發(fā)布時(shí)間：2018-05-12 14:42

  本文選題：樁基礎(chǔ) + 嵌巖樁　； 參考：《湖南大學(xué)》2015年碩士論文

【摘要】：嵌巖樁通常被用于對(duì)沉降要求嚴(yán)格、上部荷載較大的工程之中。但由于其承載力較高,很少有現(xiàn)場試驗(yàn)?zāi)芗虞d到極限狀態(tài),因此對(duì)其承載力及荷載傳遞特性的理解仍存在許多含糊之處,使得實(shí)際中常因過于保守而出現(xiàn)一些樁長和樁徑不合理的設(shè)計(jì),既加大了施工難度,降低了施工效率,又造成了經(jīng)濟(jì)上的浪費(fèi)。因此,對(duì)嵌巖樁荷載傳遞特性的研究具有較大的理論和實(shí)踐價(jià)值。由于樁巖接觸與樁土接觸存在著本質(zhì)上的區(qū)別,且通常情況下嵌巖段所提供的承載力為嵌巖樁總承載力的最重要的組成部分,本文在考慮樁巖接觸面上粗糙特性的基礎(chǔ),探討嵌巖樁的荷載傳遞特性的計(jì)算方法,并對(duì)相關(guān)的影響因素做進(jìn)一步的分析研究。首先,對(duì)現(xiàn)階段國內(nèi)外的相關(guān)研究成果進(jìn)行總結(jié)歸納,深入理解考慮樁巖接觸面粗糙及其對(duì)承載特性的影響時(shí)所面臨的困難及其可行的研究方向,并探討了嵌巖樁的荷載傳遞特性及其承載力發(fā)揮的機(jī)理,利用合理假設(shè)對(duì)樁巖結(jié)構(gòu)面上粗糙體形狀規(guī)則和不規(guī)則兩種情況進(jìn)行描述,結(jié)合相關(guān)試驗(yàn)結(jié)果給出了粗糙程度與力學(xué)參數(shù)之間的關(guān)系。其次,利用滑移線場法求得了樁巖結(jié)構(gòu)面峰值摩阻力,并求得其對(duì)應(yīng)的剪切位移,在此基礎(chǔ)上建立了考慮樁巖結(jié)構(gòu)面剪脹特性的剪切函數(shù),結(jié)合荷載傳遞法對(duì)樁身的荷載傳遞特性進(jìn)行了求解,利用荷載和位移連續(xù)條件,推導(dǎo)軸力沿深度的表達(dá)式。最后,將本文建立的荷載傳遞函數(shù)與一組室內(nèi)模型直剪試驗(yàn)的結(jié)果進(jìn)行對(duì)比,驗(yàn)證荷載傳遞函數(shù)的適用性。結(jié)合某特大橋的現(xiàn)場測試結(jié)果,將本文理論方法的計(jì)算結(jié)果與實(shí)測數(shù)據(jù)進(jìn)行對(duì)比,表明本文方法具有較好的預(yù)測效果;對(duì)相關(guān)參數(shù)做了進(jìn)一步分析,探討了其對(duì)嵌巖樁荷載傳遞特性的影響。
[Abstract]:Rock-socketed piles are usually used in projects with strict settlement requirements and high upper loads. However, because of its high bearing capacity, very few field tests can be loaded to the ultimate state, so there are still many ambiguities in the understanding of its bearing capacity and load transfer characteristics. It makes some unreasonable design of pile length and diameter often appear because of being too conservative in practice, which not only increases the construction difficulty, reduces the construction efficiency, but also causes the economic waste. Therefore, it is of great theoretical and practical value to study the load transfer characteristics of rock-socketed piles. Because there is an essential difference between pile-rock contact and pile-soil contact, and the bearing capacity provided by rock-socketed segment is the most important part of the total bearing capacity of rock-socketed pile, this paper considers the foundation of the rough characteristics of pile-rock contact surface. This paper discusses the calculation method of load transfer characteristics of rock-socketed pile, and makes further analysis and research on the related factors. First of all, it summarizes the relevant research results at home and abroad at present, and deeply understands the difficulties and feasible research directions when considering the roughness of pile-rock contact surface and its influence on bearing characteristics. The load transfer characteristics of rock-socketed pile and the mechanism of its bearing capacity are discussed, and the shape rules and irregular shape of rough body on the pile-rock structure surface are described by reasonable assumptions. The relationship between the degree of roughness and the mechanical parameters is given based on the experimental results. Secondly, the peak frictional resistance of pile-rock structure surface is obtained by slip line field method, and the corresponding shear displacement is obtained. On the basis of this, a shear function considering the shear dilatancy of pile-rock structural plane is established. Combined with the load transfer method, the load transfer characteristics of the pile body are solved, and the expression of axial force along the depth is derived by using the continuous condition of load and displacement. Finally, the load transfer function established in this paper is compared with the results of a group of indoor model direct shear tests to verify the applicability of the load transfer function. Combined with the field test results of a large bridge, the calculated results of the theoretical method in this paper are compared with the measured data, which shows that the method in this paper has a good prediction effect, and the related parameters are further analyzed. Its influence on load transfer characteristics of rock-socketed pile is discussed.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU473.1

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本文編號(hào)：1879008