三种工况下扩底楔形桩承载特性模型试验研究

发布时间：2018-03-13 13:04

本文选题：扩底楔形桩　切入点：模型试验　出处：《岩土力学》2017年07期 　论文类型：期刊论文

【摘要】：扩底楔形桩具有单位材料利用率高、竖向桩侧摩阻力和桩端阻力较常规等截面桩高的技术优点。然而,针对该桩型竖向及水平向承载力的定量模型试验研究相对较少。基于模型试验方法,开展砂性土中竖向、水平向荷载以及地面堆载等不同形工况荷载作用下扩底楔形桩的承载特性试验,测得不同荷载等级下桩侧摩阻力、桩端阻力、侧向土压力、桩顶下拽位移以及桩身下拽力等分布规律;同时,开展等混凝土用量常规等直径桩的承载特性试验作为对比分析,初步探讨了两种桩型的受力机制与异同点。研究结果表明,试验条件下,扩底楔形桩的单桩竖向承载力约为等直径圆桩的2.33倍,表现出侧阻力和端阻力都优于圆形桩的特点;水平承载力约为等直径圆桩的1.48倍,上部直径较大和扩大头的存在提高了其水平承载性能;与等直径圆桩相比,楔形角的存在可有效降低桩顶下拽位移,可见把传统桩型转变成扩底楔形桩是降低负摩阻力对桩基影响的有效方法之一。
[Abstract]:The wedge pile with enlarged bottom has the advantages of high utilization ratio of unit material, lateral friction resistance and tip resistance of vertical pile compared with that of conventional equal-section pile. However, The quantitative model test on vertical and horizontal bearing capacity of this pile type is relatively few. Based on the model test method, the vertical bearing capacity in sandy soil is carried out. The bearing characteristics of the pile under different working conditions, such as horizontal load and ground surcharge, are tested, and the lateral friction, tip resistance and lateral earth pressure of the pile are measured under different load levels, such as pile side friction, pile tip resistance, lateral earth pressure, and so on. At the same time, the load-bearing characteristic test of the normal equal diameter pile with equal concrete content is carried out as a comparative analysis, and the force mechanism and the similarities and differences of the two types of piles are preliminarily discussed. Under the test conditions, the vertical bearing capacity of single pile is about 2.33 times that of circular pile with equal diameter, which shows that the lateral resistance and end resistance are better than that of circular pile, and the horizontal bearing capacity is about 1.48 times of that of equal diameter circular pile. The existence of larger upper diameter and enlarged head improves the horizontal bearing capacity of the pile, and compared with the equal diameter circular pile, the existence of wedge angle can effectively reduce the drag displacement under the pile top. It can be seen that it is one of the effective methods to reduce the influence of negative friction on pile foundation by transforming the traditional pile type into a enlarged wedge pile.
【作者单位】：河南理工大学土木工程学院;河海大学岩土力学与堤坝工程教育部重点实验室;
【基金】：国家自然科学基金资助(No.51278170) 河南省教育厅科技攻关项目(No.14A560015)~~
【分类号】：TU473.1

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