A method for testing the actual locking rail temperature of seamless track on long-span bridges

Abstract

This invention provides a method for testing the actual locked rail temperature of seamless track on long-span bridges. The method includes: setting multiple measuring points at key locations on the seamless track of a long-span bridge; using sensors to monitor bridge deflection, rail longitudinal force, bridge longitudinal displacement, and rail temperature at each measuring point; calculating the additional flexural force of the rail based on the linear correlation between bridge deflection and the additional flexural force of the rail; calculating the additional flexural force of the rail based on the correlation between bridge longitudinal displacement and the additional flexural force of the rail; and calculating the actual locked rail temperature based on the longitudinal force, the additional flexural force, the additional flexural force, and the rail temperature. This invention utilizes the linear relationship between the longitudinal force of the rail and the spatial deformation of the bridge to sequentially eliminate the longitudinal force of the rail, obtaining real-time monitoring values ​​of the basic temperature force, and thus obtaining the actual locked rail temperature, facilitating routine maintenance and repair work of seamless track by railway engineering departments.

Description

Technical Field

[0001] This invention relates to the field of seamless track maintenance technology, and in particular to a method for testing the actual locked rail temperature of seamless track on long-span bridges. Background Technology

[0002] With the increasing development of railway operations, especially the high-speed rail technology in my country in recent years, more and more seamless tracks are being laid on ultra-long span bridges, placing higher demands on the reliability and stability of seamless tracks. Locking rail temperature is a crucial parameter for the maintenance, management, and repair of seamless tracks. If the actual locking rail temperature is significantly higher than the original locking rail temperature, the internal thermal stress of the rails will be greater in winter due to lower air temperatures, potentially leading to rail breakage. Conversely, if the actual locking rail temperature is significantly lower than the original locking rail temperature, the internal thermal stress of the rails will increase in summer due to higher air temperatures, potentially leading to rail bulging. Therefore, real-time monitoring of the actual locking rail temperature is of great significance for ensuring the safe operation of seamless tracks.

[0003] For seamless tracks on general-span bridges, current theory suggests that there exists a "fixed zone" in the main girder section where the longitudinal force of the rails remains constant, which can be determined by the following formula:

[0004] T n =T+(σ / Eα) (1)

[0005] The measured rail temperature is obtained, where T is the on-site rail temperature, E and α are constants, and σ is considered as the measured rail temperature stress.

[0006] After long-span bridges (over 1000 meters) are put into operation, the main girder will undergo significant deflection, resulting in changes in the relative displacement between the beam and rail, as well as the longitudinal force on the rail, that differ from those on seamless tracks on ordinary span bridges. This may lead to stresses within the theoretically "fixed zone" that include not only the basic temperature force but also the additional force from rail expansion and contraction, and additional deflection forces generated by various factors. The additional deflection force refers to the force generated by the relative displacement between the beam and rail due to the bridge's deflection. Therefore, for seamless tracks on 1000-meter span bridges, which are highly susceptible to these additional forces, it is necessary to separate the basic temperature force from the longitudinal force on the rail to obtain the true actual locking rail temperature, providing reliable guidance for track maintenance.

[0007] Currently, there are three main methods for monitoring the actual track temperature of seamless railway tracks in existing technologies: stress method, strain method, and energy method. However, for engineering practice, existing methods suffer from drawbacks such as expensive instruments, long measurement times, overly complex operation procedures, and cumbersome calculation processes, making it difficult to easily and effectively extract and process basic temperature forces online in real time.

[0008] Therefore, it is necessary to propose a simple, effective, and low-cost method for monitoring the temperature of locked rails to provide reliable guidance for the maintenance and repair of railway lines. Summary of the Invention

[0009] The embodiments of the present invention provide a method for testing the actual locked rail temperature of seamless track on long-span bridges, so as to realize real-time monitoring of the actual locked rail temperature of seamless track.

[0010] To achieve the above objectives, the present invention adopts the following technical solution.

[0011] A method for testing the actual locking rail temperature of seamless track on a long-span bridge, comprising:

[0012] Multiple measuring points are set at key locations of the seamless track on long-span bridges, and sensors are used to monitor the bridge deflection, rail longitudinal force, bridge longitudinal displacement and rail temperature at each measuring point.

