桥梁钻孔灌注桩后压浆技术应用研究

发布时间：2018-03-09 22:05

本文选题：桥梁工程　切入点：钻孔灌注桩　出处：《长安大学》2014年硕士论文　论文类型：学位论文

【摘要】：进入21世纪，我国经济持续以较快的速度发展，随之而来的是急剧增长交通量对现有的公共交通设施提出了更高的要求，国家为了满足日益增长交通量的需求不断的加大基础建设，每年都有上千公里高等级公路建成。部分在黄土和砂土地区修建高等级公路由于受到黄土和砂土自身结构的特殊性（摩阻力低、承载力弱、湿陷性等），会对桥梁下部桩基产生一系列的问题，如桩长过长、桩径过大和后期承载力不足等，，不仅施工难度大，而且施工费用高，造成了较大的浪费。当前钻孔灌注桩技术已得到广泛的应用，但受桩端软弱土层的影响会大大消弱桩基的承载力和稳定性，尤其是黄土和砂土地区桥梁，由于其自身结构的特殊性，还会诱发桥梁桩基产生一系列的病害。采用后压浆技术能有效提高桩端承载力和侧摩阻力，当前该技术的应用还不够广泛，因为很多技术虽然在理论上已经成熟，但相关技术规范偏少，在实际施工应用过程中因害怕操纵不当没能起到预期效果，因此，很多人宁愿多浪费也不采用该技术。本文通过分析钻孔灌注桩后压浆技术的工作原理，得出通过后压浆技术能有效提高桩底承载力和加大桩端侧土的摩阻力，能够有效缩短桩长和减小桩径。本文以西安—咸阳机场专用高速段工程桩端后压浆钻孔灌注桩为工程依托，以研究钻孔灌注桩后压浆桩基的受力机理，为后压浆技术的应用与推广提供理论基础。论文在总结当前国内外研究现状的基础上，采用了理论分析、数值模拟和现场试验等相结合的技术手段，对典型地区桥梁桩端后压浆技术进行了的研究分析，研究成果为实际工程提供理论及技术指导。论文主要研究工作如下：首先本文系统的分析了桥梁钻孔灌注桩后压浆理论和施工工艺，得出切实可行的、适合于公路桥梁建设的后压浆施工操作规程以及质量检验标准，指导、规范该工艺在公路桥梁领域的应用；进而通过数值模拟方法，在建立合理的地质力学模型和现场静载荷试验的基础上，分析对比常规直径公路桥梁后压浆灌注桩与常规灌注桩桩基极限承载力、桩身内力发挥性状等相关参数，研究公路桥梁钻孔灌注桩后压浆技术工作机理；最后通过现场静载试验，对使用后压浆和未使用压浆的试桩进行现场试验，测试在不同荷载下桩身轴力、桩侧和桩端阻力各控制参量的分布情况，并对试验数据进行对比分析，评价其实施效果，为后压浆技术的推广提供了技术支持。
[Abstract]:In 21th century, the economy of our country continues to develop at a relatively high speed, followed by a sharp increase in traffic volume to put forward higher requirements for the existing public transport facilities. In order to meet the increasing demand for traffic volume, the state has continuously increased its infrastructure, Thousands of kilometers of high grade roads are built every year. Part of the construction of high grade roads in loess and sandy areas is due to the special structure of loess and sand (low friction, weak bearing capacity, The collapsibility and so on will cause a series of problems to the pile foundation in the lower part of the bridge, for example, the pile length is too long, the pile diameter is too large and the bearing capacity in the later stage is insufficient, so it is not only difficult to construct, but also the construction cost is high. At present, bored pile technology has been widely used, but the bearing capacity and stability of pile foundation will be greatly reduced by the influence of weak soil layer at the end of pile, especially in loess and sandy area. Because of the particularity of its own structure, it can also induce a series of diseases on the bridge pile foundation. Using post-grouting technology can effectively improve the bearing capacity of pile end and side friction resistance, but the application of this technology is not wide enough at present. Because many technologies are mature in theory, but the relevant technical specifications are on the low side, in the actual construction application process, because of fear of improper manipulation did not play the expected effect, therefore, Many people prefer to waste more than to adopt this technology. By analyzing the working principle of post-grouting technology of bored pile, it is concluded that the post-grouting technology can effectively increase the bearing capacity of pile bottom and increase the friction of pile end soil. It can effectively shorten the pile length and reduce the pile diameter. Based on the post-grouting bored pile at the end of the high-speed section of Xi'an-Xianyang Airport, this paper studies the stress mechanism of the post-grouting pile foundation of the bored pile. This paper provides a theoretical basis for the application and popularization of post-grouting technology. On the basis of summing up the current research situation at home and abroad, the paper adopts a combination of theoretical analysis, numerical simulation and field test, etc. The post-grouting technology of bridge pile end in typical area is studied and analyzed. The research results provide theoretical and technical guidance for practical engineering. The main research work of this paper is as follows:. First of all, this paper systematically analyzes the theory and construction technology of post-grouting of bored cast-in-place pile of bridge, and obtains practical operation rules and quality inspection standard of post-grouting construction suitable for highway bridge construction. Standardizing the application of this technology in the field of highway and bridge; On the basis of establishing reasonable geo-mechanical model and static load test in situ, the ultimate bearing capacity of post-grouting grouting pile and conventional cast-in-place pile foundation of highway bridge with conventional diameter is analyzed and compared by numerical simulation method. The working mechanism of post-grouting technology for bored piles of highway bridges is studied by using relevant parameters such as exerting properties of internal forces of piles. Finally, through the static load test on the spot, the field test is carried out on the pile with and without the post-grouting, and the distribution of the control parameters of the axial force, the resistance of the pile side and the end of the pile under different loads is tested. The experimental data are compared and analyzed to evaluate the effect of the experiment, which provides technical support for the popularization of post-grouting technology.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445.551

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