Construction method for general and medium vibration reduction ballast bed on U-shaped beam of subway viaduct

Abstract

The invention provides a construction method of a general and medium vibration reduction ballast bed on a U-shaped beam of a subway viaduct, which comprises the following steps of: S1, hoisting and dispersing rail materials; s2, cleaning a substrate; s3, laying a track foundation control network; s4, track panel assembling and erecting; s5, binding and welding reinforcing steel bars; s6, a formwork and a formwork supporting system are manufactured and installed; s7, adjusting the geometric dimension of the track; s8, concrete pouring; and S9, track bed maintenance and form removal. The construction method disclosed by the invention can be used for track operation, and particularly for the sectional transfer track-laying construction of the bridge, i.e., when civil engineering transfers out a section of elevated bridge, the civil engineering enters the site to organize the scattered track-laying operation, so that the efficiency can be improved, and the construction period can be shortened; when only part of bridge sections are transferred for track construction, the construction method has maneuverability and high practicability. The track laying construction 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] The present application relates to the field of track bed construction, in particular to a general and medium damping track bed construction method for a subway viaduct U-shaped beam. BACKGROUND

[0002] With the continuous development of urban rail transit, the viaduct section of the subway has the advantages of economy and fast construction speed, and the U-shaped beam has the characteristics of beauty and high construction efficiency, and has become a popular choice for viaduct beams in domestic rail transit projects in recent years. Therefore, how to carry out track laying construction in the U-shaped beam has become a new direction of track engineering construction in recent years.

[0003] The track is mainly composed of steel rails, damping fasteners, short sleepers and reinforced concrete, from bottom to top, respectively, the track bed, the short sleeper, the fastener and the steel rail, referring to Figure 1 .

[0004] In the prior art, the method used in the construction of the track bed of the viaduct is to assemble a 25m track panel (25m track panel is a whole component composed of two 25m steel rails connected together by sleepers and fasteners) at the track laying base, then transfer the track panel to the track transport flat car by the gantry crane or crane at the base, then transport it to the construction site, then hoist it to the construction point by the track laying gantry crane or gantry crane, then install the track panel to the designed position by the track panel support system, and install the track bed formwork by the track bed formwork system. The track bed formwork is installed by the track bed formwork system, and the concrete pouring is carried out by the track concrete transport vehicle or pump truck.

[0005] Disadvantages: (1) In the construction of urban rail transit, the construction progress of the bridge often lags due to the difficulty in land acquisition and demolition of sections crossing roads, railways, high-voltage cables, etc. In the prior art, the bridge of the section to be constructed needs to be completed, and if there is a breakpoint in the construction of the viaduct section, the 25m track panel cannot be transported to the construction point by the transport vehicle, which requires high construction progress of the bridge.

[0006] (2) The prior art requires the construction of a track laying base, the base needs to be equipped with a gantry crane, the construction site needs to be equipped with a track laying gantry crane or a gantry crane, and the track panel transportation needs to be equipped with a track car and a flat car. Many mechanical equipment is invested, and the safety management workload is large.

[0007] (3) The track bed formwork of the prior art is installed by the track bed formwork system, and the construction error at the joint of the track bed plate is large, the appearance line type of the track bed is difficult to control, and the appearance quality of the track bed is affected. The middle formwork of the track bed is supported by steel pipes and arranged in a scissors type, which is heavy and inconvenient to operate.

[0008] (4) When the bridge section crosses a river channel, a highway, etc., and the concrete cannot be poured by a sky pump, the concrete construction is difficult.

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

[0010] Some projects are located on the main road of the city, the number of continuous beams is large, the key node bridge construction is handed over late, and the track operation surface cannot be continuously improved. In the construction process, according to the characteristics of the general and medium vibration reduction track bed of the U-shaped beam elevated section and combined with the actual situation of the construction site, a scientific, reasonable and perfect track bed construction method is urgently needed to complete the general and medium vibration reduction track bed construction of the U-shaped beam elevated section. SUMMARY

[0011] The embodiment of the present application provides a general and medium vibration reduction track bed construction method for a subway elevated bridge U-shaped beam, solves the problem that track laying base construction lags behind and cannot be constructed by a machine, can timely expand track laying construction operation, guarantees project safety and quality, and promotes construction production progress.

[0012] To achieve the above-mentioned purpose and overcome the above-mentioned technical problems, according to the embodiment of the present application, a general and medium vibration reduction track bed construction method for a subway elevated bridge U-shaped beam is provided, including, 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; S9, track bed maintenance and form removal.

