本文選題：樁基礎　切入點：豎向循環(huán)加載　出處：《浙江大學》2013年博士論文

【摘要】：隨著國民經(jīng)濟的持續(xù)快速發(fā)展,風力發(fā)電、海上石油平臺及高速鐵路等新型能源及高速交通工程陸續(xù)興建。在這些工程中,樁基礎在其服役期內(nèi)不但要承受上部結(jié)構(gòu)自重所產(chǎn)生的靜荷載,還要長期承擔由風、浪或列車等所引起的具有顯著周期性的豎向循環(huán)荷載的作用。豎向循環(huán)荷載作用下樁的承載及變形特性愈發(fā)受到設計人員的關(guān)注,特別是對于高速交通、風力發(fā)電機等這些對基礎不均勻沉降較敏感的結(jié)構(gòu),長期循環(huán)荷載作用下的樁基累積沉降已成為此類工程設計中最需控制的關(guān)鍵參數(shù)。然而目前循環(huán)下樁基的受荷性狀及控制方法尚未明確,因而開展對豎向循環(huán)荷載作用下樁基承載及變形性狀的研究具有重要的現(xiàn)實及理論意義。 本文通過大比尺模型試驗、數(shù)值模擬等方法系統(tǒng)研究了長期豎向循環(huán)荷載作用下樁的承載及變形性狀及累積沉降調(diào)控方法,提出了基于服役性能設計的循環(huán)下樁基設計方法。本文研究受到國家自然科學基金(50878193、51225804及U1234204)的資助。本文所做的主要工作和研究成果如下： (1)建立了豎向荷載作用下單樁有限元分析模型,研究了單次加卸載過程中的樁身荷載傳遞及變形規(guī)律。研究結(jié)果表明,樁頂卸載回彈下的樁身上部會產(chǎn)生負摩阻力,負摩阻力的分布深度主要受卸載幅值、長徑比、樁土剛度比及樁端土體模量的影響。負摩阻范圍隨卸載幅值的增大而變大；相同卸載幅值下,負摩阻范圍隨樁長的增加、樁土剛度比的增大、樁端土體模量的減小而減小。 (2)設計并制作了大比例模型試驗樁,提出了孔壓、土壓及軸力傳感器的樁身安裝、測試及標定技術(shù),基于浙江大學大型土工物理模型試驗系統(tǒng)開展了25組剛性單樁循環(huán)加載試驗,對飽和粉土地基中的剛性單樁在靜力及循環(huán)加載條件下的承載及變形性狀進行了系統(tǒng)試驗研究。 (3)基于模型試驗,獲得了不同循環(huán)荷載加載條件下,粉土地基中剛性樁的承載及變形性狀、樁-土界面應力變化規(guī)律及荷載傳遞變化規(guī)律；分析了單樁循環(huán)承載弱化及累積沉降產(chǎn)生的機理；提出了考慮組合循環(huán)荷載特性的樁基長期累積沉降預測公式。研究結(jié)果顯示,累積沉降隨振次的增加而增大,隨循環(huán)荷載幅值的增大而變大；循環(huán)加載將導致樁-土界面土體發(fā)生剪縮,引起界面超靜孔壓的累積及法向有效應力的下降,孔壓及有效應力的變化幅度隨剪切幅值的增大而變大；循環(huán)下側(cè)摩阻的弱化是由于界面法向有效應力的降低所引起的。 (4)利用通用有限元軟件ABAQUS所提供的二次開發(fā)平臺,開發(fā)了基于Mortara靜力/循環(huán)界面彈塑性模型的用戶界面子例程序UINTER.通過與砂-鋼界面剪切模型試驗結(jié)果的對比,驗證了本文UINTER的正確性。利用有限元模型,對界面循環(huán)加載性狀及影響因素進行了分析,提出了基于法向應力降低的界面剪切循環(huán)弱化簡化分析模型。 (5)基于理想塑性模型,采用冪函數(shù)描述法向應力隨循環(huán)次數(shù)的弱化規(guī)律,建立了樁土界面循環(huán)弱化模型；基于雙曲線型模型建立了樁端循環(huán)滯回模型。建立了基于荷載傳遞法的豎向循環(huán)加載條件下單樁的一維分析模型,編寫計算程序ACLPAP。采用該模型對豎向循環(huán)加載下的樁-土相互作用問題進行了分析,研究了長徑比、樁土剛度比、下臥層性質(zhì)、樁周土模量分布等因素對樁基循環(huán)加載性狀的影響。研究結(jié)果顯示,循環(huán)下樁基的豎向荷載傳遞規(guī)律、承載及變形性狀主要決定于樁頂循環(huán)荷載幅值水平,樁基的循環(huán)加載效應隨循環(huán)荷載比的增大而變大,存在一最小循環(huán)荷載比,當荷載比小于MCLR時,樁基性狀不會因循環(huán)加載而受到影響；相同循環(huán)荷載幅值下,樁基的循環(huán)加載效應隨樁長的增加而減小,隨樁土剛度比的增大而變大,隨樁端土體模量的增大而減小。 (6)分析了循環(huán)下樁基設計中的關(guān)鍵問題,提出了基于界限循環(huán)荷載比控制的基本設計思想。討論了組合循環(huán)荷載下樁基的變形及承載性狀,提出了循環(huán)穩(wěn)定沉降分析圖的概念。提出了循環(huán)下樁基的基本設計方法及一般流程。采用該設計方法對一個實例工程進行了驗算分析,并與實際監(jiān)測結(jié)果進行了對比,驗證了該方法的有效性。 本文研究采用模型試驗及理論研究手段對豎向循環(huán)下樁基性狀進行了較為細致的研究,所得結(jié)果對于考慮循環(huán)荷載影響的樁基設計具有重要的參考意義。本文研究結(jié)果豐富了樁基研究內(nèi)容,為循環(huán)下樁基的優(yōu)化設計奠定了理論基礎。
[Abstract]:With the sustained and rapid development of the national economy, wind power, offshore oil platforms and high-speed railway and other new energy sources and high-speed traffic engineering were built. In these projects, the pile foundation during its service period should not only bear the weight of the superstructure load generated by the longer period shall be borne by the wind, waves or caused by train the significant periodic vertical cyclic loading. The bearing and deformation characteristics increasingly emphasized by designers of pile under vertical cyclic loads, especially for high-speed traffic, the structure is sensitive to the uneven settlement of wind turbines on the basis of these, the long-term cyclic loading of pile foundation has become the key parameters of such cumulative settlement in the engineering design of control. However, the current cycle of under the pile foundation load characteristics and control method is not yet clear, so the study on pile foundation under vertical cyclic loads The study of bearing and deformable characters has important practical and theoretical significance.
In this paper, through large scale model tests and numerical simulation method to study the long-term system of vertical cyclic loading pile bearing and deformation and cumulative settlement control method, put forward the design methods of pile foundation design based on the service performance of the cycle. This research was supported by the National Natural Science Fund (5087819351225804 and U1234204) of the funding. The main work and research results are as follows:
(1) a finite element analysis model of single pile under vertical load, the pile load transfer and deformation of single loading and unloading process. The results show that the upper part of the pile pile under unloading will produce negative friction, the depth distribution of negative friction resistance is mainly affected by the magnitude of unloading, long diameter than, the influence of pile soil stiffness ratio and pile modulus. Negative friction range increases with the amplitude of the unloading is larger; the same unloading amplitude, negative friction range with the increase of pile length, pile soil stiffness ratio increases, decrease the soil modulus of pile end decreases.
