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ID:27651235
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页数:10页
时间:2018-12-05
《公路几何设计-外文翻译》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
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
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