公路几何设计-外文翻译

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1、GeometricDesignofHighwaysTheroadisonekindoflinearconstructionusedfortravel.Itismadeoftheroadbed，theroadsurface，thebridge,theculvertandthetunnel.Inaddition,italsohasthecrossingoflines，theprotectiveprojectandthetrafficengineeringandtheroutefacility.Theroadbedisthebaseofroads

2、urface，roadshoulder，sideslope，sideditchfoundations.Itisstonematerialstructure，whichisdesignedaccordingtoroute’splaneposition.Theroadbed，asthebaseoftravel，mustguaranteethatithastheenoughintensityandthestabilitythatcanpreventthewaterandothernaturaldisasterfromcorroding.Thero

3、adsurfaceisthesurfaceofroad.Itissingleorcomplexstructurebuiltwithmixture.Theroadsurfacerequirebeingsmooth，havingenoughintensity，goodstabilityandanti-slipperyfunction.Thequalityofroadsurfacedirectlyaffectsthesafe，comfortandthetraffic.HighwaygeometrydesignstoconsiderHighwayH

4、orizontalAlignment，VerticalAlignmenttwokindsoflinearandcross-sectionalcompositionofcoordination,butalsopayattentiontothesmoothflowofthelineofsight，etc.Determinetheroadgeometry，considerthetopography，surfacefeatures，rationaluseoflandandenvironmentalprotectionfactors，tomakefu

5、lluseofthehighwaygeometriccomponentsofreasonablesizeandthelinearcombination.1.AlignmentDesignThealignmentofaroadisshownontheplaneviewandisaseriesofstraightlinescalledtangentsconnectedbycircular.Inmodernpracticeitiscommontointerposetransitionorspiralcurvesbetweentangentsand

6、circularcurves.Alignmentmustbeconsistent.Suddenchangesfromflattosharpcurvesandlongtangentsfollowedbysharpcurvesmustbeavoided;otherwise，accidenthazardswillbecreated.Likewise，placingcircularcurvesofdifferentradiiendtoend(compoundcurves)orhavingashorttangentbetweentwocurvesis

7、poorpracticeunlesssuitabletransitionsbetweenthemareprovided.Long,flatcurvesarepreferableatalltimes，astheyarepleasinginappearanceanddecreasepossibilityoffutureobsolescence.However,alignmentwithouttangentsisundesirableontwo-laneroadsbecausesomedrivershesitatetopassoncurves.L

8、ong,flatcurvesshouldbeusedforsmallchangesindirection,asshortcurvesappearas“kink”.Alsohori