Construction method of subway main line external hanging shaft track laying base

Abstract

The application discloses a construction method of a subway main line externally-hung vertical shaft track laying base, which comprises the following steps: step one, selecting the externally-hung vertical shaft as a discharging port; step two, construction preparation; step three, temporary facility construction and acceptance; step four, hole equipment installation; step five, hole equipment debugging and acceptance; step six, material transportation; and step seven, track bed construction. The application can increase the working surface by adding the vertical shaft, simultaneously work at multiple points, greatly reduce the construction period and save the construction cost.

Description

Technical Field

[0001] This invention belongs to the field of subway construction technology, specifically relating to a construction method for a track-laying base with external vertical shafts on a subway mainline. Background Technology

[0002] Urban rail transit, as the backbone of my country's transportation network, features high capacity, high efficiency, and low energy consumption, offering unique advantages in alleviating urban traffic pressure and representing a resource-saving and environmentally friendly mode of transportation. In recent years, the rapid economic development of major cities has significantly increased the demand for urban rail construction, with particularly tight schedules. Due to operational needs, completed sections often need to be opened ahead of schedule, and existing track shafts closed prematurely for segmented train testing. This prevents track-laying units from following the initial construction organization for unfinished sections, resulting in high construction difficulty and tight deadlines, making it impossible to complete the project on schedule. Therefore, when constructing unfinished sections, vertical shafts are typically added along the line according to track-laying requirements. However, due to the small shaft openings and difficulties in material handling and construction, it is still difficult to complete the project on schedule. Therefore, there is an urgent need for a construction method that can improve construction efficiency and reduce construction difficulty to solve the problems of vertical shaft construction. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a construction method for a track-laying base with external shafts on a subway main line. This method can increase the number of working surfaces by adding shafts, allowing for simultaneous operation at multiple points, significantly reducing the construction period and saving construction costs.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is to provide a construction method for a track-laying base on an external vertical shaft of a subway mainline, comprising the following steps:

[0005] Step 1: Select the external shaft of the main line as the unloading port: The external shaft of the main line is a shaft located outside the track area and connected to the track area through a horizontal sliding passage.

[0006] Step 2, Construction Preparation: Prepare technical documents, personnel, equipment for installation, materials and tools, and conduct pre-construction surveying;

[0007] Step 3: Construction and acceptance of temporary facilities: Based on the location of the wellhead, construct the mobile gantry crane's running rails, harden the site, and install the mobile gantry crane. Then, arrange temporary power and water facilities, install the ash pipes, and finally conduct acceptance of the temporary facilities.

[0008] Step 4: Installation of equipment inside the tunnel: A fixed gantry crane is installed at the track crossing area of ​​the horizontal sliding passage, and a level crossing is laid above the existing track.

[0009] Step 5: Equipment debugging and acceptance inside the tunnel;

[0010] Step Six: Material Transfer: The material transfer includes the transfer of rail materials, steel reinforcement materials, precast slabs, trapezoidal sleepers and other materials, and concrete materials;

[0011] Step 7: Track bed construction.

[0012] Furthermore, the installation of the mobile gantry crane in step three specifically includes the following steps:

[0013] Step 31: Place two traveling beams, ensuring that the two traveling beams are placed parallel and their transverse centerlines are on the same straight line. Fix the lower crossbeam, splice the main beam and place the main beam in position. Install the cable trolley track for suspending the electric hoist cable on the main beam.

[0014] Step 32: Temporarily fix the flange at the end of the main beam to the flange on the outrigger using wire ropes. Use a truck crane to lift the main beam, slowly raising it 10cm off the ground. Observe it for 2 minutes and check for any abnormalities before starting the lifting. When the bottom height of the I-beam of the main beam is consistent with the height of the electric hoist placed next to the main beam, direct the truck crane to raise its boom and connect the electric hoist to the main beam. Continue lifting until the main beam and outriggers are lifted as a whole to the installation position on the traveling beam. Adjust the flanges on the lower outriggers and the flanges on the traveling beam and align them. Secure them with bolts. Adjust the flanges on the outriggers and the flanges on the traveling beam and align them. Secure the flanges on the outriggers and the flanges at the end of the main beam with bolts. Remove the lifting wire ropes from the main beam. After the main structure is installed, install and adjust the operator's cab, ladder, platform, railings, electric hoist, and electrical equipment.

[0015] Furthermore, step four, which involves installing a fixed gantry crane at the point where the horizontal sliding passage crosses the track area, includes the following steps:

[0016] Step 411, Construction of Fixed Gantry Crane Foundation: The fixed gantry crane foundation is laid out and measured, and the points are marked. According to the point positions, the fixed gantry crane foundation is excavated, reinforced, anchor bolts are pre-embedded, formwork is erected and concrete is poured in sequence to finally form a concrete support. According to the foundation elevation line, a flange is pre-embedded before concrete pouring. The upper surface of the flange is flush with the foundation elevation line, and the position of the anchor bolts corresponds to the position of the flange hole on the flange.

[0017] Step 412, Fixed Gantry Crane Installation: Connect the upper flange of the fixed gantry crane legs to the flanges at both ends of the fixed gantry crane crossbeam using bolts. Fix two hand-operated hoists above the pre-reserved lifting points on the two fixed gantry crane legs. Use wire ropes to lift the assembled fixed gantry crane legs and crossbeam as a whole until the fixed gantry crane legs are completely vertical and stable on the anchor bolts. Measure the levelness of the fixed gantry crane crossbeam and the fixed... After ensuring the verticality and height difference of the gantry crane legs are inspected and the errors of the fixed gantry crane legs and beams are qualified, the bolts on the fixed gantry crane legs are tightened, and channel steel is welded to the sides of the fixed gantry crane legs for reinforcement. After installation, reinforcement bars are tied and formwork is erected above the fixed gantry crane foundation, and then concrete of the same height as the foundation elevation line is poured to wrap the fixed gantry crane legs. After reinforcement, the electric hoist and electrical equipment are installed and adjusted after the main body of the equipment is installed.

[0018] Furthermore, step four, laying the level crossing, includes the following steps:

[0019] Step 421: After the track bed is poured and the concrete strength reaches 75%, the running rails and formwork on both sides of the track bed are removed and cleaned. Then, 250mm wooden sleepers are laid and fixed on the cleaned track bed surface. For trapezoidal sleeper sections, the 240mm wide side of the wooden sleeper is used as the contact surface of the central drainage ditch. Two layers of wooden sleepers are placed longitudinally in the central drainage ditch, with the upper surface of the upper wooden sleeper flush with the track bed surface. The connection between the wooden sleepers is reinforced with nails. The upper part of the upper wooden sleeper is the rail layer. The 160mm high side of the wooden sleeper is used as the contact surface of the track bed surface for the rail layer. The two rails are placed longitudinally and tightly from opposite sides toward the center line of the track. When the rails are placed in the center position, the wooden sleepers are cut according to the size of the remaining gap. For other track bed types without a central drainage ditch, the rail layer is laid directly.

