公路線形設(shè)計(jì)外文文獻(xiàn)中英對(duì)照

1、外文文獻(xiàn)翻譯(含：英文原文及中文譯文)文獻(xiàn)出處：YHassan.GeometricDesignofHighwaysJAdvancesinTransportationStudies2016,6(1):31-41.英文原文GeometricDesignofHighwaysYHassanA. AlignmentDesignThealignmentofaroadisshownontheplaneviewandisaseriesofstraightlinescalledtangentsconnectedbycircularcurves.Inmodempracticeitiscommontointerpo

2、setransitionorspiralcurvesbetweentangentsandcircularcurves.Thelineshapeshouldbecontinuous,suddenchangesfromflatlinetosmallradiuscurveorsuddenchangeoflonglineendconnectedtosmallradiuscurveshouldbeavoided,otherwiseatrafficaccidentmayoccur.Similarly,arcswithdifferentradiiend-to-end(complexcurves)orshor

3、tstraightlinesbetweentwoarcswithdifferentradiiarebadlinesunlessaneasingcurveisinsertedbetweenarcs.Thelong,smoothcurveisalwaysagoodlinebecauseitisbeaut血llylinedandwillnotbeabandonedinthefuture.However,itisnotidealthatthetwo-wayroadlineshapeiscomposedentirelyofcurves,becausesomedriversalwayshesitateto

4、passthroughcurvedroadsegments.Thelongandslowcurveisusedinthesmallercomers.Ifyouuseashortcurve,youwillsee"kinks."Inaddition,thedesignoftheflatandverticalsectionsofthelineshouldbeconsideredcomprehensivelyandshouldnotbeonlyone.Nomatterwhich,forexample,whenthestartingpointoftheflatcurveisneart

5、hevertexoftheverticalcurve,serioustrafficaccidentswilloccur.Vehiclesdrivingoncurvedsectionsaresubjectedtocentrifugalforce,andtheyneedaforceofthesamemagnitudeintheoppositedirectionduetotheheightandlateralfrictiontooffsetit.Fromtheviewpointofhighwaydesign,thehighorhorizontalfrictioncannotexceedacertai

6、nvalue.Them邸imum,thesecontrolvaluesforacertaindesignspeedmaylimitthecurvatureofthecurve.Ingeneraithecurvatureofac訂cularcurveisrepresentedbyitsradius.Forthelineardesign,thecurvatureisoftendescribedbythecurvature,ie,thecentralanglecorrespondingtothe100-footcurve,whichisinverselyproportionaltotheradius

7、ofthecurve.Anormalroadarchissetinastraightsectionoftheroad,andthecurvesectionissettoasuperhigh,andanexcessivelygradualroadsectionmustbesetbetweenthenorn叫sectionandthesuperhighsection.Theusualpracticeistomaintainthedesignelevationofeachmidlineoftheroadunchanged.Byraisingtheouteredgeandloweringtheinne

8、redgetoformasuperhigh,forthelineshapewherethestraightlineisd汀ectlyconnectedwiththec虹lecurve,thesuperhighshouldneverstartonthestraightlinebeforereachingthecurve.Attheotherendofthecurveatacertaindistancetoreachalltheultra-high.Ifthevehicleisdrivingatahighspeedonarestrictedsectionofroad,suchasastraight

9、lineconnectedwithasmallradiuscirclecurve,drivingwillbeextremelyuncomfortable.Whenthecarentersthecurvesection,thesuperhighstartsandthevehicletiltsinward,butthepassengermustmaintainthebodybecauseitisnotsubjectedtocentrifugalforceatthistime.Whenthecarreachesthecurvesection,centrifugalforcesuddenlyoccur

10、s,forcingpassengerstom狄efurtherpostureadjustments.Whenthecarleavesthecurve,theaboveprocessisjusttheopposite.Afterinsertingtherelaxationcurve,theradiusgraduallytransitionsfrominfinitytoacertainfixedvalueonthecirclecurve,thecentrifugalforcegraduallyincreases,andultra-highlevelsarecarefullysetalongther

