Subway track laying machinery auxiliary scattered laying construction method

Abstract

The invention relates to the technical field of subway construction, in particular to an auxiliary scattered laying construction method for a subway track laying machine. The construction method comprises the following specific steps: S1, construction preparation; s2, a walking rail and a rail laying crane are installed; s3, hoisting the materials; s4, track panel assembling and hoisting are carried out; s5, mounting a ballast bed reinforcing mesh; s6, adjusting the track state; s7, a formwork is installed; s8, ballast bed concrete is poured; and S9, maintenance and follow-up operation are conducted. By building a matched operation platform and integrating various track laying machines, full-process mechanical auxiliary operation from construction preparation, material hoisting and transportation, track panel assembly to track bed pouring and maintenance is achieved, and the problems that a mechanical laying method is high in site requirement and cannot be applied to complex areas are solved. And meanwhile, the defects that a manual scattered laying method is large in human input, low in work efficiency, unstable in quality, high in cost and has potential safety hazards are overcome, the rail laying construction requirements under the condition that the construction period is short are met, convenience and standardization of construction are considered, and efficient rail laying operation can be achieved without depending on a fixed rail laying base.

Description

Technical Field

[0001] This invention relates to the field of subway construction technology, specifically a mechanically assisted loose-laying method for subway track laying. Background Technology

[0003] Currently, the most widely used track-laying methods in urban rail transit engineering are mechanical track laying and manual track laying. Mechanical track laying relies on fixed track-laying bases and has high construction efficiency, but it requires specific site conditions, such as continuous tunnel continuity and the availability of track-laying shafts. In complex construction areas such as old urban areas, newly built subway lines often intersect or run parallel to existing pipelines. Some pipelines cannot be relocated in a timely manner due to factors such as relocation procedures and planned land occupation, resulting in discontinuous tunnel connections and numerous breaks, rendering the track-laying base ineffective. In such cases, manual track laying is often necessary, relying primarily on manpower and supplemented by small machinery. This method not only requires a large investment of manpower and has low construction efficiency, but also may affect construction quality due to differences in manual operation, while increasing construction costs and safety hazards, making it difficult to meet the track-laying needs under tight deadlines. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a mechanically assisted loose-laying construction method for subway track laying.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A mechanically assisted track-laying construction method for subways, with the following specific steps:

[0007] S1. Construction Preparation: Prepare a track laying plan and perform track layout calculations; lay out and process reinforcing bars in the track laying base; after the site handover is completed, set up temporary facilities, conduct verification measurements and benchmark setting, and complete the construction technology briefing; build a work platform, which is equipped with a track laying crane, traveling rails, track supports, and benchmark measurement components. The traveling rails are laid on the track supports, which are fixed to the tunnel floor. The track laying crane is mounted on the traveling rails and can move along the traveling rails.

[0008] S2. Install the traveling rail and track-laying crane: Select steel rails as the traveling rails, fix the bottom plate of the track support to the tunnel floor with expansion bolts, adjust the height of the track support to the preset position, and fasten the traveling rail to the upper plate of the track support with bolts to ensure that the track-laying crane moves in a balanced and safe manner on the traveling rail.

[0009] S3. Material hoisting: Steel rails, sleepers, reinforcing bars, fasteners, and other materials are hoisted and unloaded to the shield tunnel shaft opening using a truck crane. The steel rails are then vertically transported to the station floor using off-road forklifts. Finally, the various materials are transferred to their respective locations inside the tunnel using a track-laying crane. The steel rails are hoisted vertically to the bottom of the shield tunnel shaft using a single point and then transported into the tunnel using a forklift. Sleepers are hoisted as a whole. Reinforcing bars are bundled and hoisted. Small materials such as fasteners are hoisted using a hoisting bucket.

[0010] S4. Rail panel assembly and hoisting: According to the rail laying plan, the rail panels are assembled on-site in the tunnel section. During the assembly process, steel rails with the required length tolerance are selected for pairing. The spiral rail spikes are fitted with washers and coated with special grease before being screwed into nylon sleeves. The iron pads and elastic strips are installed according to the specifications. The sleeper spacing is marked with a long steel ruler. After the rail panel assembly is completed, two rail laying cranes are used to hoist the rail panels to the working surface for adjustment and positioning. The rail support frame is installed and all bolts are tightened.

[0011] S5. Install the track bed reinforcement mesh: Bundle the steel bars processed at the track laying base into bundles, transport them to the laying section by track laying crane, and tie and weld them inside the tunnel to ensure that the longitudinal steel bars also serve as stray current drainage bars and form a good electrical connection.

