratigraphicunitfromtodayanddeterminedthroughthedecayofradioactiveelementsofstrata(地層中的放射性元素).RelativetimeSedimentaryrocks

(沉積巖)StratigraphicSequence(地層層序)Lithologycontrast（巖性對比）Stratigraphiccontactrelationship(地層接觸關(guān)系)

Paleontologyfossils(古生物化石)

Magmaticrocks

Thecontactrelationwiththeknownsurroundingrocks.(與周圍已知圍巖的接觸關(guān)系)

Cross-cuttingtheory(穿插切割定律)StratigraphicSequence(地層層序)

：地層形成時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：原始產(chǎn)出的下老上新，并非現(xiàn)在野外見到的地層都是下老上新，其中又有后期地殼運動的改造。對于后期地殼運動使地層變動（傾斜、倒轉(zhuǎn)）的地層層序可用沉積構(gòu)造中的層面構(gòu)造（波痕、泥裂、雨痕等）作為“示底構(gòu)造”恢復(fù)頂?shù)缀?，判斷先后順序?/p>

Lithologycontrast（巖性對比）

：在一定的區(qū)域內(nèi)，同一時期形成的巖層，其巖性特征（成分、結(jié)構(gòu)、構(gòu)造）基本上一致或近似。Stratigraphiccontactrelationship(地層接觸關(guān)系)整合接觸conformity:新老的層產(chǎn)狀一致，地質(zhì)年代連續(xù)，無缺失；說明地層形成過程中基本保持穩(wěn)定的沉積環(huán)境，構(gòu)造運動為地殼緩慢的下沉，即使有上升，也未將沉積面上升到水面之上而遭受剝蝕。平行不整合parallelunconformity不整合面上、下地層產(chǎn)狀基本一致，地質(zhì)年代有缺失，新地層之下常有底礫巖；說明老地層沉積后有明顯的均衡抬升，遭受剝蝕后又均衡下降，接受新的地層沉積。角度不整合angularunconformity不整合面上、下地層產(chǎn)狀不一致，有缺失，新地層之下常有底礫巖；說明老地層形成后構(gòu)造運動強烈，形成斷層、褶皺等構(gòu)造，長期遭受外力剝蝕，而后下降接受新的地層沉積不整合接觸為劃分地層相對地質(zhì)年代的重要依據(jù)。沉積間斷形不整合面，不整合面以下先形成，較老；不整合面以上巖層晚形成，較新平行不整合形成示意圖

parallelunconformity(假整合）disconformity角度不整合形成示意圖angularunconformity古生物化石：生物的演化從古到今，由低級到高級，由簡單到復(fù)雜（無可逆性）；某一時代的地層中只能含有該時代生存的生物化石(間斷性)；具有相同標準化石或化石群的地層為同一時代形成（全球性）Paleontologyfossils(古生物化石)生物進化巖漿巖相對地質(zhì)年代確定

它的相對年代的確定主要依據(jù)它與已知時代圍巖的接觸關(guān)系及不同巖漿體的穿插切割關(guān)系確定接觸(contactrelation)1）侵入接觸：巖漿體晚于其侵入其中地層，一般由烘烤、變質(zhì)現(xiàn)象。2）沉積接觸：巖漿巖體早于覆蓋其上的地層（為一不整合面）。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)接觸關(guān)系穿插關(guān)系contactrelationCross-cuttingTimestratigraphicunits(時間地層單位):theformationofgeologicalstratacorrespondingtoeachgeologicaltimeingeologicalhistory.

地質(zhì)年代單位(thetimeunit)宙(eon)代(era)紀(period)世(epoch)期(stage)時間地層單位(thestrataunit)宇(eonothem)界(erathem)系(system)統(tǒng)(series)階(stage)Accordingtothefeaturesofcrustmovementandbiologicalevolution(生物演化),geologichistorywillbedividedintoseveraldifferentsizeslevelperiods.Eon(宙)Phanerozoic(顯生宙)Cenozoic(新生代)Mesozoic(中生代)Paleozoic(古生代)Cryptozoic(隱生宙)ProterozoicEra(元古代)ArcheozoicEra(太古代)QuaternaryPeriod(第四紀)TertiaryPeriod(第三紀)

