A method for integral combination sliding construction of double crossover turnout based on an operating subway line

Abstract

A method for constructing a combined sliding turnout on an operating metro line includes: utilizing a regular track maintenance window at night for temporary track switching; installing temporary fastener pads and temporary rails via pre-embedded sleeves to restore operation; transporting the pre-assembled turnout to a storage area; installing a rigid frame reinforcement device to lock the pads, rails, and fastener system into a single rigid frame; removing temporary track steel supports and installing a sliding device; moving the turnout longitudinally along a first direction, laterally perpendicular to a second direction, and then longitudinally along the first direction to the target position; after fine-tuning the positioning, anchoring and grouting are performed, with the switch position fixed to the track bed via steel supports. This invention ensures smooth operation during the transition period through temporary track switching, prevents sliding deformation through a rigid frame, and utilizes a three-stage combined sliding mechanism to adapt to narrow spaces, achieving precise overall positioning of the turnout within the track maintenance window and ensuring operational safety.

Description

Technical Field

[0001] This application relates to the field of track engineering construction technology, and in particular to a method for the integrated sliding construction of double-crossing turnouts based on operating subway lines. Background Technology

[0002] Double-ended turnouts are among the most complex and technologically advanced track equipment in urban rail transit lines. They connect multiple main lines and connecting lines, directly affecting the smoothness and safety of train operation. With the continuous operation of urban rail transit networks, early-built double-ended turnouts are generally entering their aging period and must be specially upgraded and renovated.

[0003] Taking the No. 2, 4, 6, and 8 double-cross turnouts of a certain station on Metro Line 1 as an example, this set of No. 9 double-cross turnouts with 60kg / m rails has been in service for over 20 years since it was put into use in 1999, and the following prominent problems exist: First, the condition of the track foundation is poor. The turnout area uses a short sleeper integral track bed, and the short sleepers are poorly laid. Some short sleepers are cracked and powdery. Some anchor bolts have failed due to long-term disassembly of the pre-embedded sleeves. The iron pads crack frequently. Some pads have been reinforced with multi-layer rubber pads of varying thicknesses, which increases the unevenness of stiffness in the turnout area and makes the components easy to be damaged.

[0004] Secondly, the turnout's geometric dimensions are out of specification and difficult to adjust. The left and right switch rails are misaligned, and the movable switch rail and stock rail are deformed due to long-term uneven train loads, making it impossible to replace the movable switch rail. The turnout frame dimensions cannot be adjusted to the required specifications through routine maintenance. During routine maintenance, rail components cannot be easily disassembled and replaced, and after disassembly, they cannot be adjusted back to their original state, posing a safety hazard.

[0005] Third, the condition of the equipment continues to deteriorate, and maintenance costs are high. Cracks in the iron base plates occur frequently, often requiring welding or replacement, which increases the amount and cost of maintenance; electrical equipment is difficult to install, and the condition of signaling equipment is affected.

[0006] To address the aforementioned issues, conventional modification solutions typically require a prolonged interruption of line operation to complete the overall removal and replacement of the turnouts in one go. However, operating subway lines only offer limited "maintenance windows" after nighttime shutdowns, with typical windows lasting only about two hours, which cannot meet the requirements for the complete removal, replacement, and fine-tuning of the entire turnout system. Existing technologies still face the following technical challenges: First, the double switch and obtuse-angle frog sections in the middle of the double-switching turnout have extremely complex structures. This part features a sliding plate that simultaneously locks four rails, and the upper components are interconnected and constrained. During the sliding and lifting process, the frame is prone to twisting and deformation, which changes the spacing of the mounting holes on the iron pad, making it impossible to accurately align with the sleeves pre-embedded in the track bed, thus causing rework or extending the closure time.

[0007] Secondly, the narrow space of underground tunnels makes it impossible to use large hoisting equipment. Taking a typical subway tunnel as an example, the construction area is only 4.5m wide and 4m high, while the turnout is 23m long, 3.5m wide at its widest point, and weighs about 18t. Traditional unidirectional longitudinal movement is limited by the existing track layout within the tunnel, and unidirectional lateral movement is limited by the tunnel clearance width, making it difficult to move the turnout to the target position in one go. The overall relocation of large turnouts in confined spaces is a recognized construction challenge in this field.

