大直径超长旋挖桩桩端注浆承载特性试验研究

发布时间：2018-02-27 05:30

本文关键词： 大直径超长旋挖桩静载试验承载特性桩端注浆　出处：《中外公路》2014年04期 　论文类型：期刊论文

【摘要】：实际工程中,经常采用桩端注浆的方法,利用高压水泥浆液的渗透、扩散和挤压特性,提高桩周、桩端土的强度,从而提高灌注桩的承载力。然而,桩端注浆对大直径超长桩的作用机理尚需深入研究,该文通过对广东省某高速公路工程中2根大直径超长旋挖桩(一根桩端注浆;另一根未注浆)的单桩竖向抗压静载试验结果对比,对试桩的竖向极限承载力、桩身轴力传递规律以及桩侧阻力发挥特性和桩端阻力发挥特性综合分析研究,发现桩端注浆效果明显,注浆后试桩极限承载力至少提高28%。试验结果表明:桩端注浆后试桩极限桩端阻力至少提高83%,桩端注浆对大直径超长旋挖桩桩侧摩阻力的影响沿桩身可分为3个区段:即显著增强区段、非显著增强区段以及无增强区段。对比采用桩基规范法与公路桥涵规范法计算试桩极限承载力,发现对于大直径超长旋挖桩,考虑尺寸效应的桩基规范法更安全准确。
[Abstract]:In practical engineering, the method of grouting at the end of the pile is often used to improve the strength of the pile around the pile and the soil at the end of the pile by making use of the permeation, diffusion and extrusion characteristics of the high pressure cement slurry, so as to improve the bearing capacity of the cast-in-place pile. The action mechanism of pile end grouting on large diameter super long pile needs to be deeply studied. In this paper, two large diameter super long rotary excavated piles (one pile end grouting) in a highway project in Guangdong Province are studied in this paper. The vertical ultimate bearing capacity, the axial force transfer law of pile, the exertion characteristics of pile side resistance and pile tip resistance are analyzed and studied by comparing the results of single pile vertical compression static load test with that of another pile without grouting. It is found that the grouting effect at the end of the pile is obvious. After grouting, the ultimate bearing capacity of the test pile is increased by at least 28%. The test results show that the ultimate pile end resistance increases at least 83% after grouting at the end of the pile, and the effect of grouting at the end of the pile on the frictional resistance of the pile side along the pile body can be divided into three sections. Paragraph: significantly enhanced section, Comparing pile foundation code method with highway bridge culvert code method to calculate the ultimate bearing capacity of pile test pile, it is found that the pile foundation code method considering size effect is more safe and accurate for large diameter super-long rotary excavation pile.
【作者单位】：广东潮惠高速公路有限公司;华润(深圳)有限公司;
【基金】：广东省交通运输厅科技计划项目(编号:[2012]1379(2012-01-001))
【分类号】：U416.1

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