[0020] Step 422: According to the size of the rail fastener, cut the wooden sleepers on both sides of the rail fastener into L-shapes. The L-shaped wooden sleepers can fasten the elastic clip in the rail fastener. The same method is used to lay the wooden sleepers on the outside of the rail. After laying, adjust them so that the surface of the wooden sleepers exceeds the top surface of the rail by 5-10mm. After the wooden sleepers in the track bed area are laid, reinforce them. Finally, lay steel plates on the wooden sleepers.

[0021] Step 423: Measure both sides of the track bed and determine the location of the strip foundation based on the distance from the tunnel wall to the outer side of the rail. The strip foundation is constructed by pouring concrete or by placing wooden sleepers longitudinally and fixing them with reinforcing bars on both sides. Reinforcing bar ends need to be pre-embedded in the strip foundation every 600mm. After the strip foundation is completed, clean the space between the strip foundations and store long iron wires. Cover the strip foundation with steel plates and make holes in the rail at 600mm intervals. Connect the pre-embedded holes with the reserved reinforcing bars in the strip foundation and then weld and grind them. Use rail spikes to connect the wooden sleepers.

[0022] Step 424: In steps 422 and 423, steel bars are installed at intervals above the steel plates along the track direction and welded to the steel plates. The outer edges of the steel plates on both sides of the rail are backfilled with concrete to form a ramp.

[0023] Step 425: Install guardrails on both sides according to the location of the level crossing. The length of the guardrails shall not be less than the width of the level crossing. Set up a train driver's whistle sign at the designated position before the locomotive enters the temporary level crossing. Set up a railway level crossing sign on the right side of the construction access road 20m away from the temporary level crossing. Build a level crossing duty room near the temporary level crossing and equip it with a command flag and a nighttime red light warning device.

[0024] Furthermore, the equipment commissioning and acceptance in the tunnel in step five includes, in sequence, preparatory work before the test, no-load test, static load test, overload test, dynamic load test, joint commissioning and testing, and equipment acceptance.

[0025] Furthermore, the rail material transportation in step six specifically involves the following steps: After the rail materials arrive on site, before the rail manholes of the completed construction section are sealed, the rail materials in the unconstructed section are promptly hoisted parallel through the rail manholes onto the rail flatbed, and then transported to the end of the completed construction section. The rail materials are then stored above the poured track bed or transported to the large cross-section of the unconstructed section using a forklift. When placing the materials, care should be taken to avoid the traffic clearance limits to facilitate their use in subsequent construction. If, after the rail manholes are sealed, there are still rail materials in the unconstructed section that have not yet arrived on site, the rail materials that have not yet arrived on site are hoisted vertically through the shafts to the bottom of the shafts and then transported to the work surface.

[0026] Furthermore, in step six, when transporting the reinforcing steel, the lifting point position of the entire bundle of reinforcing steel needs to be determined according to the length of the steel. When the diagonal of the shaft is greater than 12m, normal parallel hoisting is used; when the diagonal of the shaft is less than 12m, a slanted hoisting method is required. The slanted hoisting method for transporting the entire bundle of reinforcing steel includes the following steps: Select two steel wire ropes of the same length, tie one steel wire rope to 1 / 5 of the length of the reinforcing steel and wrap it around the reinforcing steel twice, tie the other steel wire rope to 3 / 5 of the length of the reinforcing steel and wrap it around the reinforcing steel once, lift it to a position 0.5 meters above the ground, and observe it at rest. After a two-minute inspection to ensure no abnormalities are found, the steel bars can be lifted to the shaft. Before lifting, the ends of the steel bars are secured with traction ropes for safety. The processed steel bars are bundled securely according to their categories, placed in net bags, and then hoisted from the shaft to the bottom of the tunnel. When the hoisted steel bars are about to reach the bottom of the tunnel, the rigging operator aligns them, places one end of the steel bar on a truck, and uses an excavator to transport the other end through a horizontal sliding passage to the level crossing. From there, a fixed gantry crane lifts the steel bars onto a rail flatcar, which then transports them to the construction site.

[0027] Furthermore, the transportation of precast slabs, trapezoidal sleepers, and other materials in step six includes the following steps: After using a mobile gantry crane to lift the precast slabs, trapezoidal sleepers, and other materials from the shaft into the tunnel, a heavy-duty truck is used to transport them from the horizontal transfer channel to the level crossing above the left and right tracks. Then, a fixed gantry crane is used to lift them onto a rail flatcar, which is finally pushed to the work surface for laying. Specifically, when lifting the precast slabs, a special lifting tool is used. Hooks are placed at pre-reserved lifting points, the lifting tool is placed into the precast lifting hole, rotated to align the slots, and anti-detachment pins are inserted. A 10T shackle is used to connect the lifting tool, and a 5T sling or a steel wire rope with a diameter of not less than 13.5mm is used for four-point lifting. When lifting the trapezoidal sleepers, a 5T sling is used to wrap around the steel beam.

[0028] Furthermore, the concrete material transportation in step six includes the following steps: After the concrete arrives on site, the workability of the concrete is first tested. If it meets the requirements, the concrete truck is aligned with the ash receiving hopper. The concrete flows through the ash chute to the transfer ash receiving hopper platform and then enters the concrete truck again through the ash chute. Before receiving the concrete, a rubber sleeve is put over the ash chute. The height of the concrete truck or ash hopper is adjusted to prevent concrete from splashing around. The concrete is placed from the external shaft discharge port into the truck-mounted concrete truck. The truck is driven to the level crossing, and the concrete is then placed into the ash hopper. A fixed gantry crane is used to lift the concrete onto a rail flatbed car, which is then transported to the work surface for pouring.

[0029] Furthermore, in step seven, the integral track bed is constructed using the loose-laying method, the trapezoidal sleeper track bed is constructed using the in-tunnel track panel method, the precast steel spring floating slab is constructed using the precast short slab splicing method, and the cast-in-place steel spring floating slab is constructed using the loose-laying method; the integral track bed with single turnout is constructed using the loose-laying method, and the seamless track is constructed using the straight-laying method.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. This invention can increase the working surface for construction by using the vertical shaft track laying base, realize multi-point simultaneous operation, improve the overall track bed construction efficiency of underground rectangular shield tunnel sections, shorten the concrete construction operation time, save construction costs, and lay a solid foundation for early trial operation and phased opening.

[0032] 2. In this invention, a fixed gantry crane is set up at the track crossing area of ​​the horizontal sliding passage for material handling and hoisting, which facilitates material transportation between the vertical shaft unloading and the on-site track laying construction.

[0033] 3. This invention uses wooden sleepers and steel plates to pave level crossings, which meets the conditions for vehicle passage and protects the rails and fasteners. At the same time, using wooden sleepers to pave level crossings allows for cutting and anchoring of the sleepers according to the on-site track bed configuration, which is highly flexible, adaptable, and saves on construction costs.

[0034] 4. The tooling and fixed gantry crane used in this invention can be reused, which reduces the cost of track laying.

[0035] 5. This invention summarizes and improves the technology of underground line tunneling and vertical shaft excavation, and on-site track laying through ventilation shaft entrances or shield tunneling starting shafts, providing valuable experience for track construction in similar sections in the future.

[0036] 6. This invention effectively solves the problem that the construction of the track panel can not be carried out due to the limitation of the size of the vertical shaft opening, thereby realizing the loose laying operation through the vertical shaft track laying base.

