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1、第32卷第3期2015年3月公路交通科技JoumalofHighwayandTransponationResearchandDevelopmentV01.32No.3Mar.2015doi:10.3969/j.issn.1002一0268.2015.03.007準飽和土中單樁豎向荷載作用下的動力響應李懷健1,張鴻2,徐斌2(1.交通運輸部公路科學研究院,北京100088;2.南昌工程學院土木與建筑工程學院,江西南昌330099)摘要:根據(jù)Biot飽和多孔連續(xù)介質波動方程,基于Bardet對準飽和土的假設,提出了準飽和土二相介質波動方程;運用Hel
2、mholtz矢量分解和傳遞、透射矩陣法(TRM)推導出準飽和土中層狀半空間受豎向荷載作用下的動力響應表達式;利用Muki虛擬樁法,在層狀半空間建立了樁和準飽和土相互作用的第二類Fredholm積分方程,通過離散的數(shù)值積分方法求解積分方程,討論了準飽和土中單樁豎向動力響應問題。算例分析表明,準飽和土中樁頂豎向阻抗隨飽和度的減少而增大,與飽和土地基相比,明顯偏大;樁側孔壓隨飽和度的減小而增大,并沿著樁長迅速衰減;樁頂位移幅值在頻率較小時變化明顯,飽和度越小,位移峰值越大,當頻率較大時,飽和度的變化對振幅的影響不大。關鍵詞:道路工程;準飽和土;單樁動力
3、響應;Helmholtz矢量分解;透射矩陣法(TRM)中圖分類號:U412文獻標識碼:A文章編號:1002—0268(2叭5)03—0037—08DynamicRespOnSeS0fSIngIePiIeEmbeddedinNearIySaturatedSO¨SubjectedtoVerticaILoadLIHuai-jianl,ZHANGHon92,XUBin92(1.ResearchInstituteofHighway,Ministryof7Ihnspon,Beijing100088,china;2.SchoolofCivilEn舀neerin
4、g&Architecture,NanchangInstituteofTechnolog)r,NanchangJiaIl弘i330099,China)Abstract:A2一phasemediumwaveequationofnearlysaturatedsoilisproposedbasedonBiot’swaveequationofsaturatedporouscontinuousmediaandBardet’sassumptionregardingnearlysaturatedsoil.ApplyingtheHelmholtz’sVectord
5、ecompositionandtransmissionandTRM,thedynamicI℃sponseexpressionsof1ayeredhalf.spaceinneadysaturatedsoilunderverticalloadarederiVed.BasedonMuki6ctitionJspilemethodology,thesecondkindofFredholminteg阻lequationsdescribinginteractionbetweenpileandnearlysaturatedsoilinhalf-spacearee
6、stablished.Theinte鏟alequationsaresolVedbyusingdiscretenumericalinte鏟a1method,andtheverticaldynamicresponseofapileembeddedinnearlysaturatedsoilisdiscussed.Thenumericalresultshowsthat(1)theverticalimpedanceatthetopofthepileembeddedinnearlysaturatedsoilincI℃asesasthesatumtiondeg
7、reedecreases,anditisquitelargecomparedwiththatofthes砒uratedsoilfoundation;(2)theporepressurealongthesideofthepileincreasesasthesaturationdegreedecreasing,andattenuatesrapidlyalongthelengthofthepile;(3)thepiletop’sdisplacementchangessignificantlywhenthef詫quencyissmaU,asmallers
8、aturationdegreeresultsinalargerpeakdisplacement,butwhenthefrequencyi