[0013] Based on the linear correlation between bridge deflection and the additional deflection force of steel rails, the additional deflection force of steel rails is calculated by bridge deflection.

[0014] Based on the linear correlation between the longitudinal displacement of the bridge and the additional force of rail expansion and contraction, the additional force of rail expansion and contraction is calculated by the longitudinal displacement of the bridge.

[0015] The actual locking rail temperature is calculated based on the longitudinal force of the rail, the additional force of rail deflection, the additional force of rail expansion and contraction, and the rail temperature.

[0016] Preferably, multiple measuring points are set at key locations on the seamless track of the long-span bridge, and sensors are used to monitor the bridge deflection, rail longitudinal force, bridge longitudinal displacement, and rail temperature at each measuring point, including:

[0017] Multiple measuring points were set at key locations of the seamless track on a long-span bridge in an actual online-bridge engineering project.

[0018] Based on the selected measuring points, sensors are used to monitor the bridge deflection D(t), rail longitudinal force σ, bridge longitudinal displacement S(t), and rail temperature T in real time at the measuring point locations. The sensors include a thermometer, a deflectometer, a fiber optic stress sensor, and an acceleration sensor.

[0019] Preferably, the step of calculating the additional deflection force of the steel rail based on the linear correlation between bridge deflection and rail deflection includes:

[0020] A linear regression model is established between bridge deflection and rail deflection-induced additional force. The rail deflection-induced additional force is then calculated from the bridge deflection using this model. The functional expression of the linear regression model is as follows:

[0021] σD (t)=b1+a1D(t)+μ(t) (2)

[0022] Where a1 and b1 are the regression parameters in the linear regression model, D(t) is the bridge deflection at time t at the measuring point, and σ D (t) represents the additional force of rail deflection at time t, and μ(t) represents the random error.

[0023] Preferably, the step of calculating the additional force of rail expansion and contraction based on the correlation between the longitudinal displacement of the bridge and the additional force of rail expansion and contraction includes:

[0024] A linear regression model is established between the longitudinal displacement of the bridge and the additional force from rail expansion and contraction. The additional force from rail expansion and contraction is calculated using this linear regression model based on the longitudinal displacement of the bridge. The functional expression of the linear regression model is as follows:

[0025] σ s (t)=b2+a2S(t)+μ(t) (3)

[0026] Where S(t) is the longitudinal displacement of the bridge at time t, σ s (t) represents the additional force of rail expansion and contraction at the corresponding time, and a2 and b2 are the regression parameters in the linear regression model.

[0027] Preferably, the step of calculating the actual locking rail temperature based on the longitudinal force of the rail, the additional force of rail deflection, the additional force of rail expansion and contraction, and the rail temperature includes:

[0028] Subtract the additional rail deflection force σ from the measured value of the longitudinal force σ of the rail. D Additional force σ due to rail expansion and contraction s The remaining longitudinal force obtained is the basic temperature force, and the actual locking rail temperature T of the seamless track is... n The representation is:

[0029] T n =T+(σ T / Eα)=T+(σ-σ D -σ S ) / Eα (4)

[0030] Where E is the elastic modulus of the rail, which is taken as 2.06 × 10⁻⁶ in the calculation. 5 MPa; α is the coefficient of linear expansion of the rail, taken as 1.18 × 10⁻⁶ in the calculation. -5 / ℃.

[0031] As can be seen from the technical solutions provided by the embodiments of the present invention above, the present invention proposes a method for monitoring the actual locked rail temperature of seamless track on ultra-long span bridges based on the mapping relationship between load, bridge spatial deformation, and rail longitudinal force. It mainly utilizes the linear relationship between rail longitudinal force and bridge spatial deformation to sequentially eliminate rail longitudinal force, obtain the real-time monitoring value of basic temperature force, and then obtain the actual locked rail temperature, which facilitates the railway engineering department to carry out daily maintenance and repair work on seamless track.

[0032] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 The present invention provides a process flow diagram for testing the actual locked rail temperature of seamless track on a long-span bridge.

[0035] Figure 2 This is a schematic diagram illustrating the correlation between rail deflection and bridge deflection.

