發(fā)布時間：2018-06-04 05:12

  本文選題：混凝土擴盤樁 + 盤徑�。� 參考：《吉林建筑大學》2017年碩士論文

【摘要】：目前,關于混凝土擴盤樁水平承載力的理論和試驗研究已取得了一定的成果,但仍處于初步階段。分析目前的研究現(xiàn)狀,對混凝土擴盤樁在水平力作用下的研究還存在一些問題:首先,混凝土擴盤樁與直孔樁相比,樁周土受力情況發(fā)生較大變化,因此,目前參考普通直孔樁得出的混凝土擴盤樁單樁極限抗傾覆承載力的計算方式不夠合理。其次,已有的研究中,多數(shù)是對樁體本身的破壞研究,而對樁周土體的破壞對承載力的影響的研究幾乎沒有。第三,對于單樁承載力的主要影響因素如:承力盤直徑、間距、位置、坡度、數(shù)量等,只是做了定性的分析,缺少可靠的理論依據(jù)。所以,還需對各影響因素、土體破壞狀態(tài)作進一步研究,提出更為合理的混凝土擴盤樁水平承載力計算模式。本文選定承力盤盤徑這一影響因素,通過理論分析和小比例模型試驗的方法深入探討盤徑對混凝土擴盤樁水平承載力及樁周土體破壞狀態(tài)的影響。理論分析采用ANSYS有限元模擬軟件,建立不同盤徑的擴盤樁樁土模型,對擴盤樁和土體的位移和應力結果進行對比分析。小比例模型試驗則在理論分析的基礎上,將樁土模型尺寸按1:30縮小,確定試驗樁土模型。試驗過程中隨時記錄荷載、位移數(shù)據(jù),并用相機記錄樁土相互作用情況。最后,對比分析理論與試驗結果,清晰的看出水平力作用下樁土相互作用機理,得出盤徑與樁徑的最優(yōu)比例,并首次提出考慮土體破壞的前提下,混凝土擴盤樁水平極限承載力計算模式。本文的重點及創(chuàng)新之處在于試驗方法,試驗方法依然采用原狀土可視試驗裝置。由于一般建(構)筑物通常處于豎向力和水平力共同作用的環(huán)境中,所以本次試驗加載裝置在原有豎向力加載裝置的基礎上經(jīng)過反復推敲、試驗、改進,實現(xiàn)了豎向力和水平力同時加載。同時在已有試驗的基礎上,對取土器及取土方法進一步改進,力求獲取更加完整的原狀土試塊。由于試驗過程全程可視,通過對樁周土體破壞過程的觀察記錄,彌補了擴盤樁研究中對土體破壞狀態(tài)研究的空白。本文關于盤徑對混凝土擴盤樁水平承載力及土體破壞狀態(tài)的影響研究成果,將完善擴盤樁樁型設計理論,豐富擴盤樁水平承載力計算方法,為混凝土擴盤樁在承受水平力的建(構)筑物中的應用起到了極大的推動作用。同時,對試驗方法的改進與創(chuàng)新,為樁基礎的研究發(fā)展提供了借鑒。
[Abstract]:At present, some achievements have been made in the theoretical and experimental study of the horizontal bearing capacity of concrete pile, but it is still in the initial stage. Based on the analysis of the present research situation, there are still some problems in the study of concrete pile under horizontal force. Firstly, compared with the pile with straight hole, the stress on the soil around the pile is greatly changed. At present, the calculation method of ultimate capsizing bearing capacity of single pile with concrete expansion plate pile is not reasonable. Secondly, most of the existing researches focus on the failure of the pile itself, but there is little research on the influence of the soil failure around the pile on the bearing capacity. Thirdly, the main influencing factors of bearing capacity of single pile such as diameter, spacing, position, slope and quantity of bearing plate are only qualitatively analyzed, lacking reliable theoretical basis. Therefore, it is necessary to further study the influence factors and the failure state of soil, and put forward a more reasonable calculation model of horizontal bearing capacity of concrete expanded disc pile. In this paper, the influence factors of bearing disc diameter are selected, and the influence of disc diameter on horizontal bearing capacity and failure state of soil around pile is discussed by theoretical analysis and small scale model test. The ANSYS finite element simulation software was used to establish the pile-soil model with different plate diameters, and the results of displacement and stress of the expanded pile and soil were compared and analyzed. On the basis of theoretical analysis, the pile-soil model size is reduced at 1:30 to determine the pile-soil model. The load and displacement data were recorded at any time during the test, and the pile-soil interaction was recorded by camera. Finally, by comparing the theoretical and experimental results, the mechanism of pile-soil interaction under horizontal force is clearly seen, and the optimal ratio of disc diameter to pile diameter is obtained, and the premise of considering soil failure is proposed for the first time. Calculation model of horizontal ultimate bearing capacity of concrete expanded disc pile. The emphasis and innovation of this paper lies in the test method, which still adopts the visible test device of undisturbed soil. Because the general construction (construction) structure is usually in the environment of the interaction of vertical force and horizontal force, the test loading device has been repeatedly studied, tested and improved on the basis of the original vertical force loading device. The vertical force and horizontal force are loaded simultaneously. At the same time, on the basis of the existing experiments, the paper further improves the soil collecting device and method, and tries to obtain a more complete undisturbed soil sample. Because the whole process of the test is visible, through the observation and record of the soil failure process around the pile, the blank in the study of the soil failure state in the study of the expanded pile is made up. In this paper, the influence of plate diameter on the horizontal bearing capacity and soil failure state of concrete expanded pile will be improved, and the design theory of pile type will be improved, and the calculation method of horizontal bearing capacity of expanded disc pile will be enriched. It plays an important role in the application of concrete pile in building (construction) under horizontal force. At the same time, the improvement and innovation of test method provide reference for the research and development of pile foundation.
【學位授予單位】：吉林建筑大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TU473.1

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本文編號：1976098