非均匀湿陷条件下黄土地基桥梁群桩承载特性离心模型试验研究
发布时间：2018-09-11 11:31
【摘要】：黄土地区的非均匀湿陷性对桥梁桩基等一系列工程具有重要的影响。因此，如何确定非均匀湿陷黄土区桩基承载力和桩侧负摩阻力大小是桥梁桩基设计中亟待解决的关键问题。本文依托山西河运高速大厚度黄土地区非均匀湿陷条件下的桥梁桩基项目，利用土工离心模型试验和数值模拟，对非均匀湿陷黄土地区群桩基础承载特性和复杂地形条件下黄土地基桥梁群桩承载特性进行了系统的研究。 在离心模型试验中，采用土中加荷载的方法模拟浸水所产生黄土的不均匀湿陷。主要进行了黄土在非均匀湿陷条件下的单桩、群桩系列的模型试验，研究了桩顶沉降、桩身轴力、桩侧摩阻力等一系列承载特性，探讨了黄土的均匀和非均匀湿陷变形对桩基负摩阻力的影响，同时分析了不同桩数和不同桩间距对群桩效应的影响，进一步分析了不同地形条件对群桩的桩负摩阻力影响。 最后，运用有限元MIDAS软件，基于黄土湿陷的机理，提出了用“力水等效”原理模拟黄土非均匀湿陷变形，，并且依托山西河运高速桥梁桩基项目，对群桩的受力特性进行数值模拟，分析了群桩在竖向荷载作用下群桩桩侧摩阻力的变化规律。
[Abstract]:The non-uniform collapsibility in loess area has an important influence on a series of projects such as bridge pile foundation. Therefore, how to determine the bearing capacity of pile foundation and the negative frictional resistance of pile side in non-uniform collapsible loess area is the key problem to be solved urgently in the design of bridge pile foundation. In this paper, based on the bridge pile foundation project in the loess region of high speed and large thickness of Shanxi River, the geotechnical centrifuge model test and numerical simulation are used. The bearing characteristics of pile group foundation in non-uniform collapsible loess area and the bearing characteristics of loess foundation bridge under complex terrain are studied systematically. In the centrifuge model test, the inhomogeneous collapsibility of loess caused by soaking is simulated by adding load in soil. The model tests of single pile and pile group series under the condition of non-uniform collapsibility of loess are carried out, and a series of bearing characteristics, such as pile top settlement, pile axial force, pile side friction and so on, are studied. The influence of uniform and non-uniform collapsing deformation of loess on the negative friction of pile foundation is discussed. At the same time, the influence of different pile number and different pile spacing on pile group effect is analyzed, and the influence of different topographic conditions on pile negative friction is further analyzed. Finally, based on the mechanism of loess collapsibility, the finite element MIDAS software is used to simulate the inhomogeneous collapsing deformation of loess, and to rely on the pile foundation project of Shanxi River high speed bridge. Numerical simulation is carried out on the mechanical characteristics of pile groups, and the variation law of lateral friction of group piles under vertical load is analyzed.
【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】：U443.15
本文编号：2236576
[Abstract]:The non-uniform collapsibility in loess area has an important influence on a series of projects such as bridge pile foundation. Therefore, how to determine the bearing capacity of pile foundation and the negative frictional resistance of pile side in non-uniform collapsible loess area is the key problem to be solved urgently in the design of bridge pile foundation. In this paper, based on the bridge pile foundation project in the loess region of high speed and large thickness of Shanxi River, the geotechnical centrifuge model test and numerical simulation are used. The bearing characteristics of pile group foundation in non-uniform collapsible loess area and the bearing characteristics of loess foundation bridge under complex terrain are studied systematically. In the centrifuge model test, the inhomogeneous collapsibility of loess caused by soaking is simulated by adding load in soil. The model tests of single pile and pile group series under the condition of non-uniform collapsibility of loess are carried out, and a series of bearing characteristics, such as pile top settlement, pile axial force, pile side friction and so on, are studied. The influence of uniform and non-uniform collapsing deformation of loess on the negative friction of pile foundation is discussed. At the same time, the influence of different pile number and different pile spacing on pile group effect is analyzed, and the influence of different topographic conditions on pile negative friction is further analyzed. Finally, based on the mechanism of loess collapsibility, the finite element MIDAS software is used to simulate the inhomogeneous collapsing deformation of loess, and to rely on the pile foundation project of Shanxi River high speed bridge. Numerical simulation is carried out on the mechanical characteristics of pile groups, and the variation law of lateral friction of group piles under vertical load is analyzed.
【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】：U443.15
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