[0036] Figure 3 A schematic diagram showing the relationship between the additional force of rail expansion and contraction and the longitudinal displacement of the bridge.

[0037] Figure 4 Flowchart of the longitudinal force separation monitoring method for seamless tracks;

[0038] Figure 5 A schematic diagram showing the measured and locked rail temperatures of the left and right rails in the downstream direction of the main span of the Wufengshan Yangtze River Bridge.

[0039] Figure 6 This is a general layout diagram of the health monitoring points for the Wufengshan Yangtze River Bridge.

[0040] Figure 7 A schematic diagram of a health monitoring system for locking the rail temperature on seamless tracks of long-span bridges;

[0041] Figure 8 This is the basic processing flow of a health monitoring system. Detailed Implementation

[0042] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0043] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0044] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0045] To facilitate understanding of the embodiments of the present invention, the following will provide further explanation and description with reference to the accompanying drawings and several specific embodiments. These embodiments do not constitute a limitation on the embodiments of the present invention.

[0046] This invention provides a processing flow for testing the actual locked rail temperature of seamless track on long-span bridges, as follows: Figure 1 As shown, it includes the following steps:

[0047] Step S1: In the actual online bridge engineering project, monitoring points are set at key locations of the seamless track on long-span bridges for safety monitoring during construction and health monitoring during operation. Then, multiple monitoring points are selected as key points for monitoring.

[0048] Step S2: Based on the selected measuring points, use sensors to monitor the bridge deflection D(t), rail longitudinal force σ, bridge longitudinal displacement S(t), and rail temperature T at the measuring point locations around the clock.

[0049] Step S3: Figure 2This is a schematic diagram illustrating the correlation between flexural force and bridge deflection, provided by an embodiment of the present invention. Figure 3 This is a schematic diagram illustrating the relationship between the additional force of rail expansion and contraction and the longitudinal displacement of a bridge, provided in an embodiment of the present invention. Figure 4 This is a flowchart of a seamless track longitudinal force separation monitoring method provided in an embodiment of the present invention.

[0050] Bridge deflection and rail deflection additional force have a high linear correlation. By establishing a linear regression model, the rail deflection additional force caused by bridge deflection can be separated. The functional expression of the regression model is as follows:

[0051] σD(t)=b1+a1D(t)+μ(t) (2)

[0052] Where a1 and b1 are the regression parameters in the linear regression model, D(t) is the bridge deflection at time t at the measuring point, and σ D (t) represents the additional force of rail deflection at time t, and μ(t) represents the random error.

[0053] Step S4: Correlation between bridge longitudinal displacement and rail expansion and contraction force. With bridge longitudinal displacement as the dependent variable, the rail expansion and contraction force is expressed as:

[0054] σ s (t)=b2+a2S(t)+μ(t) (3)

[0055] Where S(t) is the longitudinal displacement of the bridge at time t, σ s (t) represents the additional force of rail expansion and contraction at the corresponding time, a2 and b2 are the regression parameters in the linear regression model, and μ(t) is the random error.

[0056] Step S5: Subtract the additional rail deflection force σ from the measured value of the longitudinal force of the rail. D Additional force σ due to rail expansion and contraction s The remaining longitudinal force obtained can be considered to be mainly composed of basic temperature force, and the actual locking rail temperature T of the seamless track is... n The representation is:

[0057] T n =T+(σ T / Eα)=T+(σ-σ D -σ s ) / Eα (4)

[0058] Example 1

[0059] The flexural force separation monitoring method according to embodiments of the present invention will be described in detail below through specific examples:

[0060] Step 1: Selecting test points.

[0061] The Wufengshan Yangtze River Bridge is a railway suspension bridge with a main span of 1092m. The construction-locked rail temperature was 31.2℃ for the left rail and 31.0℃ for the right rail. The actual rail temperature T and longitudinal force of the rails were measured for this ultra-long span railway bridge. The measured locked rail temperature results at three measuring points on the main span of the Wufengshan Yangtze River Bridge over a period of time were calculated according to equation (1). Figure 5 This is a schematic diagram showing the measured and locked rail temperatures of the left and right rails in the downstream direction of the main span of the Wufengshan Yangtze River Bridge. Figure 5 As shown. Ideally, the measured lock-in rail temperature should be constant in the short term, without significant fluctuations, but due to... Figure 1 It is evident that in the short period before the line was opened for operation, the measured locked rail temperature decreased significantly compared to the locked value during construction, with a maximum decrease of 14.9℃. After the line was opened for operation, the rails were subjected to plastic elongation by the wheels, but the measured locked rail temperature actually increased significantly compared to before the opening, with a maximum increase of 6.9℃.