[0008] Third, the temporary track has a long transition period and significant safety risks. To ensure normal daytime operation, temporary tracks need to be quickly erected after the existing switches are removed for train passage. These temporary tracks must remain stable under repeated operational loads, and their fastening system must meet the safety requirements for trains traveling at 30 km / h. However, during long-term use, the steel support system of the temporary tracks is susceptible to settlement and displacement under dynamic train loads, and the construction period can last for several months, making safety management extremely difficult. Furthermore, extending the track maintenance window involves collaborative work among multiple disciplines such as power supply, signaling, and train operation. Existing technologies lack systematic safety protection solutions, posing safety risks such as overhead contact line leakage, false signal alarms, and intrusion by construction vehicles.

[0009] Fourth, the process coordination requirements are high, and the working time within the track maintenance window is extremely limited. Existing line construction is constrained by the operating window period, resulting in short effective working time and low efficiency. It is necessary to complete a large number of preparatory processes (such as sleeper modification, sleeve pre-embedding, turnout pre-assembly, etc.) one by one before construction. At the same time, it places extremely high demands on the precision and efficiency of the process organization on the day of core sliding.

[0010] To complete turnout modifications without interrupting daytime operations, existing technologies typically employ a segmented construction method, breaking the modification project down into multiple track maintenance windows, with temporary lines used to restore operations during the day. However, how to efficiently complete the entire process from dismantling existing turnouts to erecting temporary lines within limited track maintenance windows, how to achieve smooth overall shifting and precise alignment of turnouts in confined underground spaces, and how to systematically ensure the safety of multi-disciplinary collaborative operations within extended track maintenance windows are all pressing technical challenges that need to be addressed in this field.

[0011] Therefore, how to efficiently, accurately, and safely complete the overall renovation and upgrading of the double-switching turnout while ensuring normal daytime train operation and utilizing limited nighttime track maintenance windows (including extended maintenance windows) is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0012] This invention aims to provide a method for the overall combination and sliding construction of double-switching turnouts based on operating subway lines, in order to solve the technical problems in the prior art where the frame of the intermediate double switch and obtuse-angle frog is prone to deformation during the sliding process, resulting in inaccurate alignment of the installation holes, difficulty in moving large turnouts as a whole in narrow underground spaces, and lack of systematic multi-disciplinary collaborative safety assurance during extended track maintenance window construction.

[0013] To achieve the above objectives, the present invention adopts the following technical solution: A method for the integral sliding construction of a double-intersection turnout based on an operating subway line includes the following steps: S1. Utilize regular nighttime track maintenance windows for temporary track conversion, including: pre-drilling holes in the existing track bed to pre-embed the first batch of sleeves, removing the double switch and obtuse-angle frog parts in the existing turnouts and then drilling additional holes and pre-embedding sleeves, and installing temporary fastener pads and temporary rails to restore normal train operation. S2. Transport the pre-assembled double-cross turnout as a whole to the storage area of ​​the construction work section; S3. In the storage area, a rigid frame reinforcement device is installed on the entire double-cross turnout to lock the iron pad, rail and its fastening system into an integral rigid frame. S4. Remove the existing temporary line's steel supports and joint plates, and install a sliding device on the resulting translation channel; S5. The entire compound turning turnout is moved longitudinally along the first direction to the first position by the sliding device, then moved laterally along the second direction perpendicular to the first direction to the second position, and then moved longitudinally along the first direction to the target position. S6. Use fine-tuning fixtures to level and position the double-cross turnout; S7. Anchoring and grouting are carried out on the turnout to complete the laying; the switch position is fixed to the track bed by steel supports.

[0014] Furthermore, the on-site operation process for temporary track switching during regular nighttime track maintenance windows in step S1 includes: setting up insulating joints and installing temporary rail connectors at the rail joints before and after the construction area; coordinating with the power supply professionals to determine the grounding position of the contact rail and perform power outage protection; grinding the existing track bed surface; pre-drilling holes and pre-burying the first batch of sleeves at locations below the existing rails that do not affect train passage; after removing the double switches and obtuse-angle frogs from the existing turnouts, supplementing the holes at the remaining un-drilled locations with pre-burying sleeves; connecting the temporary fastener pads to the pre-buried sleeves with anchor bolts; laying temporary rails and performing joint connections and track fine-tuning to restore normal train operation.

