Construction method of subway viaduct U-shaped beam general and medium damping track bed

Abstract

The application provides a subway viaduct U-shaped beam general and medium damping track bed construction method, comprising the following steps: S1, track material hoisting and scattering; S2, base cleaning; S3, track foundation control network layout; S4, track row assembly and erection; S5, steel bar binding and welding; S6, template and template support system manufacturing and installation; S7, track geometric size adjustment; S8, concrete pouring; and S9, track bed maintenance and form removal. The disclosed method can carry out track operation, especially for bridge sectional handover track laying construction, that is, civil engineering organizes scattered track operation when each section of viaduct bridge is handed over, so that the efficiency is improved and the construction period is shortened. When only part of the bridge section is handed over for track construction, the method has strong maneuverability and practicality. Track laying operation can be carried out in time, the project safety and quality are guaranteed, and the construction production progress is promoted.

Description

Technical Field

[0001] This invention relates to the field of track bed construction technology, and in particular to a construction method for general and moderate vibration-damping track beds on U-shaped beams of subway viaducts. Background Technology

[0002] With the continuous development of urban rail transit, elevated subway sections offer advantages such as economy and fast construction speed, while U-shaped beams, with their aesthetic appeal and high construction efficiency, have become a popular choice for elevated beams in domestic rail transit projects in recent years. Therefore, how to conduct track laying operations within U-shaped beams has become a new area of ​​exploration in rail engineering construction in recent years.

[0003] The track mainly consists of rails, vibration-damping fasteners, short sleepers, and reinforced concrete. From bottom to top, they are the track bed, short sleepers, fasteners, and rails. (See reference) Figure 1 .

[0004] In existing technologies, the construction technology for elevated bridge track beds involves assembling 25m rail panels (a 25m rail panel is an integral component consisting of two 25m steel rails connected together by sleepers and fasteners) at the track laying base. The rail panels are then transferred to rail transport flatbed cars using a gantry crane or crane at the base, and then transported to the construction work surface. They are then lifted to the construction point using a track laying gantry crane or gantry crane. The rail panels are then installed to the designed position using a rail panel support system. The formwork system uses track bed slabs installed piece by piece, and concrete is poured using a rail concrete transport vehicle or pump truck.

[0005] Existing shortcomings: (1) In the construction of urban rail transit, the construction progress of bridges is often delayed due to the difficulty of land acquisition and demolition when crossing roads, railways, high-voltage cables and other areas. The existing technology requires that all sections of the bridge to be constructed be completed. If there are gaps in the construction of the elevated section, the 25m rail panels cannot be transported to the construction site by transport vehicle, which places high demands on the progress of bridge construction.

[0006] (2) Existing technology requires the construction of a track laying base, the base needs to be equipped with a gantry crane, the construction work surface needs to be equipped with a track laying gantry crane or gantry crane, and the track panel transportation needs to be equipped with a railcar and a flatbed car. The amount of mechanical equipment invested is large and the workload of safety management is large.

[0007] (3) The existing track bed template is installed piece by piece, which results in large construction errors at the joints of the track bed panels and makes it difficult to control the appearance and shape of the track bed, thus affecting the appearance quality of the track bed. The template in the middle of the track bed is supported by steel pipes and arranged in a scissor shape, which is heavy and inconvenient to operate.

[0008] (4) When it is not possible to use a concrete pump to pour the roadbed concrete in sections of cross-river channels, highways and other bridge sections, concrete construction is very difficult.

[0009] (5) Once the direction or sequence of track bed construction is determined, the direction cannot be adjusted.

[0010] Some projects, located on major urban roads, involve a large number of continuous beams, and experience delays in the handover of key bridge construction nodes, making it impossible to continuously raise the track working surface. During construction, based on the characteristics of general and moderate vibration-damping track beds in elevated U-shaped beam sections and considering the actual conditions of the construction site, a scientific, reasonable, and comprehensive track bed construction method is urgently needed to complete the construction of general and moderate vibration-damping track beds for elevated U-shaped beam sections. Summary of the Invention

[0011] This invention provides a construction method for general and moderate vibration-damping track beds on U-shaped beams of subway viaducts, which solves the problem of not being able to carry out mechanized track laying due to the delay in track laying base construction. It enables timely track laying operations, ensuring project safety and quality, and promoting construction progress.

