RoadbedConstructionTechnologySubgradedrainageengineeringconstructionTheoreticalknowledgeWateristhemainfactorcausingroadbeddiseases.Waterhazards,suchasimmersion,saturationandscouringofsoil,areoneoftheimportantcausesofroadbeddiseases.Thestrengthandstabilityofsubgradesarecloselyrelatedtowater.Therearemanydiseasesofroadbed,andtherearemanyreasonsfortheformationofdiseases,buttheeffectofwaterisoneofthemainfactors.Thepurposeofsubgradedrainageistoensurethatthesubgradeisalwaysdry,firmandstable.Thequalityofdrainagetreatmentwithinthesubgradehasagreatimpactontheoverallstabilityofthesubgradeandthepreventionofsubgradediseases.Thewaterthatendangersthesubgradecanbedividedintotwocategories:surfacewaterandgroundwater.TheoreticalknowledgeThepurposeofsubgradedrainageistoensurethatthesubgradeisalwaysdry,firmandstable.Thequalityofdrainagetreatmentwithinthesubgradehasagreatimpactontheoverallstabilityofthesubgradeandthepreventionofsubgradediseases.Thewaterthatendangersthesubgradecanbedividedintotwocategories:surfacewaterandgroundwater.TheoreticalknowledgeTheneveryonemustfirstunderstandwhatisgroundwaterandwhatissurfacewater.Surfacewaterisverysimple,thatis,wecanseethatitaccumulatesontheground.Orthewaterflowingonthegroundissurfacewater,andtherearemanykindsofgroundwater.Forexample,wehaveundergroundtrenchesandundergroundrivers.Forexample,theremaybeaquifersbetweenourdifferentgeologicallayers,andthereisalsowaterinourrockandsoilvoids.,thesearealsogroundwater.Everyonemustpayattention,forexample,anypileofsoilyouseecontainsgroundwater,andourundergrounddrainagefacilitiesalsoincludefacilitiesforremovingthewatercontainedintheporesofthesesoilsandrocks.TheoreticalknowledgeSubgradeconstructionSubgradewaterismainlyatmosphericprecipitation,waterincanals,naturalditchesandgroundwater,sothesubgradedrainagefacilitiesarealsodividedintosurfacedrainageandundergrounddrainage.Relativelyspeaking,undergrounddrainageismoredifficult,andthedesignisnoteasytofindgroundwaterlayers.Duringconstruction,itisnecessarynotonlytoconstructcarefullyaccordingtothedesign,butalsotohaveanin-depthunderstandingofthepossiblehazardscausedbygroundwatertopreventandcontrolthem.Commonsubgradesurfacedrainagefacilitiesmainlyincludesideditches,interceptingditches,drainageditches,culverts,etc.,andundergrounddrainagefacilitiesmainlyincludeunderdrains(pipes),seepageditches,seepagewells,etc.LearningtargetKnowthediseasescausedbywaterinsubgradeengineeringandtheimportanceofsubgradedrainage;01Cantellwhicharesurfaceandwhichareundergrounddrainagefacilities;02Canreadtheconstructiondrawingsofdrainageworks,determinethestructuraldimensionsofeachpart,andcalculatetheengineeringquantity;03Canorganizetheconstructionprocessofroadbeddrainageengineering;04Canindependentlycompletethequalityinspectionandevaluationofdrainageprojects,andfillinthequalityinspectionandevaluationmaterials.05Task1ConstructionofSurfaceDrainageFacilitiesatSubwayBaseTask1ConstructionofSurfaceDrainageFacilitiesatSubwayBase1.SideditchThetrenchessetontheoutsideoftheshoulderoftheexcavatedroadbedortheoutsideofthetoeofthelowembankmenttocollectandremoveasmallamountofsurfacewaterwithintherangeoftheroadbedandflowingtotheroadbedarecalledsideditch.Task1ConstructionofSurfaceDrainageFacilitiesatSubwayBase1.Sideditcha）b）c）Commonsectionformsofguttera)TrapezoidGutterb)Triangulargutterc)RectangulargutterThesoilgutterisgenerallytrapezoidalandtriangular,andthestonegutterisgenerallytrapezoidalorrectangular,andthecross-sectionalformisdeterminedbythetypeofsoilatthegutter.Task1ConstructionofSurfaceDrainageFacilitiesatSubwayBase1.SideditchButterflyGutterRectangularcoverplatesideditchTask1ConstructionofSurfaceDrainageFacilitiesatSubwayBase1.SideditchSideditchshallbeprovidedintheexcavationsectionandthefillingsectionwherethefillingheightislessthanthesideditchdepth.Thesizeanddepthofthesideditchflowingwatersectionshouldbedeterminedaccordingtothesizeofthecatchmentarea,andthesectionformisdeterminedbythetypeofsoilatthesideditch.Thesoilgutterisgenerallytrapezoidalortriangular,andthestonegutterisgenerallyrectangularortrapezoidal.Theslopeoftheinnersideslopeofthetrapezoidalgutterisgenerally1:1~1:1.5,andtheslopeoftheoutersideslopeisthesameasthatofthecuttingsideslope.Whenthereisacrushingplatformoutsidethegutter,theslopeoftheoutersideslopeisthesameasthatoftheinnersideslope.Thedepthandwidthofthesideditcharegenerallynotlessthan0.4m,and0.3minaridareasandwater-dividingpoints.Thecross-sectionofthesideditchforexpresswaysandfirst-classhighwaysshouldbelarger,anditsdepthandbottomwidthcanbe0.8~1.0m.Task1ConstructionofSurfaceDrainageFacilitiesatSubwayBase1.SideditchUndernormalcircumstances,sideditchesshouldnotbeusedincombinationwithotherditches.Inordertocontrolthewaterinthesideditchesfrombeingtoomuch,adrainageditchisgenerallysetupevery300~500m(200minspecialcases)todrainthesideditchwatertotheroadbedintime.outsidethescope.Task1ConstructionofSurfaceDrainageFacilitiesatSubwayBase2.InterceptingditchTheinterceptingditch,alsoknownasthegutter,islocatedoutsidethetopofthecuttingslopeorabovethehillsideembankmenttointerceptthesurfacewaterflowingfromabove.Thelocationoftheinterceptingditch,whenthereisaspoilmound,shallbelocatedoutsidethespoilmound;whenthereisnospoilmound,itshallbeatleast5mawayfromtheedgeofthecuttop,andshallnotbelessthan10mintheloessarea,andshallbereinforcedwithanti-seepage;abovethehillsideembankmentTheinterceptingditchisatleast2mawayfromthetoeoftheembankment。Task1ConstructionofSurfaceDrainageFacilitiesatSubwayBase2.InterceptingditchTheinterceptingditchisadrainagefacilityinstalledoutsidetheslopetopoftheexcavatedroadbedorabovethehillsideembankment,perpendiculartothedirectionofwaterflow,tointerceptandguidethegroundrunofffromthetopoftheroadbedtotheroadbed.Theinterceptingditchcanpreventthesurfacerunofffromscouringanderodingtheexcavationslopeandthetoeoftheembankment,andreducethedischargeburdenofthesideditch.Thecross-sectionalshapeoftheinterceptingditchisgenerallytrapezoidal,thebottomwidthshouldnotbelessthan0.5m,andthedepthshouldbedeterminedaccordingtotheinterceptedwaterflow,generallynotlessthan0.5m.:1.5.Thedistancebetweentheinterceptingditchandthetopofthecuttingslopevariesdependingonthesoilquality.Theprincipleofnotaffectingthestabilityofthecuttingslopeisgenerallytakenasd>5m,andaretainingplatformisbuiltbetweentheinterceptingditchandthecutting.Task1ConstructionofSurfaceDrainageFacilitiesatSubwayBase3.GuttersThepurposeofsettingdrainsistodischargewaterfromthesubgradetolow-lyingplacesordrainagefacilitiesbeyondthesubgrade.Task1ConstructionofSurfaceDrainageFacilitiesatSubwayBase3.GuttersThepurposeofsettingupdrainageditchesistodischargewaterflowfromthesubgradetolow-lyingplacesordrainagefacilitiesbeyondthesubgraderange.Intheplainhillyarea,whentheoriginalgroundditchismeanderingandaffectsthestabilityofthesubgrade,thedrainageditchcanbeusedtoimprovetheditchline.Sometimestoreducethenumberofculverts,drainsarealsousedtomergeditches.Thedrainageditchisgenerallyatrapezoidalsection,thebottomwidthisnotlessthan0.5m,andthedepthisdeterminedaccordingtotheflowrate,butshouldnotbelessthan0.5m.Inastraightline,ifitisnecessarytoturn,itsradiusshouldbe10~20m,andthelengthofthedrainageditchshouldbedeterminedaccordingtotheactualneeds,usuallynotmorethan500m.Task1ConstructionofSurfaceDrainageFacilitiesatSubwayBase4.WaterDropsandRapidsTheinterceptingditchesanddrainageditchesinthesteepsectionofthelongitudinalslopecanbeconnectedbysingle-stage,multi-stagewaterdroporrapi