A Construction Method for Scattered Laying of Embedded Tracks in Subway Tunnels

Abstract

The present invention discloses a construction method for the scattered laying of embedded tracks in subway tunnels, which includes the following steps: S1, construction preparation; S2, steel rail erection; S201, base treatment; S202, measurement and lofting; S203, running rail erection; S204, steel rail installation and erection; S3, installation of steel bearing rail grooves; S301, transportation of steel bearing rail grooves; S302, installation of steel bearing rail grooves; S4, construction of ballast bed reinforced concrete; S401, construction preparation; S402, steel bar fabrication and installation; S403, installation of ballast bed formwork; S404, precise adjustment of tracks; S405, pouring of ballast bed concrete; S406, formwork removal; S5, steel rail welding; S6, construction of high molecular damping materials in the grooves. By installing running rails on the chute of tunnel segments, the present invention enables the operation of track laying gantry cranes as in-tunnel transportation lines and equipment. Before the construction of the ballast bed, steel rails are erected as tool rails to fix the tooling, and then the ballast bed is constructed, reducing the investment in tooling and equipment, saving materials, and improving construction efficiency.

Description

Technical Field

[0001] The present invention relates to the field of subway tunnel construction, and particularly to a method for spreading and laying embedded tracks in subway tunnels. Background Art

[0002] Under the current development direction of "new infrastructure", the construction of urban rail transit has become the most important content of China's economic development. Most of the existing vibration reduction track types for subways are discrete supports, and the embedded track system with continuous support (referred to as "embedded track") has no fasteners to fix the rails, and uses polymer materials to restrain the rails, with the characteristics of vibration reduction and noise reduction, good insulation performance, long service life, and less daily maintenance work during operation.

[0003] At present, the embedded track has a certain number of applications in Guangzhou, Shenzhen, and Chongqing in domestic urban rail transit, but the structural forms are different, and a standardized construction process flow has not been formed. Therefore, it is of great significance to explore and summarize a set of construction methods for embedded tracks to meet the requirements of track structure design and application, improve the safety, smoothness, and comfort of vehicle operation, and provide technical guidance for rail transit construction.

[0004] The Chinese patent with the application number "201710805080.1", the publication date of "2017.11.17", and the invention name of "A rapid construction method for an embedded track system in a tunnel" discloses a method for constructing an embedded track, but this method requires a large number of tools and equipment for transporting materials during the construction of the roadbed, with high cost and slow construction efficiency.

[0005] Therefore, there is an urgent need for a method for spreading and laying embedded tracks in subway tunnels to reduce the investment in tools and equipment during the construction of the roadbed, reduce the cost, and improve the construction efficiency. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for spreading and laying embedded tracks in subway tunnels, which solves the problem that the existing construction methods for embedded tracks in subway tunnels require a large number of tools and equipment during the construction of the roadbed and have slow construction efficiency.

[0007] To solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A method for spreading and laying embedded tracks in subway tunnels according to the present invention includes the following steps:

[0009] S1. Construction preparation;

[0010] S2. Rail erection; S201. Subgrade treatment: Before the foundation construction, clean the sundries in the subgrade and the segment manholes thoroughly; S202. Surveying and setting out: According to the CPIII control network established in the tunnel, accurately position the line center, offset piles, and running rail center with a total station, mark them clearly on-site, and hand over the lifting amount to the operators; S203. Running rail erection: The running rails are laid with steel bearings. The steel bearings are fixed to the segment chute of the tunnel through T-bolts. The running rails and the steel bearings are fixed by clip plates. Adjacent running rails are connected by joint splints; S204. Rail installation and erection: Transport the rails to the vicinity of the working face by rail car, and hoist the rails with a gantry crane for track laying; According to the line center and offset piles, use a rail-lifting tooling to erect the rails to the corresponding positions, and fix the rails with rail-lifting support frames, inclined support screws, and gauge struts. The rails are temporarily connected and locked with emergency connectors, and the elevation and gauge of the rails are roughly adjusted. The rails are 200 - 300 mm higher than the designed rail surface.

[0011] S3. Installation of steel rail bearers; S301. Transportation of steel rail bearers: The steel rail bearers are transported to the working face by rail car and scattered onto the subgrade by a gantry crane for track laying; S302. Installation of steel rail bearers: Manually cooperate with the gantry crane for track laying to install the steel rail bearers under the rails. The steel rail bearers and the rails are connected by connectors; After the erection of the steel rail bearers is completed, roughly adjust the geometric positions of the steel rail bearers and the rails again.

[0012] S4. Construction of ballast bed reinforced concrete; S401. Construction preparation; S402. Fabrication and installation of steel bars: The ballast bed steel bars are processed by centralized blanking and processing in the base steel bar shed, and then tied and welded into shape on-site; After being transported to the working face by rail car, the semi-finished steel bars are tied into a ballast bed steel bar mesh according to the design requirements, and the stray current is set according to the design requirements; S403. Installation of ballast bed formwork: The ballast bed formwork is divided into expansion joint formwork and central drainage ditch formwork, which are fabricated on-site; S404. Precision adjustment of tracks: During the precision adjustment of tracks, a total station is used in cooperation with a track inspection trolley for adjustment. First, use a right-angle track gauge to adjust the direction and elevation of one rail according to the encrypted basic benchmarks, and adjust the elevation by adjusting the rail-lifting support frame and the gauge by adjusting the inclined support screw; Then adjust the other rail. After the adjustment is completed, tighten the inclined support screw and the gauge strut to fix the rail; S405. Pouring of ballast bed concrete: Use a hopper loaded on a rail car to transport concrete for ballast bed pouring construction; S406. Formwork removal.

[0013] S5. Rail welding: The rails are welded by mobile flash welding; After the ballast bed concrete reaches the designed strength, first string the rails and lay them scattered, and then adjust the welded rails to meet the requirements of flash welding. Clamp the rails with a flash welding machine for welding. After welding, grind the rail joints and conduct flaw detection on the rail joints; After completion, push the rails forward to carry out the welding of the next section of rails.

[0014] S6. Construction of polymer damping material in the slot; S601. Construction preparation before the rail is inserted into the slot; S6011. Rust removal and cleaning of the rail and the steel bearing rail slot; S6012. Coating the interface agent of the polymer damping material; S6013. Bonding the elastic cushion plate; S6014. Laying the height-adjusting cushion plate and the rail bottom slope cushion plate; S602. Inserting the rail into the slot and fine-tuning; S603. Treatment of special parts; S604. Pouring the polymer damping material; S605. Maintenance and on-site cleaning.