[0012] S6. Track condition adjustment: Perform coarse, fine, and precise adjustments on the completed track panels. Repeatedly adjust the track level first, then the gauge, then the base points first, then the distance between the base points, and finally the coarse adjustments to the fine adjustments to ensure that the track panel accuracy meets the accuracy requirements after the ballastless track is laid.

[0013] S7. Template Installation: Install the template along the track direction, ensuring that the template is straight and firmly reinforced. Apply release agent evenly before template installation to avoid contaminating the reinforcing steel.

[0014] S8. Pouring track bed concrete: The track bed concrete is fed into the hopper through a long chute and then transported to the pouring site by the track laying crane. As the pouring mileage increases, when the track bed concrete strength reaches the design requirements, the concrete is transported to the vicinity of the pouring site by a rail-mounted concrete mixer truck and then poured into the hopper by the track laying crane. During the pouring process, the concrete is vibrated, with a focus on strengthening the vibration around the sleepers.

[0015] S9. Curing and subsequent operations: Curing should be carried out in a timely manner after the concrete has set. When the concrete strength reaches the preset strength, the rail support frame should be removed. After a section of track is laid, the track laying crane and the traveling rail should be moved to the next work area. Repeat steps S4 to S8 until the entire section of track is laid.

[0016] The present invention, which adopts the above technical solution, has the following prominent features compared with the prior art:

[0017] By building a supporting operation platform and integrating various track-laying machines, the entire process of mechanical-assisted operation, from construction preparation, material hoisting, track panel assembly to track bed pouring and maintenance, is realized. This solves the problems of high site requirements and inability to be applied in complex areas by machine-laid methods. At the same time, it improves the disadvantages of manual scattered laying methods, such as high labor input, low efficiency, unstable quality, high cost and safety hazards. It is suitable for track-laying construction needs under tight schedules, takes into account the convenience and standardization of construction, and can achieve efficient track-laying operations without relying on fixed track-laying bases.

[0018] As a preferred embodiment, a further technical solution of the present invention is:

[0019] Preferably, in step S2, the traveling rail is made of 24Kg / m steel rail, the base plate of the rail support is set to an adjustable angle structure, the support point spacing of the rail support is set to 1.2 meters, and the expansion bolts are of type M16. This improves the convenience and adaptability of the traveling rail installation, facilitates manual handling and on-site adjustment, better adapts to different working conditions of the tunnel floor, ensures the stability and safety of the rail-laying crane on the traveling rail, and provides support for the smooth progress of subsequent rail-laying operations.

[0020] Preferably, in step S3, the number of sleepers hoisted each time does not exceed 12. Steel wire ropes or slings are used for hoisting and anti-wear measures are taken. Small semi-finished steel bars are hoisted using qualified hoisting buckets to reduce losses during hoisting, reduce safety risks in hoisting operations, standardize hoisting operation procedures, ensure the stability of material hoisting, and avoid material damage or safety hazards caused by improper hoisting.

[0021] Preferably, in step S4, the length tolerance of the rails selected for the same rail panel does not differ by more than 3mm, which improves the accuracy of rail panel assembly, reduces the impact of rail pairing deviation on the subsequent track laying quality, ensures the stability of the rail panel structure, and lays a good foundation for track condition adjustment.

[0022] Preferably, in step S4, the rail support frame is set perpendicular to the track in the straight section and perpendicular to the tangent of the track in the curved section. When the sleeper, support frame and reserved pipe trench coincide, the sleeper and support frame are adjusted back and forth appropriately to maintain uniform spacing, adapting to the different laying requirements of the straight section and the curved section, ensuring the support effect of the rail support frame on the rail panel. When the sleeper, support frame and reserved pipe trench coincide, the sleeper spacing can be adjusted to ensure uniformity, avoid interference with subsequent construction, and improve the standardization of track laying.

[0023] Preferably, in step S9, the rail support frame is removed when the concrete strength reaches 5MPa. The removal operation is carried out in a standardized manner after curing to avoid deformation or damage to the rail panel due to improper timing of removal, thus ensuring the quality of track laying and providing a guarantee for the safe passage of subsequent rail equipment. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the construction process of the present invention; Detailed Implementation

[0025] The present invention will be further illustrated below with reference to specific embodiments. The purpose of this illustration is solely to provide a better understanding of the invention. Therefore, the examples given do not limit the scope of protection of the present invention.