11、elaxationcurve,andthecentrifugalforceisgraduallyincreased,therebyavoidingdrivingbumps.Theeasementcurvehasbeenusedonrailwaysformanyyears,butithasrecentlybeenappliedonhighways.Thisisunderstandable.Thetrainmustfollowapreciseorbit,andtheuncomfortablefeelingmentionedabovecanonlybeeliminatedaftertheeasecu

12、rveisused.However,thedriverofacarcanchangethelateralpositionontheroadatwill,andhecanprovidearelaxationcurveforhimselfbym咄ingaroundaboutcurve.Butdoingthisinonelane(sometimesinotherlanes)isverydangerous.Awell-designedrelaxationcurvemakestheaboveroundaboutnessunnecessary.Multi-clustersafetyisameasure,a

13、ndroadsarewidelyusedastransitioncUIVes.Foracircularc田vewiththesameradius,addinganeasingcUIVeattheendwillchangetherelativepositionsofthec田veandthestraightline.Therefore,whetherornottouseaneasingcUIVeshouldbedeterminedbeforefinalalignmentsUIVey.ThestartingpointofthegeneralcUIVeislabeledPCorBCandtheend

14、pointislabeledPTorEC.ForcUIVeswithtransitionc田ves,theusualmarkerconfigurationsare:TC,SC,CS,andST.Fortwo-wayroads,theroadwidthshouldbeincreasedatsharpbends.Thisismainlybasedonthefollowingfactors:1.Thedriverisafraidtogetoutoftheedgeoftheroad.2.Duetothedifferenceinthedrivingtrajectoryofthefrontandrearw

15、heelsofthevehicle,theeffectivelateralwidthofthevehicleincreases;3.Thewidthofthefrontofthevehiclethatisinclinedrelativetothecenterlineoftheroad.Forroadsthatare24feetwide,theaddedwidthisnegligible.Onlyifthedesignspeedis30mil/handthecUIVatureisupto2ft.However,fornarrowroads,wideningisveryimportanteveno

16、nsmoothcUIVesections.Therecommendedwideningvaluesandwideneddesignsareshownin".Highwaylineardesign."B. LongitudinalslopelineTheverticalalignmentofthehighwayanditsimpactonthesafetyandeconomyofvehicleoperationconstituteoneofthemostimportantelementsinhighwaydesign.Verticallinesconsistofstraigh

17、tlinesandverticalparabolasorcircularlinescalledverticalslopelines.Whenagradelinerisesgraduallyfromahorizontalline,itiscalledanuphiliandviceversa,itiscalledadownhillslope.Intheanalysisofslopeandslopecontroi如ignersusuallyhavetostudytheeffectofchangesinslopeonthemidlineprofile.Indeterminingtheslope,the

18、idealsituationisthebalanceofexcavationandfilling,andthereisnolargeamountofborrowersandabandonedparties.Alltheearthmovingiscarrieddownasfaraspossibleandthedistanceisnotlong.TheslopeshouldchangewiththeterrainandbeconsistentwiththedirectionofascentanddescentoftheexistingdrainagesystemInthemountainsthes

19、lope-5shouldbebalancedtominimizethetotalcostIntheplainorgrasslandareastheslopeisapproximatelyparalleltothesurface,buthigherthanthesurfaceatasufficientheighttofacilitatedrainageofthesurface.Ifnecessary,windscanbeusedtoremovesurfacesnow.Iftheroadisapproachingorrunningalongariver,thecurrentheightofthes

20、lopeisdeterminedbytheexpectedfloodlevelInanycase,thegentleslopeshouldbesetattheexcavationsectioncomparedtotheshortverticalsectionconnectingtheshortverticalcurveduetotheupslopedownslope,andthesectionfromthedownslopeupslopeshouldbesetatthefill.Roadsection.Suchagoodlineardesigncanoftenavoidtheforn沮tion

21、ofamoundordepressionoppositetothecurrentlandscape.Otherconsiderationsaremuchmoreimportantwhendeterminingtheverticalslopelinethanwhenfillingthebalance.Studyandmakemoredetailedadjustmentstoadvancedissues.Ingeneral,theslopeofthedesignthatisconsistentwiththeexistingconditionsisbetter,whichcanavoidsomeun