(2) the design and fabrication of the large scale model test pile, put forward the pore water pressure, earth pressure and axial force sensor of pile installation, calibration and testing technology, Zhejiang University large geotechnical physical model test system was carried out in 25 groups of single rigid pile based on cyclic loading tests of saturated silty soil, the rigidity of single pile carrying on the static and cyclic loading conditions and deformation properties were studied.
(3) based on the model test, obtained in different cyclic loading conditions, the bearing and deformation behavior of rigid pile in silt foundation, pile-soil interface stress variation and load transfer regularity; analysis of the single pile bearing mechanism of cyclic weakening and cumulative settlement generated; the settlement prediction formula of pile foundation considering combined cycle load characteristics of long-term accumulation. The results showed that the cumulative settlement increases with the time of vibration, with the increase of the amplitude of cyclic load increases; cyclic loading will cause the pile-soil interface soil shear contraction caused by decreased accumulation of interface of the pore pressure and the effective stress, variation pore pressure and effective stress decreased with increasing shear amplitude becomes larger; lower friction weakening cycle is caused by reducing the interfacial normal effective stress of the Institute.
(4) two development platform using ABAQUS finite element software provided by the development of the Mortara static / cyclic elastoplastic model interface of the user interface sub cases program UINTER. by comparing with the sand steel interface shear model based on test results, verified the correctness of UINTER. Using the finite element model of factors cyclic loading characteristics and influence of interface are analyzed, put forward a method based on the simplified model of weakening interfacial shear stress reduced circulation to.
(5) the ideal plastic model based on the power function to describe the normal stress with the weakening regularity of cycle times, a cyclic weakening of pile-soil interface model; hyperbolic model was established based on the pile cyclic hysteretic model. Analysis model of load transfer method under cyclic loading conditions of single pile is established based on one dimension using this model, calculation program ACLPAP. of vertical cyclic loading of pile-soil interaction problems in compiling are analyzed, on the long diameter ratio, stiffness ratio of pile and soil, substratum properties, effects of soil around the pile modulus distribution of pile loading traits. The results showed that the vertical load transfer law pile foundation under cyclic loading and deformation properties of pile mainly depends on the amplitude of cyclic load, cyclic loading effect of pile foundation with the cyclic load ratio increases, there is a minimum cycle load ratio, when the load ratio is less than M When CLR is applied, the pile foundation behavior will not be affected by cyclic loading. Under the same cyclic load amplitude, the cyclic loading effect of pile foundation decreases with the increase of pile length, and increases with the increase of pile soil stiffness ratio, and decreases with the increase of pile end soil modulus.
(6) the analysis of key issues in the design of pile foundation under the circular, puts forward the basic design idea of control than a limit cycle load is discussed. Based on a combination of pile foundation deformation under cyclic loading and bearing characteristics, puts forward the concept of settlement cycle stability analysis diagram is proposed. The basic design method of pile foundation under cyclic and general process of using. The design method of an instance of engineering checking and analysis, and the actual monitoring results were compared to verify the validity of the method.
In this paper by means of model test and theoretical research on characters of pile vertical circulation is studied, the results have important reference value for the design of pile foundation considering the effect of cyclic loading. The results of this study enriches the research content of pile foundation, laid the theoretical foundation for the optimization design of pile foundation under cyclic.

