Construction method for restoring locking temperature in existing line damaged rail flash welding repair

Abstract

This invention proposes a construction method for restoring the locking temperature during flash welding repair of damaged rails on existing railway lines, belonging to the field of railway rail maintenance. The method includes: determining the rail temperature and the length of the rail construction section; calculating the allowable stretching amount of the rail based on the rail temperature and the length of the rail construction section; performing over-stretching of the rail based on the allowable stretching amount; sawing the damaged rail, inserting a new rail, and performing flash welding; and restoring the straightness of the rail construction line. This invention's method for restoring the locking temperature during flash welding repair of damaged rails on existing railway lines ensures a uniform and consistent track locking temperature, effectively guaranteeing the control and uniformity of the rail temperature. It solves the problem of track instability caused by the inconsistency between the construction temperature and the track locking temperature during the replacement of damaged rail components, which leads to the breakdown of the track's resistance to rail expansion and directly affects the stability of the line and traffic safety.

Description

Technical Field

[0001] This invention belongs to the field of railway rail maintenance, specifically involving the welding treatment of damaged rails, and proposes a construction method for restoring the lock-in temperature during the flash welding repair of damaged rails on existing lines. Background Technology

[0002] With rapid economic development, the railway industry is undergoing rapid changes. This necessitates higher requirements for railway maintenance and repair while ensuring railway transport capacity, especially for existing lines that have already carried a certain amount of traffic and have developed some defects. Maintenance and repair have become crucial for ensuring the safety and stability of railway transportation. According to the "Railway Line Repair Rules" and the "High-Speed ​​Railway Ballastless Track Line Maintenance Rules (Trial)," the handling of severely damaged and broken rails on existing lines is divided into three types based on the degree of damage: emergency treatment, temporary treatment, and permanent treatment. Currently, the permanent treatment method involves inserting a new rail into the line to replace the damaged old rail, and then welding both ends of the new rail to the existing rail using a convenient and quick aluminothermic welding method. However, because the joint metal is cast, its strength and toughness are relatively low, resulting in a high damage rate; it is prone to defects such as aluminothermic welding overflow and burrs, which seriously affect the service life of the joint; the welding quality is highly dependent on the working environment and personnel, making it unsuitable for the safety and reliability requirements of large-scale railway maintenance. Statistical data shows that severely damaged and broken aluminothermic welded joints are the primary source of damage to railway lines.

[0003] Research and practice have shown that when using aluminothermic welding for permanent treatment, a single aluminothermic weld joint can result in two additional aluminothermic weld joints, leading to a rapid increase in the number of damaged rails. This problem can be solved by using flash welding technology and processes for permanent treatment of damaged rails on existing lines. Flash welding joints are formed through forging, resulting in superior quality compared to aluminothermic weld joints formed through casting. While widely used in mainline railway track welding, flash welding is not yet widely applied in the permanent treatment of damaged rails on existing lines, and corresponding construction technology research is lacking. Therefore, researching flash welding technology and processes for permanent treatment of damaged rails on existing lines is of great significance for reducing the number of aluminothermic weld joints, reducing the rail damage rate, and meeting the needs of modern railways for high reliability and low maintenance.

[0004] Although flash welding of rail joints offers excellent performance, the process of repairing damaged rails using this method requires large-scale equipment and involves stretching a section of the rail during welding, resulting in complex construction organization, limited process margins, and time constraints. Especially when replacing damaged rail components on existing lines, if the construction temperature differs from the track locking temperature, the track's resistance to rail expansion will be compromised, potentially leading to track instability and directly impacting track stability and operational safety. Therefore, ensuring uniform track locking temperature and consistent rail temperature control are crucial for the track to withstand service life challenges.

[0005] In order to study the permanent problems of using flash welding or gas pressure welding to treat damaged rails on existing railway lines, the inventors found relevant research by some scholars in some academic papers in this field.

