文献类型：期刊文献

中文题名：洪水对桥墩的瞬间冲击效应

英文题名：Moment Impact Effect of Flood on Bridge Pier

作者：吴安杰 杨万理 赵雷

第一作者：吴安杰

机构：[1]贵州理工学院土木工程学院;[2]西南交通大学土木工程学院

第一机构：贵州理工学院土木工程学院

年份：2018

卷号：35

期号：6

起止页码：67-73

中文期刊名：公路交通科技

外文期刊名：Journal of Highway and Transportation Research and Development

收录：Scopus;北大核心:【北大核心2017】；CSCD:【CSCD2017_2018】；

基金：国家自然科学基金项目(51678491)

语种：中文

中文关键词：桥梁工程;冲击效应;数值模拟;洪水;桥墩;流固耦合作用

外文关键词：bridge engineering;impact effect;numerical simulation;flood;pier;fluid-structure interaction

摘要：为研究洪水对桥墩的瞬间冲击效应大小与规律,采用数值仿真软件ANSYS-CFX(在ANSYS Workbench平台上,采用瞬态结构模块ANSYS和流体分析模块CFX,并将2个模块进行关联)对洪水冲击不同截面形式桥墩过程进行了流固耦合瞬态模拟,首先明确了冲击放大系数和冲击效应系数的概念,并定义了冲击效应系数的表达式,然后分析了瞬间冲击效应以及流固耦合效应与洪水行近流速、水量高度之间的关系,揭示了瞬间冲击响应较大的原因,最后将冲击之后的绕流压力与规范计算值进行了对比。分析表明:(1)冲击放大系数随着水量高度的增加而增大,增加的速率随着水量高度的增大而减小,通过比较,圆形墩的冲击放大系数最大,方形墩次之,矩形墩最小;(2)瞬间冲击效应随着洪水行近流速和水量高度的增大而增大,在水量高度较高大时(>0.75H),瞬间冲击效应不容忽视,在相等的水量高度下,冲击效应随流速增大呈非线性增加的趋势,相比之下,圆形截面墩冲击效应最显著,冲击放大系数为1.67~2.62。综合考虑瞬间冲击效应和流固耦合效应,建议铁路桥梁规范对水流力取值适当乘以一个放大系数。
In order to study the moment impact effect （ magnitude and rule） of flood on bridge pier, the fluid- structure coupling transient simulation for the process of flood impact on bridge piers with different sections is carried out by using numerical simulation software ANSYS -CFX （the transient structure module ANSYS combined with fluid analysis module CFX in ANSYS Workbench platform）. First, the concept of impact amplification coefficient and impact effect coefficient are clarified, and the expression of impact effect coefficient is defined. Then, the relations of the impact effect and fluid-structure coupling effect with respect to flood velocity as well as flood height are analyzed. The reason of large sudden impulse response is revealed. Finally, the pressure of flow around pier in the post-impact stage is compared with the result derived by using the formulas specified in the bridge design codes. The analysis result shows that （1） The impact amplification coefficient increases with the increase of flood height, while the rate of increase decreases with the increase of flood height. By comparison, the impact magnification coefficient of circular pier is the largest, that of the square pier is second, and that of the rectangular pier is the smallest. （2） The moment impact effect increases with the increase of flood approaching velocity and height. When the flood height is greater （ 〉0. 75H）, the moment impact effect cannot be neglected. At the same water height, the impact effect increases nonlinearly with the increase of flood velocity, and the impact effect of circular pier is the most obvious by comparison, the impact amplification coefficient is from 1.67 to 2.62. In consideration of moment impact effect and fluid-solid coupling effect, it is suggested that the current force calculated using the formulas provided by the railway bridge codes should be multiplied by an impact amplification coefficient.