[0012] To achieve the above objectives and overcome the aforementioned technical problems, according to embodiments of the present invention, a construction method for general and moderate vibration-damping track beds on U-shaped beams of subway viaducts is provided, including: S1. Rail material hoisting and distribution; S2, Base cleaning; S3. Layout of track foundation control network; S4. Rail panel assembly and erection; S5. Reinforcing bar binding and welding; S6. Formwork and formwork support system fabrication and installation; S7, Track geometry adjustment; S8. Concrete pouring; S9. Track bed maintenance and formwork removal.

[0013] In some embodiments, step S1 includes transporting the rail material to be hoisted to the vicinity of the hoisting point. If the viaduct is in the middle of the traffic road, the end of the station is selected as the fixed hoisting point, and then the rail material is distributed by a forklift. If the viaduct is on one side of the road, the rail material is hoisted along the other side of the viaduct, and a truck crane is used to hoist the rail material to the vicinity of the work surface and then distribute it.

[0014] In some embodiments, step S2 includes adjusting the pre-reserved anchoring steel bars in the civil engineering to make them perpendicular to the beam surface and have a 90° bend, and the height should not encroach on the track steel mesh; temporarily sealing the pre-reserved drainage holes and emergency holes in the civil engineering with rigid round caps; and cleaning the residue, water and stains on the base surface.

[0015] In some embodiments, step S3 includes measuring using the CPIII method based on the precision control points provided by the owner. The CPIII points are set on the side of the upper flange of the elevated U-shaped beam segment. The CPIII points are remeasured periodically, and the centerline and side stakes of the line are laid out using the CPIII points.

[0016] In some embodiments, step S4 includes assembling the rail panel on the elevated working surface; first, assembling the fasteners and sleepers together, and then using elastic clips to fasten the sleepers with the fasteners assembled onto the rails to assemble a 25m rail panel. First, mark the sleeper position on the bottom of the inner rail with red paint or a stone pencil, and mark the curved section on the bottom of the inner rail of the outer rail. Once the track panels are assembled, the track panel installation begins.

[0017] In some embodiments, the rail panel is erected using a rail panel support system, which includes rail support brackets, elevation screws, bracket connecting rods, rail direction adjusting struts, and rail direction adjusting bolts. Two rail support brackets are respectively fixed to the bottom of two rails by the elevation screws, and the bracket connecting rods connect the two rail support brackets. Multiple rail direction adjusting bolts are provided on the rail support brackets and bracket connecting rods, respectively supporting both sides of the rails. Rail direction adjusting struts are provided on the side of the two rail support brackets near the side wall of the U-shaped beam.

[0018] In some embodiments, step S5 includes laying the steel mesh by cutting and processing it at the track laying base processing yard and binding it on the working surface.

[0019] In some embodiments, in step S6, the template support system includes lateral support rods, channel steel, intermediate support square steel, template support ribs, and positioning ribs. Track bed templates are respectively set on both sides of the two rails through the positioning ribs. Template support ribs are set between the track bed templates on both sides of the same rail. The channel steel is set on the side wall of the U-shaped beam. At least two lateral support rods are set between each track bed template and the channel steel near the side wall of the U-shaped beam. Intermediate support square steel is set between the two rows of track bed templates in the middle of the two rails.

[0020] In some embodiments, step S8 includes transporting the track bed concrete from the mixing plant to the construction site using concrete mixer trucks, and then using a boom pump to directly extend to the elevated working surface for pouring; at the crossing of roads and rivers, the boom pump is used to pump the concrete onto a rail concrete transport vehicle, which is then transported to the pouring working surface by the rail concrete transport vehicle. Before pouring, a slump test should be conducted on the concrete, and the concrete temperature upon entering the formwork should be controlled to not exceed 30°C. When pouring concrete, woven bags should be used to cover the rails and sleepers to prevent contamination of the sleepers and fasteners.

[0021] When pouring concrete, use an immersion vibrator to compact it, and avoid contact with the rails, sleepers, and formwork.

[0022] In some embodiments, step S9 includes curing the concrete by covering it with geotextile within 12 hours after the concrete is poured, keeping the concrete moist; the support frame can be removed only after the concrete strength reaches 5MPa or more, and the track can be loaded and driven after it reaches 70% or more of the design strength.