[0006] The article "A Brief Discussion on Seamless Track Insertion Welding Construction" presents a method for permanently treating damaged rails on existing railway lines using gas pressure welding. Starting with an analysis of the causes of seamless track insertion welding construction, it elaborates and analyzes single-strand and double-strand insertion welding operations in detail, covering aspects such as labor organization, equipment configuration, operation methods, operation time, and technical requirements. Based on field construction experience, relevant construction measures are formulated. (Zhang Yinliang, "A Brief Discussion on Seamless Track Insertion Welding Construction," *Collection of Excellent Academic Papers of Shanxi Railway Society, 2004*, 2005: 45-48.)

[0007] The article "Flash Welding Construction Method for Inserting Short Rails at Damaged Weld Joints" presents a flash welding construction method for inserting short rails at damaged weld joints. It introduces a case of a damaged weld joint. After on-site confirmation, flash welding (online welding) was promptly used to weld the rail at the damaged weld joint where a short rail would be inserted. On-site construction inspection and subsequent flaw detection showed no quality issues. This construction demonstrates that when damaged weld joints appear on seamless railway tracks, flash welding can be used urgently to insert short rails at the damaged weld joints and restore the track in a timely manner, with good results. It successfully solved the technical standards, construction processes, and methods for flash welding at damaged weld joints and short rail insertion points in seamless railway sections. This construction is a typical example of flash welding combined with standard short rail insertion. By adopting advanced and scientific construction techniques and rigorous construction organization, a scientific and reasonable rail welding construction process for handling damaged joints was formed. This resulted in reliable internal and external quality of the welded joints on-site, smooth track, and broke away from the manual operation mode of aluminothermic welding, which is characterized by high labor intensity, low work efficiency, and poor welding quality. It also realized the mechanized operation of short rail insertion welding construction on seamless railway tracks. This construction project successfully resolved the technical standards, construction techniques, and methods for flash welding at the short rail insertion points of damaged welded joints in seamless track sections, laying a solid foundation for future rail welding construction at these points. (Chen Kuanjun, Jin Liugang, Ji Min, Tian Haimeng, "Flash Welding Construction Method for Short Rail Insertion at Damaged Welded Joints", Science and Technology Innovation and Productivity, 2015(05): 57-58+60.)

[0008] "On the Application of Mobile Flash Welding on Operating Lines" starts from the difficulties of replacing seamless track on operating lines, proposes the necessity of applying the new mobile flash welding process, and analyzes its construction process and specific technical measures in combination with actual engineering conditions to save construction time, ensure welding quality, and meet the requirements of railway development. The application and promotion of flash welding can greatly save construction time and ensure welding quality. Because it is less affected by environmental factors during construction and is fully automated, it has a good application prospect in new track construction projects and section replacement of rails on operating lines. (Gao Guangyan, "On the Application of Mobile Flash Welding on Operating Lines", Shanxi Construction, 2017, 43(28):154-155.)

[0009] "Construction Technology for Replacing Seamless Track with Mobile Flash Welding on Operating Railway Lines" takes the seamless track replacement construction of the Longchuan to Dongguan East section of the Beijing-Kowloon Railway as an example, introducing the construction technology of replacing seamless track with mobile flash welding on operating railway lines. It elaborates on the main procedures and key control points, providing a reference for similar construction on operating railway lines and current intercity railway construction. (Chen Weidong, "Construction Technology for Replacing Seamless Track with Mobile Flash Welding on Operating Railway Lines", *China Construction*, 2008(12):105-106.)

[0010] However, the problem with the above method is that the impact of construction on the line lock-in temperature is not considered when constructing existing lines.

[0011] In view of this, based on years of experience in production and design in this and related fields, and after repeated research and experimentation, the inventor has designed a construction method for restoring the locking temperature during the flash welding repair of damaged rails on existing railway lines, in order to solve the problems existing in the prior art. Summary of the Invention

[0012] The purpose of this invention is to propose a construction method for restoring the lock-in temperature during flash welding repair of damaged rails on existing railway lines, which can reduce the impact of rail temperature on the construction track during existing line construction.

[0013] To achieve the above objectives, this invention proposes a construction method for restoring the lock-in temperature during flash welding repair of damaged rails on existing railway lines. The method involves: determining the rail temperature and the length of the rail construction section; calculating the rail's allowable stretching amount based on the rail temperature and the rail construction section length; performing overstretching of the rail based on the allowable stretching amount; sawing the damaged rail; inserting a new rail and performing flash welding; and restoring the straightness of the rail construction line.

