高速列车作用引起桥墩—水流固耦合振动特性的研究

发布时间：2018-07-17 01:55

【摘要】：随着我国高速铁路系统的飞速发展，越来越多涉水铁路桥梁的建设无法避免，且这些涉水铁路桥梁的涉水深度不断刷新国内外纪录。在当前的涉水铁路桥梁中，桥墩淹没深度最深已达168米，相当于56层楼的高度。这些处于深水中的桥墩，在高速列车运行产生的复杂激振力作用下，会发生一定的振动和变形，并引起周围水体的振动。水体的振动又反作用于桥墩，并改变桥墩的振动和变形状态，这种作用与反作用始终伴随着列车的通过。桥墩作为桥梁上部结构的关键支撑构件，一旦发生破坏，必然会导致灾难性的后果。因此，分析研究水体对桥墩自振特性的影响以及由高速列车作用引起的动力振动特性的影响，有利于桥梁结构的安全性、稳定性、使用性方面的设计与建造以及日常维护。本文在查阅大量国内外有关结构与流体之间的流固耦合计算方法和原理，以及与桥墩-水流固耦合振动特性相关文献的基础上，分析了独立的桥墩结构（主要是高墩）在水中的自振特性，重点分析了独立的桥墩结构在高速列车作用时，水体对其动力振动特性的影响。主要做了以下分析和研究： ⑴运用ANSYS有限元软件建立了实体桥墩模型和水-桥墩耦合有限元模型，，并对桥墩自振和动力振动特性进行分析。 ⑵对桥墩进行自振特性分析时，通过ANSYS建立不同水深中的桥墩模型，模拟计算其自振频率随水深的变化规律。当水深较浅（小于墩高50%）时，桥墩自振频率降低幅度不明显；当水深较大（大于墩高50%）时，桥墩自振频率随水深的增加出现明显降低。并分析了桥墩处于无水和满水情况下，桥墩的几何尺寸对其自振频率的影响。 ⑶对桥墩进行动力特性分析时，应用ANSYS建立实体桥墩模型，通过在墩顶加载60m/s、70m/s、80m/s和90m/s车速引起的激振力，模拟计算出桥墩墩顶X、Y、Z方向（横向、纵向和竖向）位移和加速度的变化规律和时程。墩顶X、Y、Z方向最大位移随车速的增加而减小，最大加速度随车速的增加而增加。 ⑷通过ANSYS建立不同水深下的桥墩-水流固耦合有限元模型，在墩顶施加高速列车运行引起的激振力，分析得出桥墩墩顶X、Y、Z方向（横向、纵向和竖向）位移和加速度随水深的变化规律和时程。当水深小于墩高80%，车速从60m/s增至90m/s时，墩顶X、Y方向最大位移随淹没深度的增大先减小后增加；当水深超过墩高的80%，不同车速情况下，墩顶X、Y方向最大位移随淹没深度的增大而大幅增加。当水深小于墩高90%时，墩顶X、Y方向最大加速度随淹没深度的增加没有发生明显的变化。但是，当水深超过墩高的90%时，墩顶X、Y方向最大加速度出现明显的减小。墩顶Z方向最大位移和加速度不随桥墩淹没深度的变化而变化。 ⑸在不同车速下，通过改变桥墩的长细比，分析了满水情况下墩顶最大位移和加速度的变化规律。墩顶X、Y方向最大位移随长细比的增加大幅增加，Z方向小幅增加。但是，墩顶三个方向的最大加速度都随桥墩长细比的增加而减小，且这些变化规律与车速无关。
[Abstract]:With the rapid development of the high-speed railway system in our country, more and more bridge construction can not be avoided, and the water related depth of these wading railway bridges constantly refreshes the record at home and abroad. In the current railway bridge, the depth of the pier is 168 meters deep, equivalent to the height of 56 stories, the pier in the deep water. Under the action of the complex excitation force produced by the high speed train, the vibration and deformation will occur and the vibration of the surrounding water will be caused. The vibration of the water body reacts on the pier and changes the vibration and deformation state of the pier. This action and reaction always accompany the passing of the train. The pier is the key support of the bridge superstructure. If the component is damaged, it will inevitably result in disastrous consequences. Therefore, the analysis and study of the influence of water on the vibration characteristics of the pier and the influence of the dynamic vibration characteristics caused by the action of the high-speed train will be beneficial to the safety, stability, the construction and the daily maintenance of the bridge structure.
In this paper, based on a large number of calculation methods and principles about fluid solid coupling between structures and fluids, and the related literature about the vibration characteristics of bridge pier and fluid solid coupling, the self vibration characteristics of the independent pier structure (mainly high piers) in water are analyzed, and the emphasis is made on the analysis of the independent pier structure when the high speed train is used. The influence of body on its dynamic vibration characteristics is analyzed and studied.
1. The finite element model of solid pier and water pier coupling finite element model are established by using ANSYS finite element software, and the natural vibration and dynamic vibration characteristics of pier are analyzed.
When analyzing the self vibration characteristics of the pier, the pier model in different water depth is established by ANSYS to simulate the variation of its natural frequency with the depth of water. When the water depth is shallow (less than 50% of the pier height), the decrease of the vibration frequency of the pier is not obvious; when the water depth is larger than the pier height of 50%, the vibration frequency of the pier appears with the increase of water depth. The influence of pier size on its natural frequency is analyzed under the condition of no water and full water.
(3) when analyzing the dynamic characteristics of the pier, the model of solid bridge pier is established by ANSYS. By loading the excitation force of 60m/s, 70m/s, 80m/s and 90m/s at the pier top, the variation law and time history of the displacement and acceleration of the pier top X, Y, Z (transverse, vertical and vertical) are simulated and calculated. The maximum displacement of the pier top X, Y, Z direction increases with the speed. The maximum acceleration increases with the increase of vehicle speed.
(4) to establish a finite element model of bridge pier fluid solid coupling under different water depth by ANSYS, the excitation force caused by high speed train operation on the top of the pier, and the variation law and time history of the pier top X, Y, Z direction (transverse, vertical and vertical) and acceleration with water depth are obtained. When the water depth is less than 80% of the pier height, the speed of vehicle speed increases from 60m/s to 90m/s. The maximum displacement of X, Y direction decreases first and then increases with the increase of the submerged depth. When the water depth exceeds the pier height of 80%, the maximum displacement of the pier top X and Y increases with the increase of the submerged depth. When the water depth is less than 90% of the pier height, the maximum acceleration of the pier top X and Y direction does not change obviously with the increase of the submerged depth. When the water depth is more than 90% of the pier height, the maximum acceleration of the pier top X and Y decreases obviously. The maximum displacement and acceleration of the pier top Z direction are not changed with the variation of the submerged depth of the pier.
At different speed, the maximum displacement and acceleration of the pier under full water are analyzed by changing the length and slenderness ratio of the pier. The maximum displacement of the pier top X, Y direction increases with the increase of the length and fineness ratio, and the direction of Z increases slightly. But the maximum acceleration of the three directions of the pier decreases with the increase of the length and fineness ratio of the pier, and these changes are also changed. The law of conversion has nothing to do with the speed of the car.
【学位授予单位】：华东交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.3;U211.3

【参考文献】