[0015] Further, in step S3, the rigid frame reinforcement device includes multiple connecting steel plates, multiple gauge tie rods, multiple rail supports, and multiple transverse rigid fixing frames. The connecting steel plates are arranged in the symmetrical areas on the upper and lower sides of the double-intersecting turnout, connecting the corresponding iron pads or sleepers. The gauge tie rods are spaced apart along the longitudinal direction of the turnout, and the transverse rigid fixing frames are straddling the rails on both sides of the turnout. By adding gauge tie rods, setting connecting steel plates between the rail supports and the iron pads, and setting transverse rigid fixing frames, the iron pads, rails, and their fastening system are locked into an integral rigid frame.

[0016] Furthermore, the sliding device in step S4 includes multiple sets of slide rails and pulley assemblies. The slide rails are arranged along the longitudinal and transverse directions of the translation channel, and the pulley assemblies are installed at the bottom of the double-cross turnout or the bottom of the rigid frame reinforcement device. The number of slide rails is at least three. When transverse movement is performed, the two ends of the slide rails are placed on the existing rails, and the middle position is supported by sleeper blocks.

[0017] Further, in step S5, the first direction is the longitudinal axis direction of the compound crossover turnout, and the second direction is the direction perpendicular to the first direction in the horizontal plane. The on-site operation process of moving the new turnout through the sliding system specifically includes: removing the rail connecting line of the temporary track and moving the old components longitudinally; removing the temporary track steel support piers and installing the transverse sliding rail and supporting sliding facilities on the track bed; pulling the new turnout in the overall rigid frame state, first moving it longitudinally along the first direction by a first distance to the first position, then moving it laterally along the second direction by a second distance to the second position, and then moving it longitudinally along the first direction by a third distance to the target position; then removing the transverse sliding rail and the temporary track rail, so that the new turnout is lowered into its original position as a whole and the anchor is locked; finally removing all anti-deformation fixing fixtures and performing track fine adjustment.

[0018] Furthermore, the fine-tuning fixtures in step S6 include a total station, a level, a track gauge, a track offset gauge, a chord line, and a steel ruler, which are used for three-dimensional fine-tuning of the track gauge, level, elevation, direction, and offset of the turnout.

[0019] Furthermore, the anchoring in step S7 includes anchoring the pre-embedded plastic sleeve with an anchoring agent, and the grouting and curing operation includes grouting the gap between the sleeper and the track bed with resin mortar; the pull-out resistance of the anchoring agent is not less than 80kN, and the 28-day compressive strength of the resin mortar is not less than 90MPa.

[0020] Furthermore, before step S4, the following steps are included: extending the construction organization steps for the track maintenance window: shutting down and de-energizing the construction section, setting up four pairs of insulating joints at the rail joints of the main line before and after the construction area, installing grounding devices outside the construction area, and setting up temporary vehicle stops and speed limit signs at both ends of the construction area; the shutdown range is the section of the subway line where the construction section is located, the power outage range is consistent with the shutdown range, and power outage points are set up on adjacent connecting lines.

[0021] Furthermore, the extended track maintenance window construction organization steps also include multi-disciplinary collaborative protection operations: cooperating with the power supply professionals to determine the contact rail grounding position, installing temporary rail connecting lines at the rail gap positions before and after the construction area to prevent leakage; cooperating with the signal professionals to simultaneously dismantle or restore electrical poles, and having the signal software system synchronously lock and shield the construction area during the rail breakage period.

[0022] Furthermore, the operating metro line is a ballastless monolithic track line.

[0023] As can be seen from the above technical solutions, compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes the regular track maintenance window at night to complete the temporary track conversion in advance, sets up insulation joints and grounding protection in the construction area, and coordinates with power supply and signaling professionals to achieve uninterrupted train operation the day after the existing turnouts are removed, providing safety assurance and a construction window for the subsequent core turnout sliding construction.

[0024] 2. This invention locks the iron pad, rail, and fastener system into an integral rigid frame by using connecting steel plates, gauge rods, rail braces, and transverse rigid fixing frames before sliding. This effectively prevents the frame from twisting and deforming during the sliding process of the double switch and obtuse-angle frog. It ensures that when the sliding returns to its original position, the mounting holes on the iron pad can be precisely aligned with the sleeves pre-embedded in the track bed in one go, avoiding repeated insertion and removal for fine-tuning and significantly shortening the closure time.

[0025] 3. This invention adopts a combined movement path of "longitudinal movement → lateral movement → further longitudinal movement", which breaks through the limitation that large hoisting equipment cannot be used in subway tunnels. It realizes the overall translational replacement of large turnouts in narrow spaces through a cross-shaped sliding rail network, and solves the problem of constraints on unidirectional sliding by existing line layout and tunnel clearance.

