筒桩承载性状及其在海堤结构中的应用研究

发布时间：2018-06-21 12:53

本文选题：筒桩 + 荷载传递　；参考：《浙江工业大学》2014年硕士论文

【摘要】：筒桩具有施工方便、成桩质量好、承载能力高、经济性好等的特点,因此其在软土地基中的基坑工程、道路工程、海洋工程等领域有着广泛的应用。筒桩作为一种新型桩,其设计理论研究落后于工程实践,筒桩在软土地基中的承载能力评价方面还缺乏较为合理且简便的计算方法,有待进一步的研究。筒桩在海堤结构中的运用是时下热点之一,但是在波浪荷载作用下,筒桩结构海堤的设计理论目前尚无规范或标准可循。为此,本文将结合实际工程,对软土地基上的筒桩的承载性能进行相关研究工作,主要的内容和结论如下： 1.利用荷载传递函数法研究筒桩的单桩竖向承载力。在考虑桩土软化、土芯分担荷载及筒桩内摩阻力发挥情况下,通过对筒桩内、外侧土选取弹塑性荷载传递函数,而对桩底土选取三折线荷载传递函数,建立微分方程,并推导出一套桩体任意截面的桩身轴力以及桩周摩阻力公式。最后,通过一个实际工程来验证公式的正确性,把现场试验得到的P-S曲线与公式计算所得到的曲线比较,发现曲线较吻合。因此,该套公式有很好的工程使用价值。 2.利用有限元软件ABAQUS分别分析了筒桩基础在竖向荷载和水平荷载下的受力过程。在竖向荷载下,通过与工程实例的现场试验结果比较,两者荷载-沉降曲线较为吻合,验证了采用有限元方法研究筒桩的承载性能是切实可行的,同时还得到了筒桩内外侧摩阻力的分布图；在水平向荷载下,通过与等截面面积的实心桩比较,发现筒桩在抵抗水平荷载作用中有较大优势；最后,分析了三种典型杭州地区的筒桩基础分别在竖向荷载和水平向荷载作用下的承载性状,得到了一些较为实用的结论。 3.在实际工程的基础上,利用等效刚度原理,将双排筒桩结构海堤受力问题由三维问题转换为平面应变问题,采用有限元分析手段研究其在波浪荷载作用下,排桩刚度、系梁刚度、系梁位置、桩间距、排距等筒桩海堤的主要设计参数对该结构水平位移的影响,得到的结论有助于筒桩结构海堤的设计与推广。
[Abstract]:Barrel pile has the characteristics of convenient construction, good pile quality, high bearing capacity and good economy. Therefore, it is widely used in the field of foundation pit engineering, road engineering, ocean engineering and so on. As a new type of pile, the design theory of cylindrical pile falls behind the engineering practice, and there is still a lack of reasonable and simple calculation method in evaluating the bearing capacity of tubular pile in soft soil foundation, which needs further study. The application of tubular pile in seawall structure is one of the hotspots at present, but under the action of wave load, there is no criterion or standard for the design theory of tubular pile structure seawall. Therefore, combined with practical engineering, this paper will study the bearing capacity of cylindrical pile on soft soil foundation. The main contents and conclusions are as follows: 1. The load transfer function method is used to study the vertical bearing capacity of single pile. Considering the softening of pile and soil, the load sharing of soil core and the exertion of friction in the cylinder pile, the differential equation is established by selecting the elastic-plastic load transfer function for the inner and outer soil of the pile, and selecting the three-fold line load transfer function for the bottom soil of the pile. A set of formulas for axial force of pile body and friction around pile are derived. Finally, a practical project is used to verify the correctness of the formula. Comparing the P-S curve obtained from the field test with the curve obtained by the formula calculation, it is found that the curve is in good agreement with that obtained by the formula calculation. Therefore, the formula has good engineering value. 2. 2. The finite element software Abaqus is used to analyze the stress process of cylindrical pile foundation under vertical and horizontal loads respectively. Under vertical load, the load-settlement curves are in good agreement with the field test results of engineering examples, which verifies the feasibility of using finite element method to study the bearing capacity of cylindrical piles. At the same time, the distribution map of the friction resistance inside and outside the cylinder pile is obtained. By comparing with the solid pile with equal cross-section area under horizontal load, it is found that the cylinder pile has a great advantage in resisting horizontal load. The bearing behavior of three typical cylindrical pile foundations in Hangzhou under vertical and horizontal loads is analyzed, and some practical conclusions are obtained. On the basis of practical engineering, using the principle of equivalent stiffness, the stress problem of double-row cylindrical pile structure is transformed from three-dimensional problem to plane strain problem, and the stiffness of row pile under wave load is studied by finite element method. The influence of the main design parameters on the horizontal displacement of the seawall, such as the stiffness of the tie beam, the position of the tie beam, the distance between the piles and the distance between the piles, is obtained. The conclusions obtained are helpful to the design and popularization of the seawall of the tubular pile structure.
【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U656.314

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