[0013] In some embodiments, in step S1, the track material to be hoisted is transported to the vicinity of the hoisting point, if the elevated bridge is in the middle of the traffic road, the station end is selected as the fixed hoisting point, and then the fork truck is used for scattering; if the elevated bridge is on one side of the road, the track material is hoisted along the other side of the elevated bridge, and then the track material is hoisted to the vicinity of the operation surface by the automobile hoist and then scattered.

[0014] In some embodiments, in step S2, the civil reserved anchoring steel bars are adjusted to be perpendicular to the beam surface and have a 90° bend, and the height cannot invade the track steel mesh; the hard round cover is selected to temporarily block the civil reserved drainage holes and emergency holes; the surface residues, accumulated water and stains of the base are cleaned.

[0015] In some embodiments, step S3 includes, according to the precision control points provided by the owner, using the CPIII method to measure, the CPIII points are arranged on the flange side of the elevated U-shaped beam section, the CPIII points are periodically re-measured, and the line center line and the side stake are laid out by using the CPIII points.

[0016] In some embodiments, step S4 includes, the track panel is assembled on the elevated working surface; the fastener is assembled with the sleeper, and the sleeper assembled with the fastener is buckled on the rail by using the elastic strip to assemble a 25m track panel; The sleeper position is marked on the rail bottom inside the rail with red paint or a stone pen, and the curve section is marked on the inside rail bottom of the outer rail; When the track panel is assembled, the track panel erection is started.

[0017] In some embodiments, the track panel erection is erected by using a track panel support system, the track panel support system includes a rail support bracket, an elevation screw rod, a bracket connecting rod, a rail direction adjusting bolt and a rail direction adjusting bolt; two rail support brackets are fixed below two rails by the elevation screw rod, and the bracket connecting rod is connected between the two rail support brackets, a plurality of rail direction adjusting bolts are arranged on the rail support bracket and the bracket connecting rod and are respectively supported on both sides of the rail, and the rail support bracket is provided with a rail direction adjusting bolt near one side of the U-shaped beam side wall.

[0018] In some embodiments, step S5 includes, the reinforcement mesh is processed by using a track laying base processing yard, and is arranged by using a working surface binding operation mode.

[0019] In some embodiments, step S6 includes, the formwork support system includes a lateral support rod, a channel steel, an intermediate support square steel, a formwork support rib and a positioning rib, a track bed formwork is arranged on both sides of the two rails by using the positioning rib, a formwork support rib is arranged between the track bed formworks on both sides of the same rail, the channel steel is arranged on the U-shaped beam side wall, at least two lateral support rods are arranged between each track bed formwork near the U-shaped beam side wall and the channel steel, and the intermediate support square steel is arranged between the two rows of track bed formworks in the middle of the two rails.

[0020] In some embodiments, step S8 includes, the track bed concrete is transported to the construction site by using a concrete mixer truck of a mixing station, a sky pump is directly stretched to the elevated working surface for pouring; at the crossing of the road and the river, the concrete is pumped to the track concrete transport vehicle by using the sky pump, and then is transported to the pouring working surface by using the track concrete transport vehicle; Before pouring, the concrete slump test should be performed, and the concrete into the mold temperature should be controlled to be not greater than 30℃, the rail and the sleeper are covered by using a woven bag during the concrete pouring, so as to prevent the sleeper and the fastener from being polluted.

[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] In the drawings, only for example, the representation is a schematic diagram, not a physical diagram, and cannot be understood as a limitation of the patent; in order to better illustrate the embodiments of the present application, some components of the drawings may be omitted, enlarged or reduced, and do not represent the actual product size; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0032] The same or similar reference numerals in the drawings of the embodiments of the present application correspond to the same or similar components; in the description of the present application, it should be understood that if the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the positional relationship described in the drawings is only for example, and cannot be understood as a limitation of the patent, for those skilled in the art, the specific meaning of the above terms can be understood according to the specific situation.

[0033] In the description of the present application, unless otherwise explicitly specified and limited, if the term "connection" and the like appear, indicating the connection relationship between the components, the term should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two components or the interaction relationship between two components. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific situation.

[0034] As Figures 1-2 shown, a general and medium damping track bed construction method for subway viaduct U-shaped beam is provided, comprising, S1, track material hoisting and scattering; S2, base cleaning; S3, track foundation control network layout; S4, track assembly and erection; S5, steel bar binding and welding; S6, template and template support system manufacturing and installation; S7, track geometry adjustment; S8, concrete pouring; S9, track bed maintenance and form removal.