[0023] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects: The construction method disclosed in this invention can be used for track laying, especially for track laying in the segmented handover of bridge sections. This means that track laying can be organized as soon as each section of the viaduct is handed over by the civil engineering team, improving efficiency and shortening the construction period. When only a portion of the bridge section is handed over for track laying, this method is highly mobile and practical. It allows for timely commencement of track laying operations, ensuring project safety and quality, and accelerating construction progress.

[0024] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0026] Figure 1 This is a cross-sectional layout diagram of the track bed for the rail support platform.

[0027] Figure 2 This is a flowchart illustrating a construction method for general and moderate vibration-damping track bed on a U-shaped beam of a subway viaduct, according to an exemplary embodiment.

[0028] Figure 3 This is a schematic diagram of a track support system according to an exemplary embodiment.

[0029] Figure 4 This is a schematic diagram of a template and template support system according to an exemplary embodiment.

[0030] In the picture, 1. Rail support bracket; 2. Elevation screw; 3. Bracket connecting rod; 4. Adjusting rail direction strut; 5. Rail direction adjusting bolt; 6. Lateral support rod; 7. Channel steel; 8. Intermediate support square steel; 9. Formwork support reinforcement; 10. Positioning reinforcement. Detailed Implementation

[0031] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual images. They should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0032] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0033] In the description of this invention, unless otherwise explicitly specified and limited, the term "connection" or similar designation indicating a connection between components should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] like Figure 1-2 As shown, a construction method for general and moderate vibration-damping track bed on U-shaped beams of subway viaducts is provided, including: S1. Rail material hoisting and distribution; S2, Base cleaning; S3. Layout of track foundation control network; S4. Rail panel assembly and erection; S5. Reinforcing bar binding and welding; S6. Formwork and formwork support system fabrication and installation; S7, Track geometry adjustment; S8. Concrete pouring; S9. Track bed maintenance and formwork removal.

[0035] Based on the construction progress of the elevated bridge section, this construction method can be applied to track laying, especially when the bridge is handed over for track laying in sections. That is, as soon as the civil engineering team hands over each section of the elevated bridge, the track laying work can be organized on site, which can improve efficiency and shorten the construction period. When only part of the bridge section is handed over for track laying, this construction method is flexible and highly practical.

[0036] Below are some specific examples of construction methods for general and moderate vibration-damping track beds on U-shaped beams of subway viaducts. Example

[0037] S1, hoisting and distribution of rail materials.

[0038] The rail materials to be hoisted are transported to the vicinity of the hoisting point. If the viaduct is in the middle of the traffic road, the end of the station is selected as the fixed hoisting point, and a 50t truck crane is used to hoist the rail materials to the U-shaped beam bridge deck. The rails are transported using forklifts and transport trolleys. The rails are first hoisted onto the trolley, and the rails are fixed with pressure plates and bolts on the trolley. Then, they are towed to the construction point by forklifts. Sleepers, fasteners, etc., are distributed using forklifts. If the viaduct is on one side of the road, the hoisting is carried out along the other side of the viaduct, and a truck crane is used to lift the rail materials to the vicinity of the work surface before distribution.

[0039] S2, Base cleaning.

[0040] Adjust the pre-reserved anchoring steel bars in the civil engineering to ensure they are perpendicular to the beam surface and have a 90° bend, without encroaching on the track reinforcement mesh. Temporarily seal the pre-reserved drainage holes and emergency holes in the civil engineering with rigid round covers to prevent rail material from falling from height. Remove the round covers promptly after the track bed construction of this section is completed. Clean the base surface of residue, accumulated water, and stains to meet acceptance requirements.

[0041] S3, Layout of track foundation control network.

[0042] Based on the precise control points provided by the owner, the CPⅢ method was used for measurement. The CPⅢ points were set on the side of the upper flange of the elevated U-shaped beam section. The CPⅢ points were remeasured regularly, and the centerline and side stakes of the line were laid out using the CPⅢ points.

[0043] S4, track panel assembly and erection.

[0044] The rail panel assembly is completed on the elevated work surface. First, the fasteners are assembled with the sleepers, and then the sleepers with the fasteners are fastened to the rails using elastic clips to assemble a 25m rail panel.

[0045] Before assembling the track panels, a track panel table is prepared based on the design documents and technical data.

[0046] First, mark the sleeper position on the inner rail base with red paint or a stone pencil; for curved sections, mark it on the inner rail base of the outer rail. The sleeper should be perpendicular to the centerline of the rail, aligned inside and out, and different types of fasteners should be assembled according to different sections.