[0037] 7. Most of the construction work in this invention is carried out inside the tunnel, which effectively reduces the interference of construction with surrounding residents and the impact on the environment, and has green and environmentally friendly benefits.

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0039] Figure 1 This is a flowchart illustrating the construction process of the track laying base at the external shaft of the main line, as described in this invention.

[0040] Figure 2 This is a schematic diagram of the horizontal channel translation of the present invention.

[0041] Figure 3 This is a schematic diagram of the installation of the traveling rail of the mobile gantry crane of the present invention.

[0042] Figure 4 This is a schematic diagram of the drainage ditch in the site hardening process of this invention.

[0043] Figure 5This is a schematic diagram of the main beam splicing of the mobile gantry crane of the present invention.

[0044] Figure 6 This is a schematic diagram of the overall lifting process of the mobile gantry crane of the present invention.

[0045] Figure 7 This is a cross-sectional view of the fixed gantry crane foundation of the present invention.

[0046] Figure 8 This is a schematic diagram of the installation of the fixed gantry crane crossbeam and legs of the present invention.

[0047] Figure 9 These are the front and side views of the fixed gantry crane of the present invention.

[0048] Figure 10 This invention is a schematic diagram of the planar position of a fixed gantry crane.

[0049] Figure 11 This is a schematic diagram of a level crossing according to the present invention.

[0050] Figure 12 This is a schematic diagram of the cross-section of a level crossing according to the present invention.

[0051] Figure 13 This is a schematic diagram of a partial cross-section of a level crossing according to the present invention.

[0052] Figure 14 This is a cross-sectional view of the pre-embedded pipeline at the level crossing of the present invention.

[0053] Figure 15 This is a schematic diagram of the vertical lowering of the rail during the vertical hoisting of the rail according to the present invention.

[0054] Figure 16 for Figure 15 A magnified view of a portion of point A in the middle.

[0055] Figure 17 This is a schematic diagram illustrating the smooth lowering of the rail during the vertical hoisting of the rail according to the present invention.

[0056] Figure 18 This is a schematic diagram of the steel rail of the present invention being moved back and forth in the horizontal channel. Detailed Implementation

[0057] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the invention. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0058] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0059] like Figure 1-18 As shown, this invention provides a construction method for a track-laying base on an external vertical shaft of a subway mainline, comprising the following steps:

[0060] Step 1: Select the external shaft of the main line as the unloading port: The external shaft of the main line is a shaft located outside the track area and connected to the track area through a horizontal sliding passage.

[0061] Step 2, Construction Preparation: Prepare technical documents, personnel, equipment for installation, materials and tools, and conduct pre-construction surveying;

[0062] Step 3: Construction and acceptance of temporary facilities: Construct a track-laying base above the wellhead, construct the mobile gantry crane's running track according to the wellhead location, harden the site and install the mobile gantry crane, then arrange temporary power and water facilities, install the ash pipe, and finally conduct acceptance of the temporary facilities.

[0063] Step 4: Installation of equipment inside the tunnel: A fixed gantry crane is installed at the track crossing area of ​​the horizontal sliding passage, and a level crossing is laid above the existing track.

[0064] Step 5: Equipment debugging and acceptance inside the tunnel;

[0065] Step Six: Material Transfer: The material transfer includes the transfer of rail materials, steel reinforcement materials, precast slabs, trapezoidal sleepers and other materials, and concrete materials;

[0066] Step 7: Track bed construction.

[0067] Explanation of construction process principles

[0068] A suitable area with ample space, flat terrain, and convenient access for large vehicles will be selected above the shaft to provide favorable conditions for track laying. A track laying base will be constructed in this area, and a mobile gantry crane or a truck crane will be installed above the shaft opening for material lifting and hoisting. At the same time, a fixed gantry crane will be set up at the cross passage crossing the track area, and a level crossing will be set up above the existing track. After all equipment has passed inspection, when various materials are hoisted to the bottom of the shaft using a mobile gantry crane or a truck crane, a heavy-duty truck will be used to transport the materials to the track level crossing above the cross passage via a horizontal sliding passage. Then, the materials will be hoisted onto a track flatcar by a fixed gantry crane and transported to the work surface for scattering operations.

[0069] The construction preparation in step two specifically includes:

[0070] I. Technical Data Preparation: Organize on-site investigation and design drawing preparation, compile implementation-oriented construction organization plan, conduct technical briefing, and prepare the data required for tunnel structure measurement.

[0071] II. Personnel Preparation: Equipment installation and operation personnel should meet the requirements and must be trained and qualified before they can carry out construction work. Operators must hold relevant national certification qualifications.

[0072] III. Equipment Installation Preparation: Organize mechanical engineers to conduct on-site investigations and design and process the dimensions of the equipment to be installed based on the tunnel structure clearance dimensions on site, and determine the equipment installation plan;

[0073] IV. Preparation of Materials and Equipment: The required materials and equipment for construction should meet the site requirements. At the same time, the incoming equipment and materials should be strictly inspected one by one according to their appearance quality, category and size. They should be counted on site, classified and stacked, and can only be used after they have passed the acceptance inspection.

[0074] V. Pre-construction surveying: This includes re-surveying of traverse points, setting up of the CPIII control network, setting up of denser benchmarks, and surveying of the civil structure clearance, as well as marking out the equipment installation locations.

[0075] The construction of temporary facilities in step three specifically involves:

[0076] I. Construction of Mobile Gantry Crane Traveling Rails: First, based on the location of the wellhead, rationally arrange two dedicated gantry crane traveling rails. The size of the wellhead and site conditions will limit the configuration of the dedicated gantry cranes. Then, according to the site conditions, lay out the centerline of the traveling rail foundation. Next, excavate, reinforce, erect formwork, and pour the foundation pit. After the traveling rail foundation reaches 75% of its design strength, install the gantry crane traveling rails. During installation, use M20 expansion bolts to fasten steel plates to the bottom of the rails, spaced 600mm apart. The gap between the rails and the foundation should be filled with rubber pads (see...). Figure 3 ).

[0077] II. Site Hardening: After the completion of the building foundation, gantry crane travel line foundation, septic tank pit excavation, and pipeline pre-laying construction, the site will be hardened. Before hardening, the concrete height will be measured and marked with rebar ends and string lines. After concrete pouring, a concrete finishing machine will be used to finish the surface, achieving a flatness of 2mm / 1m. A 1% drainage slope will be provided on the concrete surface to ensure that surface water can enter the drainage ditch. A sedimentation tank will be set at the sewage outlet, and sewage will be discharged into the municipal rainwater well after sedimentation. After site hardening, the material storage area will be arranged according to the site layout plan based on its functional use and the principle of minimizing handling. Drainage ditches will be set within the construction site and excavated according to the plan. The ditch will be 300mm wide and 360mm deep. After excavation, a 500mm high formwork will be erected, and concrete will be used for backfilling. The bottom of the ditch will have a 3‰ slope, and the top will be covered with a concrete ditch cover (see...). Figure 4 ).

