本文選題：混凝土擴(kuò)盤樁　切入點(diǎn)：破壞模式　出處：《吉林大學(xué)》2014年博士論文

【摘要】：近年來隨著國家經(jīng)濟(jì)建設(shè)的快速發(fā)展，橋梁、地下空間、高層超高層建筑等工程項(xiàng)目的數(shù)量與規(guī)模急劇增加，建設(shè)標(biāo)準(zhǔn)日趨嚴(yán)格，對樁基技術(shù)的研究與應(yīng)用也提出了更高的要求。本論文全面介紹了混凝土擴(kuò)盤樁的發(fā)展現(xiàn)狀，國內(nèi)、外的研究結(jié)果表明：混凝土擴(kuò)盤樁具有單樁承載力高、節(jié)約材料、沉降量小、設(shè)計靈活、施工操作簡便，適用區(qū)域廣等諸多方面的優(yōu)點(diǎn)。由于混凝土擴(kuò)盤樁自身特點(diǎn)所具有的潛在的、巨大的經(jīng)濟(jì)價值和社會效益，使其得到了行業(yè)內(nèi)越來越廣泛的重視，展現(xiàn)出了強(qiáng)大生命力和發(fā)展前途，也使其成為樁基技術(shù)領(lǐng)域內(nèi)的研究熱點(diǎn)之一。 目前，混凝土擴(kuò)盤樁的成樁工藝雖然得到了迅速的發(fā)展，但針對混凝土擴(kuò)盤樁作用機(jī)理的研究成果相對較少，尚未形成完整的研究體系，因此限制了該型樁的推廣應(yīng)用。為了進(jìn)一步完善混凝土擴(kuò)盤樁技術(shù)的理論基礎(chǔ)，本論文在現(xiàn)有研究成果的基礎(chǔ)上，對混凝土擴(kuò)盤樁在豎向壓力和拉力作用下的樁土共同工作機(jī)理、樁周及盤上下土體的破壞狀態(tài)等方面進(jìn)行了深入的理論分析和試驗(yàn)研究。本論文采用有限單元法，應(yīng)用ANSYS軟件建立了大量的分析模型，定性地分析了混凝土擴(kuò)盤樁的位移、應(yīng)變、應(yīng)力等變化趨勢，確定了盤徑、盤坡度及盤間距對破壞狀態(tài)的影響，并通過獨(dú)創(chuàng)的半面樁小模型試驗(yàn)和現(xiàn)場大比例實(shí)樁試驗(yàn)對理論分析結(jié)果進(jìn)行了驗(yàn)證，得出了樁側(cè)摩阻力有效長度的計算方法，進(jìn)而確定了混凝土擴(kuò)盤樁單樁抗壓、抗拔極限承載力的計算模式。 本論文研究成果完善了混凝土擴(kuò)盤樁基礎(chǔ)理論。通過對混凝土擴(kuò)盤樁在豎向壓力和拉力作用下盤上和盤下土體破壞狀態(tài)分析，，提出了樁側(cè)摩阻力有效長度的概念，并應(yīng)用新的理論得出承力擴(kuò)大盤盤端土體承載力計算方法，從而修正了現(xiàn)有的單樁承載力計算中的不合理部分。本研究提出的單樁極限承載力計算方法更符合工程實(shí)際，為混凝土擴(kuò)盤樁基礎(chǔ)設(shè)計提供了可靠的理論依據(jù)，完善了混凝土擴(kuò)盤樁基礎(chǔ)理論的研究，為進(jìn)一步推進(jìn)該技術(shù)的廣泛應(yīng)用奠定了堅實(shí)的理論基礎(chǔ)。
[Abstract]:In recent years, with the rapid development of national economic construction, the number and scale of engineering projects such as bridges, underground space, high-rise and super high-rise buildings have increased dramatically, and the construction standards have become more and more stringent.Higher requirements for the research and application of pile foundation technology are also put forward.In this paper, the development status of concrete expanded disc pile is introduced comprehensively. The results of domestic and external research show that concrete expanded plate pile has high bearing capacity, saving material, small settlement, flexible design and simple construction operation.Applicable to a wide range of advantages in many areas.Because of the potential, huge economic value and social benefit of the concrete pile with its own characteristics, it has been paid more and more attention to in the industry, showing its strong vitality and development prospects.It has also become one of the research hotspots in the field of pile foundation technology.At present, although the pile forming technology of concrete expanded disc pile has been developed rapidly, the research results on the action mechanism of concrete expanded disc pile are relatively few, and the complete research system has not been formed, so the popularization and application of this type of pile is limited.In order to further improve the theoretical basis of concrete pile expansion technology, this paper, on the basis of the existing research results, works together on the pile-soil mechanism of concrete expanded disc pile under vertical pressure and tensile force.The failure state of the soil around the pile and the top and bottom of the pile is analyzed theoretically and experimentally.In this paper, the finite element method and ANSYS software are used to establish a large number of analysis models. The change trends of displacement, strain and stress of concrete pile are analyzed qualitatively, and the influence of the diameter, slope and spacing of the plate on the failure state is determined.The theoretical analysis results are verified by the original half plane pile small model test and the field large scale real pile test, and the calculation method of the effective length of pile side friction is obtained, and then the compressive resistance of concrete expanded disc pile single pile is determined.The calculation model of ultimate bearing capacity of pullout.The research results of this paper have improved the basic theory of concrete pile.Based on the analysis of the failure state of the upper and lower soil mass under the action of vertical pressure and tensile force, the concept of effective length of friction on the side of the pile is put forward, and the method of calculating the bearing capacity of the soil bearing force at the end of the disc is obtained by applying the new theory.Thus, the unreasonable part of the existing calculation of bearing capacity of single pile is corrected.The calculation method of the ultimate bearing capacity of single pile in this study is more in line with the engineering practice, which provides a reliable theoretical basis for the design of concrete pile foundation, and improves the research on the basic theory of concrete pile.It lays a solid theoretical foundation for further promoting the wide application of this technology.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：U443.1

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