[0047] After the track panels are assembled, the track panel installation begins. (Reference) Figure 3 The rail panel support system includes rail support brackets 1, elevation screws 2, bracket connecting rods 3, rail direction adjusting struts 4, and rail direction adjusting bolts 5. Two rail support brackets 1 are fixedly installed under two rails via elevation screws 2, and the rail height is changed by adjusting the elevation screws 2. A bracket connecting rod 3 connects the two rail support brackets 1. Multiple rail direction adjusting bolts 5 are installed on the rail support brackets 1 and bracket connecting rods 3, supporting the rails on both sides. The inclination angle of the rails is changed by adjusting the adjusting bolts on both sides. Adjusting rail direction adjusting struts 4 are installed on the side of the two rail support brackets 1 closest to the U-shaped beam sidewall. The rail panel support system adjusts the rail panel height via elevation screws 2, adjusts the rail panel direction via rail direction adjusting bolts 5, and reinforces the rail panel using adjusting rail direction adjusting struts 4. This system provides the functions of supporting and fixing the rail panel, adjusting the rail panel direction and elevation, and adjusting the rail base slope. All bolts must be tightened securely; loose connections are not permitted. When sleepers and support frames overlap with reserved pipe trenches, they should be adjusted appropriately to ensure uniformity. The rail support bracket 1 is an upper-bearing type, with each rail support bracket 1 spaced 2.5m apart. On straight sections, the rail support bracket 1 should be perpendicular to the track direction, and on curved sections, it should be perpendicular to the tangent direction of the track.

[0048] S5. Reinforcing bar binding and welding.

[0049] For general and moderate vibration-damping integrated track beds, the reinforcing mesh is fabricated at the track-laying base processing yard and then tied on the work surface. The reinforcing bars are bundled near the elevated loading point and hoisted onto the elevated work surface. During installation, materials are transported to the track-laying work surface manually and by a lifting vehicle. After being dispersed in bundles, the reinforcing bars are manually lifted and distributed onto the track bed base slab or the concrete filling surface of the section base slab; they are then manually tied and secured. The bottom and surface layers of reinforcing bars are tied on-site and connected to the inserted longitudinal bars to form a reinforcing cage.

[0050] The dimensions of the steel bars must be processed strictly in accordance with the design requirements and the actual measured elevation.

[0051] Reinforcing bar binding requirements: (1) The double-row steel bars are tied together, and the local deviation between the rows is ±5mm.

[0052] (2) Local deviation of the stressed steel bars in the same row is ±20mm.

[0053] (3) The spacing deviation of the distributed reinforcing bars is ±20mm.

[0054] (4) Stirrup spacing deviation ±20mm.

[0055] (5) The thickness of the concrete protective layer of the lower layer of the track bed deviates from the design by ±5mm, and the thickness of the concrete protective layer of the upper layer and the surrounding area of ​​the track bed deviates from the design by ±10mm.

[0056] The steel mesh construction must be carried out in accordance with the design requirements. Only after the supervisor's hidden inspection is qualified and the pre-embedded pipelines meet the relevant professional requirements can the next process be carried out.

[0057] Requirements for welding of track bed reinforcement: (1) The track bed between two adjacent expansion joints of the overall track bed is called a track bed structure. In each track bed structure, two upper longitudinal structural steel bars are selected and welded to all transverse steel bars.

[0058] (2) Select one transverse steel bar every 5m (or less than 5m) between the upper and lower layers and weld it to all the longitudinal steel bars and the erected steel bars that intersect.

[0059] (3) The lap joints of the longitudinal reinforcement bars in each structural section must be welded.

[0060] (4) The welding between longitudinal reinforcement and total transverse reinforcement shall meet the requirements of GB50204-2010 "Design of Concrete Structures".

[0061] (5) There shall be no electrical connection between the main collection network reinforcement of stray current and the main structure of the station and the elevated structure.

[0062] (6) Drain terminal welding requirements: 1) The transverse reinforcing bars (flat steel) at the outlet of the drain terminal should be welded to all longitudinal structural reinforcing bars in the structural section.

[0063] 2) The end of the embedded copper terminal protrudes 7-10mm from the bed surface. When the terminal is led out, it should avoid conflict with the installation position of other equipment.