[0078] III. Installation of Mobile Gantry Crane:

[0079] 1) When unloading the lower crossbeam, place the lower crossbeam directly on the designated position on one side of the strip foundation of the mobile gantry crane. Use sleepers to support the gearbox to ensure that the traveling beam is placed horizontally and vertically. Then measure the distance between the diagonal ends of the two traveling beams and adjust the position of the traveling beams until the distance between the two diagonals is equal. After that, install supports around it to ensure that the two traveling beams are placed parallel and the transverse centerline is on the same straight line.

[0080] 2) Correct the lower crossbeam according to the "Crossbeam Installation Measurement Values", and fix the lower crossbeam with channel steel and angle steel. When splicing the main beam, the main beam of the mobile gantry crane is composed of 4 box-type short beams spliced ​​together by flange plates. During splicing, the beams are hoisted and arranged in sequence according to their numbers. Using one main beam as a reference, the other 3 main beams are connected to it in sequence with the assistance of the truck crane (see...). Figure 5 ), and fasten with bolts;

[0081] 3) When flipping the main beam, use the large and small hooks of two truck cranes to slowly flip the main beam so that the I-beam (trolley track) of the main beam faces the ground and is placed on the pre-built stack of sleepers in a position perpendicular to the traveling rail. After the main beam is stabilized by a hand chain hoist, one truck crane is used to maintain the position of the main beam, and the other truck crane is used to release the hook and untie the rope for later use. Then, a cable trolley track for suspending the electric hoist cable is installed on the main beam.

[0082] 4) When installing the outriggers, use a truck crane to lift the four rigid outriggers to the assembly positions at both ends of the main beam, based on the position used when lifting the main beam. Lift the flanges on the outriggers to the height of the flanges at the ends of the main beam. Use three Φ18 steel wire ropes to pass through the bolt holes corresponding to the flanges on the outriggers and the flanges at the ends of the main beam, and use steel wire rope clips to fix the steel wire ropes into a rope loop for lifting the outriggers as a whole. Finally, install I-beams on the outriggers to support the light and small auxiliary steel structures such as the driver's cab.

[0083] 5) Before lifting the main beam and outriggers as a whole, check the position and working radius of the truck crane, and remove all obstacles in the direction of outrigger movement. Use two truck cranes to slowly lift the main beam 10cm off the ground, observe it for 2 minutes, and start lifting after checking that there are no abnormalities. When the bottom height of the main beam I-beam is consistent with the height of the electric hoist placed next to the main beam, direct the truck crane to raise its boom, connect the electric hoist to the main beam, and continue to direct the truck crane to lift. During the lifting process, try to keep the entire main beam horizontal and lift it steadily. The two outriggers will slowly close to the middle position under their own weight. After closing until the outrigger flange is close to the end beam flange, continue to lift and lift the main beam and outriggers as a whole to the installation position on the traveling beam. Adjust the outrigger flange and the flange on the traveling beam and align them. Use bolts to connect them firmly. Finally, use bolts to connect the outrigger flange and the end beam flange firmly before removing the lifting wire rope from the main beam.

[0084] 6) After the main structure is installed, the operator's cab, ladder, platform, railings, electric hoist, and electrical equipment will be installed and adjusted (see...). Figure 6 ).

[0085] IV. Arrangement of Temporary Power and Water Facilities: Based on the actual site conditions, determine the location of the primary power distribution room, taking into account the margin and the special characteristics of the cable type, and determine YC-3×95mm. 2 +2×50mm 2 The copper core cable is 300m long, YC-3×50mm. 2 +2×25mm 2 The copper core cable length is specified, and domestic water is introduced from the domestic water interface of the civil engineering unit. Based on the on-site construction survey, the water supply pipeline is laid underground using PVC pipes at a depth of 0.5m, leading to the water use area. TPE water pipes are used to spray water on the production area to prevent dust.

[0086] V. Installation of the mortar discharge pipe: Install the mortar discharge pipe at the end of the track manhole in the concrete pouring area. The mortar discharge pipe is set along the track manhole. First, use I-beams and 5mm steel plates to fabricate a mortar receiving funnel platform. The mortar discharge pipe is inclined at 45° to 60° along the structural manhole wall, connected to the intermediate mortar receiving funnel platform and reinforced. Then, within a range of 5m-8m below the structure, use I-beams and 5mm steel plates to fabricate another intermediate mortar receiving funnel platform (the number of intermediate mortar receiving funnel platforms is determined according to the height of the vertical shaft). The mortar discharge pipe is connected to the bottom of the funnel and installed vertically along the structural manhole wall, exposed above the structural wall at the tunnel entrance. Finally, a rubber sleeve is put on the mortar discharge pipe to adjust the height of the concrete mixer truck or mortar hopper and to prevent concrete splashing.

[0087] Other production area equipment and facilities are constructed in accordance with the company's "China Railway First Group Temporary Engineering Construction Standards", "Temporary Engineering Management Implementation Rules", "Temporary Engineering Management Implementation Rules" and "Temporary Construction Plan for Track Laying Base".

[0088] Step four: Installation of equipment inside the tunnel:

[0089] 1. Install a fixed gantry crane at the point where the horizontal sliding passage crosses the track area:

[0090] 1) Construction of Fixed Gantry Crane Foundation: First, the fixed gantry crane foundation is laid out and measured, and the points are marked. Then, according to the point locations, the fixed gantry crane foundation is excavated, reinforced with steel bars, fixed with anchor bolts, erected with formwork, and concrete is poured to finally form a concrete support. The fixed gantry crane foundation uses 1m*1m concrete supports with a pouring height of 300mm (see...). Figure 7 Within the concrete pier area, φ22 anchor bolts are embedded in the structural base slab, with an embedment depth of not less than 100mm. Based on the foundation elevation line, 800mm*800mm flanges are pre-embedded before concrete pouring, with the upper surface of the flange flush with the support elevation. The pre-embedded positions of the anchor bolts correspond to the positions of the flange holes on the flange. The fixed gantry crane foundation dimensions are 1m*1m*30cm, poured with C35 concrete, and the foundation compressive strength is greater than 220kPa.

[0091] 2) Installing a fixed gantry crane: On the ground, align the upper flanges of the fixed gantry crane's outriggers with the flanges at both ends of the fixed gantry crane's crossbeam (see...). Figure 8 After connecting all the parts with 16*20mm high-strength bolts, fix two 3t-9m hand-operated hoists on the pre-reserved hoisting points above the two fixed gantry crane legs. Use steel wire ropes with a diameter of not less than 15.5mm to lift the fixed gantry crane legs and the fixed gantry crane beam simultaneously (with rubber pads at the corners) until the fixed gantry crane legs are completely vertical downwards. After the whole structure is stable and does not shake, align it and place it on the pre-embedded φ22mm anchor bolts. Use instruments to measure the verticality and height difference of the fixed gantry crane legs and the horizontality of the fixed gantry crane beam. The error should not exceed 2mm / 10m. After all are qualified, tighten the bolts of the upper and lower flanges of the fixed gantry crane legs to make them stable and without shaking. Then use 100*8mm channel steel to weld and reinforce the sides. After installation, reinforce the foundation of the fixed gantry crane by tying reinforcing bars and erecting formwork, then pour a 300mm high layer of concrete to enclose the support legs of the fixed gantry crane and reinforce it. After the main body of the equipment is installed, install and adjust the electric hoist and electrical equipment.