[0014] Compared with existing technologies, the construction method for restoring the lock-in temperature during flash welding repair of damaged rails on existing railway lines proposed in this invention has the following characteristics and advantages:

[0015] The construction method for restoring the locking temperature during the flash welding repair of damaged rails on existing lines proposed in this invention can ensure the uniformity of the track's release and locking temperature, effectively guaranteeing uniform control of the rail temperature. This effectively avoids track instability caused by the failure of the track's resistance to rail expansion due to the inconsistency between the construction temperature and the track locking temperature when replacing damaged rail components on existing lines, thus ensuring the stability of the line and the safety of train operation. Attached Figure Description

[0016] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, can select various possible shapes and proportions to implement the invention according to specific circumstances.

[0017] Figure 1 This is a flowchart of the construction method proposed in this invention;

[0018] Figure 2 This is a schematic diagram of the pre-construction planning of the line according to the present invention;

[0019] Figure 3This is a schematic diagram of the rail being cut at the track end according to the present invention;

[0020] Figure 4 This is a schematic diagram of the secondary track cutting method of the present invention;

[0021] Figure 5 This is a schematic diagram illustrating the sawing of damaged rails according to the present invention;

[0022] Figure 6 This is a schematic diagram of inserting a new rail after sawing the damaged rail according to the present invention;

[0023] Figure 7 This is a schematic diagram of welding a new rail after inserting it, according to the present invention.

[0024] Figure 8 This is a schematic diagram illustrating the bending of the old rail during the welding of the new rail according to the present invention;

[0025] Figure 9 This is a schematic diagram showing the straightening of the track after the new rail welding of the present invention is completed;

[0026] Figure 10 This is a schematic diagram of the circuit after the new rail welding of the present invention is completed;

[0027] Figure 11 This is a flowchart of the rail super-stretching construction method of the present invention.

[0028] Explanation of the attached figure numbers:

[0029] 100. Flash insertion welding section; 200. Super-stretching section;

[0030] 110. First rail cutting position; 300. New rail;

[0031] 120. Second rail cutting position; 400. Special tool;

[0032] 130. Construction section at the flash welding machine end. Detailed Implementation

[0033] The details of the present invention can be more clearly understood by referring to the accompanying drawings and the description of specific embodiments. However, the specific embodiments of the present invention described herein are for illustrative purposes only and should not be construed as limiting the invention in any way. Under the teachings of this invention, those skilled in the art can conceive of any possible modifications based on the invention, and these should all be considered to fall within the scope of the invention.

[0034] This invention proposes a construction method for restoring the lock-in temperature during flash welding repair of damaged rails on existing railway lines. The construction method includes determining the rail temperature and the length of the rail construction section; calculating the rail allowance for stretching based on the rail temperature and the length of the rail construction section; performing overstretching of the rail based on the rail allowance for stretching; sawing the damaged rail, inserting a new rail and performing flash welding; and restoring the straightness of the rail construction line.

[0035] The construction method for restoring the locking temperature during the flash welding repair of damaged rails on existing lines proposed in this invention can ensure the uniformity of the track's release locking temperature, effectively guaranteeing the control and uniformity of rail temperature. This effectively solves the problem of track instability caused by the inconsistency between the construction temperature and the track locking temperature when replacing damaged rail components on existing lines, which leads to the destruction of the resistance to rail expansion. Ultimately, this ensures the stability of the line and the safety of train operation.

[0036] The present invention proposes a construction method for restoring the locking temperature during the repair of damaged rails on existing lines using flash welding. When using flash welding to treat damaged rails, the construction temperature is kept consistent with the track locking temperature. This ensures uniform track release and locking temperature, as well as rail temperature control and uniformity. When replacing damaged rail components on existing lines, there will be no resistance to rail expansion, maintaining track stability and ensuring track stability and train operation safety.

