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1、河海大學(xué)博士學(xué)位論文靜壓樁沉樁擠土效應(yīng)和樁間土固結(jié)特征理論分析姓名:高子坤申請(qǐng)學(xué)位級(jí)別:博士專(zhuān)業(yè):巖土工程指導(dǎo)教師:施建勇20070601摘要靜壓法施工是當(dāng)前應(yīng)用較為廣泛的沉樁工藝,具有很多優(yōu)點(diǎn),但也有較多的理論和工程問(wèn)題需要解決。本文對(duì)靜壓樁施工過(guò)程中,沉樁擠土產(chǎn)生的位移、應(yīng)力和超靜孔隙水壓力分布,以及成樁后單樁樁周和群樁樁問(wèn)土體固結(jié)規(guī)律展開(kāi)研究,主要包括下述內(nèi)容:1.綜合考慮樁長(zhǎng)有限、地面自由、終孔孔壁形狀、孔壁位移邊界條件和土體材料非線性,應(yīng)用變分原理推導(dǎo)位移、應(yīng)變和應(yīng)力場(chǎng)解答,并應(yīng)用經(jīng)典土壓力和小孔擴(kuò)張理論、模型試驗(yàn)數(shù)據(jù)和現(xiàn)場(chǎng)沉樁試驗(yàn)實(shí)測(cè)數(shù)據(jù)對(duì)研究結(jié)果進(jìn)行對(duì)
2、比驗(yàn)證:2.借鑒砂井地基固結(jié)的研究思想。首先建立單樁和群樁的針對(duì)正交各向異性土體固結(jié)問(wèn)題的數(shù)學(xué)模型。然后,通過(guò)對(duì)實(shí)際樁基工程的滲流邊界條件和初始超靜孔隙水壓力分布條件的分析,用數(shù)學(xué)物理方法求解得到問(wèn)題的解答。最后,通過(guò)土體固結(jié)與樁承載力的時(shí)效性之問(wèn)的關(guān)系,驗(yàn)證了解答的合理性和適用性。3.綜合考慮位移變分法得到的應(yīng)力場(chǎng),以及上述的樁周土體固結(jié)級(jí)數(shù)解答,重點(diǎn)研究沉樁后樁周土體中的初始超靜孔隙水壓力分布規(guī)律。同時(shí),結(jié)合工程實(shí)例,對(duì)沉樁擠土的位移、應(yīng)力、超靜孔隙壓力分布規(guī)律和成樁后孔壓消散的完整過(guò)程進(jìn)行較為系統(tǒng)的研究和驗(yàn)證;4.使用坐標(biāo)變換方法,得到滿足位移邊界條件,包括孔
3、壁邊界、直線邊界和無(wú)窮遠(yuǎn)處邊界的位移函數(shù)。然后,根據(jù)幾何方程和物理進(jìn)一步得到問(wèn)題的應(yīng)變、應(yīng)力解答。最后,通過(guò)極限運(yùn)算以及算例的有限元計(jì)算結(jié)果的比較分析對(duì)理論結(jié)果進(jìn)行驗(yàn)證分析?!娟P(guān)鍵詞】:靜力壓樁、空間軸對(duì)稱(chēng)、位移變分法、固結(jié)級(jí)數(shù)解、超孔隙水壓力、平面應(yīng)變問(wèn)題、坐標(biāo)變換AbstractTheconstructionofjacked-inpilesisawidely-usedtechniqueofpileengineeringatpresenLThejobpracticehasmanymerits,butmanytheoreticalandpracticalproble
4、msstillneedtobesolved.Inthispaper,Soildisplacement,stressfieldsandeXCeSShydrostaticwaterpressureduetopilejackedareexploredbasedontheanalysisofthepilesinkingprogress.Theundermentionedcontentsareincluded:I.SoilsqueezingmodelduetopilesBnkenisconstructed,consideringtheeffectofthefinalshape
5、anddisplacementboundaryofpilewall,stressfreegroundsurface,thefiniteofpilelengthandnon-linearofsoilmaterial.Successionally,soildisplacemenl,strainandstresssolutionsareobtainedbasedonvariationprincipal.L硒Lcomparisonsaremadetoprovethereasonabilityofthesolutionsusingpassivesoilpressuretheo
6、ryandclassicalCEMresultsandtheexperimentaltestingdata.2.Borrowingideasfromsanddraintheory,thetwo·dimensionalsoilconsolidationarestudiedinsaturatedandorthogonalanisotropicsoilaroundandamongslmkenpiles.Consideredtheinitialdistributionandboundaryconditionofexoessporewaterpressurecausedbys
7、ettingpiles.theprogressionsolutionscanbefoundbyusingmethodsofmathematicalphysicsindifferentevironments.Thecomparisonbetweentheprogressionsolutionsandtheconsolidationdegreevalueswhicharededucedfromthepracticalbearingcapacityshowsthattheprogressionsolutionisreasonable.3.Thecontributing