Atrapezoidvalleysiteischosenasaresearchsite,andaccordingtonumericalmodelsbasedonorthogonaldesign,thefactorsinfluencinggroundmotioninthevalleysitearestudiedwithtwo-dimensionalfinitedifferencemethod.Theinfluencingfactorsareranked,andthenthecalculationresultsareverifiedbygroundmotionanalysis.Theconclusionsareasfollows:therearefourfactorsthathaveimportanteffectsongroundmotionoftrapezoidvalleysites,buttheeffectsaredifferentasthelocationofsiteschanges,theinfluencingfactorsrankdifferentlywithdifferentsitelocations;Therankingoftheinfluencingfactorsisthesameforallthesiteslocatedwithinadistanceof40mfromthevalley'sside,amongthem,themosteffectiveoneisthevalleyslopeangleranks,followedbydepth-to-widthratio,overburdenthickness,atlasttheinputgroundmotionintensity.Theimpactofthefactorsonsurfacegroundmotionisroughlythesameinthevalleysiteswithinacertaindistancetothevalleyside,andthegeometricparametersofthevalleyterrainplayagreaterpartininfluencinggroundmotion.Withtheincreaseofdistanceawayfromthevalley'sside,therankingoftheinfluencingfactorsalsochanges,theratingofslopeanglemovesbackward,therankingoftheinputgroundmotionandoverburdenthicknessmoveahead.Theeffectofvalleygeometricparametersongroundmotionsisgraduallyweakened,buttheeffectofothertwoinfluencefactorsaregraduallyincreased,similartocasesofahorizontallayeredsite.StrongmotionrecordsinAnningRivervalleysitewereanalyzed,andtheresultsshowthatthevalleytopographyhasasignificantamplificationeffectongroundmotion,andthatthenumericalresultsofthispaperarecredible.
