資源描述:
《各向異性固結(jié)飽和軟粘土動(dòng)力特性研究》由會(huì)員上傳分享,免費(fèi)在線閱讀,更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫(kù)。
1、洳專(zhuān):j-碩士學(xué)位論文⑧所在學(xué)院建氫墨猩堂墮浙江大學(xué)碩士學(xué)位論文各向異性固結(jié)飽和軟粘土動(dòng)力特性研究摘要地震是一種嚴(yán)重的自然災(zāi)害,特別是軟土場(chǎng)地,因?yàn)閷?duì)地震動(dòng)的放大作用顯著,造成的危害更大。而在我國(guó)沿海地區(qū)及部分內(nèi)陸城市廣泛分布著深厚軟粘土層,因此,研究這些軟土層的地震反應(yīng)具有十分重要的意義。但是,動(dòng)荷載作用下,土體的行為十分復(fù)雜。因而,在地震反應(yīng)分析中,如何確定實(shí)用的土體應(yīng)力一應(yīng)變關(guān)系又成為問(wèn)題的核心?!け疚氖紫仍谇叭搜芯康幕A(chǔ)上,針對(duì)實(shí)際工程中軟粘土存在的各向異性,采用英國(guó)GDS公司研制生產(chǎn)豹高精
2、度動(dòng)靜三軸試驗(yàn)設(shè)備進(jìn)行應(yīng)力控制的循環(huán)三軸試驗(yàn),研究分析了初始靜偏應(yīng)力、循環(huán)應(yīng)力比、加荷周數(shù)、頻率及超固結(jié)比對(duì)循環(huán)荷載作用下杭州地區(qū)飽和軟粘土的應(yīng)變和孔壓的影響。其次,本文根據(jù)試驗(yàn)結(jié)果,提出了杭州地區(qū)飽和軟粘土在循環(huán)荷載作用下的應(yīng)變軟化模型和應(yīng)變累積模型,并確定了參數(shù)。然后將其引入1wan模型中,結(jié)合Masing準(zhǔn)則對(duì)軟粘土的動(dòng)應(yīng)力一應(yīng)變關(guān)系進(jìn)行描述。通過(guò)計(jì)算結(jié)果和試驗(yàn)數(shù)據(jù)的對(duì)比分析表明,此模型能正確反映土體的循環(huán)特性。最后,本文基于一維非線性波傳播的原理,采用修正的1wan模型模擬每一層土的動(dòng)應(yīng)力一
3、應(yīng)變特性,并結(jié)合顯式有限差分法數(shù)值求解,自編計(jì)算程序?qū)Φ卣鸬乃俣?加速度)時(shí)程以及反應(yīng)譜進(jìn)行對(duì)比分析,得出了一些有益的結(jié)論。關(guān)鍵詞:各向異性應(yīng)變軟化殘余應(yīng)變飽和軟粘土本構(gòu)模型非線性地震反應(yīng)分析浙江大學(xué)碩士學(xué)位論文StudyonDynamicPropertiesofAnisotropicSaturatedClayABSTRACTEarthquakeisakindofcatastrophe.Specially,itwillinducemoreheavydisasterinclaysitebecauseo
4、famplificationofseismicgroundmotion.However,therearecoverdbydeepandthicksoftsoillayersincoastalareasandinlandcitiesinChin亂So,seismicsiteresponseanalysesisaveryimportantproblem.But,soilbehavioriscomplexunderdynamicloading.Thus,‘Howtodetcmlmestress-strai
5、nrelationship’becomesthekeyoflheproblem.Firstly,basedOllpreviousresearchesandanisotropicclayinaerialengineering,aseriesofundrainedcyclicstresscontrolledtriaxialtestswereperformedoiltypicalHangzhousoftdaybyGDSdynamictriaxialsystem.Theeffectsofinitialsta
6、ticdeviatorstress,cyclicsh'es5ratio,loadingcycles,loadingfrequencyandoverconsolidafionratioonstrainandpore-pressurewereinvestigated.Secondlyaccordingtoexperimentaldata,thispaperproposedacyclicdegradationmodelandaempiricalequationofplastic硝豫in.a(chǎn)nddeterm
7、inedtheparametersinthemodels.Andthen,theempiricalmodelswereincorporatedinto1wan’sseries-parallelmodeltoaccountforcyclicdegradationandcumulativeplasticstrainduringcyclicloadingindividually.Subsequently,thedynamicstress-strainrelationshipofsaturatedsoftc
8、layisdescribedwithmodifiedMasing’srule&Ascomparedwithexperimentaldataandothermodels,thepresentmodelisprovedtobereasonableandeffective.Fmally,inthepresentpaper,thedynaInicbehaviorofsoillayerswasdescribedbymodified1wan’sseries-parallelmod