[0035] According to the construction progress of the elevated bridge, the track operation can be carried out by using the method, especially when the bridge is handed over in sections for track construction, that is, the civil engineering hands over an elevated bridge section, and the track operation is carried out on site, which can improve the efficiency and shorten the construction period. When only part of the bridge section is handed over for track construction, the method has high maneuverability and strong practicability.

[0036] Some specific embodiments of the general and medium damping track bed construction method for the U-shaped beam of the elevated bridge of the subway are provided below. Embodiment

[0037] S1, track material hoisting and scattering.

[0038] The track material to be hoisted is transported to the vicinity of the hoisting point. If the elevated bridge is in the middle of the traffic road, the station end is selected as the fixed hoisting point, and the 50t truck crane is used to hoist the track material to the U-shaped beam. The steel rails are transported by forklift and supporting trolley, first hoisted to the trolley, fixed by the trolley pressing plate and bolt, then pulled to the construction point by the forklift; the sleepers and fasteners are scattered by the forklift. If the elevated bridge is on one side of the road, the track material is hoisted along the other side of the elevated bridge and scattered after being hoisted to the working surface by the truck crane.

[0039] S2, base cleaning.

[0040] Adjust the civil reserved anchoring steel bars to be perpendicular to the beam surface and have a 90° bend, and the height cannot invade the track reinforcement mesh. Temporary hard round covers are selected to block the civil reserved drainage holes and emergency holes to prevent the track material from falling from a high altitude, and the round covers are removed in time after the completion of the track bed construction in this section. The surface of the base is cleaned of residues, accumulated water and stains to meet the acceptance requirements.

[0041] S3, track foundation control network layout.

[0042] According to the precise control points provided by the owner, the CPIII method is used for measurement, the CPIII points are laid on the upper flange side of the elevated U-shaped beam section, the CPIII points are periodically re-measured, and the line center line and side stake lofting are carried out by using the CPIII points.

[0043] S4, track panel assembly and erection.

[0044] The track panel assembly is completed on the elevated working surface. First, the fasteners are assembled with the sleepers, and then the assembled fasteners are clamped on the steel rails by elastic strips to form 25m track panels.

[0045] Before the track panel assembly, the track panel table is prepared according to the design documents and technical data.

[0046] The sleeper position is marked on the inside rail bottom of the steel rail with red paint or a stone pen, and on the inside rail bottom of the outer rail of the curved section. The sleeper should be perpendicular to the center axis of the steel rail, aligned inside and outside, and different types of fasteners should be assembled according to different sections.

[0047] When the track panel is assembled, the track panel erection is started. Referring to Figure 3 , the track panel support system includes a rail support bracket 1, an elevation screw rod 2, a bracket connecting rod 3, a rail direction adjusting support rod 4, and a rail direction adjusting bolt 5. Two rail support brackets 1 are respectively fixedly installed below two rails through the elevation screw rod 2, and the height of the rail is changed by adjusting the elevation screw rod 2. The bracket connecting rod 3 is connected between the two rail support brackets 1, and a plurality of rail direction adjusting bolts 5 are installed on the rail support bracket 1 and the bracket connecting rod 3 and are respectively supported on both sides of the rail, the inclination angle of the rail is changed by adjusting the adjusting bolts on both sides of the rail, and the rail direction adjusting support rod 4 is installed on one side of the rail support bracket 1 close to the side wall of the U-shaped beam. The track panel support system adjusts the height of the track panel through the elevation screw rod 2, adjusts the direction of the track panel through the rail direction adjusting bolt 5, and strengthens the fixation of the track panel by using the rail direction adjusting support rod 4. The track panel support system has the functions of supporting and fixing the track panel, adjusting the direction, elevation, and slope of the track panel, and each bolt needs to be tightened, and cannot be loosely connected. When the sleeper and the support frame coincide with the reserved pipe trench, the front and rear are properly adjusted to strive for uniformity. The rail support bracket 1 adopts an upper bearing type rail support bracket 1, the rail support bracket 1 is arranged at an interval of 2.5 m, and the rail support bracket 1 of the straight section should be perpendicular to the direction of the line, and the rail support bracket 1 of the curved section should be perpendicular to the tangent direction of the line.

[0048] S5, steel bar binding and welding.