22、necessarycosts.Inslopeanalysisandcontrol,theimpactofslopeonmotorvehicleoperatingcostsisoneofthemostimportantconsiderations.Astheslopeincreases,thefuelconsumptionwillobviouslyincreaseandthespeedwillslowdown.Amoreeconomicalsolutioncanbalancetheannualincreaseintheannualcostofreducingtheslopeandincreasi

23、ngtheannualcostofrunningthevehiclewithoutincreasingtheslope.Theexactsolutiontothisproblemdependsontheunderstandingoftrafficflowandtraffictype,whichcanonlybeknownthroughtrafficinvestigations.Indifferentstates,wherethemaximumlongitudinalgradientisalsoverydifferent,AASHTOrecommendsthatthemaximumlongitu

24、dinalslopebeselectedbasedonthetimeandterrain.Thecurrentdesignhasamaximumlongitudinalgradientof5%atadesignspeedof70mil/h.Atadesignspeedof30mil/h,themaximumlongitudinalslopeisgenerally7%-12%dependingonthetopography.Whenusinglongersustainedclimbs,theslopelengthcannotexceedthecriticalslopelengthwhennosl

25、ow-movingvehicleisprovided.Thecriticalslopelengthcanvaryfrom1700ftin3%gradeto500ftin8%grade.Theslopeofthecontinuouslongslopemustbelessthanthemaximumslopeofanyendsurfaceofthehighway.Usuallythelongcontinuoussingleslopeisdisconnectedandthelowerpartisdesignedasasteepslope,whileapproachingthetopoftheslop

26、eallowstheslopetodecrease.Atthesametime,itisnecessarytoavoidobstructionoftheviewduetotheinclinationofthelongitudinalsection.Them邸imumlongitudinalgradientofthehighwayis9%.Onlywhenthedrainageoftheroadisaproblem,ifthewatermustbedrainedtothesideditchorthedrainageditch,theminimumgradientcriterionisofimpo

27、rtance.Inthiscase,心HTOrecommendsaminimumgradientof0.35%.C. sightdistanceInordertoensurethesafetyofdriving,theroadmustbedesignedtohaveasufficientdistanceinfrontofthedriver'slineofsight,sothattheycanavoidobstaclesotherthantheobstacles,orsafelyovertake.Theline-of-sightisthelengthoftheroadvisibletot

28、hedriverofthevehicle.Twomeanings:"parkingdistance"or"non-passingsightdistance"or"overtakingsightdistance."Nomatterwhathappens,reasonabledesignrequiresthedrivertoseethisdangeroutsideacertaindistance,andbrakethecarbeforehittingit.Inaddition,itisnotsafetothinkthatthevehicl

29、ecanavoiddangerbyleavingthedrivinglane.Becausethiscancausethevehicletolosecontrolortocollidewithanothercar.Theparkingdistanceiscomposedoftwoparts:Thefirstpartisthedistancethatthedrivertakesbeforethedriverfindsanobstacleandbrakes.Inthisdetectionandreactionphase,thevehicletravelsatitsinitialspeed;thes

30、econdpartisthedriver'sPartoftheparkingdistancedependsonthespeedofthevehicleandthedriver'svisualtimeandbrakingtime.Thesecondpartoftheparkingdistancedependsonthespeed,thebrakes,thetires,theconditionsoftheroadsurface,andthelineshapeandslopeoftheroad.Otherwise,thecapacityofthehighwaywillbereduce

31、d,andtheaccidentwillincrease,becausetheirritabledriverwouldriskacollisionandovertakethevehicleifhecannotsafelyovertakethevehicle.Theminimumdistanceinfrontofwhichthedrivercansafelybeseeniscalledtheovertakingdistance.Whenmakingadecisiononwhethertopassornot,thedrivermustcomparethevisibilitydistanceahea

32、dandthedistancerequiredtocompletetheoverta柜ngmovement.Thefactorsthatinfluencehimtom咄eadecisionarethedegreeofcautionindrivingandtheaccelerationperformanceofthevehicle.Duetothesignificantdifferencesbetweenhumans,theovertakingbehavior,whichismainlydeterminedbyhumanjudgmentsandactionsratherthanthemechan

33、icaltheorem,variesgreatlyfromdrivertodriver.Inordertoestablishtheline-of-sightvalueforovertaking,engineersobservedmanydrivers'overtakingbehavior.Between1938and1941,abasicsurveywasestablishedtoestablishastandardofover-sightdistance.Assumethattheoperatingconditionsareasfollows:1. Itisdrivenataunif

34、ormspeedbytheovertakingvehicle.2. OvertakingWhenenteringtheovertakingarea,decelerateafterbeingovertak:en.3. Whenarrivingattheovertakingarea,thedriverneedstoobservethepassingareaforashorttimeandstartovertaking.4. Inthefaceoftheoppositevehicle,theovertakingiscompletedinadelayedstart-upandahurriedturn.