[0092] II. Paving at level crossings:

[0093] 1) After the track bed is poured and the concrete strength reaches 75%, the running rails and formwork on both sides of the track bed are removed and cleaned. Then, 250mm wooden sleepers are laid and fixed on the cleaned track bed surface. Specifically, before laying the wooden sleepers, the top surface of the track bed slab should be clean and free of contamination. When laying, lay the sleepers layer by layer from the center of the track to both sides, following the principle of laying from bottom to top and from the center of the track bed to the sides. The area under the wooden sleepers should be flat. Uneven sections should be paved with square wooden strips. The gap between two adjacent wooden sleepers on the same horizontal plane should not exceed 100mm. Loose; In the trapezoidal sleeper section, the 240mm wide side of the wooden sleeper serves as the contact surface for the central drainage ditch. Two layers of wooden sleepers are placed longitudinally in the central drainage ditch, with the upper surface of the upper layer flush with the track bed surface. The connections between the wooden sleepers are reinforced with bracing. Above the upper layer of wooden sleepers is the rail layer, with the 160mm high side of the wooden sleeper serving as the contact surface for the track bed surface. The two rails are placed longitudinally and tightly against each other from opposite sides towards the track centerline. When placed in the center position, the wooden sleeper is cut according to the remaining gap. Other track bed types without a central drainage ditch are laid directly using the rail layer method (see...). Figure 13 );

[0094] 2) To prevent the road surface from contacting the outer wheel due to wear of the rails and wheels, and thus avoid danger, wooden sleepers are cut into L-shapes according to the size of the rail fasteners and attached to both sides of the rail fasteners. The inner side of the L-shaped wooden sleeper is 70mm-100mm away from the rail web, so that the L-shaped wooden sleeper can fasten the elastic clip in the rail fastener. The same method is used to lay the outer side of the rail. After laying, it is adjusted so that the surface of the wooden sleeper exceeds the top surface of the rail by 5-10mm. After the wooden sleepers in the track bed area are laid, they are reinforced. Finally, steel plates are laid on the wooden sleepers.

[0095] 3) According to site requirements, the spacing of reserved cable trays is generally set at 200mm, and steel plates are laid on the strip base to allow vehicles to pass (see...). Figure 14 First, measurements were taken on both sides of the track bed. The location of the strip foundation was determined based on the distance from the tunnel wall to the outer edge of the rail. A concrete foundation with a width of 160±... was then poured.

[0096] A strip foundation with a thickness of 20mm and a height of 240±10mm can be constructed, or wooden sleepers can be laid longitudinally and fixed with reinforcing bars on both sides to form a strip foundation. For the strip foundation, φ16mm steel bars need to be pre-embedded every 600mm in the foundation. After the strip foundation is completed, the inside of the strip foundation should be cleaned and a long iron wire should be placed to facilitate the passage of pipelines and prevent the channel from being blocked. A 10mm steel plate is laid on top of the strip foundation, and holes with a diameter of φ25mm are made at 600mm intervals on the steel plate. The holes are then connected to the reserved reinforcing bars in the concrete foundation and welded and polished. If wooden sleepers are used, the wooden sleepers are connected to the holes made in the steel plate with road spikes.

[0097] 4) In steps 422 and 423, steel bars with a spacing of 200mm and a diameter of φ12mm are installed above the steel plate along the track direction and welded to the steel plate. The outer edges of the steel plates on both sides of the rail are backfilled with concrete to form a ramp.

[0098] 5) Guardrails shall be installed on both sides of the level crossing according to its location. The length of the guardrails shall not be less than the width of the level crossing. The guardrails shall be made of steel pipes and painted with alternating yellow and black stripes spaced 250mm apart. A train driver's horn sign shall be placed at the designated location before the locomotive enters the temporary level crossing. A railway level crossing sign shall be placed on the right side of the construction access road 20m away from the temporary level crossing. One level crossing duty room shall be erected near the temporary level crossing, equipped with one command flag and two red nighttime warning lights.

[0099] Step five involves equipment commissioning and acceptance inside the tunnel:

[0100] I. Preparatory work before the experiment

[0101] Turn off the power and check the tightness of all connecting parts; check the winding of the wire rope in the pulleys and on the drum; check the insulation of the circuit system with a megohmmeter; check the lubrication of all lubrication points, reducers, etc., and add oil as required; remove all objects that may obstruct the operation of the fixed gantry crane in the test area, and personnel not involved in the test must leave the fixed gantry crane test site; take measures to prevent personnel participating in the test on site from touching the live equipment; prepare the heavy object for the load test.

[0102] II. No-load test

[0103] Run at rated speed and observe that each mechanism should operate smoothly without abnormal vibration or noise; check whether the direction of each control indicator is consistent with the direction of motor rotation; check the hoisting drum and the support for abnormal vibration; check the condition of the guide rope pulley; measure and record the hoisting height, and adjust the hoisting height limiter; test the hoisting speed and descent speed under no-load conditions.

[0104] III. Static Load Test

[0105] First, lift 0.5 and 0.75 times the rated lifting capacity, running each twice, with two ascents and two descents each. Then, take the rated load and repeat the above actions. Remove the load, move the electric hoist to the outriggers, and use a level or wire rope method to check the camber h at the mid-span of the fixed gantry crane's beam (≥ L / 1000) and h1 at the cantilever end (≥ L1 / 300). Next, move the trolley to the mid-span and cantilever end positions, lift the rated load, and measure the mid-span deflection, cantilever, and camber. When performing at least three tests, the load should be lifted 100–200 mm off the ground and suspended for 10 minutes. After unloading the load, move the trolley to the outriggers. The camber of the fixed gantry crane's beam should completely disappear, meaning it should fully recover to the designed and manufactured camber value during measurement.

[0106] IV. Overload Test

[0107] The trolley lifts 1.25 times the rated load at mid-span, lifts it 100-200mm off the ground, holds it suspended for 10 minutes, unloads the load, and then moves the trolley to the outriggers to check for plastic deformation in the beams of the fixed gantry crane.

[0108] V. Dynamic Load Test

[0109] After the rated load test, the trolleys are run separately, and the two mechanisms are required to operate in conjunction. The total working time should not be less than 10 minutes. Each mechanism should operate flexibly, the wheels should not slip, and the beam of the fixed gantry crane should not have obvious abnormal vibration. Then, a test load of 1.1 times the rated lifting capacity is lifted, with the operation sequence and basic requirements being met simultaneously. Each mechanism should operate reliably and its performance should meet the design requirements. The reliability of the limit switches and interlocking devices should also be checked.

[0110] VI. Joint Commissioning and Testing

[0111] After the fixed gantry crane is debugged, the railcar will pass through the level crossing at a speed not exceeding 5 km / h. Ensure the railcar wheel track and the reserved wheel flange groove position at the crossing meet the requirements. Then, align the railcar with the fixed gantry crane, push the railcar under the fixed gantry crane, and then reverse the truck to the position under the fixed gantry crane and align it with the railcar. Once the position meets the lifting conditions, use the fixed gantry crane to lift the truckload of materials onto the railcar.