【學位授予單位】：浙江大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TU473.1

【共引文獻】

相關(guān)期刊論文 前10條

1 林慧常;馬威銘;;基于靜載荷數(shù)據(jù)的樁土模型的擬合分析[J];建筑監(jiān)督檢測與造價;2010年05期

2 黃海松;陳超;;考慮樁側(cè)土軟化時水泥土樁樁土應力比的探討[J];四川建筑;2006年04期

3 莫慧劍;;某住宅樓樁基靜載試驗[J];四川建材;2009年04期

4 奚笑舟;陳龍珠;;自平衡法試驗上段樁荷載-位移曲線的解析擬合算法[J];上海交通大學學報;2011年10期

5 曾友金,章為民,王年香,徐光明;超長單樁軸向剛度的計算及其影響因素[J];水利水運工程學報;2003年03期

6 陳明中,龔曉南,嚴平;單樁沉降的一種解析解法[J];水利學報;2000年08期

7 周文宇;張礫元;于天來;;樁基沉降控制設計的研究[J];森林工程;2006年02期

8 李華東;姜永玲;鄧輝;;列車振動荷載作用下某巖質(zhì)邊坡應力應變動力響應分析[J];水文地質(zhì)工程地質(zhì);2011年03期

9 黃志全;李冰冰;白蘭蘭;杜延華;;考慮樁土變形協(xié)調(diào)的復合地基變形計算模型的初步研究[J];中國水運(學術(shù)版);2007年02期