35、Intheovertakingprocess,overtakingacceleratesintheovertakinglaneandtheaveragespeedis10mil/hfasterthanbeingovertaken.5. Whenovertakingreturnstoitsoriginallane,theremustbeasafedistancebetweenitandtheoppositevehicleontheotherlane.Thesumoftheabovefiveitemsistheoversightdistance.中文譯文公路線形設(shè)計(jì)作者：YHassanA.平面設(shè)計(jì)

36、道路的線形反映在平面圖上是由一系列的直線和與直線相連的圓曲線構(gòu)成的?，F(xiàn)代設(shè)計(jì)時(shí)常在直線與圓曲線之間插入緩和曲線。線形應(yīng)是連續(xù)的，應(yīng)避免平緩線形到小半徑曲線的突變或者長(zhǎng)直線末端與小半徑曲線相連接的突然變化，否則會(huì)發(fā)生交通事故。同樣，不同半徑的圓弧首尾相接（復(fù)曲線）或在兩半徑不同的圓弧之間插入短直線都是不良的線形，除非在圓弧之間插入緩和曲線。長(zhǎng)而平緩的曲線總是良好的線形，因?yàn)檫@種曲線線形優(yōu)美，將來(lái)也不會(huì)廢棄。然而，雙向道路線形全由曲線構(gòu)成也是不理想的，因?yàn)橐恍{駛員通過曲線路段時(shí)總是猶豫。長(zhǎng)而緩的曲線應(yīng)用在拐角較小的地方。如果采用短曲線則會(huì)出現(xiàn)“扭結(jié)”。另外，線路的平，縱斷面設(shè)計(jì)應(yīng)綜合考慮，而不應(yīng)

37、只顧其一，不顧其二，例如，當(dāng)平曲線的起點(diǎn)位千豎曲線的頂點(diǎn)附近時(shí)將會(huì)產(chǎn)生嚴(yán)重的交通事故。行駛在曲線路段上的車輛受到離心力的作用，就需要一個(gè)大小相同方向相反的由超高和側(cè)向摩擦提供的力抵消它，從公路設(shè)計(jì)的角度看，超高或橫向摩擦力都不能超過某一最大值，這些控制值對(duì)千某一規(guī)定設(shè)計(jì)車速可育睬用曲線的曲率作了限制。通常情況下，某一圓曲線的曲率是由其半徑來(lái)體現(xiàn)的。而對(duì)千線形設(shè)計(jì)而言，曲率常常通過曲度來(lái)描述即100ft長(zhǎng)的曲線所對(duì)應(yīng)的中心角，曲度與曲線的半徑成反比。公路的直線地段設(shè)置正常的路拱，而曲線地段則設(shè)置超高，在正常斷面與超高斷面之間必須設(shè)置過度漸變路段。通常的做法是維持道路每一條中線設(shè)計(jì)標(biāo)高不變，通過抬

38、高外側(cè)邊緣，降低內(nèi)側(cè)邊緣以形成超高對(duì)千直線與圓曲線直接相連的線形，超高應(yīng)從未到達(dá)曲線之前的直線上開始，在曲線頂點(diǎn)另一端一定距離以外達(dá)到全部超高。如果車輛以高速度行駛在一段受限制的路段，如直線與小半徑的圓曲線相連行車會(huì)極不舒服。汽車駛進(jìn)曲線路段時(shí)，超高開始，車輛向內(nèi)側(cè)傾斜，但乘客須維持身體的垂直狀態(tài)，因?yàn)榇藭r(shí)未受到離心力的作用。當(dāng)汽車到達(dá)曲線路段時(shí)離心力突然產(chǎn)生，迫使乘客須作進(jìn)一步的姿勢(shì)調(diào)整。當(dāng)汽車離開曲線時(shí)，上述過程剛好相反。插入緩和曲線后，半徑從無(wú)窮大逐漸過渡到圓曲線上的某一固定值，離b力逐漸增大，沿緩和曲線精心設(shè)置超高，離心力平緩逐漸增加避免了行車顛簸。緩和曲線在鐵路上已經(jīng)使用多年，但在公

