顾及有色噪声的铁路大跨度桥梁BDS变形分析

BDS deformation analysis of railway long-span bridge considering colored noise

利用GNSS技术对铁路大跨度桥梁进行变形监测,对于桥梁的安全控制和铁路行车安全具有重要意义。目前对桥梁的GNSS变形分析研究绝大部分集中于公路桥梁,涉及对变形控制要求更加严格的铁路桥梁的研究较少,且以往研究忽略了变形时间序列中有色噪声的影响。以上因素不利于对铁路大跨度桥梁的GNSS精确变形分析。本文以位于江西赣州的赣江特大桥的GPS和BDS监测数据为例,利用主成分分析对有色噪声进行滤波,分析了有色噪声对铁路桥梁变形分析结果的的影响。试验结果表明,昼夜温差变化导致铁路斜拉桥的中跨和索塔分别在垂向以及纵向均产生周期约为一天的变形;根据GPS和BDS变形时间序列获得的变形结果之间存在差异;有色噪声对变形参数估计结果影响较小,但忽略有色噪声会使变形参数估值的不确定度减小80%,导致对变形分析结果的精度过于乐观。利用主成分分析可以显著地削弱有色噪声,使变形参数估值的不确定度降低约73%。

At present,most of the GNSS deformation analysis research on bridges is focused on highway bridges,and there are few studies involving railway bridges with stricter deformation control requirements.Moreover,previous studies have ignored the influence of colored noise in the deformed time series.The above factors are not conducive to accurate GNSS deformation analysis of railway long-span bridges.Therefore,this paper takes GPS and BDS monitoring data of the Ganjiang Bridge in Ganzhou City,Jiangxi Province as an example,uses principal component analysis to filter colored noise,and analyzes the effect of colored noise on the results of railway bridge deformation analysis.The experimental results show that the temperature difference between day and night causes the mid-span and the tower of the railway cable-stayed bridge to deform with a period of about one day in the vertical and longitudinal directions,respectively.There is a difference between the deformation results obtained from GPS and BDS deformation time series.Colored noise has little effect on the deformation parameter estimation results,but ignoring the colored noise will reduce the uncertainty of the deformation parameter estimation by 80%,resulting in too optimistic about the accuracy of the deformation analysis results.The use of principal component analysis can significantly weaken the colored noise and reduce the uncertainty of the deformation parameter estimation by about 73%.