A monitoring method based on time-series InSAR technology in a fully enclosed high-speed railway

Abstract

Aiming at the problem that fully enclosed high-speed railways cannot be monitored by non-contact measurement mode, the present invention proposes a monitoring method in fully enclosed high-speed railways based on time-series InSAR technology. By using PS-InSAR technology and SBAS-InSAR technology to monitor fully enclosed high-speed railways, the settlement value and settlement rate of each position of the high-speed railway are calculated. By screening the PS points on the fully enclosed high-speed railway and leaving the PS points scattered on the roadbed through the main structure, the deformation information of the roadbed of the fully enclosed high-speed railway can be accurately obtained; the deformation value of the target point is obtained by the regional radius method, the monitoring accuracy of the target point can be improved, and the deformation amount at each position can be calculated; since the fully enclosed sound barrier can reduce the noise of the high-speed railway to the greatest extent, the settlement monitoring of the fully enclosed high-speed railway using time-series InSAR technology can not only replace the daily leveling measurement, but also has great significance for the disaster warning of the fully enclosed high-speed railway.

Description

Technical Field

[0001] The invention belongs to the field of deformation monitoring, and in particular relates to a monitoring method in a fully enclosed high-speed railway based on time-series InSAR technology. Background Art

[0002] As the ground subsidence occurs silently, it also has a huge impact on high-speed railways. When high-speed trains travel at high speed in areas of ground subsidence, especially areas of uneven ground subsidence, it is easy to cause deformation of high-speed railway foundations and bridges in some areas, threatening the operation of high-speed railways. With the rapid development of high-speed railways, the noise pollution caused by high-speed railways has become the primary environmental problem. The biggest environmental problem caused by high-speed railways is noise pollution. The noise generated by high-speed railways is listed as one of the seven major international environmental pollution problems. A fully enclosed "soundproof tunnel" high-speed railway has been built on the Guba Bridge of the Beijing-Xiong'an High-speed Railway. It is the first fully enclosed high-speed railway in China with a metal soundproof board on the outside, which will minimize the noise generated when the high-speed railway passes. The "soundproof tunnel" of the Beijing-Xiong'an High-speed Railway is not only an important innovation in the development of high-speed railways, but also makes a huge contribution to the protection of high-speed railway noise.

[0003] The settlement observation of high-speed railway includes the settlement observation of roadbed, bridges and tunnels, re-survey of high-speed railway control network and track inspection. The important parts in high-speed railway settlement monitoring are roadbed, bridges and tunnels. Among them, their transition sections are most prone to uneven settlement, which is also the weakest link in the construction of high-speed railway projects, directly threatening the operation of high-speed railways. Traditional monitoring methods for high-speed railways include precision leveling, precision trigonometric height measurement and liquid static leveling. Although traditional monitoring methods can accurately monitor the settlement information of high-speed railways, they take a lot of time and cost, and cannot reflect the deformation trend along the high-speed railway on a large scale.

[0004] Compared with the conventional leveling technology, the synthetic aperture radar interferometry (InSAR) technology belongs to the non-contact measurement mode. InSAR technology has the characteristics of low cost, high safety, no weather influence, all-weather uninterrupted observation, long monitoring period and high monitoring accuracy. Permanent scatterer interferometry (PS-InSAR) and small baseline set interferometry (SBAS-InSAR) are suitable for monitoring the changes in deformation trend of objects over a long period of time. With the maturity of InSAR technology in recent years, this new technology has been gradually added to the settlement monitoring of high-speed railways. The deformation rate and settlement accuracy of the technology can reach the millimeter level.

[0005] Domestic research on InSAR technology in high-speed rail and highways is still in its infancy. With the rapid development of China's high-speed rail, more and more scholars are conducting research on the application of InSAR technology in high-speed rail settlement. In the early stages of the study, Ma Chuangguang and others applied InSAR technology to the geological line selection of high-speed rail goaf areas. The Beijing-Tianjin area is the birthplace of China's railway development. In 2014, Shi Hongyun used time-series InSAR technology to select C-band radar data to evaluate the settlement stability of the Beijing-Tianjin High-Speed ​​Railway. In 2017, Zhou Yuying and others used 45 high-resolution Terra SAR-X image data to obtain the distribution information of ground settlement in the Beijing section of the Beijing-Tianjin High-Speed ​​Railway through the PS-InSAR method. Summary of the invention

[0006] In view of the problem that a fully enclosed high-speed railway cannot be monitored through a non-contact measurement mode, the present invention proposes a monitoring method in a fully enclosed high-speed railway based on time-series InSAR technology. By utilizing PS-InSAR technology and SBAS-InSAR technology to monitor the fully enclosed high-speed railway, the settlement value and settlement rate at each position of the high-speed railway are calculated to achieve the same effect as traditional leveling measurement.