[0062] This embodiment focuses on the Wufengshan Yangtze River Bridge before it was put into operation, and separates the various flexural forces. There are three measuring points distributed throughout the bridge. The measuring points at K318+550 and K319+250 are located near the bridge towers on both sides, and the measuring point at K318+900 is located near the mid-span. Figure 6 The overall layout diagram of the health monitoring points of the Wufengshan Yangtze River Bridge is shown below. Figure 6 As shown. The steel rails of the Wufengshan Bridge tested in this study are 60kg / m thick, U71Mn(G), and the coefficient of linear expansion α is taken as 1.18×10⁻⁶ for calculation. -5 ℃ -1 .

[0063] Step 2: Select the test time.

[0064] Data was collected continuously for 18 hours from 6:00 to 24:00 on a selected day.

[0065] Step 3: Separate the monitoring system.

[0066] This invention employs a long-term monitoring system for seamless railway lines. Modern line-bridge structure health monitoring technology is not merely a simple improvement on traditional detection techniques, but rather utilizes modern sensing and communication technologies to monitor the structural response and behavior of seamless railway lines in real time during operation. It acquires various information reflecting the structural condition and environmental factors, thereby analyzing the health status of the structure, assessing its reliability, and providing a scientific basis for the management and maintenance decisions of seamless railway lines.

[0067] Figure 7 This is a structural schematic diagram of a health monitoring system for locking the rail temperature on seamless tracks of a long-span bridge. Figure 8 This is the basic processing flow of a health monitoring system. For example... Figures 7-8The health monitoring system mainly consists of three subsystems: a sensor system, a data acquisition and transmission system, and a data management, analysis, and safety assessment system.

[0068] The functions of each are described below:

[0069] (1) Sensor System: The sensor system serves as the foundation for the seamless track structure health monitoring system to realize all its monitoring items and functions. Its main task is to sense the structural response signals of the bridge structure's operational status through various types of sensors and transmit the sensor signals to the control center of the health monitoring system as important data for the safety assessment of the seamless track structure. The construction of the sensor subsystem of the structural health monitoring system of this invention involves various types of sensors, such as thermometers, deflectometers, fiber optic stress sensors, and accelerometers.

[0070] (2) Data acquisition and transmission system: In the actual locking track temperature health monitoring system on the ultra-long span bridge, the main task of the data acquisition and transmission system is to sense, collect, transmit and save signals from various types of sensors, so as to provide basic data for data management, analysis and safety assessment.

[0071] (3) Data Management, Analysis and Safety Assessment System: The function of the data management, analysis and safety assessment system is to visualize and analyze massive amounts of health monitoring data, and to transform raw data into seamless track health status information. This subsystem is divided into data preprocessing, data secondary processing and data postprocessing. Data preprocessing first performs flexural displacement regression analysis on the raw data according to formula (2) to eliminate the influence of flexural force. The data obtained from preprocessing is then processed in the secondary process, and the rail expansion and contraction additional force is separated according to formula (3) to obtain the "pure" basic temperature force. Data postprocessing calculates the actual locked rail temperature according to formula (4) and displays it in real time on the user interface. The user terminal is placed in the railway engineering department, which can realize the real-time display of the locked rail temperature with high timeliness and high accuracy. Based on this method, the actual locked rail temperature is obtained for normal maintenance and repair of the seamless track.

[0072] In summary, this invention provides a method for obtaining the actual locking rail temperature on ultra-long span bridges. Based on the linear relationship between various additional forces and bridge spatial deformation, a linear regression model is established to effectively eliminate the influence of the additional forces of rail expansion and contraction on ultra-long span bridges, obtaining the basic temperature force. This enables real-time monitoring of the actual locking rail temperature and solves the problem of unclear additional forces of deflection on ultra-long span road-rail dual-purpose bridges. This method can be used to form an actual locking rail temperature monitoring system for ultra-long span bridges, facilitating the daily maintenance and repair work of seamless tracks by railway engineering departments.

