本文選題：屈曲分析 + 超長樁　； 參考：《江蘇大學》2017年碩士論文

【摘要】：樁基礎因其承載力高、沉降量小等優(yōu)點在深厚軟土地區(qū)廣泛應用。近年來,隨著我國大型基礎設施建設的迅猛發(fā)展,在我國東部沿海深厚軟土地區(qū)超高層建筑、大跨度橋梁以及港口工程中超長樁、楔形樁等樁基礎的應用日益廣泛。軟土地區(qū)超長樁與普通樁的最大不同之處在于其屈曲穩(wěn)定問題更值得關注。已有研究表明影響樁屈曲荷載的重要因素不僅有樁側(cè)土彈性抗力,還有樁側(cè)摩阻力和樁身自重,能夠同時考慮這些因素影響的超長樁屈曲荷載計算目前還很少報道。楔形樁因其承載力大大高于同體積等截面樁而受到越來越多的關注,從而使設計者在樁基礎選型時有更多選擇。但現(xiàn)有的楔形樁計算理論大多基于等截面樁展開,其并不能完全體現(xiàn)楔形樁自身特性,這也是楔形樁不能在工程中被廣泛應用的原因之一。目前針對楔形樁自身特性的屈曲穩(wěn)定分析理論研究也相對較少�；诖�,本文應用尖點突變理論對超長樁和楔形樁屈曲穩(wěn)定性進行研究。同時考慮樁身自重、樁側(cè)摩阻力和樁側(cè)土彈性抗力,通過確定樁-土體系的勢函數(shù)和分岔集方程,基于尖點突變理論建立樁-土體系的尖點突變模型并導出樁-土體系失穩(wěn)條件,進而得到樁基的屈曲臨界荷載。同時基于能量法原理并應用瑞利-里茲法得到樁基的屈曲臨界荷載,從而驗證突變理論計算結(jié)果的可靠性。主要研究內(nèi)容包括以下幾個方面:1.樁側(cè)土彈性抗力模式是影響樁基屈曲穩(wěn)定的重要因素。鑒于經(jīng)典m法和常數(shù)法在超長樁、楔形樁等樁基礎屈曲分析中的局限性,考慮樁側(cè)土彈性抗力系數(shù)為更為復雜的冪數(shù)分布模式,通過Winkle彈性地基梁理論建立樁-土體系總勢能方程,基于能量法和最小勢能原理,導出樁身屈曲臨界荷載和樁身穩(wěn)定計算長度的計算公式,并據(jù)此著重分析了樁側(cè)土彈性抗力分布模式對樁身屈曲穩(wěn)定的影響規(guī)律。2.引入非線性科學中的尖點突變理論,同時考慮樁側(cè)土抗力、樁側(cè)摩阻力和樁身自重的影響,根據(jù)樁端約束條件選取樁身撓曲變形函數(shù),通過確定樁-土體系的勢函數(shù)和分岔集方程,基于尖點突變理論建立樁-土體系的尖點突變模型并導出樁-土體系失穩(wěn)條件,進而得到超長樁的屈曲臨界荷載。同時基于能量法原理并應用瑞利-里茲法計算超長樁的屈曲臨界荷載,從而驗證突變理論計算結(jié)果的可靠性。最后著重分析了樁側(cè)土抗力、樁側(cè)摩阻力和樁身自重對超長樁屈曲穩(wěn)定的影響。3.在考慮楔形樁樁側(cè)土彈性抗力的基礎上,計入樁身自重,首先應用尖點突變理論對楔形樁屈曲穩(wěn)定性進行分析,給出楔形樁屈曲失穩(wěn)臨界荷載的計算方法。同時應用能量法進一步驗證突變理論計算的屈曲臨界荷載的可靠性。最后著重分析楔形樁的樁身自重和楔形樁樁徑變化對屈曲臨界荷載的影響。
[Abstract]:Pile foundation is widely used in deep soft soil area because of its high bearing capacity and small settlement. In recent years, with the rapid development of large-scale infrastructure construction in China, the application of super-tall buildings, long-span bridges, super-long piles, wedge-shaped piles and other pile foundations in deep soft soil areas along the eastern coast of China has become increasingly widespread. The biggest difference between super-long pile and ordinary pile in soft soil area is that the buckling stability of pile is more worthy of attention. It has been shown that the important factors affecting pile buckling load are not only the elastic resistance of pile side soil, but also pile friction and pile body weight. The calculation of buckling load of super-long pile which can take account of these factors at the same time is seldom reported at present. Because the bearing capacity of wedge pile is much higher than that of the same volume and equal section pile, more and more attention is paid to it, which makes the designer have more choice in pile foundation selection. However, most of the existing theories of wedge pile are based on the equal section pile, which can not fully reflect the characteristics of the wedge pile itself, which is one of the reasons why the wedge pile can not be widely used in engineering. At present, there are few researches on buckling stability analysis of wedge pile. Based on this, the buckling stability of super-long pile and wedge-shaped pile is studied by using the cusp catastrophe theory. At the same time, considering the weight of the pile body, the friction of the pile side and the elastic resistance of the soil around the pile, the potential function and bifurcation set equation of the pile-soil system are determined. Based on the cusp catastrophe theory, the cusp catastrophe model of pile-soil system is established and the instability condition of pile-soil system is derived, and the critical buckling load of pile foundation is obtained. At the same time, based on the principle of energy method and using Rayleigh-Ritz method, the buckling critical load of pile foundation is obtained, which verifies the reliability of the calculation results of catastrophe theory. The main research contents include the following aspects: 1. The elastic resistance model of pile side soil is an important factor affecting the buckling stability of pile foundation. In view of the limitations of the classical m method and the constant method in the buckling analysis of super-long pile, wedge-shaped pile and other pile foundations, the elastic resistance coefficient of the soil around the pile is considered as a more complex power distribution model. Based on the Winkle elastic foundation beam theory, the total potential energy equation of pile-soil system is established. Based on the energy method and the principle of minimum potential energy, the formulas for calculating the critical buckling load of pile body and the calculating length of pile body stability are derived. Based on this, the influence of elastic resistance distribution mode of pile side soil on the buckling stability of pile body is analyzed emphatically. In this paper, the cusp catastrophe theory of nonlinear science is introduced. Considering the influence of soil resistance, frictional resistance and weight of pile body, the deflection deformation function of pile body is selected according to the constraint condition of pile end. By determining the potential function and bifurcation set equation of pile-soil system, the cusp catastrophe model of pile-soil system is established based on the cusp catastrophe theory, and the instability condition of pile-soil system is derived, and the buckling critical load of super-long pile is obtained. At the same time, based on the principle of energy method and using Rayleigh-Ritz method, the buckling critical load of super-long pile is calculated, which verifies the reliability of the calculation results of catastrophe theory. Finally, the effects of soil resistance, friction and weight on the buckling stability of super-long pile are analyzed. On the basis of considering the elastic resistance of soil on the side of wedge-shaped pile and taking into account the weight of pile body, the buckling stability of wedge-shaped pile is analyzed by using the cusp-point catastrophe theory, and the calculation method of critical buckling load of wedge-shaped pile is given. At the same time, the reliability of the buckling critical load calculated by the catastrophe theory is further verified by the energy method. Finally, the influence of pile weight and diameter variation on buckling critical load of wedge pile is analyzed.
【學位授予單位】：江蘇大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TU473.1