[0064] 3) The embedded copper terminal is an integrated product, formed by exothermic welding of copper terminals and 20mm diameter galvanized flat steel. The length of the round steel welded to the bottom of the copper terminal is not less than 100mm. The surface of the copper terminal and the bolt holes of the whole device are protected by plastic bolt caps to prevent other impurities from covering the surface of the pier or entering the bolt holes during civil construction and affecting its conductivity.

[0065] S6. Formwork and formwork support system fabrication and installation.

[0066] refer to Figure 4The template support system includes lateral support rods 6, channel steel 7, intermediate support square steel 8, template support ribs 9, and positioning ribs 10. Track bed templates are positioned and installed on both sides of the two rails using positioning ribs 10. Adjacent track bed templates are connected and fixed using template clamps. Template support ribs 9 are installed between the track bed templates on both sides of the same rail. Channel steel 7 is fixedly installed on the side wall of the U-shaped beam. At least two lateral support rods 6 are installed between each track bed template near the side wall of the U-shaped beam and the channel steel 7. The two lateral support rods 6 abut against the two side plates of the channel steel 7. Intermediate support square steel 8 is installed between the two rows of track bed templates in the middle of the two rails, ensuring that the track bed templates are fixedly supported from both sides and the middle, resulting in a stable position and forming an "external support and internal bracing" template support structure.

[0067] The installation of the formwork directly affects the appearance and alignment of the track bed; therefore, the installation must be smooth, correctly positioned, and firmly secured. Standard steel formwork is used, with a thickness of 5mm and 50mm ribs. The 100mm wide joints between track slabs are formed by assembling two formwork panels for easy assembly and disassembly.

[0068] The templates are connected by M12 bolts, with the side templates running the entire length of the track to ensure longitudinal alignment. Inside the templates, 8mm positioning ribs 10 are installed on the beam surface to ensure an 800mm width for the track bed, and 16mm diameter steel bars are used as internal support ribs at 1m intervals to fix the track bed width. Outside the templates, lateral support rods 6 are supported on channel steel 7 on the U-shaped beam. The channel steel 7 is fixed to the pre-embedded sliding groove of the U-shaped beam with M12 T-bolts, with the lateral support rods 6 spaced 1.5m longitudinally. The middle template of the track bed has 20*40mm square steel bars at the bottom as intermediate supports, with a length of 790mm, supporting the template at 1m intervals. 16mm diameter steel bars are installed on top as internal support ribs, and the two sides of the steel bars are welded into an N-shape for easy fixing to the top of the template. The 100mm wide joints in the track bed are assembled from two 30mm thick templates and 20*40mm square steel pipes. When disassembling the templates, the square steel pipes are removed first, followed by the 30mm templates, making the operation convenient. This formwork and support system have the advantages of clear stress distribution, convenient installation and dismantling, and sturdiness and reliability. Uneven areas where the formwork contacts the beam surface can be sealed with foam adhesive to prevent grout leakage during concrete pouring.

[0069] After the template is installed, it must be reported to the supervision unit for hidden inspection. Concrete can only be poured after the requirements are met.

[0070] Template installation quality requirements: Positional deviation not greater than ±5mm, perpendicularity not greater than ±2mm, surface unevenness not greater than ±3mm, elevation error not greater than ±2mm.

[0071] S7, Track geometry adjustment.

[0072] The track geometry is finely adjusted using instruments such as track inspection trolleys, track gauges, and L-shaped gauges. The accuracy should meet the following requirements: the allowable deviation between the track centerline and the benchmark centerline is ±2mm; for straight sections of the track, a 10m chord is used, with an allowable deviation of 1mm.

[0073] The permissible deviations for the orbital geometry are as follows:

[0074] For curved sections, the allowable deviation should conform to the specifications in the table below:

[0075] S8. Concrete pouring.

[0076] The track bed concrete is transported from the batching plant to the construction site by concrete mixer trucks, and then poured directly onto the elevated working surface using overhead pumps. Where it crosses roads and rivers, overhead pumps can be used to pump concrete onto rail concrete transport vehicles, which then transport the concrete to the pouring surface. Existing rail concrete transport vehicles are used, such as those disclosed in the utility model patent (patent number 2023225314163, patentee: China Railway Electrification Bureau Group Co., Ltd.).

[0077] Before pouring, a slump test must be conducted on the concrete to ensure that it meets the design requirements. The concrete temperature upon entering the formwork should be controlled to not exceed 30°C. During concrete pouring, woven bags should be used to cover the rails and sleepers to prevent contamination of the sleepers and fasteners.