39、路上最近才得以應(yīng)用，這可以理解?；疖嚤仨氉裱_的運(yùn)行軌道，只有采用緩和曲線后，上述那種不舒服的感覺才能消除。然而，汽車司機(jī)在公路上可以隨意改變側(cè)向位置通過迂回進(jìn)入圓曲線來(lái)為自己提供緩和曲線。但是在一個(gè)車道上（有時(shí)在其他車道上）做這種迂回行駛是非常危險(xiǎn)的。設(shè)計(jì)合理的緩和曲線使得上述迂回沒有必要。多叢安全為計(jì)，公路廣泛采用緩和曲線,對(duì)千半徑相同的圓曲線來(lái)說，在末端加上緩和曲線就會(huì)改變曲線和直線的相關(guān)位置，因此應(yīng)在最終定線勘測(cè)之前應(yīng)決定是否采用緩和曲線。一般曲線的起點(diǎn)標(biāo)為PC或BC'終點(diǎn)標(biāo)為PT或EC。對(duì)含有緩和曲線的曲線，通常的標(biāo)記配置為：TCSC,C褥口ST。對(duì)千雙向道路急彎處應(yīng)增加路

40、面寬度，注要基千以下因素：1.駕駛員害怕駛出路面邊緣；2.由千車輛前輪和后輪的行駛軌跡不同，車輛有效橫向?qū)挾燃哟?3.車輛前方相對(duì)千公路中線傾斜而增加的寬度。對(duì)千寬度為24ft的道路，增加的寬度很小，可以忽略。只有當(dāng)設(shè)計(jì)車速為30miVh,且曲度可達(dá)2ft然而，對(duì)F較窄的路面，艮I®是在較平緩的曲線路段上，加寬也是很重要的，推薦加寬值及加寬設(shè)計(jì)見公路線形設(shè)計(jì)。B.縱坡線公路的豎向線形及其對(duì)車連運(yùn)行的安全性和經(jīng)濟(jì)性的影響構(gòu)成了公路設(shè)計(jì)中最重要的要素之一。豎向線形由直線和豎向拋物線或圓曲線組成稱為縱坡線?？v坡線從水平線逐漸上升時(shí)稱為上坡，反之，則稱為下坡。在分析坡度與坡度控制中，設(shè)計(jì)人員

41、通常要研究中線縱斷面上坡度變化的影響。在確定坡度時(shí)，最理想的情況是挖方和填方平衡，沒有大量的借方和棄方。所有的運(yùn)土都盡可能下坡運(yùn)并且距離不長(zhǎng)，坡度應(yīng)隨地形而變并且與既有排水系統(tǒng)的升，降方向一致。在山區(qū)，坡度要使得挖填平衡以使總成本最低。在平原或草原地區(qū)坡度與地表近似平行，但高千地表足夠的高度，以利千路面排水，若有必要，可利用風(fēng)力來(lái)清除表面積雪。如公路接近或沿河流走行，縱坡現(xiàn)的高度由預(yù)期洪水位來(lái)決定。無(wú)論在何種情況下，平緩的坡度現(xiàn)要比由短直線段連接短豎曲線構(gòu)成的不斷變向的坡度線好得多。由上坡向下坡變化的路段應(yīng)設(shè)在挖方路段，而由下坡向上坡變化的路段應(yīng)設(shè)在填方路段。這樣的線形設(shè)計(jì)較好往往可以避免形成與現(xiàn)狀地貌相反的土堆或是凹地。在挖填方平衡相比，在確定縱坡線時(shí)，其他考慮則重要得多。城市項(xiàng)目往往比農(nóng)村項(xiàng)目要求對(duì)控制要素進(jìn)行更詳盡的研究對(duì)高程進(jìn)行更細(xì)致的調(diào)整。一般來(lái)說設(shè)計(jì)與現(xiàn)有條件相符的坡度較好，