[0037] In one optional embodiment of the present invention, such as Figure 2 As shown, the rail construction section includes a flash insertion welding section 100 and a super-stretching section 200. Specifically, the damage is located in the flash insertion welding section 100, which is used to cut off the damaged rail and insert a new one. The super-stretching section 200 is used to release the stress on the original track.

[0038] In one alternative example of this implementation, such as Figure 11 As shown, the rail overstretching process includes: cutting the rail at the planned location of the flash insertion welding construction section 100; loosening the fasteners of the flash insertion welding construction section 100 and the overstretching section 200 to release the original track stress; cutting the rail again in the flash insertion welding construction section 100, reserving the stretching amount; stretching the overstretching section according to the reserved stretching amount; uniformly distributing the track stress and locking the rail in the overstretching section.

[0039] In an optional example, the planned location (first rail cutting location 110) is the end of the flash insertion welding section 100 near the original seamless track.

[0040] In an optional example, the second rail cutting position 120 is near the first rail cutting position 110, with a reserved stretching amount △L, which is the length cut off during the second rail cutting. During the two rail cutting processes, the first rail cutting cuts the rail completely, and the second rail cutting cuts off a section of the rail, i.e., the reserved stretching amount △L.

[0041] It should be noted that when permanently repairing existing track damage using flash welding, to ensure the track's locking temperature and stability during construction, the rails need to be overstretched before inserting new rails. The track locking temperature (rail temperature) is a value determined by the railway design unit based on years of rail temperature records. The track locking temperature during track laying must match the designed locking rail temperature. During later seamless track maintenance, after the rails are cut, unless the rail temperature during construction matches the locking temperature, the track's locking temperature will be compromised. During construction, if the rail temperature is lower than the locking temperature after cutting, the rail in the open section of the fastener will shrink due to thermal expansion and contraction. Before restoring the track, the shrinkage of the free rail needs to be stretched to ensure the locked temperature after restoration matches the original track locking temperature. When the rail temperature is higher than the locking temperature during construction, seamless track rail cutting is generally not performed because the rail cannot be compressed, and the locking temperature cannot be guaranteed. Therefore, it is necessary to maintain the lock-in temperature of the circuit during resoldering to be consistent with the design temperature in order to maintain the stability of the seamless circuit state.

[0042] In an optional example, such as Figure 3 As shown, in the planned flash insertion welding construction section 100, the rail is cut near the original seamless track end (first rail cut), forming the cross-section of the flash insertion welding construction section, and a 12m long flash welding machine end construction section is reserved. The reserved flash welding machine end construction section is located on the right side of the cross-section, and its length is 12m. Figure 2 As shown, loosen the fasteners on the flash insertion welding section 100 and the super-stretch section 200 to release the original line stress. Figure 4 As shown, the rail is cut again near the section at position 110 of the first rail cut, with a pre-existing tension allowance ΔL. The rail is then overstretched using a rail tensioner, with a tension amount of ΔL. After tensioning, the track stress is uniformly distributed, and the overstretched section of the rail is locked in place.

[0043] In one optional embodiment of this implementation, after sawing the damaged rail, a gap is formed in the flash insertion welding section. The flash welding operation includes welding a new rail 300 to the rail at one end of the gap using a flash welding machine, with the other end of the new rail 300 having a reserved amount for welding burnout and offset from the rail at the other end of the gap; bending the rail at the other end and making the weld joint between the rail at the other end and the new rail 300 straight; welding the rail at the other end to the new rail 300 using a flash welding machine and consuming the welding burnout amount.

[0044] Further, the process of inserting a new 300mm rail after sawing the damaged rail. First, insert the new 300mm rail according to the track maintenance rules. The length of the new 300mm rail is no less than 6m for conventional speed lines and no less than 12m for high-speed lines. For example... Figure 5 and Figure 6 As shown, the length of the new rail 300 must be longer than the length of the sawn rail, with allowance for welding melt. For example... Figure 7 As shown, a flash welding machine is used to weld one end of the new 300mm rail to one end of the rail in the construction section, with the other end offset. The offset end has a pre-existing overlap allowance to account for weld burn-through. If the overlap is too long, a rail saw can be used to cut the new or old rail to make the overlap equal to the weld burn-through allowance. Figure 8 As shown, the old rail is bent to straighten the other end of the new rail 300 at the weld joint with the track rail, facilitating flash welding. It is important to note that during flash welding, both rails at the weld joint must be straight. Additionally, to facilitate bending the old rail, a special tool 400 can be used as a support at the bending point.