10 王哲,龔曉南,陳建強;大直徑灌注筒樁軸向荷載傳遞性狀分析[J];蘇州科技學院學報(工程技術(shù)版);2005年01期

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1 梅國雄;宰金珉;宋林輝;徐美娟;;巖土工程半解析半數(shù)值方法若干進展[A];第九屆全國巖土力學數(shù)值分析與解析方法討論會論文集[C];2007年

2 許宏發(fā);程學新;奚水清;汪耀明;;抗拔樁軸力分布函數(shù)和位移分布函數(shù)間的關(guān)系模型[A];第九屆全國巖土力學數(shù)值分析與解析方法討論會論文集[C];2007年

3 黃雨;黃清;吳曉峰;葉為民;;循環(huán)荷載作用下基樁模型試驗設備的開發(fā)[A];中國地質(zhì)學會工程地質(zhì)專業(yè)委員會2007年學術(shù)年會暨“生態(tài)環(huán)境脆弱區(qū)工程地質(zhì)”學術(shù)論壇論文集[C];2007年

4 鄧洪亮;謝向文;郭玉松;;擴底樁荷載傳遞機理及承載力確定方法研究[A];第九屆全國巖石動力學學術(shù)會議論文集[C];2005年

相關(guān)博士學位論文 前10條

1 殷昊;基坑逆作法及土體—支護結(jié)構(gòu)變形性狀研究[D];中國地質(zhì)大學（北京）;2011年

2 陳輝;超高層建筑樁基礎承載性能的試驗研究與模擬分析[D];中國地質(zhì)科學院;2009年

3 楊奇;高速鐵路橋梁樁基礎變形性狀試驗與工后沉降研究[D];中南大學;2011年

4 崔科宇;人工挖孔嵌巖灌注樁承載性狀的試驗與理論分析[D];中南大學;2010年

5 郭忠賢;夯實水泥土樁復合地基特性研究[D];北京工業(yè)大學;2010年

6 張立明;考慮深開挖影響的超長樁荷載傳遞機理及沉降計算研究[D];天津大學;2012年

7 茅曉輝;變剛度復合地基變形控制設計理論研究[D];山東科技大學;2010年

8 劉俊偉;靜壓開口混凝土管樁施工效應試驗及理論研究[D];浙江大學;2012年

9 劉思思;基樁自錨靜載測試技術(shù)的理論與試驗研究[D];湖南大學;2010年

10 陳仁朋;軟弱地基中樁筏基礎工作性狀及分析設計方法研究[D];浙江大學;2001年

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1 彭奎森;豎向荷載作用下螺桿樁受力特性分析研究[D];湘潭大學;2010年

2 郭俊豪;廣州某區(qū)軟土層中樁基豎向荷載下承載力性狀研究[D];華南理工大學;2010年

3 吳競;地下結(jié)構(gòu)抗浮設計中抗拔樁的應用研究[D];南昌大學;2010年

4 林宏劍;預應力管樁抗拔承載性狀研究和應用分析[D];浙江大學;2011年

5 崔連蓮;軟土地基中疏樁基礎沉降特性的數(shù)值模擬分析[D];昆明理工大學;2010年

6 劉超;樁筏基礎變剛度調(diào)平設計的研究[D];山東建筑大學;2011年

7 陳培震;大直徑鉆孔灌注樁群樁豎向承載性能數(shù)值分析與研究[D];大連理工大學;2011年

8 宋學舟;基于監(jiān)測的導管架平臺樁基沉降分析[D];大連理工大學;2011年

9 楊景松;復合載體夯擴預應力管樁施工及承載性狀研究[D];河北工程大學;2011年

10 李緒慧;擠擴支盤樁的有限元數(shù)值仿真模擬及應用研究[D];河北工程大學;2011年

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