Deformation Monitoring Of Northwest High Speed Railway Based On Time Series Radar Interferometry

Railway deformation is a major problem that can not be ignored in the process of railway operation and maintenance.Compared with ordinary railway,high-speed railway has more strict requirements on railway deformation.Lanzhou-Wulumuqi high-speed railway in northwest China is an important part of the "One Belt And One Road" Silk Road Economic Belt,the operation maintenance and operation safety of high-speed railway are the pillars of the development of high-speed railway,so it is of great significance to monitor railway deformation of Lanzhou-Wulumuqi high-speed railway.Based on the current understanding of the characteristics and mechanism of subgrade diseases of Lanxin high speed railway,geological environment is one of the main factors for the formation and development of diseases.Because the traditional field measurement methods can not extract the distribution characteristics of large-scale deformation,it is urgent to solve the application of new technologies and methods in high-speed railway subgrade deformation monitoring.Synthetic aperture radar interferometry is a deformation monitoring method developed at the end of the 20 th century and the beginning of this century,which has the advantages of all-weather,large range and wide time span.These advantages of this technology can make up for the shortcomings of traditional railway monitoring methods,and form mutual complement with traditional methods.In this paper,the method of time series radar interferometry is used to monitor the deformation of Lanzhou-Wulumuqi high-speed railway in Lanzhou City,Yumen City and Minle County,which further proves the practicability of this method in the field of railway deformation monitoring.The main work of this paper is as follows:1.This paper summarizes the development status of Radar Interferometry Technology,and understands the application status of time series Radar Interferometry Technology in the field of railway deformation monitoring.2.The basic principle of InSAR technology is explained,and the principle and process of permanent scatterer time series interferometry and small baseline set time series interferometry are summarized.3.Prepared the radar image data of the three study areas,completed the data format conversion,the loading of precision orbit data and other preparatory work.4.The permanent scatterer interferometry technique was used to obtain the surface deformation of Lanzhou West Station on February 19,2017 solstice on June 9,2019,Yumen Station on June 17,2018 solstice on June 18,2020,and Minle Station on June19,2018 solstice on September 12,2020.The experimental results show that there are several obvious settlement funnels near Lanzhou West Railway Station,and the maximum settlement rate of the high-speed railway line is-13.31mm/year;The highspeed railway line near Yumen station presents two different deformation trends: in the inaccessible Gobi area,the railway deformation trend is uplift,while in the urban area,the railway deformation trend is settlement;The deformation trend of the high-speed railway line near Minle station is that subsidence and uplift occur alternately.5.The accuracy of the experimental results is verified.For the area of Lanzhou west station which lacks of measured data,the small baseline set interferometry method is used for cross validation.For the area of Minle and Yumen,the orbit measurement data is used for accuracy validation.The validation results show that the monitoring results of the permanent scatterer technology are more accurate.6.The causes of railway deformation are briefly analyzed.It is speculated that railway deformation in Lanzhou and Minle research area is related to loess collapsibility,railway deformation in Gobi area of Yumen research area is related to saline expansion,and railway deformation in urban area is related to karst collapse.