[0112] VII. Equipment Acceptance

[0113] After the equipment installation is completed, technical and safety personnel, in conjunction with the relevant equipment management unit, will inspect the lines and other equipment. Any problems found will be rectified immediately. After inspection and acceptance, if the conditions for commissioning are met, the technical supervisor will have the equipment management unit sign the commissioning confirmation form and report to the construction supervisor. Once the construction supervisor confirms that the line meets the commissioning conditions, they will order the relevant operation and protection personnel to carry out the construction. Professional personnel will be assigned to perform regular maintenance to ensure the reliable and safe use of the equipment.

[0114] The material transfer in step six:

[0115] I. Rail material transportation:

[0116] 1) Rail Storage: After the rail materials arrive on site, before the rail manholes of the completed sections are sealed, a portion of the rail materials in the uncompleted sections are promptly hoisted parallel through the rail manholes onto rail flatcars, and then transported to the end of the completed sections. The rail materials are then stored above the poured track bed or transported to the large cross-section of the uncompleted sections using forklifts. Care is taken to avoid the traffic clearance limits during placement to facilitate later paving. Specifically, the rail materials entering through the rail manholes are first divided into categories A, B, and C from the largest mileage to the smallest mileage and pre-stored at the end of the completed sections. Material C is dispersed and spread evenly in the center of the track and in the ditch at the end of the completed sections, without obstructing the passage of railcars. To avoid obstructing railcar passage, materials A and B are moved away. At the starting point of the uncompleted sections, category B materials are scattered throughout the section from far to near, while category A materials are stored. Then category A materials are scattered, and finally category C materials are moved away. The storage and transportation of materials do not affect the passage of railcars.

[0117] 2) If, after the track laying shaft is sealed, there are still rail materials that have not been delivered to the site in the unconstructed section, the rail materials that have not been delivered will be hoisted vertically through the shaft to the bottom of the shaft and then transported to the work surface. Specifically, the vertical hoisting steps for the rail materials are as follows: During the track laying process, due to the narrowness of the shaft (diagonal length c < 25m) and the lack of conditions for horizontal rail laying, it is necessary to use a truck crane to vertically unload the materials from the shaft and use rail clamps for hoisting. During the rail hoisting process, two sets of rail clamps are first fixed to the hoisting section of the rail to be hoisted. A first shackle is installed at the lifting hole of each set of rail clamps. Then, a first wire rope is connected to each first shackle. The distance between the two sets of rail clamps is 0.5m, and the distance between the outermost set of rail clamps and the outer end of the hoisting section is 1m. The diameter of the first wire rope is 15.5mm. The length of the first wire rope at the outer end of the hoisting section is 2m, and the length of the first wire rope at the inner end of the hoisting section is 1m (see...). Figure 16 After installation, connect the other end of the first wire rope on the first shackle to the hook of the truck crane. Then, use the truck crane to vertically lift the rail and slowly lower it from the unloading well (see...). Figure 15 Once the lower end of the rail touches the ground, secure it firmly with rail clamps. Specifically, fix another set of rail clamps to the lower end of the rail, install a second shackle at the lifting hole of this clamp, and connect a second wire rope to the second shackle. Then, connect the other end of the second wire rope to a forklift and use the forklift to pull it, coordinating with a truck crane to slide the rail to the ground. During this process, the slinger must simultaneously direct the forklift and truck crane to ensure the rail is lowered smoothly (see...). Figure 17For special rails such as turnout rails, vertical hoisting can be used for transport. During track laying, if the length of the rail panel opening is greater than 25m, parallel hoisting is used for rail hoisting. Two gantry cranes are used for rail hoisting. The lifting capacity of a single MH16t crane is no more than 13.6t, and the combined lifting capacity of the two cranes is no more than 25t. Each 60-type rail weighs 1.52t. Therefore, a maximum of 16 rails can be hoisted by two gantry cranes when unloading. However, in actual field operations, a single crane is generally allowed to hoist a maximum of 12 rails. Multi-strand intertwined steel wire ropes with a diameter of no less than 23mm are used for hoisting during unloading.

[0118] 3) Parallel transport of rails: After the hoisted rails are completely lowered to the ground, the operators remove both sets of rail clamps from the hoisting section, fix the rail ends to a special lifting vehicle, and use the special lifting vehicle in conjunction with a forklift to transport the rails to the level crossing. The rails are then laid out as a whole along the track direction, and a fixed gantry crane is used to load the rails onto a rail flatbed cart or a hand-pushed flatbed cart for transport to the work site (see...). Figure 18 ).

[0119] During track laying, the vertical material unloading efficiency in the shaft is too low and the construction difficulty is too great. Except for special conditions, the rails are stored in advance for construction: a rail section plan is prepared in advance based on the length of the unconstructed section of the track, taking into account the amount of rail loss due to welding and other losses, and the number of rails to be inserted is stored above the already poured ladder sleeper track bed to ensure that the rails are stored stably. During the secondary transportation of the rails stored on the track bed, two gantry rail hangers are made to lift the rails. After the rails are lifted by the track chain, they are slid onto the flatbed. The lifting point is determined according to the length of the rail and placed on the hand-pushed flatbed.

[0120] II. Reinforcing steel material transportation:

[0121] During the rebar hoisting process, when unloading a bundle of rebar from the shaft, the hoisting point position is first determined based on the rebar length. If the diagonal of the shaft is greater than 12m, normal parallel hoisting can be used. If the diagonal is less than 12m, an oblique hoisting method is required. Select two steel wire ropes of the same length. Tie one steel wire rope around the rebar at 1 / 5 of its length and wrap it around the rebar twice. Tie the other steel wire rope around the rebar at 3 / 5 of its length and wrap it around the rebar once. Hoist the rebar to a position 0.5 meters above the ground and observe it for 2 minutes. After checking for any abnormalities, the rebar can be hoisted to the shaft. Before hoisting, tie a traction rope to the end of the rebar for safety. The processed loose rebar is then bundled securely according to its classification, placed in a net bag, and then hoisted from the shaft to the bottom of the tunnel.

[0122] When the hoisted steel bars are about to reach the bottom of the tunnel, the slinger will align them and place one end on a truck. The other end will be transported to the tunnel entrance via a horizontal transfer channel using an excavator. The steel bars will then be hoisted onto a rail flatbed truck using a fixed gantry crane and transported to the construction site by the rail flatbed truck.

[0123] III. Transportation of precast slabs, trapezoidal sleepers, and other materials:

[0124] When hoisting precast slabs and trapezoidal sleepers, the required materials are first lifted from the external shaft into the tunnel using a mobile gantry crane. Then, heavy-duty trucks transport them from the horizontal transfer channel to the level crossing above the left and right tracks. A fixed gantry crane then lifts them onto a rail flatcar, which is finally pushed to the work surface for laying. Other materials and equipment can be handled using the same method. "Other materials" refers to materials used in track engineering, electromechanical engineering, and other related specialties. Special lifting tools are used when hoisting precast slabs. Hooks are placed at pre-reserved lifting points, the lifting tools are placed into the precast lifting holes, rotated to align the slots, and anti-detachment pins are inserted. A 10T shackle is used to connect the lifting tools, and 5T slings or steel wire ropes with a diameter of not less than 13.5 mm are used for four-point lifting. Trapezoidal sleepers are hoisted using 5T slings wrapped around the steel beams.