[0015] In some embodiments, in step S1, the construction preparation includes: S101. Organizing technicians to conduct a review of the construction drawings to master the technical requirements of the construction drawings; S102. Preparing the corresponding materials and supplies in advance according to the design drawings and construction requirements, and conducting inspections and records in advance to ensure effective and safe use; S103. Establishing a CPIII control network based on the measurement handover pile data, and the measurement results are approved; S104. Organizing the construction machinery and equipment to enter the site, and doing a good job in the inspection and acceptance of the equipment entering the site; S105. Compiling a construction plan and submitting it to the owner and the supervisor for approval; S106. Compiling an operation instruction manual for the embedded track, and completing the technical training and safety technical disclosure for the on-site operators; S107. Completing the installation of the upper and lower channels at the wellhead, the lighting in the tunnel, and the construction electricity.

[0016] In some embodiments, in step S2, S203. The steel bearing is a height-adjustable steel bearing, and the distance between two adjacent steel bearings is 1.2 m. The gauge of the running rail in the tunnel is set to 4.1 m; S204. Fix the rail with a track-lifting support frame, an inclined support screw rod, and a gauge strut. The distance between two adjacent track-lifting support frames is 3 m, and the length of the inclined support screw rod is 1.15 m.

[0017] In some embodiments, in step S3, S301. The length of each steel bearing rail slot is 2 m, the cross-section height is 165 mm, the width is 200 mm, and the thickness is 10 mm. Anchor bars with a diameter of 16 mm are arranged on both sides of the steel bearing rail slot every 200 mm; S302. The bottom end of the connecting piece is connected and fixed to the steel bearing rail slot by bolts, and the top end fixes the rail pressing plate by bolts to anchor the bottom of the rail; The adjustment and positioning procedure of the steel bearing rail slot is to adjust the elevation first, then the direction, and then conduct a review of the elevation; Adjust one side of the steel slot first, then the other side, and conduct rough adjustment first and then fine adjustment, and repeatedly adjust until it meets the standards; The technical requirements for the bearing rail slot are an elevation control error of ±3 mm and a center line control error of 3 mm.

[0018] In some embodiments, in step S4, S401. Construction preparation includes having all the required steel bars, earthing terminals, and track bed formworks for track bed construction, and completing the on-site acceptance and tests in advance; checking and recording the materials required for construction in advance to ensure their effective and safe use; after manual cleaning in the tunnel, removing floating debris with high-pressure air or high-pressure water; arranging for construction drainage to ensure that there is no flowing water or accumulated water at the working face; measuring and positioning the installation positions of steel bars, expansion joint formworks, and central drainage ditch formworks.

[0019] In some embodiments, in step S4, S402. When processing steel bars, rationally allocate the sizes of steel bars to minimize waste; use the lofted position of the base side line for spreading, adjusting the spacing, welding, and tying; both ends of the transverse steel bars and erection steel bars have hook designs. When bending the steel bars into shape, bend them at the designed bending angle in one go and do not bend them repeatedly; the technical requirements for steel bar installation are that the control error of the steel bar spacing is ±20 mm; the steel bar protection layer thickness is 0 to +5 mm.

[0020] For the longitudinal steel bars of the stray current collection network during the setting of stray current, it is required that they are electrically fully connected within the section. If there are lap joints for the longitudinal steel bars, lap welding must be carried out, and the weld length is greater than 6 times the diameter of the steel bar; select 4 longitudinal steel bars at the top and bottom layers of the track bed steel bars and weld them to all transverse structural steel bars. These longitudinal steel bars serve as drainage bars.

[0021] In some embodiments, in step S4, S403. Expansion joints are provided for the embedded track every 12 m. The expansion joint formwork uses asphalt oil wood boards with a thickness of 20 mm. The height of the expansion joint formwork is 230 mm lower than the height of the track bed, and the length is the same as the width of the track bed main body. The width of the track bed slab joint at the upper part of the expansion joint is 200 mm, which is used as the later maintenance interface and also serves as the drainage open ditch on both sides; the expansion joint formwork needs to be installed firmly. Transverse steel bars can be welded respectively at the upper and lower parts on both sides of the expansion joint for fixation, and wooden wedges are used in combination at the upper part to limit the movement of the expansion joint formwork; install a wooden formwork box with a length × height × width = 2400 mm × 230 mm × 200 mm on the top surface of the expansion joint formwork. Fix the middle part of the expansion joint formwork with wooden wedges for convenient formwork removal.

[0022] The width of the central drainage ditch formwork is 800 mm, and the depth is processed on-site according to the thickness of the track bed; the cross-section of the drainage ditch crossbeam is 200*200*800 mm; both the central drainage ditch formwork and the drainage ditch crossbeam formwork are processed with bamboo plywood, and the formwork is supported with 4*8 cm square timbers; the formwork is anchored with wire by installing anchor bolts at the base.

[0023] In some embodiments, in step S6, S601, construction preparation before the rails are put into the grooves; S6011, rust removal and cleaning of the rails and steel rail bearing grooves; first, the rails are lifted above the top surface of the steel grooves, wooden squares are placed on the top of the steel grooves to support the rails, and the rails and steel rail bearing grooves are grinded and rust removed by a hand-held grinder. After grinding, the rails and rail bearing grooves should ensure that the surface is smooth and clean without oxide scale, floating dust, floating rust, and oil stains; after grinding, attention should be paid to surface protection to prevent oil and water pollution; S6012, brushing polymer damping material interface agent; pour the A and B components of the polymer damping material interface agent into a mixing bucket, and stir them thoroughly and evenly with a hand-held stirrer for no less than 2 minutes. n; The coating shall be applied by roller, and all the bonding surfaces of rails and steel rail bearing grooves with polymer damping materials shall be evenly coated, and some parts may be brushed with a brush; the coating height on both sides of the rails shall be higher than the pouring height of the polymer damping material, and the pouring of the polymer damping material shall be completed within 48 hours after the polymer damping material interface agent is completely dried; S6013, bonding elastic pads; continuously and evenly apply pad glue on the bottom of the steel rail bearing groove, and continuously lay the elastic pad with the embossed surface downward on the bottom of the steel rail bearing groove, and press it evenly with a rubber hammer; elastic pads The allowable deviation of the center line of the laying pad is ≤5mm, and hollows are not allowed. There shall be no overlap at the joints, and the spacing at the joints is ≤2mm; S6014, laying height adjustment pads and rail bottom slope pads; use a total station to measure the elevation of the elastic pads at the laying position of the height adjustment pads and record them; calculate the configuration thickness of the height adjustment pads at each point, mark the height adjustment amount on the side of the steel rail bearing groove, the number of combined height adjustment pad layers is not more than 5, and the thickness deviation is ±1mm; lay the rail bottom slope pads on the top of the height adjustment pads, and the rail bottom slope pads should be laid with the thicker side on the outside of the line.