[0045] In one optional example of this implementation, the rail temperature includes the track locking temperature (TS) and the track operating temperature (TZ). Before construction, the track locking temperature (TS) and the track operating temperature (TZ), i.e., the rail temperature during construction, need to be determined. During the super-stretching method, the rail stretching is accurately calculated based on the track locking temperature (TS) and the track operating temperature (TZ). By keeping the track locking temperature constant before and after construction, the stability of the track is ensured.

[0046] In this invention, the track locking temperature refers to the zero-stress rail temperature of a seamless track, that is, the rail temperature when the seamless track rail is fully locked, at which point the internal temperature stress of the rail is zero. This initial temperature value is determined through calculations during the laying of the seamless track. The locking temperature is the benchmark for determining the rail temperature stress level, reflecting the longitudinal internal stress of the rail under different temperature conditions, i.e., the magnitude of tensile and compressive stresses borne by the seamless track rail. It is a quantitative representation of the strength and stability of the seamless track. Therefore, the locking temperature directly affects the track's stability, maintenance, management, repair, and safety.

[0047] In an optional example, restoring the straightness of the rail construction line includes: loosening the super-stretched section of the rail, causing the super-stretched section of the rail to retract by a predetermined amount, and extending the flash-insertion welded section of the rail by a predetermined amount, locking the rail construction section after the rail temperature of the rail construction section reaches the locking temperature and the stress of the rail construction section is uniformly distributed.

[0048] Furthermore, such as Figure 9 and Figure 10 As shown, the joint welding is completed, consuming the melted rail and restoring the track to straightness. Next, the fasteners on the 200mm high-strength rail section are loosened, allowing the high-strength rail to retract and the construction section rail to extend. The retraction amount of the high-strength rail and the extension amount of the construction section rail are calculated to ensure the entire construction section reaches the locking temperature. Finally, the track stress is evenly distributed, the track is locked, and the construction is complete.

[0049] In an optional embodiment of the present invention, the reserved stretching amount is the sum of the total stretching amount of the flash insertion welding construction section and the total stretching amount of the super-stretching section.

[0050] △L=△LS 总 +△LY 总

[0051] Where △L is the reserved stretching amount, △LS 总 The total tensile strength of the flash insertion welding section; △LY 总 This represents the total stretching of the super-stretched section.

[0052] In one alternative embodiment of this implementation, the total tensile strength of the flash insertion welding section is:

[0053] △LS 总 =△LY 总 / LY×LS

[0054] Among them, △LS 总 △LY represents the total tensile strength of the flash insertion welding section. 总 LY represents the total stretching of the super-stretched section, LY represents the rail length of the super-stretched section, and LS represents the rail length of the flash insertion welding section.

[0055] In one alternative embodiment of this implementation, the total stretch of the super-stretched segment

[0056] △LY 总 =△LY+△LS

[0057] Among them, △LY 总 ΔLS represents the total stretching amount of the super-stretching section, ΔLY represents the planned stretching amount of the flash insertion welding section, and ΔLY represents the planned stretching amount of the super-stretching section.

[0058] In an optional example, the planned stretching amount for the flash insertion welding section:

[0059] △LS=0.0118×LS×(TS-TZ)

[0060] Where △LS is the planned stretching amount of the flash insertion welding construction section, LS is the rail length of the flash insertion welding construction section; TS is the track locking temperature; TZ is the track operating temperature, i.e. the rail temperature during construction.

[0061] In one optional example, the planned stretch amount for the super-stretch segment is:

[0062] △LY=0.0118×LY×(TS-TZ)

[0063] Where △LY is the planned stretching amount of the super-stretched section, LY is the rail length of the super-stretched section, TS is the track locking temperature, and TZ is the track operating temperature, i.e., the rail temperature during construction.