[0007] A monitoring method in a fully enclosed high-speed railway based on time-series InSAR technology comprises the following steps:

[0008] Step 1: Obtain image data of the study area, determine the scope of the fully enclosed high-speed railway section and crop the image, and simultaneously obtain image data of the fully enclosed high-speed railway in combination with precise track data and DEM data;

[0009] Step 2: Use PS-InSAR technology to perform time-series interferometry processing and obtain PS points by controlling the amplitude deviation index and the interference coefficient threshold;

[0010] Step 3: The PS points obtained on the fully enclosed high-speed railway are used to obtain the deformation value of the target point through the area radius method, and the deformation value at each position is calculated using the spatial position relationship;

[0011] Step 4: Use SBAS-InSAR technology to perform interferometric workflow processing to generate deformation results in the geographic coordinate system, and obtain the annual average settlement rate of the high-speed railway after vertical projection;

[0012] Step 5: Use the time series analysis tool software to perform PS-InSAR and SBAS-InSAR time series analysis on the fully enclosed high-speed railway to obtain the settlement value in any time period.

[0013] The specific steps for obtaining PS points described in step 2 are as follows:

[0014] Step 2-1, select the appropriate amplitude deviation index and set the coherence coefficient threshold, so that the PS points are distributed on railways, roads and tall buildings in urban areas, and eliminate low-coherence or incoherent PS points on rivers and farmlands;

[0015] Step 2-2: Filter the PS points on the fully enclosed high-speed railway, remove the PS points that fall on the main structure of the metal material, and keep the PS points that pass through the main structure and are scattered on the roadbed.

[0016] The specific steps of obtaining the deformation value of each position in step 3 are as follows:

[0017] Step 3-1, the PS points left on the fully enclosed high-speed railway are calculated by the area radius method to obtain the deformation value of the target point, with the target point as the center of the circle and the rail width as the radius. The average value of the PS points within the circle is taken as the deformation value of the target point;

[0018] Step 3-2: Establish a spatial model of each position and the target point based on the actual position, and use mathematical functions to calculate the deformation value of the roadbed at the remaining non-PS points.

[0019] Advantages of the present invention:

[0020] This patent aims to solve the problem that fully enclosed high-speed railways cannot be monitored through non-contact measurement mode. It proposes a monitoring method based on time-series InSAR technology in fully enclosed high-speed railways. By using PS-InSAR technology and SBAS-InSAR technology to monitor fully enclosed high-speed railways, the settlement value and settlement rate of each position of the high-speed railway are calculated. By screening the PS points on the fully enclosed high-speed railway and leaving the PS points scattered on the roadbed through the main structure, the deformation information of the fully enclosed high-speed railway roadbed can be accurately obtained; the deformation value of the target point is obtained by the regional radius method, the monitoring accuracy of the target point can be improved, and the deformation amount at each position can be calculated; because the fully enclosed sound barrier can reduce the noise of the high-speed railway to the greatest extent, the settlement monitoring of the fully enclosed high-speed railway using time-series InSAR technology can not only replace daily leveling measurement, but also has great significance for the disaster warning of the fully enclosed high-speed railway. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A diagram of a fully enclosed sound barrier high-speed railway in the Beijing-Xiongan Railway in a specific implementation manner of the present invention;

[0022] Figure 2 It is a structural diagram of a fully enclosed sound barrier device in a specific embodiment of the present invention;

[0023] Figure 3 It is a schematic diagram of the area radius method in a specific implementation manner of the present invention. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] A monitoring method in a fully enclosed high-speed railway based on time-series InSAR technology comprises the following steps:

[0026] Step 1: Obtain image data of the study area, determine the scope of the fully enclosed high-speed railway section and crop the image, and simultaneously obtain image data of the fully enclosed high-speed railway in combination with precise track data and DEM data;

[0027] Taking the Beijing-Xiong'an Railway as an example, there is a Guba Bridge between the Bazhou North Station and Beilucundian of the high-speed railway. A "soundproof tunnel" has been built here, becoming the world's first fully enclosed sound barrier high-speed railway (such as Figure 1 ). Obtain image data of fully enclosed high-speed railways and download precise track data and DEM data of the same period.

[0028] Step 2: Use PS-InSAR technology to perform time-series interferometry processing and obtain PS points by controlling the amplitude deviation index and the interference coefficient threshold;

[0029] The PS-InSAR technical process is as follows:

[0030] (1) Selection and registration of primary images;

[0031] (2) Image registration;

[0032] (3) SAR image radiometric calibration;

[0033] (4) SAR data differential processing;

[0034] (5) PS point target extraction;

[0035] (6) PS-InSAR phase unwrapping;

[0036] (7) Residual phase analysis

[0037] (8) PS deformation field estimation.