[0026] 4. This invention constructs a multi-level comprehensive safety protection system through measures such as shutdown, power outage, insulation joint isolation, grounding protection, temporary vehicle stops, speed limit signs, and collaborative protection measures between power supply and signaling professionals. This effectively prevents safety risks such as contact network leakage and false signal alarms, and ensures the absolute safety of construction personnel, operating equipment, and trains during extended maintenance windows.

[0027] 5. This invention combines pre-assembled data with precise on-site alignment, along with three-dimensional adjustments using fine-tuning fixtures, to ensure that the geometric dimensions of the new turnout meet acceptance standards at once after installation. This reduces the workload of subsequent fine-tuning and enables the overall update of complex turnouts without interrupting daytime operations. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall process of the present invention for the integrated sliding construction method of double-intersecting turnouts based on an operating subway line; Figure 2 This is a schematic diagram of the overall track layout after the temporary track is restored and a new double-headed turnout is installed. Detailed Implementation

[0029] A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0030] like Figure 2 As shown, this embodiment uses the overall reconstruction of a set of 60kg / m rail No. 9 double-crossing turnouts on an operating subway line as an example. This turnout is located in an underground tunnel and includes a double switch and obtuse-angle frog section (core turnout), four sets of guard rails and guide rails (6#, 8#, 2#, 4#), and two frog sections 6#-8# and 2#-4#. The central core double switch and obtuse-angle frog section weighs approximately 18 tons (excluding sleepers), is 23 meters long, and has a maximum width of 3.5 meters. Before construction, the removal of the existing double switch and obtuse-angle frog section, temporary track switching, and sleeper adaptation modifications were completed through several regular track maintenance windows.

[0031] In this embodiment, the overall construction sequence of the new double-crossing turnout after the temporary track is restored is as follows: first, replace the frogs and guard rails at turnouts #6 and #8; then, replace the middle obtuse-angle frogs and double switches; finally, replace the frogs and guard rails at turnouts #2 and #4. After the turnouts are installed, the switches are debugged. The middle obtuse-angle frogs and double switches are constructed during extended track maintenance windows (i.e., core steps S3-S7 of this invention), while the other parts are constructed during normal track maintenance windows.

[0032] The following focuses on describing the core step of this invention—the overall combined sliding construction of the intermediate core turnout (double switch and obtuse-angle frog section).

[0033] like Figure 1 As shown in the figure, the integral combination sliding construction method of the double-intersection turnout based on the operating subway line described in this embodiment specifically includes the following steps: I. Temporary Line Conversion (Step S1) Before entering the track area for construction, multi-disciplinary collaborative protection is first implemented: insulating joints are installed at the rail joints before and after the construction area, and temporary rail connectors are installed. The power supply professionals are coordinated to determine the grounding location of the contact rail and implement power outage protection.

[0034] During several regular track maintenance windows prior to the core turnout sliding construction, temporary track switching needs to be completed to ensure that trains can still operate normally during the daytime after the existing turnouts are removed. In order to shorten the occupation time of the track maintenance windows, this embodiment grinds the existing track bed surface in advance to ensure its flatness during several regular track maintenance windows before the removal of the existing turnouts; and drills are made in advance and the first batch of sleeves are pre-embedded in the track bed under the existing rails in positions that do not affect the normal passage of trains.

[0035] After safety measures were in place, during the nighttime track maintenance window, the double-switcher and obtuse-angle frog sections of the existing turnout were quickly cut off and removed. Holes were drilled and sleeves were pre-embedded at the remaining un-drilled locations on the track bed. Subsequently, temporary fastener pads were connected and fixed to the pre-embedded sleeves using anchor bolts. The temporary track was reinforced in three ways: anchoring the pads through holes drilled in the integral track bed; anchoring the pads through holes drilled in the sleepers; and anchoring the pads using steel supports through holes drilled in the track bed within the switch machine pit. Temporary rails were laid, and joints were connected and the track was fine-tuned. After a track rolling test, trains began normal passenger service through this temporary track structure the following day.

[0036] In this step, the temporary fasteners are flexible split fasteners. The standard assembly height of the fasteners is 42mm, the height adjustment range is 0-70mm, and the track gauge adjustment range is 1435mm (-28mm to +24mm). The pull-out resistance of the pre-embedded plastic sleeve is not less than 80kN.