【參考文獻】

中國期刊全文數(shù)據(jù)庫 前10條

1 宋鑫華;閆鴻浩;;基于尖點突變理論的漿砌塊石邊坡穩(wěn)定性研究[J];巖土力學;2016年12期

2 宋鑫華;包太;莊錦亮;劉豪;彭鴻湖;;基于尖點突變理論的土質(zhì)邊坡穩(wěn)定性分析[J];南水北調(diào)與水利科技;2016年03期

3 禹奇才;劉愛榮;肖才濤;傅繼陽;;基于尖點突變理論的平行組拼雙肋拱側(cè)傾失穩(wěn)臨界荷載計算新方法[J];中山大學學報(自然科學版);2014年02期

4 朱彥鵬;王婧;;尖點突變模型在濕陷性黃土微結(jié)構(gòu)失穩(wěn)中的應用[J];蘭州理工大學學報;2012年06期

5 姚文娟;郭志興;程澤坤;;基于突變理論的超長樁橫向動力穩(wěn)定性分析[J];水運工程;2011年08期

6 馬莎;肖明;;基于突變理論和監(jiān)測位移的地下洞室穩(wěn)定評判方法[J];巖石力學與工程學報;2010年S2期

7 劉杰;何杰;閔長青;;楔形樁與圓柱形樁復合地基承載性狀對比研究[J];巖土力學;2010年07期

8 沈細中;冷元寶;蘭雁;張俊霞;;深基坑工程安全評價的尖點突變模型[J];哈爾濱工業(yè)大學學報;2009年04期

9 李凱;陳國榮;;以尖點突變模型為邊坡臨界失穩(wěn)的判據(jù)研究[J];桂林工學院學報;2009年01期

10 王新泉;陳永輝;劉漢龍;;基于尖點突變理論的基樁極限承載力判定及預測[J];河海大學學報(自然科學版);2008年02期

中國博士學位論文全文數(shù)據(jù)庫 前1條

1 方鵬飛;超長樁承載性狀研究[D];浙江大學;2003年

，

本文編號：1878761