[0026] This embodiment provides a mechanically assisted loose-laying construction method for subway track laying, and the specific steps are as follows:

[0027] S1. Construction Preparation: Prepare a track-laying plan and perform track layout calculations. Based on the line design parameters, section length, and track bed type, calculate the required specifications and quantities of rails, sleepers, reinforcing bars, and fasteners to avoid material stockpiling or shortages. Track layout calculations must strictly adhere to the integrated track-laying drawings after alignment and gradient adjustments, design documents, and the seamless track construction design scheme approved by the construction unit. For straight sections, calculations are performed continuously based on rail length and reserved rail gaps. For curved sections, the outer rail length is used as the basis, converting the line centerline length into the outer rail length. Track layout is then performed continuously based on the outer rail length and reserved rail gaps, and appropriate inner rail lengths are added according to specifications. When the location is configured with shortened rails, the planned stagger amount for each joint on the curve section and the distance from the beginning and end points of the curve to the rail joint are clearly defined. Temporary facilities include material storage areas, processing areas, machinery parking areas, and office areas. Each area is clearly divided and sufficient working space is reserved. During site handover, the elevation and dimensions of the handed-over tunnel section and station site are checked to ensure there are no remaining civil engineering debris before the temporary facilities are laid. Reinforcing steel layout and processing are carried out within the track laying base. After the site handover is completed, temporary facilities are laid out, verification measurements and benchmark setting are conducted, and construction technology briefings are completed. High-precision total stations and levels are used to measure every 50 meters along the tunnel line. A baseline control point is set every meter, and the control point is buried firmly and protected to avoid construction disturbance. A working platform is built, which is constructed by welding and assembling steel sections to ensure that the platform structure is stable and its load-bearing capacity meets the requirements of track laying. The working platform is equipped with a track laying crane, running rails, track supports, and baseline measuring components. The running rails are laid on the track supports, which are fixed to the tunnel floor. The track laying crane is mounted on the running rails and can move along them. The track laying crane is a 5t-class remote-controlled track laying crane, which has multiple functions such as sleeper unloading, distribution, track panel assembly, track lifting, and concrete pouring. The baseline measuring components are equipped with a level and track gauge for subsequent track condition adjustments. At the same time, the track bed base is roughened according to design requirements, and all kinds of debris and sewage are thoroughly removed from the site to ensure that the base meets the conditions for track laying construction.

[0028] S2. Installation of Traveling Rails and Track Laying Hoist: Steel rails are selected as the traveling rails. Based on the ease of manual handling and the load-bearing requirements of the track laying hoist, the specifications of the traveling rails are chosen. 24Kg / m steel rails are selected for the traveling rails, as this specification has a moderate weight, facilitating manual handling and on-site adjustment. The base plate of the track support is fixed to the tunnel floor using expansion bolts. M16 expansion bolts are used, with four expansion bolts for each track support base plate. Before fixing, the concrete strength of the tunnel floor is checked to ensure it meets the anchoring requirements of the expansion bolts, and the anchoring depth conforms to the design specifications. The height of the track support is adjusted to the preset position. The traveling rails are then connected to the upper plate of the track support with bolts. A torque wrench is used to tighten the bolts, ensuring the tightening torque meets the design and specification requirements. The spacing between the travel rail support points is set at 1.2 meters. After laying, the straightness and levelness of the traveling rails are checked, and the deviations are controlled within the allowable range to ensure the track laying hoist moves safely and smoothly on the traveling rails.

[0029] S3. Material Lifting: Steel rails, sleepers, reinforcing bars, fasteners, and other materials are lifted and unloaded to the shield tunnel shaft opening using a truck-mounted crane. A 5-ton off-road forklift is then used in conjunction with a rail transport vehicle to transport the rails one by one. The forklifts maintain a constant speed during transport, avoiding sudden stops and turns to ensure stable rail transport. Finally, a rail-laying crane transfers all materials to their respective locations within the tunnel. The steel rails are lifted vertically to the bottom of the shield tunnel shaft using a single-point lifting method, and then placed into the tunnel using a forklift. The rails are 25 meters long, longer than the shield tunnel opening, hence the single-point lifting method. Before lifting, a suitable lifting point is selected to ensure the rail remains horizontal after lifting. During placement into the tunnel, a dedicated person guides the rail to prevent collisions with the tunnel walls. Collisions are strictly prohibited during sleeper transport; severely chipped or cracked sleepers are prohibited from use. Sleepers are lifted as a whole; reinforcing bars are bundled and lifted; and small materials such as fasteners are lifted using a hoisting bucket.

