資源描述:
《基于被動(dòng)條件下樁-土相互作用機(jī)理及被動(dòng)樁工作性能分析》由會(huì)員上傳分享,免費(fèi)在線(xiàn)閱讀,更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫(kù)。
1、大連理工大學(xué)碩士學(xué)位論文被動(dòng)條件下樁-土相互作用機(jī)理及被動(dòng)樁工作性能分析姓名:韓麗娟申請(qǐng)學(xué)位級(jí)別:碩士專(zhuān)業(yè):巖土工程指導(dǎo)教師:欒茂田20040601摘要樁土相互作用問(wèn)題是近年來(lái)樁基工程中的研究熱點(diǎn)與難點(diǎn)課題。通常各類(lèi)建筑工程中的樁基礎(chǔ)主要是主動(dòng)受荷樁,即上部結(jié)構(gòu)的荷載通過(guò)承臺(tái)傳遞給下部的樁基礎(chǔ),由樁土間的相互作用來(lái)分擔(dān)上部結(jié)構(gòu)荷載。然而.在樁基工程中仍有許多情況是樁基承受被動(dòng)荷載,即樁周土體豎向或水平運(yùn)動(dòng)行為引入的荷載,如粘性土的固結(jié)、膨脹土的膨脹或沉降、隧道的開(kāi)挖、洞穴擴(kuò)展及邊坡滑動(dòng)等對(duì)樁基礎(chǔ)所產(chǎn)生的荷載。其表現(xiàn)為在樁基中引起附加作用力和附加應(yīng)力,這將對(duì)樁基的承載機(jī)制與變形特性產(chǎn)生
2、重要的影響。本文針對(duì)大面積地面堆載條件下的鄰近樁基進(jìn)行分析,假定樁為簡(jiǎn)單的彈性地基梁.而樁周土作為彈塑性變形體?;跇杜c土的變形協(xié)調(diào)條件,確定樁側(cè)土壓力的表達(dá)式,在此基礎(chǔ)上建立樁身?yè)锨刂莆⒎址匠?,?lián)合采用非線(xiàn)性P—Y曲線(xiàn)與有限差分法進(jìn)行求解,并編制了相應(yīng)的計(jì)算程序。通過(guò)算例分析,驗(yàn)證了所建議分析方法的合理性和實(shí)用性。同時(shí)。對(duì)影響被動(dòng)樁樁一土體系變形的各種復(fù)雜因素進(jìn)行了系統(tǒng)的比較分析,結(jié)果表明:樁的水平位移與樁的抗彎剛度以及樁土間水平作用力密切相關(guān),相應(yīng)的樁周土的位移取決于土體強(qiáng)度、樁土間相互作用力以及自由場(chǎng)地的土體水平運(yùn)動(dòng)等。通過(guò)分析還得出了其它一些有意義的結(jié)論。關(guān)鍵詞:被動(dòng)樁:有
3、限差分法;p-y關(guān)系曲線(xiàn);相互作用:彈塑性AbstractTheissueofpile—soilinteractionistheresearchhotspotanddifficultsubjectinpilefoundationengineeringforrecentlyseveralyears.Themajorityofpilesaredesignedtosuppon‘‘a(chǎn)ctive”loadings,thatistosay,loadsfromupperstructurearedirectlytransferredtothepilefoundationbythecap.Howeve
4、r,therearemanycasesinwhichthepileshavetowithstand‘‘passive”loading,i.e.10adsinthepilesareofteninducedbythemovementofsoilspastthepilesverticallyand/orhorizontally.Examplesincludeconsolidationofclay;swellingorshrinkingofanexpansiveclay;tunneling;excavation;cavitydevelopment;slopemovement.Theseext
5、ernally-imposedsoilmovementswillleadtOadditionalforcesandstressesintopilefoundations.Therefore,itisveryimportanttoreasonablyassesstheseforcesandthecorrespondingeffectsonthebearinganddeformationperformanceofpilefoundation.Thispaperanalyzesthepile·soilinteractionaajacenttosuperficialsurcharge,the
6、pileismodeledsimpleelasticfoundationbeam,soiltobeelastic-plasticdeformationbody.Basedonthecompatibilityconditionofdeformationofpilesandsurroundingsoils,theexpressionformulationoflateralearthpressureonpilesispresented.Andthenthepartialdifferentialequationforgoverningdeflectionofpileisestablished
7、andisnumericallysolvedbycombininglion—linearp-yrelationshipcurveofpileandfinitedifferenceprocedure.Theauthorencodesthecorrespondingprogram.Throughanexampleanalysis,thereasonabilityandapplicabilityoftheproposedmethodareverified.The