扩底桩承载能力数值模拟与分析

发布时间：2018-07-06 17:31

本文选题：扩底桩 + 承载能力　；参考：《安徽理工大学》2017年硕士论文

【摘要】：桩基承载力测定主要采用静载试验法,对于扩底桩来说,由于其承载力高,需要堆载大,不仅花费时间长、成本高并且静载试验测出来的结果往往远低于扩底桩实际的承载力。本文阐述了桩基的发展,分析了扩底桩的国内外专家学者的研究现状与成果及扩底桩的分类、技术特点以及适用场合,对比了两种方法对扩底桩承载力的确定。采用有限差分软件FLAC3D进行数值模拟,建立了一系列桩基模型,模拟分析发现:在相同地质条件下扩底桩相比等径桩具有明显的承载优势,施加2512kN时,直径为0.8m的等径桩沉降量41.7mm,而上部直径0.8m底端直径2.0m的扩底桩则只有7.3mm的沉降。这表明扩底桩在荷载作用下不会一次性刺入土中,避免了应力集中现象出现。当等径桩达到最大沉降量时,扩底桩的桩底位移为14.0mm,仍能承受更大的荷载。扩底桩与一般等径桩,在同一土体中相同的桩长、桩径,当沉降量均为20mm时,扩底桩承载力是等直径桩的承载力的8倍。在相同载荷作用下,扩底桩的沉降仅仅只有等直径桩的1/5。并且随着桩顶上部荷载的一级级的递增,扩底桩的桩底沉降量增加的无论是幅度还是速率都比等径桩要小。数值模拟扩底桩的承载能力,对工程实践具有借鉴意义。
[Abstract]:The bearing capacity of pile foundation is mainly measured by static load test method. Because of its high bearing capacity and high heaped load, it takes a long time and high cost, and the results of static load test are often far lower than the actual bearing capacity of bottom pile. This paper expounds the development of pile foundation, analyzes the research status and achievements of experts and scholars at home and abroad, and the classification, technical characteristics and applicable situation of reamed pile, and compares the determination of bearing capacity of reamed pile with two methods. The finite difference software FLAC3D is used to carry out numerical simulation, and a series of pile foundation models are established. The simulation results show that under the same geological conditions, the pile with enlarged bottom has obvious advantages over equal-diameter pile, when 2512kN is applied. The settlement of equal-diameter pile with 0.8 m diameter is 41.7 mm, while that of the top pile with 0.8 m bottom diameter 2.0 m is only the settlement of 7.3mm. This indicates that the pile under the load will not burrow into the soil at one time, thus avoiding the phenomenon of stress concentration. When the maximum settlement of equal-diameter pile is reached, the displacement of pile bottom is 14.0mm, which can still bear larger load. When the settlement of the pile with the same length and diameter in the same soil mass is 20mm, the bearing capacity of the enlarged pile is 8 times of the bearing capacity of the equal-diameter pile. Under the same load, the settlement of the reamed pile is only 1 / 5 of that of the equal-diameter pile. With the increase of the first order of the load on the top of the pile, the settlement of the pile bottom of the reamed pile is smaller than that of the equal-diameter pile. Numerical simulation of bearing capacity of reamed pile has reference significance for engineering practice.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU473.1

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