[0030] S4. Rail Panel Assembly and Lifting: According to the rail laying plan, the rail panels are assembled on-site within the tunnel section. During the assembly process, rails with the required length tolerances are selected for pairing. The spiral spikes are fitted with washers and coated with special grease before being screwed into nylon sleeves. The special grease used is a rust-preventive grease that meets the design requirements. The grease is applied evenly and without omissions. The spiral spikes are screwed into the depth specified in the design to ensure a firm connection. The iron pads and elastic strips are installed according to the specifications. The sleeper spacing is marked with a long steel ruler. After the rail panel assembly is completed, two rail-laying cranes are used to lift the rail panels to the work surface for adjustment and positioning. The rail support frame is installed and all bolts are tightened.

[0031] S5. Install the track bed reinforcement mesh: Bundle the steel bars processed at the track laying base into bundles and transport them to the laying section using a track laying crane. During the transportation process, control the lifting speed to prevent the steel bar bundles from swaying and colliding with the rails, sleepers, and tunnel walls. Bind and weld them inside the tunnel to ensure that the longitudinal steel bars also serve as stray current drainage bars and form a good electrical connection. According to the stray current professional requirements, the welded connection of the longitudinal steel bars meets the electrical conductivity requirements. After welding, use a multimeter to test the conductivity of the connection nodes to ensure the formation of a stable drainage network.

[0032] S6. Track Condition Adjustment: The completed track panels undergo coarse, fine, and precise adjustments. Adjustments are made repeatedly in the following order: first adjust the level, then the gauge; first adjust the base points, then the distances between base points; and first coarse, then fine. In the coarse adjustment stage, the height and position of the rail support frames are adjusted to initially correct the levelness and gauge of the track panels, using a level and gauge ruler for preliminary testing. In the fine adjustment stage, high-precision measuring instruments are used to accurately measure the levelness, gauge, and height difference of the track panels, and adjustments are made gradually based on the measurement results. In the fine adjustment stage, after the coarse and fine adjustments are completed, a comprehensive measurement is performed again, and adjustments are made repeatedly until all parameters meet the standards, ensuring that the track panel accuracy meets the accuracy requirements after the ballastless track is laid.

[0033] S7. Template Installation: Install templates along the track direction. Steel templates are selected to ensure the rigidity and flatness of the templates. The template specifications should conform to the track bed design dimensions. Ensure that the templates are straight and firmly reinforced. The templates are firmly connected with splicing parts, and the splicing gaps are sealed to prevent grout leakage during concrete pouring. The templates are reinforced with tie rods and supports. During the reinforcement process, ensure that there is no risk of template displacement or deformation and meet the lateral pressure requirements of concrete pouring. Apply release agent evenly before template installation to avoid contaminating the reinforcing steel.

[0034] S8. Pouring Track Bed Concrete: Track bed concrete is fed into the hopper via a long chute and then transported to the pouring location by a rail-laying crane. The rail-mounted concrete mixer trucks are modified to meet the requirements of the tunnel tracks. Before operation, the tunnel tracks are inspected to ensure they are flat and free of obstructions. Red lights are installed inside the tunnel for the rail-mounted concrete mixer trucks, and track guards are installed on the tracks to prevent the trucks from crossing these red lights. As the pouring mileage increases, once the track bed concrete strength reaches the design requirements, the concrete is transported to the vicinity of the pouring location using rail-mounted concrete mixer trucks, then poured into the hopper and poured by a rail-laying crane. During pouring, the concrete is vibrated, with a focus on the area around the sleepers. An immersion vibrator is used, with uniform spacing between vibration points. The vibration depth extends 50mm below the bottom of the sleeper, and the vibration time is controlled at 20-30 seconds, until no air bubbles appear on the concrete surface and cement slurry emerges. During vibration, the vibrator must avoid touching the rail support frame, rails, and reinforcing bars to prevent structural deformation.

[0035] S9. Curing and Subsequent Operations: Curing should be carried out promptly after the concrete pouring reaches its final set. Water curing should be used for at least 14 days. During curing, the concrete surface should be kept moist to prevent cracking. Geotextile can be used to cover the concrete surface, and water should be sprayed regularly to maintain moisture. When the concrete strength reaches the preset strength, the rail support frame should be removed. Before removal, the concrete strength should be tested using the rebound method or core drilling method to ensure that the strength reaches 5MPa. Removal should be carried out symmetrically and slowly to avoid instantaneous impact on the rail panel. The removed rail support frame should be cleaned and maintained promptly for reuse. Rail equipment is prohibited from running on the track before the concrete reaches the design strength. Vehicles and loads are prohibited from running on the track until the concrete reaches 70% of the strength specified in the design documents to prevent deformation of the rail panel due to the load on the rail equipment. After completing one section of track laying, move the track-laying crane and traveling rail to the next work area, repeating steps S4 to S8 until the entire section of track is laid.