[0049] For general and medium damping overall track bed, the steel mesh adopts the operation mode of unloading and processing in the track laying base processing yard, and binding on the operation surface. The steel bars are bundled near the overhead feeding point and lifted into the overhead operation surface; during the laying, the overhead line is transported to the track laying operation surface by manual and truck; after being arranged one by one, the steel bars are manually lifted and scattered on the track bed bottom plate or the concrete filling surface of the interval bottom plate; and manually bound and fixed. The bottom layer and surface layer steel bars are bound and connected with the longitudinal bars to form a steel cage in the construction site.

[0050] The steel bar processing size is strictly processed according to the design requirements and combined with the actual measured elevation.

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

[0052] (2) The local deviation of the stress steel bars in the same row is ±20 mm.

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

[0054] (4) The spacing deviation of the stirrups is ±20 mm.

[0055] (5) The thickness of the concrete protective layer under the track bed is ±5mm different from the design, and the thickness of the concrete protective layer on the track bed and around is ±10mm different from the design.

[0056] The steel mesh construction is carried out according to the design requirements. After the supervision inspection is qualified and the embedded pipelines meet the relevant professional requirements, the next process can be transferred.

[0057] Track bed steel welding requirements: (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 layer longitudinal structure steels are welded with all the transverse steels.

[0058] (2) Every 5m (or less than 5m), one transverse steel is selected from the upper and lower layers and welded with all the intersecting longitudinal steels and the erected steels.

[0059] (3) The longitudinal steels in each structure section must be welded at the lap joints.

[0060] (4) The welding between the longitudinal steels and the total transverse steels should also meet the requirements of "Concrete Structure Design" GB50204-2010.

[0061] (5) The main collection net of stray current should not be electrically connected with the station and the main structure of the elevated body.

[0062] (6) Drainage terminal welding requirements: 1) The transverse steel (flat steel) of the drainage terminal leading-out point should be welded with all the longitudinal structure steels in the structure section.

[0063] 2) The end of the embedded copper terminal is exposed 7-10mm above the track bed surface. When the terminal is led out, conflicts with other equipment installation positions should be avoided.

[0064] 3) The embedded copper terminal is an integrated product formed by heat welding of the copper terminal and the galvanized flat steel with a diameter of 20mm. The length of the round steel welded at the lower part of the copper terminal is not less than 100mm. The surface of the copper terminal of the whole device and the bolt cavity are protected by plastic bolt covers to prevent other impurities from covering the terminal surface or entering the bolt hole during civil construction, which affects the conductivity of the terminal.

[0065] S6, Formwork and formwork support system manufacturing and installation.

[0066] Reference Figure 4The template support system comprises lateral support rods 6, channel steel 7, intermediate support square steel 8, template support rib 9 and positioning rib 10. The ballast bed template is installed on both sides of the two rails through the positioning rib 10, and the adjacent ballast bed templates are connected and fixed through the template fixture. The ballast bed templates on both sides of the same rail are installed with the template support rib 9. The channel steel 7 is fixedly arranged on the side wall of the U-shaped beam. At least two lateral support rods 6 are installed between each ballast bed template close to the side wall of the U-shaped beam and the channel steel 7. The two lateral support rods 6 are respectively arranged on the two side plates of the channel steel 7. The intermediate support square steel 8 is installed between the two rows of ballast bed templates in the middle of the two rails, so that the ballast bed template is fixed and supported from both sides and the middle, is stable in position and forms the template support structure of “outer support and inner support”.

[0067] The template installation directly affects the appearance line type of the ballast bed, and therefore the installation must be smooth, correct in position and firm without loosening. The template adopts a shaped steel template, the thickness of the template is 5 mm, and the template is provided with a 50 mm rib plate. The 100 mm wide slab joint of the ballast bed is assembled by two templates, which is convenient for disassembly and assembly.