GretaceousK(白堊紀)JurassicJ(侏羅紀)TriassicT(三疊紀)LatePaleozoic(晚古生代)EarlyPaleozoic(早古生代)PermianP(二疊紀)CarboniferousC(石炭紀)DevonianD(泥盆紀)SilurianS(志留紀)OrdovicianO(奧陶紀)Cambrian(寒武紀)Section2GeologicalstructureDefinition:resultsofrockdeformationleavedbythecrustmovement.TypesStrataoccurrence(巖層的產(chǎn)狀)Definitionofoccurrence:Occurrenceistheorientationofastructuralplaneorastructuralline.Itcanbedescribedbystrike,dipanddipangle.Definitionofthestrata’sshape:Thestrata’sspacelocationcalledstrata’sshape.Itisusuallyexpressedbystrata’sstrike(巖層的走向),dip

direction(傾向)anddipangel(傾角).Horizontalstructure(水平構(gòu)造)Tiltstructure(傾斜構(gòu)造)Fold(褶皺)Fracture(斷裂)Threeelementsofstrataoccurrences(巖層產(chǎn)狀的三要素)：1).strikeline(走向線):

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(巖層產(chǎn)狀的表示方法):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(基準)（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(樞紐)orfoldaxis(褶皺軸),axisplane(軸面),axialtrace(軸跡),foldlength,widthandheight.core(核),limb(翼),crest(弧尖),hinge(樞紐)orfoldaxis(褶皺軸),axisplane(軸面),axialtrace(軸跡),Thebasictypesoffoldareanticline(背斜)andsyncline(向斜).Foldswhichhavebothlimbsdippingawayfromthefoldaxisarecalledanticlines.Whenananticlineisupliftedanderoded,olderrocksareexposednearthefoldaxisandyoungerrocksareexposedawayfromtheaxis.Foldswhichhavebothlimbsdippingtowardsthefoldaxisarecalledsynclines.Whenasynclineisupliftedanderoded,youngerrocksareexposednearthefoldaxisandolderrocksareexposedawayfromtheaxis.Eachtypeoffoldcanbefurtherclassifiedbytherelationshipoftheaxialplanetothelimbs.symmetricalfold(對稱褶皺)orverticalfold(直立褶皺)hasaverticalaxialplaneandthetwolimbsfromamirrorimageofeachotherwithoutbeingoverturnedinanyside.

Asymmetricalfold(非對稱褶皺)orinclinedfold(傾斜褶皺)hasaninclinedaxiswithonelimbdippingsteeperthantheother.

Overturnedfold(倒轉(zhuǎn)褶皺)alsohasaninclinedaxiswithbothlimbsdippingtothesamedirection.

Arecumbentfold(平臥褶皺)hasanalmosthorizonaxiswithbothlimbsbeingnearlyhorizontaltoo.Obviously,inarecumbentfold,onelimbisoverturnedandtheotherisnormal.Overturnedfold(倒轉(zhuǎn)褶皺)：Figureexample:Recumbentfold(平臥褶皺):b).Foldscanalsobeclassifiedintonon-plungingfoldandplungingfoldaccordingtotheorientationofhinges.

non-plunging(非傾伏褶皺)oruprightfold(平軸褶皺/水平褶皺),

plungingfold(傾伏褶皺)

：plungeorpitch(傾伏角)

；Plungingdirection(傾伏向)Accordingtotheirrelativelengthandwidth,foldscanalsobeclassifiedintolinearfold(線狀褶皺),inwhichtheratiooflengthtowidth(L/W)isgreaterthan10,brachy-fold(短軸褶皺),inwhichtheratioisbetween3and10,anddome(穹隆)orbasin(盆地),inwhichtheratioislessthan3.DomeBasinDomeBasin傾伏的褶皺長寬比小于1：3時，背斜稱為穹窿，向斜稱為盆地野外對大型褶皺的研究方法穿越法：垂直巖層走向觀測，了解巖層的產(chǎn)狀、層序、新老關(guān)系；根據(jù)巖層出露的層序及新老關(guān)系，判斷背斜還是向斜；根據(jù)兩翼巖層的產(chǎn)狀及與軸面的關(guān)系，判斷褶皺的形態(tài)。追索法：平行于巖層走向進行觀測，查明褶皺的延伸方向及其構(gòu)造變化，判斷為傾伏褶皺還是水平褶皺。在實踐中一般以穿越法為主，追索法為輔。褶皺構(gòu)造的野外鑒別

順或逆著傾向方向，地層重復(fù)出現(xiàn)，傾角變化有規(guī)律；anticline（背斜）：新—

老—

新syncline(向斜)：老—

新—

老褶皺構(gòu)造的野外鑒別正地形：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)

；。褶皺的工程地質(zhì)評價

轉(zhuǎn)折端(crest)巖石破碎嚴重，完整性差、強度低、穩(wěn)定性差，抗風(fēng)化的能力較弱，透水、儲水能力強.道路、橋梁、隧道等工程建筑物，可能遇到巖層坍塌、涌水等問題。翼部(limb)巖體的完整性較好，巖層的抗風(fēng)化能力較強，透水、儲水能力弱；如開挖邊坡走向近于巖層走向，邊坡坡角大于巖層傾角時，易造成順層滑動；如邊坡坡角小于巖層傾角或傾向相反時，有利于邊坡穩(wěn)定；如開挖邊坡走向與巖層走向斜交，交角越大越穩(wěn)定。隧道等地下工程，一般布置在翼部，隧道方向與巖層走向交角越大越好。斷裂構(gòu)造

