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1、北京交通大學(xué)碩士學(xué)位論文循環(huán)荷載作用下碎石樁加固液化地基試驗(yàn)研究姓名:靳建軍申請(qǐng)學(xué)位級(jí)別:碩士專業(yè):巖土工程指導(dǎo)教師:張鴻儒20050301北京交通大學(xué)2005屆碩士研究生學(xué)位論文中文摘要循環(huán)荷載作用下碎石樁加固液化地基試驗(yàn)研究中文摘要在本論文中作者主要做了以下工作:首先,基于砂土動(dòng)三軸試驗(yàn),研究了砂土液化過(guò)程中振動(dòng)孔壓的發(fā)展規(guī)律,獲得了偏壓固結(jié)條件下振動(dòng)孔壓計(jì)算模式;結(jié)合應(yīng)力J懂變滯回環(huán),將液化過(guò)程劃分為4個(gè)階段,并對(duì)各階段的軸向應(yīng)變發(fā)展特點(diǎn)進(jìn)行了分析;分析了液化過(guò)程中動(dòng)模量的衰減特性,得到了動(dòng)彈性模量和動(dòng)剪切模量隨應(yīng)變發(fā)展的衰減特性曲線:研究了砂土的抗液化強(qiáng)度。其次,介紹了簡(jiǎn)
2、易振動(dòng)臺(tái)和疊層剪切變形模型箱,并進(jìn)行了飽和砂土自由場(chǎng)地的振動(dòng)臺(tái)試驗(yàn)。循環(huán)荷載作用下的振動(dòng)臺(tái)試驗(yàn)表明:細(xì)砂上極易液化;E1一Centro波作用下的振動(dòng)臺(tái)試驗(yàn)結(jié)果表明:疊層剪切變形模型箱成功地模擬了土體的側(cè)向邊界條件。最后,進(jìn)行了循環(huán)荷載作用下碎石樁復(fù)合地基振動(dòng)臺(tái)試驗(yàn),并著重分析了碎石樁的排水效應(yīng)。試驗(yàn)結(jié)果表明:無(wú)論是矩形加吲方案還是三角形加固方案,碎石樁均有效地防止了地基液化,并且,激振結(jié)束后,碎石樁加速了孑L隙水壓力的消散。關(guān)鍵詞:動(dòng)三軸試驗(yàn)、砂土液化、簡(jiǎn)易振動(dòng)臺(tái)、疊層剪切變形模型箱、振動(dòng)臺(tái)試驗(yàn)、循環(huán)荷載、碎石樁、復(fù)合地基北京交通大學(xué)2005屬碩士研究生學(xué)位論文ABSTRACTE
3、xperimentalStudyontheLiquefiableFoundationImprovedbyStoneColumnsunderCyclicLoadingABSTRACTInthepaper,thefollowingworkisdone:First,thedevelopmentofdynamicporewaterpressureduringsandliquefactionprocessisstudiedbasedonthedynamictriaxialtest.Thedynamicporewaterpressurecurveisobtainedinanisotropic
4、consolidation.Then,accordingtothedifferentbehaviourofhysteresisloop,thesandliquefactionprocessisdividedintofourphases.Accordingly,thedevelopmentcharacteristicsofaxialstrainduringthefourphasesaleanalyzed.Also,thedecaycharacteristicsofdynamicmoduleareanalyzed.Byconnectingthedynamicmodulewithaxi
5、alstrain,thedecaycurvesofdynamicelasticmoduleanddynamicshearmoduleareobtained.Besides,thestrengthresistingliquefactionisstudied.Secondly,thesimpleshakingtableandthelaminarshearboxusedinthefreefieldtestareintroduced.AndthetestundercyclicloadingindicatesthatthesandiSeasilyliquefied.Also,thetest
6、resultunderE1一Centrowaveshowsthatthelaminarshearboxisverysuccessfulinsimulatingthesoilboundary.Last,stonecolumnscompositefoundationshakingtabletestsundercyclicloadingareperformed.And,especially,thedrainageeffectofstonecolumnsisanalyzed.Thetestresultsshowthatboththerectangularreinforcementproj
7、ectandthetriangularonecaneffectivelypreventsandliquefaction.Also,II托京交通大學(xué)2005屆碩士研究生學(xué)位論文ABSTRACTthestonecolumnsacceleratethedissipationofporewaterpressureattheendofexcitation.KeyWords:dynamictriaxialtest;sandliquefaction;simpleshakingtable;lam