[0125] IV. Concrete Material Handling

[0126] After the concrete arrives on site, its workability is first tested. Once it meets the requirements, the concrete mixer truck is aligned with the ash receiving hopper. The concrete flows through the ash chute to the transfer ash receiving hopper platform, and then back into the mixer truck through the ash chute. Before receiving the concrete, a rubber sleeve is fitted over the ash chute, and the height of the mixer truck or ash hopper is adjusted to prevent concrete from splashing around. The concrete is poured from the external shaft discharge port into the truck-mounted mixer truck. The mixer truck is driven to the level crossing, where the concrete is then placed into the ash hopper. A fixed gantry crane is used to lift the concrete onto a rail flatbed car, which is then transported to the work site for pouring.

[0127] Step seven involves the construction of the track bed:

[0128] According to the overall construction plan, the general integral track bed is constructed using the "scattered track laying method"; the trapezoidal sleeper track bed is constructed using the "in-tunnel track panel laying method"; the precast steel spring floating slab is constructed using the "precast short slab splicing method"; the cast-in-place steel spring floating slab is constructed using the "scattered track laying method"; the integral track bed single turnout is constructed using the "scattered track laying method"; and the seamless track is constructed using the straight laying method.

[0129] Due to the size limitations of the shaft, the track panels of ladder sleepers and short sleepers cannot be assembled and nailed together on the site before being transported to the site for laying. Therefore, the track panels for this section need to be transported to the track bed that has been laid in the previous construction section for on-site assembly. Then, the assembled 25m track panels are transported to the work surface for erection using a track-laying crane. The track direction, level, gauge, superelevation, etc. are adjusted to ensure that the track geometry meets the design standards. After that, the track bed concrete is poured and the rail support frame is removed.

[0130] Application Examples

[0131] The track engineering project for the southern extension of the Changping Line (Xierqi to Jimenqiao) of the Beijing Rail Transit, undertaken by China Railway First Group New Transportation Engineering Company, commenced in July 2022 and concluded in September 2022. A total of 4.624 km of track bed was completed on the underground section from Xueyuanqiao Station to Jimenqiao Station. This included 2.074 km of trapezoidal sleeper track bed, 0.625 km of cast-in-place floating slab track bed, 1.527 km of precast steel spring floating slab track bed (a total of 318 precast slabs), 0.398 km of general integral track bed, and 2 sets of steel spring floating slab turnouts. The project employed a novel vertical shaft material unloading technique for on-site construction, presented significant challenges, and had a tight construction schedule. After entering the site in July 2022, in order to complete the construction task on time, with high quality and quantity, we promptly organized a large number of engineering and technical personnel to discuss and continuously study, optimize and adjust the construction plan in a timely manner. We successfully summarized this construction method and realized the construction method of laying track at the external shaft track laying base of the main line. This greatly solved the unfavorable factors in on-site construction, improved construction efficiency, greatly alleviated the pressure of the construction period, and accumulated valuable construction experience.

[0132] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A construction method for a track-laying base with an external vertical shaft on a subway mainline, characterized in that, Includes the following steps: Step 1: Select the external shaft of the main line as the unloading port: The external shaft of the main line is a shaft located outside the track area and connected to the track area through a horizontal sliding passage. Step 2, Construction Preparation: Prepare technical documents, personnel, equipment for installation, materials and tools, and conduct pre-construction surveying; Step 3: Construction and acceptance of temporary facilities: Based on the location of the wellhead, construct the mobile gantry crane's running rails, harden the site, and install the mobile gantry crane. Then, arrange temporary power and water facilities, install the ash pipes, and finally conduct acceptance of the temporary facilities. Step 4: Installation of equipment inside the tunnel: A fixed gantry crane is installed at the track crossing area of ​​the horizontal sliding passage, and a level crossing is laid above the existing track. Step 5: Equipment debugging and acceptance inside the tunnel; Step Six: Material Transfer: The material transfer includes the transfer of rail materials, steel reinforcement materials, precast slabs, trapezoidal sleepers and other materials, and concrete materials; Step 7: Track bed construction; The installation of the mobile gantry crane in step three specifically includes the following steps: Step 31: Place two traveling beams, ensuring that the two traveling beams are placed parallel and their transverse centerlines are on the same straight line. Fix the lower crossbeam, splice the main beam and place the main beam in position. Install the cable trolley track for suspending the electric hoist cable on the main beam. Step 32: Temporarily fix the flange at the end of the main beam to the flange on the outrigger using wire ropes. Use a truck crane to lift the main beam, slowly raising it 10cm off the ground. Observe it for 2 minutes and check for any abnormalities before starting the actual lifting. When the bottom height of the I-beam of the main beam is consistent with the height of the electric hoist placed next to the main beam, instruct the truck crane to raise its boom and connect the electric hoist to the main beam. Continue lifting until the main beam and outriggers are lifted as a whole to the installation position on the traveling beam. Adjust the flanges on the lower outriggers and the flanges on the traveling beam and align them. Secure them with bolts. Adjust the flanges on the outriggers and the flanges on the traveling beam and align them. Secure the flanges on the outriggers and the flanges at the end of the main beam with bolts. Remove the lifting wire ropes from the main beam. After the main structure is installed, proceed with the installation and adjustment of the operator's cab, ladder, platform, railings, electric hoist, and electrical equipment. Step four involves installing a fixed gantry crane at the point where the horizontal sliding passage crosses the track area, including the following steps: Step 411, Construction of Fixed Gantry Crane Foundation: The fixed gantry crane foundation is laid out and measured, and the points are marked. According to the point positions, the fixed gantry crane foundation is excavated, reinforced, anchor bolts are pre-embedded, formwork is erected and concrete is poured in sequence to finally form a concrete support. According to the foundation elevation line, a flange is pre-embedded before concrete pouring. The upper surface of the flange is flush with the foundation elevation line, and the position of the anchor bolts corresponds to the position of the flange hole on the flange. Step 412, Fixed Gantry Crane Installation: Connect the upper flange of the fixed gantry crane legs to the flanges at both ends of the fixed gantry crane crossbeam using bolts. Fix two hand-operated hoists above the pre-reserved lifting points on the two fixed gantry crane legs. Use wire ropes to lift the assembled fixed gantry crane legs and crossbeam as a whole until the fixed gantry crane legs are completely vertical and stable on the anchor bolts. Measure the levelness of the fixed gantry crane crossbeam and the fixed... After ensuring the verticality and height difference of the gantry crane outriggers and the error of the fixed gantry crane outriggers and crossbeams pass the inspection, tighten the bolts on the fixed gantry crane outriggers and weld channel steel to the sides of the fixed gantry crane outriggers for reinforcement. After installation, tie reinforcement bars and erect formwork above the fixed gantry crane foundation, then pour concrete at the same elevation as the foundation line to wrap the fixed gantry crane outriggers and reinforce them. After the main body of the equipment is installed, install and adjust the electric hoist and electrical equipment. Step four, laying the level crossing, includes the following steps: Step 421: After the track bed is poured and the concrete strength reaches 75%, the running rails and formwork on both sides of the track bed are removed and cleaned. Then, 250mm wooden sleepers are laid and fixed on the cleaned track bed surface. For trapezoidal sleeper sections, the 240mm wide side of the wooden sleeper is used as the contact surface of the central drainage ditch. Two layers of wooden sleepers are placed longitudinally in the central drainage ditch, with the upper surface of the upper wooden sleeper flush with the track bed surface. The connection between the wooden sleepers is reinforced with nails. The upper part of the upper wooden sleeper is the rail layer. The 160mm high side of the wooden sleeper is used as the contact surface of the track bed surface for the rail layer. The two rails are placed longitudinally and tightly from opposite sides toward the center line of the track. When the rails are placed in the center position, the wooden sleepers are cut according to the size of the remaining gap. For other track bed types without a central drainage ditch, the rail layer is laid directly. Step 422: According to the size of the rail fastener, cut the wooden sleepers on both sides of the rail fastener into L-shapes. The L-shaped wooden sleepers can fasten the elastic clip in the rail fastener. The same method is used to lay the wooden sleepers on the outside of the rail. After laying, adjust them so that the surface of the wooden sleepers exceeds the top surface of the rail by 5-10mm. After the wooden sleepers in the track bed area are laid, reinforce them. Finally, lay steel plates on the wooden sleepers. Step 423: Measure both sides of the track bed and determine the location of the strip foundation based on the distance from the tunnel wall to the outer side of the rail. The strip foundation is constructed by pouring concrete or by placing wooden sleepers longitudinally and fixing them with reinforcing bars on both sides. Reinforcing bar ends need to be pre-embedded in the strip foundation every 600mm. After the strip foundation is completed, clean the space between the strip foundations and store long iron wires. Cover the strip foundation with steel plates and make holes in the rail at 600mm intervals. Connect the pre-embedded holes with the reserved reinforcing bars in the strip foundation and then weld and grind them. Use rail spikes to connect the wooden sleepers. Step 424: In steps 422 and 423, steel bars are installed at intervals above the steel plates along the track direction and welded to the steel plates. The outer edges of the steel plates on both sides of the rail are backfilled with concrete to form a ramp. Step 425: Install guardrails on both sides according to the location of the level crossing. The length of the guardrails shall not be less than the width of the level crossing. Set up a train driver's whistle sign at the designated position before the locomotive enters the temporary level crossing. Set up a railway level crossing sign on the right side of the construction access road 20m away from the temporary level crossing. Build a level crossing duty room near the temporary level crossing and equip it with a command flag and a nighttime red light warning device.