[0078] When pouring concrete, use an immersion vibrator to compact it, and avoid contact with the rails, sleepers, and formwork; the vibration must meet the following requirements.

[0079] 1. Insert vertically, quickly when inserting and slowly when pulling out, to avoid leaving gaps in the concrete.

[0080] 2. Each insertion and vibration time should be about 20-30 seconds, and the time should be taken as the standard when the concrete no longer sinks significantly, no air bubbles appear, and the cement paste begins to rise.

[0081] 3. Vibration time should not be too long. If it is too long, the sand and cement paste will separate, the stones will sink, and a sand layer will form on the concrete surface, which will affect the quality of the concrete.

[0082] 4. When vibrating, the vibrator should be inserted 10cm into the lower layer of concrete to strengthen the bond between the upper and lower layers.

[0083] 5. The spacing between the vibrator insertion points before and after insertion is generally 30-50cm to prevent missed vibration.

[0084] 6. Do not touch the formwork during vibration. When vibrating steel bars, rails, sleepers, and embedded parts near the formwork, the formwork should be lightly tapped with a wooden hammer at the same time. In areas with dense steel bars and at the corners of the formwork, iron rods should be used to compact the material.

[0085] After vibration, the concrete surface of the track bed must be smoothed to prevent reverse slope, which would affect drainage. The track bed elevation is controlled by ensuring that the rail bearing surface of the sleeper is 30mm higher than the track bed surface.

[0086] Before the initial setting of the track bed concrete, the surface layer should be plastered in a timely manner, and the mortar on the surfaces of rails, sleepers, fasteners, support frames, etc. should be cleaned.

[0087] S9. Track bed maintenance and formwork removal.

[0088] Within 12 hours of concrete pouring, it should be cured by covering it with geotextile fabric to keep it moist. The support frame can only be removed after the concrete strength reaches 5MPa or above, and the track can be loaded with loads and vehicles can run after it reaches 70% or more of the design strength.

[0089] Concrete pouring must meet design requirements and be approved by the supervising engineer.

[0090] For concrete compressive strength test specimens, two sets of specimens should be taken for every 100m of concrete poured for the same mix proportion (less than 100m is counted as 100m). One set should be cured under standard conditions, and the other set should be cured under the same conditions as the track bed. The supervisor must be present when the specimens are taken.

[0091] The advantages of this construction method, as described in the above embodiments, are that, depending on site conditions, a truck crane is used to lift the track material into sections onto the bridge deck, where the track panels are assembled. This saves on the need for a track-laying base and large machinery such as gantry cranes. Using forklifts and rail transport trolleys to transport the rails reduces damage to the embedded reinforcing bars on the beam surface and the beam joints, meeting both construction safety and finished product protection requirements while improving construction efficiency. An optimized and adopted formwork and formwork support system utilizes steel formwork, intermediate supports, formwork clamps, and U-shaped beam sidewall supports to form a non-destructive support system. The method improves the formwork support from individual track slabs to continuous side formwork support, followed by the installation of joint formwork, effectively fixing the track slab formwork and improving the track alignment quality. The track slab concrete pouring is highly operable; it can be poured directly using a concrete pump or using a specially developed concrete transport vehicle.

[0092] In addition, more detailed safeguards are in place to ensure the construction quality, safety, and environmental protection of this method.

[0093] The relevant standards and specifications for this construction method are as follows: Railway Track Engineering Construction Quality Acceptance Standard (TB10413-2018); Code for Construction and Acceptance of Underground Railway Engineering (GB50299-2018); Code for Acceptance of Construction Quality of Concrete Structures (GB50204-2015); Standard for Acceptance of Construction Quality of Railway Concrete Engineering (TB10424-2018); Specifications for Surveying and Mapping of Urban Rail Transit Engineering (GB / T50308-2017).

[0094] Key performance indicator quality control standards (1) Allowable deviations of track fine-tuning geometric dimensions; the allowable deviations of track static geometric dimensions are shown in the table below:

[0095] (2) Allowable deviations in the external dimensions of the track bed; the allowable deviations in the external dimensions of the track bed are shown in the table below:

[0096] (3) Deviation of the versine of the track curve; The table of deviations of the versine of the track curve is as follows:

[0097] Quality Measures (1) The base should be cleaned and free of standing water and loose debris.