[0073] The method of this invention is based on the linear relationship between the additional force of the rail and the spatial deformation and temperature of the bridge. By utilizing the frequency difference between the temperature effect and the live load effect, and by establishing a linear regression model and extracting trend terms, the additional forces and the basic temperature force are effectively separated, which can realize real-time monitoring of the actual locked rail temperature of seamless track.

[0074] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0075] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present invention.

[0076] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for apparatus or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The apparatus and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0077] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for testing the actual locked rail temperature of seamless track on a long-span bridge, characterized in that, include: Multiple measuring points are set at key locations of the seamless track on long-span bridges, and sensors are used to monitor the bridge deflection, rail longitudinal force, bridge longitudinal displacement and rail temperature at each measuring point. Based on the linear correlation between bridge deflection and rail deflection additional force, the rail deflection additional force is calculated by bridge deflection. Based on the linear correlation between the longitudinal displacement of the bridge and the additional force of rail expansion and contraction, the additional force of rail expansion and contraction is calculated by the longitudinal displacement of the bridge. The actual locking rail temperature is calculated based on the longitudinal force of the rail, the additional force of rail deflection, the additional force of rail expansion and contraction, and the rail temperature. The method of calculating the additional rail deflection force based on the linear correlation between bridge deflection and rail deflection includes: A linear regression model is established between bridge deflection and rail deflection-induced additional force. The rail deflection-induced additional force is then calculated from the bridge deflection using this model. The functional expression of the linear regression model is as follows: σ D (t)=b1+a1D(t)+µ(t) (2) Where a1 and b1 are the regression parameters in the linear regression model, D(t) is the bridge deflection at time t at the measuring point, and σ D (t) represents the additional force of rail deflection at time t, and μ(t) represents the random error.

2. The method according to claim 1, characterized in that, Multiple measuring points are set at key locations on the seamless track of the long-span bridge. Sensors are used to monitor the bridge deflection, rail longitudinal force, bridge longitudinal displacement, and rail temperature at each measuring point, including: Multiple measuring points were set at key locations of the seamless track on a long-span bridge in an actual online-bridge engineering project. Based on the selected measuring points, sensors are used to monitor the bridge deflection D(t), rail longitudinal force σ, bridge longitudinal displacement S(t), and rail temperature T in real time at the measuring point locations. The sensors include a thermometer, a deflectometer, a fiber optic stress sensor, and an acceleration sensor.

3. The method according to claim 1, characterized in that, The method of calculating the additional force of rail expansion and contraction based on the correlation between the longitudinal displacement of the bridge and the additional force of rail expansion and contraction includes: A linear regression model is established between the longitudinal displacement of the bridge and the additional force from rail expansion and contraction. The additional force from rail expansion and contraction is calculated using this linear regression model based on the longitudinal displacement of the bridge. The functional expression of the linear regression model is as follows: σ s (t)=b2+a2S(t)+μ(t) (3) Where S(t) is the longitudinal displacement of the bridge at time t, σ S (t) represents the additional force of rail expansion and contraction at the corresponding time, and a2 and b2 are the regression parameters in the linear regression model.

4. The method according to claim 3, characterized in that, The calculation of the actual locking rail temperature based on the longitudinal force of the rail, the additional force of rail deflection, the additional force of rail expansion and contraction, and the rail temperature includes: Subtract the additional rail deflection force σ from the measured value of the longitudinal force σ of the rail. D Additional force σ due to rail expansion and contraction S The remaining longitudinal force obtained is the basic temperature force, and the actual locking rail temperature T of the seamless track is... n The representation is: T n =T+(σ T / Eα)=T+(σ-σ D -s S ) / Ea (4) Where E is the elastic modulus of the rail, which is taken as 2.06 × 10⁻⁶ in the calculation. 5 MPa; α is the coefficient of linear expansion of the rail, taken as 1.18 × 10⁻⁶ in the calculation. -5 / ℃.

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