[0064] Please refer to Figures 1 to 11 The following is a detailed description of the construction method for restoring the locking temperature during the flash welding repair of damaged rails on existing railway lines, as proposed in this invention, with reference to an embodiment.

[0065] I. Construction process of this embodiment

[0066] When permanently repairing existing railway line damage using flash welding, the rails need to be overstretched before inserting new rails to ensure the track's locking temperature. The specific solution is as follows:

[0067] 1. Route Survey

[0068] Before construction, determine the line operating temperature TZ and the line locking temperature TS. Also, plan the length of the flash insertion welding section LS and the length of the super-stretching section LY.

[0069] 2. Rail cutting

[0070] The rail is cut near the original seamless track end of the planned flash insertion welding construction section, with a reserved construction section length of 12m at the flash welding machine end (of which, the flash insertion welding construction section is located on the right side indicated by the arrow, and the rail length is 12m).

[0071] 3. Loosen the fasteners in the construction section and the over-stretch section to release the original track stress. Cut the rail again near the first rail cut, leaving room for a stretching allowance △L.

[0072] 4. Use a rail tensioner to perform overstretching of the rail, with a pre-set tension amount of △L.

[0073] 5. After stretching, uniform track stress is achieved, and the overstretched rail is locked in place.

[0074] 6. Cut the damaged rail and insert a new 300mm rail. According to the track maintenance rules, the length of the new rail should be no less than 6m for conventional speed lines and no less than 12m for high-speed lines. The length of the new 300mm rail should be longer than the length of the cut rail to allow for welding melt.

[0075] 7. Use a flash welding machine to weld one end of the new 300 rail to one end of the rail in the construction section, with the other end offset. The overlap at the offset end is reserved for the welding burn-out amount. If the overlap is too long, a rail saw can be used to cut the new or old rail so that the overlap is equal to the welding burn-out amount.

[0076] 8. Bend the old rail and straighten the other end of the new rail 300 to the weld joint with the track rail to facilitate flash welding construction.

[0077] To facilitate the bending of old rails, a special tool 400 can be placed at the bending point.

[0078] 9. Welding the joints consumes the amount of steel rails that have burned off, restoring the track to straightness.

[0079] 10. Loosen the fasteners on the super-stretched section rail, allowing it to retract and the construction section rail to extend. The retraction and extension amounts of the super-stretched section rail and the construction section rail are calculated to ensure the entire construction section reaches the locking temperature. Lock the track after uniformly distributing the track stress.

[0080] 11. Clean up the site and complete the construction.

[0081] II. Calculation of the reserved stretching amount △L during construction in this embodiment

[0082] In this embodiment, the parameters used are as follows: TS is the track locking temperature (°C); TZ is the track operating temperature (i.e., the rail temperature during construction) (°C); LY is the length of the super-stretched section rail (m); and LS is the length of the working section rail (m).

[0083] The specific process for calculating the reserved stretching amount △L is as follows: Calculate the planned stretching amount of the overstretching section at the operating temperature:

[0084] △LY=0.0118*LY*(TS-TZ)

[0085] Calculate the planned tensile strength of the flash welding entry section at the operating temperature:

[0086] △LS=0.0118*LS*(TS-TZ)

[0087] Increase the stretching amount of the super-stretching section so that its total stretching includes the stretching amount of the flash welding entry section. Total stretching amount of the super-stretching section:

[0088] △LY total = △LY + △LS

[0089] When the super-stretched section reaches the total stretch amount ΔLY, the total stretch amount of the flash welding entry section is:

[0090] △LS total = △LY total / LY * LS

[0091] Therefore, when stretching the rails during construction, the allowance for stretching should be:

[0092] △L=△LS_total+△LY_total

[0093] =(△LY+△LS) / LY*LS+△LY+△LS

[0094] = (△LY + △LS) * (1 + LS / LY)

[0095] =0.0118*(TS-TL)*(LS+LY)*(1+LS / LY)

[0096] The detailed explanations of the above embodiments are intended only to explain the present invention so as to facilitate a better understanding of the present invention. However, these descriptions should not be construed as limiting the present invention for any reason. In particular, the various features described in different embodiments can be arbitrarily combined with each other to form other embodiments. Unless there is an explicit description to the contrary, these features should be understood to be applicable to any embodiment, and not limited to the described embodiments.

