膨胀土地基上桥梁桩承载力计算参数研究

发布时间：2018-01-31 00:25

本文关键词： 膨胀土桥梁桩单桩静载试验单桩承载力计算参数　出处：《河北工程大学》2014年硕士论文　论文类型：学位论文

【摘要】：膨胀土是一种具有湿胀干缩性质的特殊的粘性土，由于膨胀土的特殊工程性质使得桩与膨胀土之间的相互作用要比一般土中复杂得多，计算其单桩承载力时也应对其特殊性加以考虑，，计算膨胀土地区的单桩竖向承载力时若直接采用《公路桥涵地基与基础设计规范》和《建筑桩基技术规范》中给出的计算方法，得出的承载力与实际的桩基础承载力有很大的差距，不能满足要求。因此，对膨胀土中桩侧摩阻力的分布规律研究对确定膨胀土中桥梁桩的承载力计算参数具有重要意义。本文以河北省交通运输厅立项的重点科研项目为依托，以国内外岩土工程界对膨胀土中桩基础研究成果为参考，通过室内物理力学性质试验、单桩静载荷试验、轴力测试和桩侧摩阻力计算分析，取得了如下研究成果：（1）以南水北调总干渠跨线桥邯郸市郭河生产桥附近的膨胀土为研究对象，在国家规范和本试验相关研究资料的基础上，通过大量的室内试验，分析了膨胀土的物理力学特性和胀缩特性；（2）对桥梁桩基础的受力原理、承载性状进行了分析，找到了影响桩基竖向承载力的因素，对现在普遍采用桥梁桩承载力的计算方法进行了归纳总结；（3）对南水北调邯郸段郭和桥南侧膨胀土地基上的三根试验桩进行了静载荷试验，根据曲线图确定了单桩极限承载力和承载力标准值，研究了桩身轴力和桩侧摩阻力的大小和沿桩身的分布规律；（4）通过分析桩侧土样的物理力学指标在桩身深度范围内的变化规律，找到了其与桩侧摩阻力变化规律之间的内在联系，分析了桩侧摩阻力的影响因素；（5）通过采用不同的计算参数对单桩承载力的标准值进行计算，得到了较为合理的单桩承载力的计算参数。
[Abstract]:Expansive soil is a kind of special clay soil with the property of wet expansion and shrinkage. The interaction between pile and expansive soil is much more complicated than that in general soil because of the special engineering properties of expansive soil. The particularity should also be taken into account when calculating the bearing capacity of single pile. When calculating the vertical bearing capacity of single pile in expansive soil area, the calculation method given in "Design Code for Highway Bridge and culvert Foundation" and "Technical Specification for Building pile Foundation" is adopted directly. There is a big gap between the bearing capacity and the actual bearing capacity of pile foundation, which can not meet the requirements. It is of great significance to study the distribution of lateral friction of pile in expansive soil to determine the bearing capacity parameters of bridge pile in expansive soil. In this paper, based on the key scientific research projects of Hebei Provincial Communications and Transportation Department, and taking the research results of pile foundation in expansive soil as a reference, the physical and mechanical properties of the soil are tested in the laboratory in the field of geotechnical engineering at home and abroad. Single pile static load test, axial force test and pile side friction calculation and analysis, obtained the following research results: 1) taking the expansive soil near the production bridge of Guo River in Handan City as the research object, a large number of indoor tests were carried out on the basis of the national code and the relevant research data of this test. The physical and mechanical properties and dilatation characteristics of expansive soil are analyzed. (2) the paper analyzes the stress principle and bearing behavior of bridge pile foundation, finds out the factors that influence the vertical bearing capacity of pile foundation, and sums up the calculation method of bridge pile bearing capacity. The static load test of three test piles on the expansive soil foundation of Guohe Bridge in Handan section of South-to-North Water transfer Project is carried out, and the ultimate bearing capacity and bearing capacity standard value of single pile are determined according to the curve diagram. In this paper, the axial force of pile body, the magnitude of pile side friction and the distribution law along pile body are studied. 4) through the analysis of the variation law of the physical and mechanical indexes of the soil samples on the pile side in the depth range of the pile body, the inherent relation between the variation law of the pile side friction and the pile side friction is found, and the influencing factors of the pile side friction are analyzed. 5) by using different calculation parameters to calculate the standard value of the bearing capacity of a single pile, a reasonable calculation parameter of the bearing capacity of a single pile is obtained.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U443.15

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