定義：構(gòu)成地殼的巖石受地應(yīng)力作用后變形，當變形達到一定程度，巖石地連續(xù)性和完整性遭到破壞，產(chǎn)生各種大小不同的斷裂，稱為斷裂構(gòu)造。

類型裂隙(節(jié)理)：巖層沿斷裂面沒有明顯的位移，稱為裂隙或節(jié)理；斷層：巖層沿破裂面（一個或一組）兩側(cè)發(fā)生了明顯位移或較大錯動，稱為斷層。

Fracture(斷裂構(gòu)造)Definition:Fracturesincludefaults(斷層)andjoints/fissure(節(jié)理、裂隙).Ajoint/fissureisacrackalongwhichtherehasbeennoappreciablemovement.Afaultisafracturewithrelativemovementoftherocksonbothsidesofit,paralleltothefracture.Joints/fissure（節(jié)理、裂隙）

tectonicjoints/fissure:

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

定義:巖石受到剪（扭）應(yīng)力的作用形成的破裂面特征產(chǎn)狀穩(wěn)定，在平面和剖面上的延伸距離較長節(jié)理面光滑，常具有擦痕、鏡面等現(xiàn)象，緊密閉合常成對呈X狀出現(xiàn)，又稱共軛裂隙或X裂隙一般發(fā)育密實，裂隙間距小，在軟弱薄層巖石中常密集成帶，剪裂隙交叉切割巖體，破壞巖體完整性，故剪裂隙常是易于滑動的軟弱面構(gòu)造裂隙（二）tectonicjoints/fissure

張裂隙(tensionfissure)定義：巖層受到張應(yīng)力作用而形成的破裂面；特征裂隙產(chǎn)狀不穩(wěn)定，延伸距離短；裂隙面彎曲、粗糙，裂縫較寬，常被巖脈充填；一般發(fā)育較稀，裂隙間距大，很少密集成帶；張裂隙往往是地下水滲透的良好通道。裂隙形成示意圖非構(gòu)造裂隙non-tectonicjoints/fissure定義：由于成巖作用、外動力和重力等非構(gòu)造因素所形成的裂縫.類型原生裂隙風(fēng)化裂隙卸荷裂隙裂隙的工程地質(zhì)評價

巖體中的裂隙雖有利于開挖，但巖體的強度和穩(wěn)定性均有不利影響；裂隙破壞了巖石的整體性，促使風(fēng)化速度加快；增加了巖體的透水性，強度和穩(wěn)定性降低；裂隙的主要發(fā)育方向與路線的走向平行，傾向與邊坡一致，不論巖體的產(chǎn)狀如何，路塹邊坡都易發(fā)生崩塌和碎落；影響爆破作業(yè)的效果。Faults(斷層構(gòu)造)faultplaneorfault

surface(斷面層).hangingwallblock(上盤）footwallblock(下盤）Upliftside(上升盤）Downthrownside(下降盤）Thefaultscanbeclassifiedintothreebasictypes:normalfaults(正斷層）：thehangingwallmoveddownwardandthefootwallmovedupwardalongthefaultplane.Anormalfaultisgenerallyinducedbyhorizontalextensioninthecrust.reversefaults(逆斷層)：isoneinwhichtherocksabovethefaultplanemoveupwardinrelationtotherockbelow,causingashorteningofthesection.Thatistosay,reversefaultingresultsfromcompression.strike-slipfaults(走滑斷層，平移斷層).：isoneinwhichthemovementishorizontal,paralleltothestrikeoffaultplane.normalfaults(正斷層）

reverse

faults(逆斷層)strike-slipfault(走滑斷層,平推斷層)sinistralfault(左旋斷層).dextralfault(右旋斷層);斷層的組合形式正斷層：階梯狀：由一組走向大致平行，傾向相同的正斷層組成。地塹：由兩走向近平行，傾向相對的正斷層組成地壘：由兩走向近平行，傾向相背的正斷層組成。逆斷層迭瓦狀：由一組大致平行的傾向相同的逆斷層組成。地塹與地壘斷層的工程地質(zhì)評價斷層構(gòu)造破壞了巖體的完整性，加速風(fēng)化作用和地下水活動，降低了巖石的強度和穩(wěn)定性，對工程產(chǎn)生不利的影響.（1）對于道路：路基的穩(wěn)定性差（2）對于隧道：應(yīng)避開或大角度通過影響隧道的穩(wěn)定性和襯砌開挖出現(xiàn)涌水的現(xiàn)象（3）橋梁：基礎(chǔ)及臨近活動斷層是否存在橋基的穩(wěn)定性橋基的過量沉降和不均勻沉降斷層的野外識別地貌特征：