[0068] The templates are connected through M12 bolts, the side templates are arranged along the length of the line to ensure the longitudinal line type. The inside of the template is provided with an 8 mm positioning rib 10 on the beam surface to ensure the 800 mm width of the ballast bed, and a diameter 16 mm steel bar is used as an inner support rib with a spacing of 1 m for fixing the width of the ballast bed. The outer side of the template is supported on the channel steel 7 on the U-shaped beam by the lateral support rod 6, the channel steel 7 is fixed on the embedded sliding groove of the U-shaped beam by the M12 T-shaped bolt, and the longitudinal spacing of the lateral support rod 6 is 1.5 m. The middle template of the ballast bed is provided at the bottom with a 20*40 mm square steel as an intermediate support, the length of the square steel is 790 mm, the square steel is supported on the template with a spacing of 1 m, and a diameter 16 mm steel bar is not arranged above the template as an inner support rib, the two sides of the steel bar are welded into an N shape for convenient fixing above the template. The 100 mm wide slab joint of the ballast bed is assembled by two 30 mm thick templates and 20*40 mm square steel pipes, when the template is disassembled, the square steel pipe is disassembled first, and then the 30 mm template is disassembled, which is convenient to operate. The template and the template support system have the advantages of clear stress, convenient installation and disassembly, firmness and reliability. The uneven part of the contact part between the template and the beam surface can be sealed by foam glue to prevent concrete leakage during concrete pouring.

[0069] After the template installation is completed, the supervision unit shall be reported for hidden inspection, and the concrete can be poured only after it is determined to meet the requirements.

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

[0071] S7, track geometric dimension adjustment.

[0072] The track geometry state is fine-tuned by track inspection trolley, track gauge, L-shaped ruler and other instruments, and the accuracy shall meet the following provisions: the allowable deviation of track center line from base mark center line is ±2mm, and the allowable deviation of track direction straight section measured by 10m chord is 1mm.

[0073] The allowable deviation of track geometry is as follows:

[0074] The allowable deviation of curve section measured by 10m chord shall meet the following table:

[0075] S8, concrete pouring.

[0076] The track bed concrete is transported to the construction site by the concrete mixer truck from the mixing station, and is poured by the aerial pump directly extending to the elevated working surface; at the crossing of roads and rivers, the concrete can be pumped to the track concrete transport vehicle by the aerial pump, and then is transported to the pouring working surface by the track concrete transport vehicle. The track concrete transport vehicle uses the existing track concrete transport vehicle, for example, the utility model patent (patent No. 2023225314163, patentee: China Railway Electrification Bureau Group Co., Ltd., disclosed track concrete transport vehicle).

[0077] Before pouring, the slump test of the concrete must be carried out to ensure that it meets the design requirements, and the concrete pouring temperature should be controlled not to exceed 30℃, and the steel rail and sleeper are covered with a woven bag during concrete pouring to prevent pollution to the sleeper and fastener.

[0078] During concrete pouring, the inserted type vibrating rod is used for vibration and compaction, and shall not collide with the steel rail, sleeper and formwork; the vibration shall meet the following requirements.

[0079] 1. Vertical insertion, fast insertion and slow extraction to avoid leaving gaps in the concrete.

[0080] 2. The insertion time of each vibration is about 20-30 seconds, and the concrete no longer significantly subsides, no bubbles appear, and the beginning of the slurry is used as the criterion.

[0081] 3. The vibration time should not be too long, too long will cause the separation of sand and cement slurry, stone sinking, and the formation of sand layer on the surface of the concrete, affecting the quality of the concrete.

[0082] 4. The vibrator shall be inserted into the lower layer of concrete by 10cm to enhance the combination of upper and lower layers of concrete.

[0083] 5. The distance between the front and rear insertion of the vibrator is generally 30-50cm to prevent vibration leakage.

[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 (GB 50299-2018); Code for Construction and Acceptance of Concrete Structure Engineering (GB 50204-2015); Code for Construction and Acceptance of Railway Concrete Engineering (TB 10424-2018); Code for Survey of Urban Rail Transit Engineering (GB / T 50308-2017).

[0094] Key Index Quality Control Standards (1) Allowable deviation of track fine adjustment geometric dimension; the allowable deviation table of track static geometric dimension is as follows:

[0095] (2) Allowable deviation of track bed shape dimension; the allowable deviation table of track bed shape dimension is as follows:

[0096] (3) Allowable deviation of track line curve versine; the allowable deviation table of track line curve versine is as follows:

[0097] Quality Measures (1) The base should be clean, without accumulated water and debris.

[0098] (2) Sleeper, fastener and accessories should be stacked neatly in groups or by parts, and steel rails should be stacked correctly without random placement.

[0099] (3) The base marker should be firmly embedded, and the precision should meet the requirements. The base marker with doubts or looseness should not be used.

[0100] (4) The track gauge should be calibrated before use, and the allowable deviation of precision is (0, +0.5) mm. The track gauge without calibration should not be used.