Claims

1. A construction method for restoring the lock-in temperature during flash welding repair of damaged rails on existing railway lines, characterized in that, Determine the rail temperature and the length of the rail construction section; Calculate the reserved tension amount of the rail based on the rail temperature and the length of the rail construction section; The rail construction section length information includes: the length of the flash insertion welding construction section and the length of the super-stretching section; The reserved tension amount of the rail is the sum of the total tension of the flash insertion welding construction section and the total tension of the super-tension section; △L=△LS 总 +△LY 总 Where △L is the reserved stretching amount, △LS 总 △LY represents the total tensile strength of the flash insertion welding section. 总 This represents the total tensile strength of the super-stretched segment. Total tensile strength of the flash insertion welding section: △LS 总 =△LY 总 / LY×LS Among them, △LS 总 △LY represents the total tensile strength of the flash insertion welding section. 总 LY represents the total tensile strength of the super-stretched section, LY represents the rail length of the super-stretched section, and LS represents the rail length of the flash-insertion welding section. The total tensile strength of the super-stretched section △LY 总 =△LY+△LS Among them, △LY 总 ΔLS represents the total tensile strength of the super-tensile section, ΔLY represents the planned tensile strength of the flash insertion welding section, and ΔLY represents the planned tensile strength of the super-tensile section. The planned tensile amount for the flash insertion welding section: △LS=0.0118×LS×(TS-TZ) Where △LS is the planned tension of the flash-insert welding section, LS is the rail length of the flash-insert welding section; TS is the track locking temperature; and TZ is the track operating temperature, i.e., the rail temperature during construction. The planned tensile amount for the flash insertion welding section: △LS=0.0118×LS×(TS-TZ) Where △LS is the planned stretching amount of the flash insertion welding construction section, LS is the rail length of the flash insertion welding construction section; TS is the track locking temperature; TZ is the track operating temperature, i.e. the rail temperature during construction. The planned stretching amount of the super-stretched section: △LY = 0.0118 × LY × (TS - TZ) Where △LY is the planned stretching amount of the super-stretched section, LY is the rail length of the super-stretched section, TS is the track locking temperature, and TZ is the track operating temperature, i.e. the rail temperature during construction. Perform overstretching of the rails according to the pre-reserved stretching allowance; The damaged rails were sawn off, new rails were inserted, and flash welding was performed. The rail construction line has been restored to a straight line.

2. The construction method as described in claim 1, characterized in that, The rail overstretching process includes: cutting the rail at the planned location of the flash-insert welding section; loosening the fasteners of the flash-insert welding section and the overstretching section to release the original track stress; cutting the rail again in the flash-insert welding section and reserving the stretching amount; stretching the overstretching section according to the reserved stretching amount; uniformly distributing the track stress and locking the rail in the overstretching section.

3. The construction method as described in claim 2, characterized in that, The planned location is the end of the flash insertion welding section near the original seamless line.

4. The construction method as described in claim 1, characterized in that, After sawing the damaged rail, a gap is formed in the flash insertion welding section. The flash welding process includes welding the new rail to the rail at one end of the gap using a flash welding machine, with the other end of the new rail having a reserved amount for welding burn-off and offset from the rail at the other end of the gap; bending the rail at the other end and making the weld joint between the rail at the other end and the new rail straight; welding the rail at the other end to the new rail using a flash welding machine and consuming the welding burn-off amount.

5. The construction method as described in claim 1, characterized in that, The rail temperature of the rail line includes: the track locking temperature and the track operating temperature.

6. The construction method as described in claim 5, characterized in that, The process of restoring the straightness of the rail construction line includes: loosening the super-stretched section of the rail, causing the super-stretched section of the rail to retract by a predetermined amount, and extending the rail of the flash insertion welding section by a predetermined amount. After the rail temperature of the rail construction section reaches the locking temperature and the stress of the rail construction section is uniformly distributed, the rail construction section is locked.

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