[0024] In some embodiments, in step S6, S602, the rails are slotted and fine-tuned; the rails are hoisted into the steel rail bearing slots using rail slotting tools and track hoists; after the rails are slotted, the rails are first adjusted in elevation and then in gauge; after fine-tuning into place using a total station and a track inspection trolley, the rails are locked with wedge blocks to collect data and adjust the next section of the rails; the elevation adjustment is performed by replacing the height adjustment pads at the bottom of the rails, and the rail elevations are adjusted uniformly first. After the adjustment is completed, the elevations are remeasured, and the gauges are adjusted after the requirements are met; the gauge of the rails is adjusted by adjusting the left and right positions of the wedge blocks installed on both sides of the rail waist, the inner wedge blocks are taken out, and the outer wedge blocks are tightened to reduce the gauge. After the gauge is adjusted into place, the wedge blocks on both sides are tightened at the same time to fix the plane position of the rails; after all the rails are adjusted into place, the geometric shapes and positions of the rails are uniformly reviewed and measurement data is collected.

[0025] In some embodiments, in step S6, S603, special parts treatment; tape or tarpaulin is used to protect the R on both sides of the rail top and the top surface of the track plate, and the protective tape or tarpaulin shall not penetrate into the groove; the bonding interface and wedge block interface damaged during the installation of the rail into the groove and fine-tuning need to be re-coated with the polymer damping material interface agent, and the polymer damping material can only be poured after the polymer damping material interface agent is completely dry; the end of the casting section is sealed with an end-sealing tool, and local gaps are sealed with foam glue; each end face is sealed without gaps; S604, polymer damping material pouring; the polymer damping material needs to be evenly stirred on site, the polymer damping material uses polyurethane A and B components, all polyurethane B components should be shaken before use, the polyurethane A and B components are poured into a mixing bucket respectively, and fully stirred with a stirrer for 2mi n; The stirring head must not be exposed to the surface of the material during stirring to avoid introducing a large number of bubbles, and manual stirring is prohibited; Pour from one side of the rail first, and after the polymer damping material flows out from the other side of the rail, pour the other side to achieve continuous locking of the rail by the polymer damping material of the track system; When pouring, gradually ensure that the pouring height reaches the reserved height of the wheel flange groove, and after the fluidity of the polymer damping material decreases, pour the polymer damping material on the outside of the rail flush with the top surface of the steel rail bearing groove; It is strictly forbidden to pour on both sides of the rail at the same time to avoid air pockets at the bottom of the rail; S605, maintenance and site cleaning; There is a period of curing time after the pouring of the polymer damping material. During the curing period, protective measures must be taken for the polymer damping material. After it is completely cured, check the pouring status of the polymer damping material and clean up the garbage on the ballast bed and rail surface.

[0026] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0027] The forming time of the embedded track is relatively long. The scattered laying method of the present invention can utilize the station end well to organize the construction in advance and complete the embedded track in advance. The present invention installs the running rail on the tunnel segment slideway so that the track-laying gantry crane can be operated as the transportation line and equipment in the tunnel. Before the ballast bed construction, the steel rail is first set up as the tool rail to fix the tooling, and then the ballast bed is constructed, which reduces the investment in tooling and equipment, saves materials, and improves the construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below in conjunction with the accompanying drawings.

[0029] Figure 1 This is a flow chart of a construction method for scattered laying of embedded tracks in subway tunnels according to the present invention;

[0030] Figure 2 A flow chart of the rail erection steps of the present invention;

[0031] Figure 3 It is a flow chart of the construction steps of the reinforced concrete of the ballast bed of the present invention;

[0032] Figure 4 Schematic diagram of the rail installation structure of the present invention;

[0033] Figure 5 Schematic diagram of the installation structure of the steel rail bearing groove of the present invention;

[0034] Figure 6 Top view of the steel rail bearing groove of the present invention;

[0035] Figure 7 is Figure 6 Cross-sectional view taken along line "A-A" in

[0036] Figure 8 is Figure 6 Cross-sectional view taken along line "B-B" in

[0037] Figure 9 Track cross-sectional view after the construction of the present invention is completed;

[0038] Explanation of reference numerals: 1, track lifting support frame; 2, inclined support screw rod; 3, steel rail bearing groove; 4, rail; 5, connecting piece; 6, rail pressing plate; 7, polymer damping material; 8, inner wedge block; 9, outer wedge block; 10, cage; 11, rail bottom slope cushion plate; 12, height adjustment cushion plate; 13, elastic cushion plate. Specific implementation manner

[0039] As Figures 1-3 shown, one embodiment of a construction method for scattered laying of embedded tracks in a subway tunnel includes the following steps:

[0040] S1. Construction preparation;

[0041] S2. Rail erection;

[0042] S201. Subgrade treatment; Before the foundation construction, first clean the sundries in the subgrade and the segment manholes, and use high-pressure water flushing or wet mops to clean the soil and dust in the subgrade and the segment manholes.

[0043] S202. Measurement and lofting; According to the CPIII control network established in the tunnel, use a total station to accurately locate the line center line, outer offset pile, and running rail center line, and mark them clearly on the site, and hand over the track lifting amount to the operators for precise control of the rail height and center line.

[0044] S203. Running rail erection; The running rail is laid using steel bearings. The steel bearings are fixed to the tunnel segment chute through T-bolts. The running rail and the steel bearing are fixed through a buckle, and adjacent running rails are connected through a joint splint.

[0045] S204. Rail installation and erection: Transport the rails to the vicinity of the working surface by railcar, and use a gantry crane for rail lifting. According to the line center and offset stakes, use a rail-lifting tooling to erect the rails to the corresponding positions, and fix the rails with rail-lifting support frames, inclined support screws and gauge rods. Temporarily connect and lock the rails with emergency connectors, and roughly adjust the rail elevation and gauge. The rails are 200 - 300 mm higher than the designed rail surface. In this process, the rails are used as tool rails to reduce the investment in tooling and equipment and save materials. After the reinforced concrete bed construction is completed, then lower the rails into the steel rail bearers.

[0046] S3. Installation of steel rail bearers;

[0047] S301. Transportation of steel rail bearers: Transport the steel rail bearers to the working surface by railcar, and use a gantry crane to scatter and transport them to the base.

[0048] S302. Installation of steel rail bearers: Manually cooperate with the gantry crane to install the steel rail bearers under the rails, and connect the steel rail bearers and the rails through connectors. After the installation of the steel rail bearers is completed, roughly adjust the geometric positions of the steel rail bearers and the rails again to ensure the accurate position of the steel rail bearers.

[0049] S4. Construction of the bed reinforced concrete;

[0050] S401. Construction preparation.

[0051] S402. Steel bar fabrication and installation: The bed steel bars are fabricated and processed in a centralized manner in the base steel bar shed, and are tied and welded on-site at the construction site. After being transported to the working surface by railcar, the semi-finished steel bars are tied into a bed steel bar mesh according to the design requirements, and the stray current is set according to the design requirements.

[0052] S403. Installation of bed formwork: The bed formwork is divided into expansion joint formwork and central drainage ditch formwork, and is fabricated on-site.

