非线性桩—土作用对车桥耦合振动的影响研究

发布时间：2018-05-18 06:00

本文选题：高速铁路 + 车桥耦合　；参考：《天津大学》2014年硕士论文

【摘要】：车桥耦合计算方法已经成为评价桥梁动力设计参数合理与否以及列车安全性评估的重要手段。建立准确的车桥耦合计算模型是进行车桥耦合计算的前提和关键。对于车桥耦合作用而言，其动力特性的影响因素除了上部结构外，，桩基系统也是一个不可忽略的因素。在目前的车桥耦合研究较少考虑桩-土的非线性相互作用。实际上，在动力荷载作用下，桩和土之间存在着变形的相互制约和能量的相互传递。因此考虑非线性桩-土相互作用的车桥耦合振动成为一个值得研究的课题。本文基于土-结构动力学以及车桥耦合理论建立了桩-土-桥-车的动力作用分析模型。分析了考虑非线性桩-土相互作用的车桥耦合响应，并不考虑桩-土相互作用的车桥耦合响应进行了对比分析。其主要研究内容如下： 1.基于文克尔地基梁理论，利用修正的P-Y曲线法和荷载传递双曲线法，模拟桩-土水平方向和竖直方向的非线性相互作用。采用了桩和土相对刚度来计算水平方向桩-土相互作用的初始刚度。通过Mohr-Coulomb法则得到土的极限抗力，并结合Matlock P-Y曲线法对极限抗力的表达式进行了修正，充分考虑了土的极限抗力的深度效应。从而建立了非线性桩-土相互作用模型。并分析桩基各主要参数对桩基承载力的影响。 2.针对包含31个自由度的二系悬挂四轴动车模型，包含12个自由度的空间梁单元桥梁动力学模型，以及建立的非线性桩-土相互作用模型，建立了桩-土-桥-车体系动力学模型。为提高桩-土-桥-车动力体系振动微分方程的求解速度，采用了“新型显式Newmark-β”法与传统隐式“Newmark-β”法分别求解车辆动力方程和桥梁（包含桩-土）的动力方程。 3.以某一位于深厚软弱场地的高速铁路桥梁为背景，建立了包含非线性桩-土相互作用的车-桥耦合有限元模型。在此基础上对该高速铁路桥梁振动特性以及高速列车在其上运行的安全性能进行了分析。发现考虑非线性桩-土相互作用后桥梁振动的位移响应变大，加速度响应变小。非线性桩-土相互作用对车辆的安全性能有利。此计算方法和结果为软弱基础的高速铁路线路的分析和设计提供了参数和依据。
[Abstract]:The vehicle-bridge coupling calculation method has become an important means to evaluate whether the bridge dynamic design parameters are reasonable or not and the train safety evaluation. The establishment of accurate vehicle-bridge coupling calculation model is the premise and key of vehicle-bridge coupling calculation. As far as vehicle-bridge coupling is concerned, the influence factor of its dynamic characteristics is not only the superstructure, but also the pile foundation system can not be ignored. In the current vehicle-bridge coupling research, the pile-soil nonlinear interaction is seldom considered. In fact, under the action of dynamic load, there are mutual constraints of deformation and energy transfer between pile and soil. Therefore, the vehicle-bridge coupling vibration considering nonlinear pile-soil interaction becomes a subject worth studying. Based on soil-structure dynamics and vehicle-bridge coupling theory, a dynamic model of pile-soil-bridge-vehicle is established in this paper. The vehicle-bridge coupling response considering nonlinear pile-soil interaction is analyzed, and the vehicle-bridge coupling response without considering pile-soil interaction is compared. The main research contents are as follows: 1. Based on Winkler's foundation beam theory, the modified P-Y curve method and the load transfer hyperbolic method are used to simulate the nonlinear interaction between the horizontal direction and vertical direction of pile-soil. The initial stiffness of pile-soil interaction in horizontal direction is calculated by using the relative stiffness of pile and soil. The limit resistance of soil is obtained by Mohr-Coulomb rule, and the expression of limit resistance is modified by Matlock P-Y curve method. The depth effect of ultimate resistance of soil is fully considered. A nonlinear pile-soil interaction model is established. The influence of the main parameters of pile foundation on the bearing capacity of pile foundation is analyzed. 2. Aiming at the two-system suspension four-axis motor vehicle model with 31 degrees of freedom, the dynamic model of spatial beam element bridge with 12 degrees of freedom, and the nonlinear pile-soil interaction model, a nonlinear pile-soil interaction model is established. The dynamic model of pile-soil-bridge-vehicle system is established. In order to improve the speed of solving the vibration differential equation of pile-soil-bridge-vehicle dynamic system, the "new explicit Newmark- 尾" method and the traditional implicit "Newmark- 尾" method are used to solve the vehicle dynamic equation and the bridge (including pile-soil) dynamic equation respectively. 3. A vehicle-bridge coupling finite element model including nonlinear pile-soil interaction is established based on a high-speed railway bridge located in a deep weak site. On this basis, the vibration characteristics of the high-speed railway bridge and the safety performance of the high-speed train running on the bridge are analyzed. It is found that the displacement response of bridge vibration becomes larger and the acceleration response is smaller when nonlinear pile-soil interaction is considered. Nonlinear pile-soil interaction is beneficial to vehicle safety performance. The calculation method and results provide parameters and basis for the analysis and design of high-speed railway lines with weak foundation.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.3;U211.3

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