斷層崖；

斷層三角面地形；

溝谷或峽谷地形；

山脊錯斷、錯開；

河谷跌水瀑布；

河谷方向發(fā)生突然轉(zhuǎn)折等。地層特征：

巖層發(fā)生重復(fù)或缺失，

巖脈被錯斷，

巖層沿走向突然發(fā)生中斷，與不同性質(zhì)的巖層突然接觸等。

斷層的伴生構(gòu)造現(xiàn)象：巖層牽引彎曲、斷層角礫、糜棱巖、斷層泥和斷層擦痕等。斷層的野外識別——斷層崖斷層的野外識別——地層缺失或重復(fù)地層重復(fù)地層缺失斷層的野外識別——構(gòu)造巖斷層角礫巖斷層的野外識別——擦痕、鏡面、階步擦痕階步Engineeringgeologicalevaluationoffaults(斷層的工程地質(zhì)評價)Faultdestroytheintegrity(整體性)ofrockmass,accelerateweatheringandgroundwateractivities,reducetherockofstrengthandstabilityandcausesomeadverseeffectstotheengineering.Faultfracturezonewhichreducefoundationbearingcapacityandstabilityofrockmassandeasytocauselargersettlementofbuildingproduce,evencausetiltedorfault;haslowintensity,poorstability,largecompressibility.Faultcausesomeimportantimpacttothestabilityofslopeandfoundation(邊坡和橋基).Suchasthebridgebuildingswhichcrossthefracturedzones,maycauseunevensubsidencebecauseofdifferentlithologic(巖性)oftwoplates.Itiseasytoproduceroofcollapsewhenthetunnelcrossthefaultzone,weshouldavoidlarge-scalefaultfracturezonewhendeterminingthetunnelplaneposition.Whenthetunnelaxisandfaultstrikeparallels,weshouldavoidcontactbetweentunnelandfracturezone.Whenthetunnelacrossthefault,faultcausesmallaffectontunnelengineering,westillshalltakereasonableprotectivemeasuresandengineeringmeasurestoensureconstructionsafety.Faultwildidentification(斷層野外識別)Faultscarp(斷層崖)Stratamissingorrepeated(地層缺失或重復(fù))Tectonicrock(構(gòu)造巖)Faultbreccia(斷層角礫巖)Slickensides(擦痕、摩擦鏡面),step(階步)Tractionfold(牽引褶皺)1)Faultoftenassociateddensejoints(密集的節(jié)理)whichparallelwithfaultplane.2)Asuddeninterruptionalongthestrikeofrockororebed(礦層).3)Negativeterrain(負地形),faulttriangleface(斷層三角面).4)Alongtherockfaultfracturezone,springislinearexposed(呈線狀出露).Section3ReadinggeologicalmapsLocalgeologicalconditionsshouldbeconsideredintheconstructionofroads,bridgesandtunnelsinordertoensurethesafety,stableandreasonableeconomyoftheprojects.Geologicalmapsclearlyshowthetopography,landformsandhydrogeological(水文地質(zhì))conditionsofthecoveredareasandtheyalsoshowtherockstrata,thegeologicaltectonicconditionsandthedevelopmentprocessofthegeologicalhistory.Itisnecessaryforthebuilderstoobtaincorrespondinggeologicalinformationingeologicalmaps.GeologicalmapsAgeologicalmapisadrawingthatexpressesthegeologicalconditionofaregiontoreflectstrata,lithologyandthedistributionofgeologicalstructurewithacertaincolormaps,symbols,codes.Awholegeologicalmapincludesplan(平面圖),profile(剖面圖)andhistogram(柱狀圖).Geologicalmaps’content1)Topographycharacteristic:Usingcontourstoexpress.2)Lithology(巖性):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(水文地質(zhì)圖):Reflectaregion’shydrogeologicalconditions6)Engineeringgeologicalmap:ReflectregionalengineeringgeologicalconditionsorfieldgeologicalconditionsThestepsofreadinggeologicalmaps1)Readmapname,scale,understandmap’spositionandprecision.2)Readillustrations,establishinitialconceptofstrata,lithology,geologicalstructureofthegraph.3)Analysistheterrainandtheriversystemdistribution.4)Readingstratadistribution,oldandyoungrelationship,occurrence,anditsrelationshipwiththeterrain;analysisgeologicalstructure.Theperformanceformofgeologicalstructureing