[0036] Preferably, in step S2, the traveling rail is made of 24Kg / m steel rail, the base plate of the rail support is set to an adjustable angle structure, the support point spacing of the rail support is set to 1.2 meters, and the expansion bolts are of type M16. This improves the convenience and adaptability of the traveling rail installation, facilitates manual handling and on-site adjustment, better adapts to different working conditions of the tunnel floor, ensures the stability and safety of the rail-laying crane on the traveling rail, and provides support for the smooth progress of subsequent rail-laying operations.

[0037] Preferably, in step S3, the number of sleepers hoisted each time does not exceed 12. Steel wire ropes or slings are used for hoisting and anti-wear measures are taken. Small semi-finished steel bars are hoisted using qualified hoisting buckets to reduce losses during hoisting, reduce safety risks in hoisting operations, standardize hoisting operation procedures, ensure the stability of material hoisting, and avoid material damage or safety hazards caused by improper hoisting.

[0038] Preferably, in step S4, the length tolerance of the rails selected for the same rail panel does not differ by more than 3mm, which improves the accuracy of rail panel assembly, reduces the impact of rail pairing deviation on the subsequent track laying quality, ensures the stability of the rail panel structure, and lays a good foundation for track condition adjustment.

[0039] Preferably, in step S4, the rail support frame is set perpendicular to the track in the straight section and perpendicular to the tangent of the track in the curved section. When the sleeper, support frame and reserved pipe trench coincide, the sleeper and support frame are adjusted back and forth appropriately to maintain uniform spacing, adapting to the different laying requirements of the straight section and the curved section, ensuring the support effect of the rail support frame on the rail panel. When the sleeper, support frame and reserved pipe trench coincide, the sleeper spacing can be adjusted to ensure uniformity, avoid interference with subsequent construction, and improve the standardization of track laying.

[0040] Preferably, in step S9, the rail support frame is removed when the concrete strength reaches 5MPa. The removal operation is carried out in a standardized manner after curing to avoid deformation or damage to the rail panel due to improper timing of removal, thus ensuring the quality of track laying and providing a guarantee for the safe passage of subsequent rail equipment.

[0041] The core advantages of the mechanized track laying method for subway construction are prominent. It effectively avoids the challenges of mechanized track laying, such as stringent site requirements and incompatibility with complex areas like old urban areas with numerous tunnel breaks and discontinuities. It also completely overcomes the drawbacks of traditional manual track laying, including high labor input, low efficiency, poor quality stability, high cost, and significant safety hazards. By establishing a standardized operating platform and integrating various highly adaptable track laying machines, it achieves fully mechanized operations from construction preparation, material hoisting, track panel assembly, track bed reinforcement laying, track condition adjustment to formwork installation, concrete pouring, and curing. It can carry out efficient construction by relying on a fixed track laying base; during the construction process, by clarifying equipment parameters, standardizing operating procedures, and refining quality control points, it takes into account the convenience, standardization, and reliability of construction. It can not only meet the track laying needs with tight schedules, but also effectively ensure track laying accuracy and construction safety. At the same time, it reduces manpower input, improves construction efficiency, and reduces construction costs. It can also adapt to different working conditions such as straight sections and curved sections, as well as various track bed laying needs. It has good practicality, economy, and social benefits, and can be widely used in urban rail transit track laying projects where tunnels are discontinuous and mechanical laying conditions are not available.

[0042] The above description is merely a preferred embodiment of the present invention and does not limit the scope of the present invention. All equivalent changes made based on the description and drawings of the present invention are included within the scope of the present invention.