[0053] S404. Track fine adjustment: When performing track fine adjustment, use a total station in cooperation with a track inspection trolley to adjust. First, use a right-angle track gauge to adjust the direction and elevation of one rail according to the encrypted base marks, and adjust the elevation by adjusting the rail-lifting support frame and the gauge by adjusting the inclined support screw; then adjust the other rail. After the adjustment is completed, tighten the inclined support screw and the gauge rod to fix the rail.

[0054] S405. Bed concrete pouring: Use a hopper loaded on a railcar to transport concrete for bed pouring construction.

[0055] S406. Formwork removal.

[0056] S5. Rail welding;

[0057] The rails are welded by means of mobile flash welding; after the ballast concrete reaches the design strength, the rails are first strung, the rails are scattered and laid, and then the welded rails are adjusted to meet the requirements of flash welding. The flash welding machine clamps the rails for welding. After welding, the rail joints are ground and the rail joints are inspected for defects; after completion, the rails are pushed forward to weld the next section of rails.

[0058] S6. Construction of the polymer damping material in the groove;

[0059] S601. Construction preparation before the rails are put into the groove; S6011. Rust removal and cleaning of the rails and steel bearing rails; S6012. Painting the interface agent of the polymer damping material; S6013. Bonding the elastic cushion plate; S6014. Laying the height-adjusting cushion plate and the rail bottom slope cushion plate.

[0060] S602. Rails are put into the groove and finely adjusted.

[0061] S603. Treatment of special parts.

[0062] S604. Pouring of the polymer damping material.

[0063] S605. Maintenance and on-site cleaning.

[0064] The forming time of the embedded track is relatively long. The above-mentioned scattered laying method can utilize the station end shaft to organize construction in advance and complete the embedded track ahead of schedule. Moreover, adopting this "bed first and rail later" method can reduce the deviation caused by the ballast construction to the track and improve the track construction accuracy. During construction, the rails are first erected and used as tool rails, which reduces the investment in tooling and equipment and saves materials. The construction process is concise and the construction flow is simple, which is conducive to ensuring the construction quality of the embedded track.

[0065] As Figures 1-9 shown, another more specific embodiment is provided. A more specific construction method for scattered laying of the embedded track in the subway tunnel includes the following steps:

[0066] S1. Construction preparation;

[0067] S101. Organize technical personnel to conduct a joint review of the drawings and master the technical requirements of the construction drawings.

[0068] S102. Prepare the corresponding materials and supplies in advance according to the design drawings and construction requirements, and conduct inspections and records in advance to ensure effective and safe use.

[0069] S103. Establish a CPIII control network according to the measurement handover pile data, and the measurement results are approved.

[0070] S104. Organize the construction mechanical equipment to enter the site and do a good job in the on-site inspection and acceptance.

[0071] S105. Prepare the construction plan and submit it to the owner and supervisor for approval.

[0072] S106. Compile the operation instruction for the embedded track, and complete the technical training and safety technical disclosure for the on-site operators.

[0073] S107. Complete the installation of the access channels at the wellhead, the lighting inside the tunnel, and the construction power supply.

[0074] S2. Erection of steel rails;

[0075] S201. Subgrade treatment; Before the foundation construction, first clean the sundries in the subgrade and the segment manholes, and use high-pressure water flushing or wet mops to clean the soil and dust in the subgrade and the segment manholes.

[0076] S202. Survey and layout; According to the CPIII control network established in the tunnel, use a total station to accurately locate the line center line, the off-track stake, and the running rail center line, and clearly mark them on-site, and hand over the lifting amount to the operators to accurately control the height and center line of the steel rails.

[0077] S203. Erection of running rails; According to the axle load when the MHP12t rail-laying small crane is lifting, select the 24Kg / m rail as the running rail. The running rail is laid with steel supports, and the steel supports are height-adjustable steel supports, which are convenient for adjusting the height of the running rail. The distance between two adjacent steel supports is 1.2m, and the steel supports are fixed to the tunnel segment chute through T-bolts to avoid damage to the segments and improve the construction efficiency. The running rail and the steel support are fixed by buckle plates, and adjacent running rails are connected by joint splints. The gauge of the running rail in the tunnel is set to 4.1m.

[0078] S204. Installation and erection of steel rails (refer to Figure 4 ); Transport the steel rail 4 to the vicinity of the working face by railcar, and use a rail-laying gantry crane to lift the steel rail; According to the line center line and the off-track stake, use a rail-lifting tooling to erect the steel rail to the corresponding position, and fix the steel rail 4 with the rail-lifting support frame 1, the inclined support screw rod 2, and the gauge strut. The distance between two adjacent rail-lifting support frames 1 is 3m, and the length of the inclined support screw rod 2 is 1.15 meters. The steel rails are temporarily connected and locked with emergency devices, and the elevation and gauge of the steel rails are roughly adjusted. The steel rail is 230mm higher than the designed rail surface. In this process, the steel rail 4 is used as a tool rail to reduce the investment in tooling and equipment and save materials. After the reinforced concrete roadbed construction is completed, then lower the steel rail into the steel bearing rail groove 3.

[0079] S3. Installation of steel bearing rail grooves (refer to Figure 5 );

[0080] S301. Steel load-bearing track trough transportation: The length of each steel load-bearing track trough 3 is 2 m, the cross-section height is 165 mm, the width is 200 mm, and the thickness is 10 mm. Anchor bars with a diameter of 16 mm are arranged on both sides of the steel load-bearing track trough 3 every 200 mm. The steel load-bearing track trough 3 is transported to the working surface by a railcar and then scattered and transported to the base by a gantry crane for track laying.

[0081] S302. Steel load-bearing track trough installation: Manpower is used in cooperation with the gantry crane for track laying to install the steel load-bearing track trough 3 under the rail 4. The steel load-bearing track trough 3 and the rail 4 are connected by a connecting piece 5. The spacing of the connecting pieces 5 is 1 m. The bottom end of the connecting piece 5 is connected and fixed to the steel load-bearing track trough 3 by bolts, and the top end fixes the rail pressing plate 6 by bolts to anchor the bottom of the rail 4. The traveling speed of the gantry crane for track laying should be uniform and not too fast. Due to the narrow space in the tunnel, during hoisting, construction workers should stop other operations in the hoisting area, and it is strictly prohibited to have people standing under the steel load-bearing track trough 3. After the steel load-bearing track trough 3 is erected, the geometric positions of the steel load-bearing track trough 3 and the rail 4 should be roughly adjusted again to ensure the accurate position of the steel load-bearing track trough 3. The adjustment and positioning procedure of the steel load-bearing track trough is to adjust the elevation first, then the direction, and then conduct a review of the elevation; adjust one side of the steel trough first, and then the other side. First, conduct a rough adjustment and then a fine adjustment, and repeatedly adjust until it meets the standards. The technical requirements for the steel load-bearing track trough are an elevation control error of ±3 mm and a center line control error of 3 mm.