[0098] (2) Sleepers, fasteners and accessories should be grouped together or stacked neatly by component. Rails should be stacked correctly and not placed randomly.

[0099] (3) The base markers should be firmly buried and the accuracy should meet the requirements. Base markers that are questionable or loose are strictly prohibited from use.

[0100] (4) The track gauge should be calibrated before use. The allowable deviation of the accuracy is (0, +0.5) mm. It is strictly forbidden to use an uncalibrated track gauge.

[0101] (5) The number of concrete compressive strength test specimens should meet the requirements for construction strength assessment. The number of specimens may be increased appropriately to strengthen the monitoring of concrete strength.

[0102] (6) The surface of the reinforcing bars shall not have oily particles or flaky rust. The position shall be marked with lines, and the bars shall be tied and divided into sections strictly according to the drawings. There shall be no incorrect or missing binding.

[0103] (7) All workers should undergo safety training and assessment and safety technical briefing before construction, and special workers should be certified to work. All kinds of machinery and tools required for construction should be fully inspected before construction to ensure that they are in good condition. Construction materials required for construction can only be brought to the site after they have passed inspection.

[0104] (8) Strengthen on-site construction technical guidance and quality supervision, assign a technician to be in charge of on-site technical work, and a quality inspector to be in charge of quality supervision.

[0105] (9) The binding and welding methods of the track bed steel mesh shall comply with the construction specifications and design requirements. Connection terminals shall be reserved at the joints at both ends of the track support platform. The setting of connection terminals shall comply with the technical standards.

[0106] (10) Before pouring the track bed concrete, take anti-pollution measures for the rails, fasteners and sleepers. After the concrete is poured, compact it to ensure density, and water it for curing in a timely manner. Assign a special person to be responsible for the on-site concrete testing, and make test specimens in accordance with relevant regulations, send them for testing in a timely manner, and submit the test results to the supervising engineer for review.

[0107] (11) The pouring of the track bed should be arranged in the evening shift as much as possible to avoid the impact of traffic congestion on the arrival of concrete, and strengthen communication with the concrete supplier to ensure the continuity of concrete pouring.

[0108] Safety measures (1) Operators at each workstation must receive pre-job training and hold a certificate before starting work. During work, they must strictly follow the operating procedures to operate machinery and tools.

[0109] (2) Rails, sleepers, spare parts and other rail materials shall be transported, hoisted and installed in strict accordance with the “Safety Construction Specifications” and “Construction Safety Measures Briefing”. Illegal construction is prohibited and safe construction shall be ensured.

[0110] (3) When erecting the mold, the outline must be marked to ensure the accurate appearance dimensions of the support platform. When erecting the mold and adjusting the rough and fine rails, prevent tools from colliding and causing injury.

[0111] (4) Welding workers and concrete vibrators should take precautions to protect electrical lines to prevent electric shock.

[0112] (5) The construction site shall be laid out strictly in accordance with the general layout plan, and the facilities on site shall be arranged in a reasonable and orderly manner. Production area: Machinery and equipment shall be parked in designated locations, neat and clean; materials shall be stacked in accordance with the construction design location, with labels on them, in a neat and orderly manner, and materials that need to be protected from rain shall be stored in warehouses or covered with rainproof tarpaulins. Safety warning signs shall be hung at the entrances and exits of the construction work area.

[0113] (6) When this construction method is used on the elevated subway line, measures should be taken to prevent falls from height and to ensure safety in summer and winter.

[0114] Environmental protection measures (1) Establish an environmental protection management agency, strictly abide by the relevant laws, regulations and rules on environmental protection issued by the state and local governments during the track laying process, and earnestly carry out environmental protection, ecological protection and soil and water conservation work during construction.

[0115] (2) The construction site shall prevent fuel and release agent from leaking and polluting the track bed and environment; when refueling the generator set and truck crane through the transfer tank, the operators shall not use fire.

[0116] (3) Nighttime operation (22:00~5:00) Strictly control noise. Construction machinery and transport vehicles with strong noise are strictly prohibited from nighttime construction. During construction, staff should be arranged to take turns operating machinery, and low-noise work should be arranged in between to reduce the time of exposure to noise. Earplugs should be provided. At the same time, attention should be paid to the maintenance of machinery to reduce noise. For projects within 150m of residential areas, the construction time should be limited.

