高速铁路桥梁桩基础抗震性能研究
发布时间：2018-08-03 08:59
【摘要】：随着高速铁路的发展,桥梁结构得到了广泛应用。高速铁路桥梁与一般铁路桥梁相比,其横桥向剪跨比较小,有可能伴随剪切破坏。由于高速铁路桥梁设计主要受刚度控制,因此通过增大桥墩截面的尺寸,使其屈服强度增大从而提高其刚度。此设计在地震作用下,可能造成桥墩在横桥向的抗剪能力高于桩基础,而在强震作用下,无法保证塑性铰只出现在墩底,桩基础会先进入塑性状态而发生破坏。由于现行规范未考虑桩基在强震作用下的屈服破坏,因此本文主要对桥墩在横向地震作用下的破坏机理、单桩的破坏模式以及群桩结构的抗震稳定性评估方法进行了研究。 本文以京沪高铁沿线简支梁桥桥墩为试验原型,设计了2个缩尺比为1／5的桥墩模型,对桥墩横桥向进行了低周期反复荷载试验,主要研究两个桥墩的破坏机理,计算桥墩模型的位移延性,骨架曲线并与SAP2000数值模拟结果进行对比,验证有限元分析的可行性,分析桥墩破坏模式,并对桥墩模型的抗剪能力进行验算,为进一步研究桩基的抗震性能提供依据。 应用Pushover分析方法对单桩的破坏机制及影响因素进行了研究。桩基采用分布塑性铰单元模拟,桩土相互作用采用p-y曲线法模拟。采用高速铁路桥梁常用的两种直径(1.25m和1.5m)单桩进行分析,并选取直径1.5m的单桩改变其土参数,得到不同土参数对结构的影响程度。 群桩部分比较上部结构、群桩基础和整体结构在顺桥向和横桥向的抗震能力,得到不同方向整体破坏形态,并基于折减系数谱对其稳定水平进行评估。在考虑群桩效应的基础上,对五组群桩基础施加Pushover水平荷载,得到桩基破坏基本形式,桩顶与承台连接处为抗震设计重点考虑部分。 本文通过对高速铁路桥梁地震作用下桩基失效机制的研究,得到桥梁桩基在地震作用下的危险区域以及不同地震作用方向下桥梁桩基的破坏形式,这对完善国内桩基抗震设计起到了指引作用。
[Abstract]:With the development of high speed railway, the bridge structure has been widely used. Compared with the general railway bridge, the high speed railway bridge is smaller than the general railway bridge, and it may be accompanied by shear failure. As the design of the high-speed railway bridge is mainly controlled by the stiffness, the size of the pier section is increased to increase its yield strength and improve its stiffness. Under the action of earthquake, the shear ability of the pier may be higher than that of the pile foundation. Under the action of strong earthquake, the plastic hinge can not be guaranteed only at the bottom of the pier, and the pile foundation will be damaged in the advanced plastic state. The failure mechanism of single pile under transverse earthquake, the failure mode of single pile and the evaluation method of seismic stability of pile group structure are studied.
Taking the pier of simple supported beam bridge along Beijing-Shanghai high-speed railway as experimental prototype, 2 pier models with scale ratio of 1 / 5 are designed. Low cyclic cyclic loading tests on bridge piers are carried out. The failure mechanism of two pier is mainly studied. The displacement ductility of the pier model is calculated, and the skeleton curve is compared with the results of SAP2000 numerical simulation. The feasibility of the finite element analysis is used to analyze the failure mode of the pier and to check the shear capacity of the pier model, which provides the basis for the further study of the seismic performance of the pile foundation.
The failure mechanism and influence factors of single pile are studied by Pushover method. The pile foundation is simulated with distributed plastic hinge unit. The interaction of pile and soil is simulated by p-y curve method. Two kinds of diameter (1.25m and 1.5m) single pile used in high speed railway bridge are analyzed, and the single pile with diameter 1.5m is selected to change its soil parameters. The influence of the same soil parameters on the structure.
The group pile part is compared with the upper structure, the pile group foundation and the whole structure are in different direction as a whole, and the stability level is evaluated in different directions. Based on the group pile effect, the Pushover horizontal load is applied to the five groups of group pile foundations to get the basic form of the pile foundation failure. The connection between pile top and pile cap is the key part of aseismic design.
Through the study of the failure mechanism of the pile foundation under the earthquake action of the high speed railway bridge, the damage form of the bridge pile foundation under the earthquake action and the different direction of the earthquake action is obtained. This plays a guiding role in improving the seismic design of the domestic pile foundation.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U442.55;U443.15
本文编号：2161250
[Abstract]:With the development of high speed railway, the bridge structure has been widely used. Compared with the general railway bridge, the high speed railway bridge is smaller than the general railway bridge, and it may be accompanied by shear failure. As the design of the high-speed railway bridge is mainly controlled by the stiffness, the size of the pier section is increased to increase its yield strength and improve its stiffness. Under the action of earthquake, the shear ability of the pier may be higher than that of the pile foundation. Under the action of strong earthquake, the plastic hinge can not be guaranteed only at the bottom of the pier, and the pile foundation will be damaged in the advanced plastic state. The failure mechanism of single pile under transverse earthquake, the failure mode of single pile and the evaluation method of seismic stability of pile group structure are studied.
Taking the pier of simple supported beam bridge along Beijing-Shanghai high-speed railway as experimental prototype, 2 pier models with scale ratio of 1 / 5 are designed. Low cyclic cyclic loading tests on bridge piers are carried out. The failure mechanism of two pier is mainly studied. The displacement ductility of the pier model is calculated, and the skeleton curve is compared with the results of SAP2000 numerical simulation. The feasibility of the finite element analysis is used to analyze the failure mode of the pier and to check the shear capacity of the pier model, which provides the basis for the further study of the seismic performance of the pile foundation.
The failure mechanism and influence factors of single pile are studied by Pushover method. The pile foundation is simulated with distributed plastic hinge unit. The interaction of pile and soil is simulated by p-y curve method. Two kinds of diameter (1.25m and 1.5m) single pile used in high speed railway bridge are analyzed, and the single pile with diameter 1.5m is selected to change its soil parameters. The influence of the same soil parameters on the structure.
The group pile part is compared with the upper structure, the pile group foundation and the whole structure are in different direction as a whole, and the stability level is evaluated in different directions. Based on the group pile effect, the Pushover horizontal load is applied to the five groups of group pile foundations to get the basic form of the pile foundation failure. The connection between pile top and pile cap is the key part of aseismic design.
Through the study of the failure mechanism of the pile foundation under the earthquake action of the high speed railway bridge, the damage form of the bridge pile foundation under the earthquake action and the different direction of the earthquake action is obtained. This plays a guiding role in improving the seismic design of the domestic pile foundation.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U442.55;U443.15
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