[0082] S4. Construction of the ballast bed reinforced concrete

[0083] S401. Construction preparation specifically includes having all the steel bars, grounding terminals, and ballast bed formwork required for the ballast bed construction equipped, and conducting in-advance acceptance and tests; checking and recording the materials required for construction in advance to ensure their effective and safe use; manually cleaning the inside of the tunnel and then using high-pressure air or high-pressure water to remove floating debris; doing a good job in construction drainage to ensure that there is no flowing water or accumulated water on the working surface to ensure the overall adhesion between the ballast bed and the base; measuring and positioning the installation positions of the steel bars, the expansion joint formwork, and the center gutter formwork.

[0084] S402. Steel bar fabrication and installation: The ballast bed steel bars are fabricated by centralized cutting and processing in the on-site steel bar shed and then tied and welded into shape at the construction site. After being transported to the working surface by a railcar, the semi-finished steel bars are tied into a ballast bed steel bar mesh according to the design requirements, and the stray current is set according to the design requirements.

[0085] When processing steel bars, rationally allocate the dimensions of steel bars to minimize waste; utilize the position of the lofted base line for dispersion, spacing adjustment, welding, and binding; both ends of the transverse steel bars and erection bars are designed with hook bends. When bending the steel bars into shape, bend them at the designed bending angle in one go and do not repeatedly bend them. The construction of steel bars shall comply with the relevant requirements of GB 50204-2002 "Code for Acceptance of Construction Quality of Concrete Structures". The technical requirements for steel bar installation are that the control error of steel bar spacing is ±20mm; the thickness of the steel bar protective layer is 0 to +5mm.

[0086] For the longitudinal steel bars of the stray current collection network during the setting of stray current, it is required to be electrically fully connected within the section. If there are lap joints for the longitudinal steel bars, lap welding must be carried out, and the weld length is greater than 6 times the diameter of the steel bar; select 4 longitudinal steel bars at the top and bottom of the ballast bed steel bars to weld with all transverse structural steel bars, and this longitudinal steel bar serves as the drainage strip.

[0087] S403. Installation of ballast bed formwork; The ballast bed formwork is divided into expansion joint formwork and central drainage ditch formwork, and is fabricated on-site. Expansion joints are provided every 12m for the embedded track. The expansion joint formwork uses asphalt oil wood boards with a thickness of 20mm. The height of the expansion joint formwork is 230mm lower than the height of the ballast bed, and the length is the same as the width of the main body of the ballast bed. The width of the ballast bed slab joint at the upper part of the expansion joint is 200mm, which is used as the later maintenance interface and also serves as the open drainage ditch on both sides; The expansion joint formwork needs to be installed firmly. Transverse steel bars can be welded respectively at the upper and lower parts on both sides of the expansion joint for fixation, and wooden wedges are used in combination at the upper part to limit the movement of the expansion joint formwork; Install a wooden formwork box with a length × height × width = 2400mm × 230mm × 200mm on the top surface of the expansion joint formwork, and use wooden wedges to fix the middle part of the expansion joint formwork for convenient formwork removal.

[0088] The width of the central drainage ditch formwork is 800mm, and the depth is processed on-site according to the thickness of the ballast bed. The cross-section of the drainage ditch crossbeam is 200*200*800mm. Both the central drainage ditch formwork and the drainage ditch crossbeam formwork are processed with bamboo plywood, and the formwork is supported by 4*8cm square timbers.

[0089] The ballast bed formwork is anchored with wire by installing anchor bolts at the base to prevent the formwork from floating during concrete pouring.

[0090] The allowable deviations for the installation of the ballast bed formwork are shown in the following table:

[0091]

[0092] S404, track fine-tuning: When fine-tuning the track, use a total station with a track inspection trolley for adjustment. First, use a right-angle track ruler to adjust the direction and elevation of one rail according to the encrypted base mark, adjust the elevation by adjusting the track support frame, and adjust the track gauge by adjusting the inclined support screw rod; then adjust the other rail, and after the adjustment is completed, tighten the inclined support screw rod and track gauge support rod to fix the rail. The allowable deviation should comply with the provisions of the following table ("Subway Engineering Construction and Acceptance Specifications" GB / T50299-2018).

[0093] The allowable deviation before concrete pouring is shown in the following table:

[0094]

[0095] S405, Concrete pouring of the ballast bed: concrete is transported by loading hoppers on rail cars for ballast bed pouring. The concrete is transported to the construction site by a concrete mixer truck from the mixing station and directly pumped into the concrete hopper on the rail car, and then hoisted to the working surface for pouring by the track-laying door. Before pouring, the slump test of each truckload of concrete should be carried out, and the temperature of the concrete entering the mold should be controlled not to be greater than 30°C. Before pouring the concrete, the rails, rail frames, and embedded parts should be covered with woven tape to avoid contamination and difficulty in cleaning.

[0096] When pouring concrete, use an inserted vibrator to tamp it, and do not collide with the rails, formwork, rail frame tools, especially the lower part of the beam, which is not easy to tamp and compact. The tamping should be strengthened to ensure the compactness of the overall roadbed concrete. Before concrete construction, the floating slab reinforcement cage should be fully inspected. After the concrete construction is completed, the geometric dimensions of each part should be carefully checked according to the designed dimensions and allowable deviations.

[0097] After the tamping is completed, the surface of the roadbed concrete should be plastered for no less than three times. After 2 hours of pouring the roadbed concrete, the roadbed surface has gradually set and the final finishing is carried out.

[0098] After the concrete pouring construction is completed, the rails, concrete roadbed, etc. should be cleaned in time.

[0099] S406. Formwork removal. After the concrete is poured, watering and curing shall be carried out in time, and the curing time shall be no less than 7 days. The formwork shall be removed one day after the pouring is completed. The surface and edges of the roadbed shall not be damaged during the removal of the formwork, and the waste shall be transported out of the site in time.

[0100] S5, rail welding;

[0101] The rails are welded by the mobile flash welding method; after the ballast concrete reaches the designed strength, the rails are first strung, the rails are laid loose, and then the welded rails are adjusted to meet the requirements of flash welding. The flash welding machine clamps the rails for welding. After welding, the rail joints are ground and the rail joints are inspected for flaws; after completion, the rails are pushed forward for welding the next section of rails.