2. The construction method for the track-laying base of the external vertical shaft of the subway main line according to claim 1, characterized in that, Step five, the commissioning and acceptance of equipment inside the tunnel, includes, in sequence, preparatory work before testing, no-load test, static load test, overload test, dynamic load test, joint commissioning and testing, and equipment acceptance.

3. The construction method for the track-laying base of the external vertical shaft of the subway main line according to claim 1, characterized in that, The specific steps for transporting rail materials in step six are as follows: After the rail materials arrive on site, before the rail manholes of the completed sections are sealed, the rail materials in the uncompleted sections are promptly hoisted parallel through the rail manholes onto the rail flatcars, and then transported to the end of the completed sections. The rail materials are then stored above the poured track bed or transported to the large cross-section of the uncompleted sections using forklifts. When placing the materials, care should be taken to avoid the traffic clearance limits to facilitate the subsequent paving. If, after the rail manholes are sealed, there are still rail materials in the uncompleted sections that have not yet arrived on site, the rail materials that have not yet arrived are hoisted vertically through the shafts to the bottom of the shafts and then transported to the work surface.

4. The construction method for the track-laying base of the external vertical shaft of the subway main line according to claim 3, characterized in that, In step six, when transporting the reinforcing steel, the lifting point position for the entire bundle of reinforcing steel needs to be determined based on the length of the steel bars. When the diagonal of the shaft is greater than 12m, normal parallel hoisting is used. When the diagonal of the shaft is less than 12m, a slanted hoisting method is required. The slanted hoisting method for transporting the entire bundle of reinforcing steel includes the following steps: Select two steel wire ropes of the same length. Tie one steel wire rope around the reinforcing steel at 1 / 5 of its length and wrap it around the reinforcing steel twice. Tie the other steel wire rope around the reinforcing steel at 3 / 5 of its length and wrap it around the reinforcing steel once. Lift the reinforcing steel to a position 0.5 meters above the ground and observe it statically for 2 seconds. After a few minutes of inspection and no abnormalities are found, the steel bars can be lifted to the shaft. Before lifting, the ends of the steel bars are tied with traction ropes to ensure safety. The processed steel bars are bundled securely according to their categories, put into net bags, and then hoisted from the shaft to the bottom of the tunnel. When the hoisted steel bars are about to reach the bottom of the tunnel, the slinger will align them, place one end of the steel bar on a truck, and use an excavator to transport the other end through a horizontal sliding passage to the level crossing. The steel bars are then hoisted onto a rail flatcar by a fixed gantry crane and transported to the construction site by the rail flatcar.

5. The construction method for the track-laying base of the external vertical shaft of the subway main line according to claim 4, characterized in that, The transport of precast slabs, trapezoidal sleepers and other materials in step six includes the following steps: After the precast slabs, trapezoidal sleepers and other materials are hoisted from the shaft into the tunnel using a mobile gantry crane, they are transported by a heavy truck from the horizontal transfer channel to the top of the left and right track crossings, then hoisted onto the rail flatcar using a fixed gantry crane, and finally pushed to the work surface for laying using the rail flatcar. Special lifting tools are used for hoisting precast slabs. Hooks are placed at the reserved lifting points, the lifting tools are placed into the precast hoisting holes, rotated to align the slots, and anti-detachment pins are inserted. 10T shackles are used to connect the lifting tools, and 5T slings or steel wire ropes with a diameter of not less than 13.5 are used for four-point hoisting. Trapezoidal sleepers are hoisted by using 5T slings wrapped around the steel beams.

6. The construction method for the track-laying base of the external vertical shaft of the subway main line according to claim 5, characterized in that, The concrete material transportation in step six includes the following steps: After the concrete arrives on site, its workability is first tested. If it meets the requirements, the concrete truck is aligned with the ash receiving hopper. The concrete flows through the ash chute to the transfer ash receiving hopper platform and then back into the concrete truck through the ash chute. Before receiving the concrete, a rubber sleeve is put over the ash chute. The height of the concrete truck or ash hopper is adjusted to prevent concrete from splashing around. The concrete is placed from the external shaft discharge port into the truck-mounted concrete truck. The truck is driven to the level crossing, and the concrete is then placed into the ash hopper. A fixed gantry crane is used to lift the concrete onto a rail flatbed car, which is then transported to the work surface for pouring.

7. The construction method for a track-laying base with external vertical shafts for subway mainlines according to any one of claims 1-6, characterized in that, In step seven, the integral track bed is constructed using the loose-laying method, the trapezoidal sleeper track bed is constructed using the in-tunnel track panel method, the precast steel spring floating slab is constructed using the precast short slab splicing method, and the cast-in-place steel spring floating slab is constructed using the loose-laying method; the integral track bed with single turnout is constructed using the loose-laying method, and the seamless track is constructed using the straight-laying method.

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