[0038] Step 2-1, select the appropriate amplitude deviation index and set the coherence coefficient threshold, so that the PS points are distributed on railways, roads and tall buildings in urban areas, and eliminate low-coherence or incoherent PS points on rivers and farmlands;

[0039] Step 2-2: Filter the PS points on the fully enclosed high-speed railway, remove the PS points that fall on the main structure of the metal material, and keep the PS points that pass through the main structure and are scattered on the roadbed.

[0040] The specific steps are as follows: Figure 2It can be seen that there is a blank space at the top of the arched body. This position allows the radar signal emitted by the satellite to propagate to the rails, forming a stable PS point. Since the main structure is made of metal, the PS points scattered on the main body have poor reflection effect and poor stability. The amplitude deviation index is adjusted and the coherence coefficient threshold is set to eliminate the unstable PS points on the main structure and leave the stable PS points on the rails.

[0041] Step 3: The PS points obtained on the fully enclosed high-speed railway are used to obtain the deformation value of the target point through the area radius method, and the deformation value at each position is calculated using the spatial position relationship;

[0042] The details are as follows:

[0043] Step 3-1, the PS points left on the fully enclosed high-speed railway are calculated by the area radius method to obtain the deformation value of the target point, with the target point as the center of the circle and the rail width as the radius. The average value of the PS points within the circle is taken as the deformation value of the target point;

[0044] Area radius method: With the target point as the center O and the rail width as the radius R, the standard track distance of my country's high-speed railway is 1435 mm, which can be set to R = 1.5 m (e.g. Figure 3 ), and take the average of the deformation values ​​of all PS points within this range as the deformation value of the target point.

[0045] Step 3-2: Establish a spatial model of each position and the target point based on the actual position, and use mathematical functions to calculate the deformation value of the roadbed at the remaining non-PS points.

[0046] Step 4: Use SBAS-InSAR technology to perform interferometric workflow processing to generate deformation results in the geographic coordinate system, and obtain the annual average settlement rate of the high-speed railway after vertical projection;

[0047] The specific SBAS-InSAR technical process is as follows:

[0048] (1) Selection of registration reference images and image registration;

[0049] (2) Select the interference pair;

[0050] (3) Differential interferometry processing;

[0051] (4) SVD deformation parameter solution;

[0052] (5) Deformation sequence recovery.

[0053] Step 5: Use the time series analysis tool software to perform PS-InSAR and SBAS-InSAR time series analysis on the fully enclosed high-speed railway to obtain the settlement value in any time period.

[0054] The details are as follows: open the time series analysis tool software, input the PS-InSAR and SBAS-InSAR monitoring results respectively, find the longitude and latitude coordinates of the corresponding point on the image results, click time series analysis to obtain the deformation information of the point, and obtain the settlement amount of the target point at any time period.

Claims

1. A monitoring method based on time-series InSAR technology in a fully enclosed high-speed railway, characterized in that: The following steps are involved: Step 1: Obtain image data of the study area, determine the scope of the fully enclosed high-speed railway section and crop the image, and simultaneously obtain image data of the fully enclosed high-speed railway in combination with precise track data and DEM data; Step 2: Use PS-InSAR technology to perform time-series interferometry processing and obtain PS points by controlling the amplitude deviation index and the interference coefficient threshold; Step 2-1, select the appropriate amplitude deviation index and set the coherence coefficient threshold, so that the PS points are distributed on railways, roads and tall buildings in urban areas, and eliminate low-coherence or incoherent PS points on rivers and farmlands; Step 2-2, filter the PS points on the fully enclosed high-speed railway, remove the PS points that fall on the main structure of the metal material, and keep the PS points that pass through the main structure and scatter on the roadbed; Step 3: The PS points obtained on the fully enclosed high-speed railway are used to obtain the deformation value of the target point through the area radius method, and the deformation value at each position is calculated using the spatial position relationship; Step 3-1, the PS points left on the fully enclosed high-speed railway are calculated by the area radius method to obtain the deformation value of the target point, with the target point as the center of the circle and the rail width as the radius. The average value of the PS points within the circle is taken as the deformation value of the target point; Step 3-2: Establish a spatial model of each position and the target point based on the actual position, and use mathematical functions to calculate the deformation value of the roadbed at the remaining points without PS; Step 4: Use SBAS-InSAR technology to perform interferometric workflow processing to generate deformation results in the geographic coordinate system, and obtain the annual average settlement rate of the high-speed railway after vertical projection; Step 5: Use the time series analysis tool software to perform PS-InSAR and SBAS-InSAR time series analysis on the fully enclosed high-speed railway to obtain the settlement value in any time period.

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