[0102] Flatness standard of welded joint (mm / 1m)

[0103] Item Top surface Inner working surface Rail bottom surface Main line 0，+0.3 0，±0.3 0，+0.5

[0104] S6. Construction of polymer damping material in the groove (for reference Figure 6 , 7 , 8);

[0105] S601. Construction preparation before the rail is inserted into the groove. S6011. Rust removal and cleaning of the rail 4 and the steel bearing groove 3; to ensure the adhesion of the polymer damping material 7 in the groove to the rail 4 and the side walls of the steel bearing groove 3, and the adhesion of the elastic pad 13 to the steel bearing groove 3, it is necessary to remove rust and polish the rail waist, the side walls and the bottom of the steel bearing groove. First, lift the rail 4 above the top surface of the steel bearing groove 3, and place wooden squares at the top of the steel bearing groove 3 to support the rail 4. Use a hand-held grinding machine to grind and remove rust from the rail and the steel bearing groove. Pay special attention to grinding the lower jaw of the rail head clean, and clean the oil stain on the rail surface with a cleaning agent. After grinding, the rail and the bearing groove should ensure that the surface is smooth and clean, without oxide scale, floating ash, floating rust, and oil stain, and there is no greasy feeling when touched by hand; after grinding, pay attention to the protection of the surface to prevent oil and water pollution. S6012. Apply the polymer damping material interface agent; pour the A and B components of the polymer damping material interface agent into the mixing bucket, and stir evenly with a hand-held stirrer for no less than 2 min; apply it by roller coating. All the bonding surfaces of the rail 4 and the steel bearing groove 3 with the polymer damping material 7 should be evenly coated, and the local area can be supplemented with a brush; pay attention that the coating height on both sides of the rail should be higher than the pouring height of the polymer damping material. Except for the rail adjustment components, all the contact surfaces with the polymer damping material need to be coated, and the side walls of the steel bearing groove should be evenly coated with the adhesive. After the polymer damping material interface agent is completely dry on the surface, pour the polymer damping material within 48 h. S6013. Bond the elastic pad; continuously and evenly apply the pad glue on the bottom of the steel bearing groove, and there should be no local missed coating. Lay the elastic pad with the embossed surface facing down continuously on the bottom of the steel bearing groove, and press it evenly with a rubber hammer; after the elastic pad is laid, cover it to ensure that the inside of the groove is clean and dry. The allowable deviation of the center line of the elastic pad laying is ≤5 mm, there should be no air pockets, and there should be no overlap at the joints, and the spacing at the joints is ≤2 mm. S6014. Lay the height adjustment pad 12 and the rail bottom slope pad 11; use a total station to measure the elevation of the elastic pad 13 at the laying position of the height adjustment pad 12 and record it; calculate the configured thickness of the height adjustment pad 12 at each point, mark the height adjustment amount on the side of the steel bearing groove 3, and the combined number of layers of the height adjustment pad 12 is not more than 5 layers, and the thickness deviation is ±1 mm. Lay the rail bottom slope pad 11 on the top surface of the height adjustment pad 12, and the rail bottom slope pad 11 should be laid to ensure that the thicker side is on the outside of the line.

[0106] S602, Rail slotting and fine adjustment. Use the rail slotting tooling and track lifting machine to hoist the rail into the steel rail bearing slot. After the rail is put into the groove, the rail is first adjusted in elevation, and then the gauge is adjusted; after fine adjustment in place using the total station and the track inspection trolley, the inner wedge block 8 and the outer wedge block 9 are used in conjunction with the retaining frame 10 to lock the rail 4 to collect data and adjust the next section of the rail 4; the elevation adjustment is adjusted by replacing the height adjustment pad 12 at the bottom of the rail 4, and the rail 4 elevation adjustment is first performed uniformly. After the adjustment is completed, the elevation is re-measured, and the gauge is adjusted after the requirements are met; the gauge of the rail 4 is adjusted by adjusting the height of the inner wedge block 8 and the outer wedge block 9 installed on both sides of the rail waist to adjust the left and right positions of the rail 4, take out the inner wedge block 8, and knock the outer wedge block 9 to reduce the gauge, otherwise it becomes larger, and after the gauge is adjusted in place, the inner wedge blocks 8 and the outer wedge blocks 9 on both sides are simultaneously tightened to fix the plane position of the rail 4; after all the rails are adjusted in place, the geometric shape and position of the rails are uniformly checked and the measurement data are collected.

[0107] Fine-tuning technical requirements:

[0108] (1) The inner wedge block 8 and the outer wedge block 9 must be used in pairs according to the design requirements. The top surface of the inner wedge block 8 and the outer wedge block 9 must be at least 20 mm lower than the top surface of the steel rail groove.

[0109] (2) Track gauge: 1435±2mm.

[0110] (3) Horizontal 2mm.

[0111] (4) Height: 2mm.

[0112] (5) Track direction: 2 mm (chord length: 10 m).

[0113] S603. Treatment of special parts. To protect the overall cleanliness of the rail top and the surface of the ballast bed, tape or tarpaulin is used to protect the R on both sides of the rail top and the top surface of the track plate. The protective tape or tarpaulin must not penetrate into the groove. The bonding interface and wedge block interface damaged during the installation of the rail into the groove and fine-tuning need to be re-coated with the polymer damping material interface agent. The polymer damping material can only be poured after the polymer damping material interface agent is completely dry; the end of the pouring section is sealed with an end-sealing tool, and local gaps are sealed with foam glue; each end face is sealed without gaps.

[0114] S604. Pouring of polymer damping material. The polymer damping material needs to be stirred evenly on-site. The polymer damping material uses polyurethane components A and B. All polyurethane component B should be shaken well before use. Pour polyurethane components A and B into the mixing bucket respectively, and stir thoroughly with a stirrer for 2 min. During stirring, the stirring head should not expose the material surface to avoid introducing a large number of air bubbles. Manual stirring is prohibited. Pour from one side of the rail first. After the polymer damping material flows out from the other side of the rail, then pour on the other side to achieve continuous locking of the rail by the polymer damping material in the track system. During pouring, gradually ensure the pouring height to the reserved height of the wheel flange groove. After the fluidity of the polymer damping material decreases, then pour the polymer damping material outside the rail until it is flush with the top surface of the steel bearing rail groove. It is strictly prohibited to pour on both sides of the rail simultaneously to avoid air accumulation at the bottom of the rail.

[0115] S605. Curing and on-site cleaning. After the pouring of the polymer damping material is completed, there is a curing time. During the curing period, protective measures need to be taken for the polymer damping material. After it is completely cured, check the pouring state of the polymer damping material and clean the garbage on the bed and the surface of the rail.

[0116] This construction method is applicable to the construction of embedded tracks in urban rail transit. The reference of the track cross-section diagram after construction according to this method Figure 9 . The loose laying construction of the embedded track adopts the "bed first, rail later" construction method. Use the end shaft of the station to hoist materials, install the running rail and the track-laying gantry crane on the tunnel segment as the in-tunnel transportation line and equipment, and use the track rail as the tool rail to fix the tooling. First, construct the bed, and after the bed is formed, then put the rail into the groove, finely adjust the line, and anchor the rail.

[0117] The forming time of the embedded track is relatively long. The above-mentioned loose laying method can use the end shaft of the station to organize construction in advance and complete the embedded track in advance. And adopting this "bed first, rail later" method can reduce the deviation of the track caused by the bed construction and improve the construction accuracy of the track. During construction, first erect the rail and use this rail as the tool rail to reduce the investment in tooling and equipment and save materials. The construction process is concise and the construction flow is simple, which is beneficial to ensuring the construction quality of the embedded track.