[0117] (4) For processes that generate smoke and harmful gases during construction, operators shall be equipped with protective clothing, masks and other labor protection equipment, and strictly follow the operating procedures to prevent environmental pollution.

[0118] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0119] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A construction method for general and moderate vibration-damping track beds on U-shaped beams of subway viaducts, characterized in that, include, S1. Rail material hoisting and distribution, including transporting the rail material to be hoisted to the vicinity of the hoisting point. If the viaduct is in the middle of the traffic road, the station end is selected as the fixed hoisting point, and then the rail material is distributed by forklift. If the viaduct is on one side of the road, the rail material is hoisted along the other side of the viaduct. A truck crane is used to hoist the rail material to the vicinity of the work surface and then distribute it. S2, Base cleaning; S3. Layout of track foundation control network; S4. Rail panel assembly and erection, including: rail panel assembly is completed on the elevated working surface; first, the fasteners are assembled with the sleepers, and then the sleepers with the fasteners are fastened to the rails with elastic clips to form a 25m rail panel; the sleeper positions are first marked on the inner rail bottom with red paint or a stone pencil, and the curved sections are marked on the inner rail bottom of the outer rail; after the rail panel assembly is completed, the rail panel erection begins; S5. Reinforcing bar binding and welding; S6. Formwork and formwork support system fabrication and installation, wherein the formwork support system includes lateral support rods, channel steel, intermediate support square steel, formwork support ribs and positioning ribs. Track bed formwork is set on both sides of the two rails through the positioning ribs. Formwork support ribs are set between the track bed formwork on both sides of the same rail. The channel steel is set on the side wall of the U-shaped beam. At least two lateral support rods are set between each track bed formwork near the side wall of the U-shaped beam and the channel steel. Intermediate support square steel is set between the two rows of track bed formwork in the middle of the two rails. S7, Track geometry adjustment; S8. Concrete pouring; S9. Track bed maintenance and formwork removal.

2. The construction method for general and moderate vibration-damping track beds on U-shaped beams of subway viaducts according to claim 1, characterized in that, Step S2 includes adjusting the anchoring steel bars reserved by the civil engineering to make them perpendicular to the beam surface and with a 90° bend, and ensuring that their height does not encroach on the track steel mesh; temporarily sealing the drainage holes and emergency holes reserved by the civil engineering with rigid round caps; and cleaning the residue, water, and stains from the base surface.

3. The construction method for general and moderate vibration-damping track beds on U-shaped beams of subway viaducts according to claim 1, characterized in that, Step S3 includes measuring using the CPIII method based on the precision control points provided by the owner. The CPIII points are set on the side of the upper flange of the elevated U-shaped beam section. The CPIII points are remeasured periodically, and the centerline and side stakes of the line are laid out using the CPIII points.

4. The construction method for general and moderate vibration-damping track beds on U-shaped beams of subway viaducts according to claim 1, characterized in that, The track panel is erected using a track panel support system, which includes rail support brackets, elevation screws, bracket connecting rods, rail direction adjustment struts, and rail direction adjustment bolts. The two rail support brackets are respectively fixed to the bottom of the two rails by the elevation screw, and the two rail support brackets are connected by the bracket connecting rod. Multiple rail direction adjustment bolts are provided on the rail support brackets and the bracket connecting rod, respectively supporting the two sides of the rail. Adjustable rail direction struts are provided on the side of the two rail support brackets near the side wall of the U-shaped beam.

5. The construction method for general and moderate vibration-damping track beds on U-shaped beams of subway viaducts according to claim 1, characterized in that, Step S5 includes the installation of the steel mesh by cutting and processing materials at the track laying base processing yard and binding them on the working surface.

6. The construction method for general and moderate vibration-damping track beds on U-shaped beams of subway viaducts according to claim 1, characterized in that, Step S8 includes the following steps: the track bed concrete is transported from the batching plant to the construction site by concrete mixer trucks, and poured directly onto the elevated working surface using a boom pump; where the concrete crosses roads and rivers, the boom pump is used to pump the concrete onto a rail concrete transport vehicle, which then transports it to the pouring working surface. Before pouring, a slump test should be conducted on the concrete, and the concrete temperature should be controlled to not exceed 30°C. When pouring concrete, woven bags should be used to cover the rails and sleepers to prevent contamination of the sleepers and fasteners. When pouring concrete, use an immersion vibrator to compact it, and avoid contact with the rails, sleepers, and formwork.

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