基于VMD-SVD的桥梁挠度监测温度效应分离方法研究  

Separation of Temperature Effect in Monitored Deflection of Bridges Based on VMD-SVD

作　　者：谭冬梅[1] 郭泰 甘沁霖 TAN Dong-mei;GUO Tai;GAN Qin-lin(School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学土木工程与建筑学院,湖北武汉430070

出　　处：《桥梁建设》2023年第3期87-94,共8页Bridge Construction

基　　金：国家自然科学基金项目(42271453);湖北省重点实验室开放基金项目(DQJJ201906)。

摘　　要：为实现桥梁挠度监测信号中温度效应的分离,提出一种基于VMD-SVD的挠度监测信号温度效应分离方法。该方法首先利用奇异值分解(SVD)对信号进行降噪,然后利用变分模态分解(VMD)对降噪后的信号进行分解,得到日温差效应分离结果;同时考虑到年温差效应的频率接近0与长期挠度难以分离,对采样频率进行修正,使年温差效应的频率远离长期挠度,利用VMD实现长期挠度和年温差效应的分离。为验证VMD-SVD信号分离法的可行性,以武汉某大跨斜拉桥为背景,采用MIDAS Civil软件建立大桥有限元模型进行挠度模拟分离,并对桥梁实测挠度监测信号进行温度效应分离。结果表明:挠度监测信号经SVD降噪处理后,温差效应分离精度显著提高;修正采样频率可解决长期挠度与年温差效应难以分离的问题;桥梁实测挠度监测信号温度效应的分离结果具有空间上的相关性和时间上的连续性,该方法可有效分离桥梁挠度监测信号中的温度效应。Aiming at the problem of temperature effect separation in the monitoring signal of bridge deflection,a method combining VMD-SVD is proposed in this paper.Firstly,Singular Value Decomposition(SVD)is used to de-noise the signal.Secondly,the signal after denoising is decomposed by Variational Mode Decomposition(VMD)to obtain the separation result of diurnal temperature difference effect.Considering that the frequency of annual temperature difference effect is close to zero and is difficult to separate from the long-term deflection,the sampling frequency is modified to make the frequency of annual temperature difference effect far away from the long-term deflection,and then the separation of the long-term deflection and the annual temperature difference effect is realized by VMD.The application of the method is illustrated by the case of a long-span cable-stayed bridge in Wuhan,and the finite element model of the bridge built up by MIDAS Civil is used to simulate the separation of temperature effect from the monitored deflection signals of the bridge.It is shown that after the monitoring signals are denoised by SVD,the separation accuracy of temperature difference effect is significantly improved.The problem that it is difficult to separate the long-term deflection from the annual temperature difference effect can be solved by modifying the sampling frequency.The separation results of temperature effect in measured bridge monitoring signals have spatial correlation and temporal continuity,indicating that this method can effectively separate the temperature effect in bridge deflection monitoring signals.

关 键 词：桥梁挠度 监测信号 降噪 温度效应分离 变分模态分解 奇异值分解 桥梁监测 

分 类 号：U446.2[建筑科学—桥梁与隧道工程]