[0118] The embodiments described above are only used to describe the preferred mode of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solution of the present invention should fall within the protection scope determined by the claims of the present invention.

Claims

1. A construction method for the scattered laying of embedded tracks in a subway tunnel, characterized in that, It includes the following steps: S1. Construction preparation; S2. Rail erection; S201. Subgrade treatment; Before the foundation construction, clean the sundries in the subgrade and the segment manholes. S202. Surveying and setting out; According to the CPIII control network established in the tunnel, use a total station to accurately locate the line center line, outer deviation piles, and running rail center line, and mark them clearly on the site, and hand over the lifting amount to the operators. S203. Running rail erection; The running rails are laid with steel bearings. The steel bearings are fixed to the segment chute of the tunnel through T-bolts. The running rails and the steel bearings are fixed through fasteners. Adjacent running rails are connected through joint splints. S204. Rail installation and erection; Transport the rails to the vicinity of the working face by railcar, and use a gantry crane for rail lifting; According to the line center line and outer deviation piles, use a rail lifting tool to erect the rails to the corresponding positions, and use rail lifting supports, inclined support screws, and gauge struts to fix the rails. The rails are temporarily connected and locked with emergency devices, and the elevation and gauge of the rails are roughly adjusted. The rails are 200-300 mm higher than the designed rail surface. S3. Installation of steel bearing troughs; S301. Transportation of steel bearing troughs; The steel bearing troughs are transported to the working face by railcar and scattered to the subgrade by a gantry crane. S302. Installation of steel bearing troughs; Use manual labor in cooperation with a gantry crane to install the steel bearing troughs under the rails. The steel bearing troughs and the rails are connected through connectors; After the erection of the steel bearing troughs is completed, the geometric positions of the steel bearing troughs and the rails need to be roughly adjusted again. S4. Construction of ballast reinforced concrete; S401. Construction preparation; S402. Steel bar fabrication and installation; The ballast steel bars are processed by centralized cutting and processing in the on-site steel bar shed, and are tied and welded into shape at the construction site; After being transported to the working face by railcar, the semi-finished steel bars are tied into a ballast steel bar mesh according to the design requirements, and the stray current is set according to the design requirements. S403. Installation of ballast forms; The ballast forms are divided into expansion joint forms and central drainage ditch forms, and are fabricated on-site. S404. Track fine adjustment; When the track is finely adjusted, a total station is used in cooperation with a track inspection trolley for adjustment. First, use a right-angle track gauge to adjust the direction and elevation of one rail according to the encrypted basic benchmarks, and adjust the elevation through the rail lifting support and the gauge through the inclined support screw; Then adjust the other rail. After the adjustment is completed, tighten the inclined support screw and the gauge strut to fix the rail. S405. Ballast concrete pouring; Use a hopper on the railcar to transport concrete for ballast pouring construction. S406. Form removal; S5. Rail welding; The rails are welded by mobile flash welding; After the ballast concrete reaches the designed strength, first string the rails and spread the rails, and then adjust the welded rails to meet the requirements of flash welding. The flash welding machine clamps the rails for welding. After welding, grind the rail joints and conduct rail joint flaw detection; After completion, push the rails forward for the welding of the next section of rails. S6. Construction of polymer damping material in the slot; S601. Construction preparation before the rail is inserted into the slot; S6011. Rust removal and cleaning of the rail and the steel bearing rail slot; S6012. Coating the interface agent of the polymer damping material; S6013. Bonding the elastic cushion plate; S6014. Laying the height-adjusting cushion plate and the rail bottom slope cushion plate; S602. Inserting the rail into the slot and fine-tuning; S603. Treatment of special parts; S604. Pouring the polymer damping material; S605. Maintenance and on-site cleaning.

2. The construction method for the loose laying of embedded tracks in subway tunnels according to claim 1 is characterized in that: In step S1, the construction preparation includes: S101. Organizing technicians to conduct a joint review of the drawings and mastering the technical requirements of the construction drawings; S102. Preparing the corresponding materials and supplies in advance according to the design drawings and construction requirements, and conducting inspections and records in advance to ensure effective and safe use; S103. Establishing a CPIII control network based on the measurement handover pile data, and the measurement results are approved; S104. Organizing the construction mechanical equipment to enter the site and doing a good job in the on-site inspection and acceptance; S105. Compiling the construction plan and submitting it to the owner and the supervisor for approval; S106. Compiling the operation instruction book for the embedded track, and completing the technical training and safety technical disclosure for the on-site operators; S107. Completing the installation of the upper and lower access channels at the wellhead, the lighting in the tunnel and the construction electricity.

3. The embedded track loose-laying construction method for subway tunnels according to claim 1 is characterized in that: In step S2, S203. The steel bearing is a height-adjustable steel bearing, and the distance between two adjacent steel bearings is 1.2 m. The gauge of the running rail in the tunnel is set to 4.1 m; S204. Fix the rail with the track lifting support frame, the inclined support screw rod and the gauge strut. The distance between two adjacent track lifting support frames is 3 m, and the length of the inclined support screw rod is 1.15 m.

4. The construction method for the loose laying of the embedded track in the subway tunnel according to claim 1 is characterized in that: In step S3, S301. The length of each steel bearing rail slot is 2 m, the cross-section height is 165 mm, the width is 200 mm, and the thickness is 10 mm. Anchor bars with a diameter of 16 mm are arranged on both sides of the steel bearing rail slot every 200 mm; S302. The bottom end of the connecting piece is connected and fixed to the steel bearing rail slot by bolts, and the top end is fixed with a rail pressing plate by bolts to anchor the bottom of the rail; The adjustment and positioning procedure of the steel bearing rail slot is to adjust the elevation first, then the direction, and then conduct a review of the elevation; Adjust one side of the steel slot first, and then the other side. First, rough adjustment and then fine adjustment are carried out, and it is repeatedly adjusted until it meets the standards; The technical requirements for the bearing rail slot are that the elevation control error is ±3 mm and the center line control error is 3 mm.

5. The construction method for scattered laying of embedded tracks in subway tunnels according to claim 1 is characterized in that: In step S4, S401. The construction preparation includes that the steel bars, grounding terminals and bed forms required for the bed construction are fully equipped, and the on-site acceptance and tests are done in advance; The materials required for the construction should be inspected and recorded in advance to ensure effective and safe use; After manual cleaning in the tunnel, floating debris is removed with high-pressure air or high-pressure water; Construction drainage should be done well to ensure that there is no flowing water and ponding on the working surface; Measure and position the installation positions of the steel bars, the expansion joint forms and the center channel forms.