[0101] (5) The number of concrete compression test specimens should meet the construction strength evaluation, and the number of groups can be appropriately increased to strengthen the monitoring of concrete strength.

[0102] (6) The surface of steel bars should not have oil stains, particles or sheet rust. The position should be marked and positioned, and the binding and slicing should be strictly according to the drawing requirements without wrong or missed binding.

[0103] (7) All operating personnel should pass the safety training examination and safety technical briefing before construction, and special workers should hold certificates to work; various machines required for construction should be fully inspected before starting work to ensure good condition; engineering materials required for construction should be inspected and qualified before entering the site.

[0104] (8) Strengthen the field construction technology guidance and quality supervision, send a technical staff responsible for the field technology work, quality inspectors responsible for quality supervision.

[0105] (9) The way of binding and welding of the track bed reinforcement mesh conforms to the construction specification and design requirements. The connecting terminals are reserved at the joint of the rail support platform ends. The setting of the connecting terminals must conform to the technical standards.

[0106] (10) Before pouring the track bed concrete, take pollution prevention measures for the steel rails, fasteners and sleepers. After pouring the concrete, carry out tamping to ensure compactness and timely watering and maintenance. Assign a person to be responsible for the on-site concrete testing and make test pieces according to the relevant provisions and send them for testing in time. Report the test results to the supervising engineer for review.

[0107] (11) Try to arrange the pouring of the track bed in the late shift to avoid the impact of traffic congestion on the arrival of the concrete and strengthen the contact with the concrete supplier to ensure the continuity of the pouring concrete.

[0108] Safety measures (1) Each workstation operator receives pre-service training before work and works with a certificate. Operate the machinery and tools strictly according to the operation procedures.

[0109] (2) In the process of transporting, hoisting and installing the rails, sleepers and fastener spare parts, strictly follow the "Safety Construction Specification" and "Construction Safety Measures Interchange" to ensure safe construction.

[0110] (3) The appearance size of the rail support platform must be accurate after the pop line. When setting the formwork, fine and coarse track adjustment, prevent mutual collision when using tools.

[0111] (4) The electric welding operators and concrete vibrating personnel should pay attention to the protection of the electric line to prevent electric shock.

[0112] (5) The construction site is strictly arranged according to the general plan. The facilities in the field are reasonably and orderly arranged. The production area: the mechanical equipment is parked in a fixed point, neat and clean; the materials are hung and stacked according to the construction design position, neat and orderly. The materials that need to be protected from rain are stored in the warehouse or covered with rainproof tarpaulin. Safety warning signs are hung at the entrance of the construction operation area.

[0113] (6) This construction method is used in the construction of the elevated line of the subway. Measures should be taken to prevent high-altitude falling and summer and winter safety measures.

[0114] Environmental protection measures (1) Establish an environmental protection management institution. Strictly follow the relevant laws, regulations and rules of environmental protection issued by the state and local government during the track laying construction process. Effectively do the construction environmental protection and ecological protection, water and soil conservation work.

[0115] (2) The construction site should prevent fuel and release agent leakage pollution bed and environment; through the transfer tank for generator set and automobile crane refueling, operating personnel prohibited the use of fireworks.

[0116] (3) Night operation (22:00~5:00) strictly control noise, noise of construction machinery and transport vehicles, strictly prohibited night construction, construction reasonable arrangement of staff rotation operation machinery, interspersed with low noise work, reduce the time of exposure to noise, and equipped with earplugs, while paying attention to mechanical maintenance, reduce noise, within 150m from the residential area of the project, limit the construction time.

[0117] (4) For the construction of smoke and harmful gas process, operating workers equipped with protective clothing, masks and other labor protection articles, strictly operating procedures, to prevent pollution of the environment.

[0118] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses or adaptations of the application following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice in the art to which the application pertains. It is intended that the specification and examples be considered exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0119] It is to be understood that the application is not limited to the precise construction here described and as shown in the attached drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the present application. The scope of the application 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; 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.

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 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 material is distributed by forklift. If the viaduct is on one side of the road, the material is hoisted along the other side of the viaduct, and a truck crane is used to lift the rail material to the vicinity of the work surface and then distribute it.

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 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.

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, 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.

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 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.

6. The construction method for general and moderate vibration-damping track beds on U-shaped beams of subway viaducts according to claim 5, 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 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.

7. 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.

8. 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, 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 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.

9. 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.

10. 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 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 above, and the track can be loaded and driven after it reaches 70% or more of the design strength.

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