Claims

1. A mechanically assisted loose-laying construction method for subway track laying, characterized in that: The specific steps are as follows: S1. Construction Preparation: Prepare a track laying plan and perform track layout calculations; lay out and process steel bars in the track laying base; after the site handover is completed, set up temporary facilities; conduct verification measurements and benchmark setting, and complete the construction technology briefing; build a working platform, which is equipped with a track laying crane, traveling rails, track supports, and benchmark measurement components. The traveling rails are laid on the track supports, which are fixed to the tunnel floor. The track laying crane is mounted on the traveling rails and can move along the traveling rails. S2. Install the traveling rail and track-laying crane: Select steel rails as the traveling rails, fix the bottom plate of the track support to the tunnel floor with expansion bolts, adjust the height of the track support to the preset position, and fasten the traveling rail to the upper plate of the track support with bolts to ensure that the track-laying crane travels in a balanced and safe manner on the traveling rails. S3. Material Lifting: Steel rails, sleepers, reinforcing bars, fasteners, and other materials are lifted and unloaded to the shield tunnel shaft opening using a truck-mounted crane. A cross-country forklift is then used to vertically transport the rails to the station floor. Finally, a track-laying crane is used to transfer all materials to their respective locations within the tunnel. Specifically, steel rails are lifted vertically from a single point to the bottom of the shield tunnel shaft and then transported into the tunnel using a forklift. Sleepers are lifted as a whole; reinforcing bars are bundled and lifted; and smaller materials such as fasteners are lifted using a hoisting bucket. S4. Rail panel assembly and hoisting: According to the rail laying plan, the rail panels are assembled on-site in the tunnel section. During the assembly process, steel rails with the required length tolerance are selected for pairing. The spiral rail spikes are fitted with washers and coated with special grease before being screwed into nylon sleeves. The iron pads and elastic strips are installed according to the specifications. The sleeper spacing is marked with a long steel ruler. After the rail panel assembly is completed, two rail laying cranes are used to hoist the rail panels to the working surface for adjustment and positioning. The rail support frame is installed and all bolts are tightened. S5. Install the track bed steel mesh: Bundle the steel bars processed at the track laying base into bundles, and transport them to the laying section by track laying crane. Bind and weld them inside the tunnel to ensure that the longitudinal steel bars also serve as stray current drainage bars and form a good electrical connection. S6. Track condition adjustment: The completed track panels are coarsely adjusted, finely adjusted, and precisely adjusted. The adjustment is repeated in the order of adjusting the level first and then the gauge, adjusting the base points first and then the distance between the base points, and coarse adjustment first and then fine adjustment, to ensure that the accuracy of the track panels meets the accuracy requirements after the ballastless track is laid. S7. Template installation: Install the template along the track direction, ensuring that the template is straight and firmly reinforced. Apply release agent evenly before template installation to avoid contaminating the reinforcing steel. S8. Pouring track bed concrete: The track bed concrete is fed into the hopper through a long chute and then transported to the pouring site by the track laying crane. As the pouring mileage increases, when the track bed concrete strength reaches the design requirements, the concrete is transported to the vicinity of the pouring site by a rail-mounted concrete mixer truck, and then poured into the hopper by the track laying crane. During the pouring process, the concrete is vibrated, with a focus on strengthening the vibration around the sleepers. S9. Curing and subsequent operations: Curing should be carried out in a timely manner after the concrete has set. When the concrete strength reaches the preset strength, the rail support frame should be removed. After a section of track is laid, the track laying crane and the traveling rail should be moved to the next work area. Repeat steps S4 to S8 until the entire section of track is laid.

2. The metro track-laying mechanically assisted loose-laying construction method according to claim 1, characterized in that: In step S2, the running rail is made of 24Kg / m steel rail, the base plate of the rail support is set to an adjustable angle structure, the spacing between the support points of the rail support is set to 1.2 meters, and the expansion bolts are of type M16.

3. The metro track-laying mechanically assisted loose-laying construction method according to claim 1, characterized in that: In step S3, the number of sleepers hoisted at one time shall not exceed 12. Steel wire ropes or slings shall be used for hoisting and anti-wear measures shall be taken. Small semi-finished steel bars shall be hoisted using a qualified hoisting bucket.

4. The mechanized track-laying method for subway construction according to claim 1, characterized in that: In step S4, the difference in rail length tolerance between rails selected for the same rail panel shall not exceed 3mm.

5. The metro track-laying mechanically assisted loose-laying construction method according to claim 1, characterized in that: In step S4, the rail support frame is set perpendicular to the track in the straight section and perpendicular to the tangent of the track in the curved section. When the sleeper, support frame and reserved pipe trench coincide, the sleeper and support frame are adjusted back and forth appropriately to maintain uniform spacing.

6. The metro track-laying mechanically assisted loose-laying construction method according to claim 1, characterized in that: In step S9, the rail support frame is removed when the concrete strength reaches 5MPa.

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