6. The embedded track paving construction method for subway tunnels according to claim 1, characterized in that: In step S4, in S402, when processing steel bars, rationally allocate the sizes of steel bars to minimize waste; utilize the position of the base line that has been lofted to scatter, adjust the spacing, weld, and tie; both ends of the transverse steel bars and the erection steel bars have hook designs. When bending the steel bars into shape, bend them at one time according to the designed bending angle and do not bend them repeatedly; the technical requirements for steel bar installation are that the control error of the steel bar spacing is ±20 mm; the thickness of the steel bar protective layer is 0 to +5 mm. When setting up the stray current, the longitudinal steel bars of the stray current collection network in the interval are required to be electrically fully connected. If there are lap joints in the longitudinal steel bars, lap welding must be carried out, and the weld length is greater than 6 times the diameter of the steel bar; select 4 longitudinal steel bars at the top and bottom of the ballast bed steel bars to weld with all the transverse structural steel bars, and these longitudinal steel bars serve as the drainage strips.

7. The construction method for the loose laying of the embedded track in the subway tunnel according to claim 1 is characterized in that: In step S4, in S403, expansion joints are provided every 12 m for the embedded track. The expansion joint formwork is made of asphalt oil wood board with a thickness of 20 mm. The height of the expansion joint formwork is 230 mm lower than the height of the ballast bed, and the length is the same as the width of the main body of the ballast bed. The width of the ballast bed slab joint at the upper part of the expansion joint is 200 mm, which is used as the later maintenance interface and also serves as the drainage open ditch on both sides; the expansion joint formwork needs to be installed firmly, and transverse steel bars are welded respectively at the upper and lower parts on both sides of the expansion joint for fixation, and wooden wedges are used in cooperation at the upper part to limit the movement of the expansion joint formwork; install a wooden formwork box with a length × height × width = 2400 mm × 230 mm × 200 mm on the top surface of the expansion joint formwork, and use wooden wedges to fix the middle part of the expansion joint formwork for easy formwork removal. The width of the central gutter formwork is 800 mm, and the depth is processed on-site according to the thickness of the ballast bed; the cross-section of the gutter cross beam is 200*200*800 mm; both the central gutter formwork and the gutter cross beam formwork are processed with bamboo plywood, and the formwork is supported with 4*8 cm square timbers; the formwork is anchored with wire by installing anchor bolts at the base.

8. The construction method for the scattered paving of the embedded track in the subway tunnel according to claim 1, characterized in that: In step S6, S601, construction preparation before the rails are put into the grooves; S6011, rust removal and cleaning of the rails and steel rail bearing grooves; first lift the rails to above the top surface of the steel grooves, place wooden squares on the top of the steel grooves to support the rails, use a handheld grinder to grind and remove rust from the rails and steel rail bearing grooves, and after grinding, the rails and rail bearing grooves should ensure that the surface is smooth and clean without oxide scale, floating dust, floating rust, and oil stains; after grinding, attention should be paid to surface protection to prevent oil and water pollution; S6012, apply polymer damping material interface agent; pour the A and B components of the polymer damping material interface agent into a mixing bucket, and stir them evenly with a handheld stirrer for at least 2 minutes; the application is carried out by roller coating, and all rails and steel rail bearing grooves and the polymer damping material bonding surfaces should be evenly painted, and local brushing should be used for supplementary brushing; the painting height on both sides of the rails should be higher than the casting height of the polymer damping material After the polymer damping material interface agent is completely dry, the pouring of the polymer damping material shall be completed within 48 hours; S6013, bonding elastic pads; continuously and evenly apply pad glue on the bottom of the steel rail bearing groove, lay the elastic pad with the embossed surface downward on the bottom of the steel rail bearing groove, and press it evenly with a rubber hammer; the allowable deviation of the laying center line of the elastic pad is ≤5mm, and no hollowing is allowed. There shall be no overlap at the joints, and the spacing at the joints is ≤2mm; S6014, laying height adjustment pads and rail bottom slope pads; use a total station to measure the elevation of the elastic pad at the laying position of the height adjustment pad and record it; calculate the configuration thickness of the height adjustment pad at each point, mark the height adjustment amount on the side of the steel rail bearing groove, the number of combined layers of the height adjustment pads shall not exceed 5 layers, and the thickness deviation shall be ±1mm; the rail bottom slope pad is laid on the top surface of the height adjustment pad, and the rail bottom slope pad should be laid to ensure that the thicker side is on the outside of the line.

9. The construction method for scattered laying of embedded tracks in subway tunnels according to claim 1 is characterized in that: In step S6, S602, the rails are slotted and fine-tuned; the rail slotting tooling and track lifting machine are used to hoist the rails into the steel rail bearing slots; after the rails are slotted, the rails are first adjusted in elevation and then in gauge; after fine-tuning in place using the total station and the track inspection trolley, the rails are locked with wedge blocks to collect data and adjust the next section of the rails; the elevation adjustment is made by replacing the height adjustment pads at the bottom of the rails, and the rail elevations are adjusted uniformly first. After the adjustment is completed, the elevations are re-measured, and the gauges are adjusted after the requirements are met; the gauge of the rails is adjusted by adjusting the left and right positions of the rails through the height positions of the wedge blocks installed on both sides of the rail waist, the inner wedge blocks are taken out, and the outer wedge blocks are knocked tight to reduce the gauge. After the gauge is adjusted in place, the wedge blocks on both sides are simultaneously knocked tight to fix the plane position of the rails; after all the rails are adjusted in place, the geometric shapes and positions of the rails are uniformly reviewed and measurement data is collected.

10. The subway tunnel embedded track loose-laying construction method according to claim 1, characterized in that: In step S6, S603. Treatment of special parts: Protect the two sides R of the rail head and the top surface of the track slab with tape or oilcloth. The protective tape or oilcloth shall not extend into the groove. The bonding interface and the wedge block interface damaged during the process of hoisting the rail into the groove and fine adjustment need to be recoated with the polymer damping material interface agent. After the polymer damping material interface agent is completely surface-dried, the polymer damping material can be poured. Seal the end of the pouring section with a sealing tool and plug the local gaps with foam rubber. Seal all end faces without gaps. S604. Pouring of polymer damping material: The polymer damping material needs to be stirred evenly on site. The polymer damping material uses polyurethane components A and B. All polyurethane component B should be shaken well before use. Pour polyurethane components A and B into the mixing bucket respectively and stir thoroughly with a stirrer for 2 minutes. When stirring, the stirring head shall not expose above the material surface to avoid bringing in a large number of air bubbles. Manual stirring is prohibited. Pour from one side of the rail first. After the polymer damping material flows out from the other side of the rail, then pour on the other side to achieve continuous locking of the rail by the polymer damping material in the track system. During pouring, gradually ensure the pouring height to the reserved height of the wheel flange groove. After the fluidity of the polymer damping material decreases, then pour the polymer damping material outside the rail to be flush with the top surface of the steel bearing rail groove. It is strictly prohibited to pour on both sides of the rail simultaneously to avoid air accumulation at the bottom of the rail. S605. Curing and on-site cleaning: After the polymer damping material is poured, there is a curing time. During the curing period, protective measures need to be taken for the polymer damping material. After it is completely cured, check the pouring state of the polymer damping material and clean the garbage on the ballast bed and the rail surface.

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