[0037] Once this step is completed, the temporary track will be put into use. Subsequent work such as core turnout sliding and sleeper modification will be carried out gradually during subsequent track maintenance windows, provided that daytime operation of the temporary track is guaranteed.

[0038] The aforementioned temporary track switching was completed in batches within multiple regular track maintenance windows (approximately 2 hours each). After the temporary track was put into use, the subsequent core turnout sliding construction (steps S2 to S7) was completed within a single extended track maintenance window (8 hours).

[0039] II. Construction Preparation and Pre-assembly Transportation (Step S2) Before commencing construction in the track area, data is first collected on the existing turnouts and track bed (3D laser scanning technology can be used to obtain on-site topographic data). The new turnouts are then pre-assembled at a 1:1 scale in an open area outside the track area (such as the Tuqiao Depot). After the pre-assembly and switch machine debugging are completed, the turnouts are disassembled after confirmation by relevant professionals such as track, power supply, and signaling.

[0040] After pre-assembly, the new turnout (including iron pads, rails, fastening system, sleepers, etc.) is disassembled into two parts for easy transportation (single-sided obtuse angle frog and double switch part, each weighing about 9t), and transported to the storage area of ​​the construction work section by railcar.

[0041] In this embodiment, the storage area is set on the connecting line (north-yong connecting line) adjacent to the construction section. The area is 4.5m wide, 4m high and 23m long, which meets the requirements for turnout storage and assembly before subsequent relocation.

[0042] III. Install the rigid frame reinforcement device (step S3) Within the storage area, the pre-assembled parts of the new turnout are reassembled into a whole, and then a rigid frame reinforcement device is installed on the turnout as a whole.

[0043] Specific procedures: Multiple connecting steel plates are installed on the symmetrical upper and lower sides of the double-headed turnout to connect the corresponding iron pads; gauge tie rods are installed at intervals along the longitudinal direction of the turnout to maintain the standard gauge (1435mm) of the two rails; rail braces are installed on both sides of the iron pads; and a transverse rigid fixing frame is installed above the turnout. Through these reinforcement measures, the iron pads, rails, and their fastening system are locked into a single rigid frame. This frame effectively resists torsional deformation caused by uneven stress during the shifting process, ensuring that the turnout maintains its dimensional stability during subsequent sliding.

[0044] Technical effect verification: Field tests show that after installing the rigid frame reinforcement device, the geometric dimension fluctuation of the overall turnout frame is less than ±2mm, which meets the requirements for frame stability before sliding.

[0045] IV. Construction Organization and Multidisciplinary Collaborative Protection for Extended Skylight Points Before step S4 (i.e. before entering the extended skylight point construction), it is necessary to organize and arrange the construction of the extended skylight point, and implement multi-disciplinary collaborative protection during the dismantling and laying process.

[0046] Construction Organization: In this embodiment, the extended maintenance window is set at 8 hours (22:00 to 06:00 the next day). The construction section (e.g., the section between Dongdan Station and Yong'anli Station on Metro Line 1) will be shut down and power will be cut off: Within the shutdown area, trains will turn back at Wangfujing Station (smaller mileage end) and Guomao Station (larger mileage end); the power outage area will be the same as the shutdown area, and a power cut-off point will be set up at the adjacent connecting line (Beian Station on the Beiyong connecting line). Four pairs of insulating joints will be installed at the rail joints before and after the construction area, and grounding devices will be installed outside the construction area (to be confirmed by the power supply professionals). Temporary stops and speed limit signs will be set up at both ends of the construction area.

[0047] Multi-disciplinary collaborative protection: Power supply coordination: The power supply professionals will determine the grounding location of the contact rail and install temporary rail connectors at the rail joints before and after the construction area to prevent leakage. The removal and restoration of the rail connectors will be carried out and confirmed by power supply professionals.

[0048] Signal coordination: The signal specialists will simultaneously remove or restore electrical poles (switches, transponders, etc.), and during the rail break, the signal software system will synchronously lock and shield the construction area to prevent the interlocking system from falsely reporting track occupancy.

[0049] 5. Remove the temporary lines and install the sliding device (step S4) After the extended track maintenance period begins, the steel supports and joint plates on the existing temporary track will be removed first to clear the path for relocation.

[0050] A sliding device is installed on the translation channel, which includes multiple sets of slide rails and pulley assemblies. The slide rails are arranged along the longitudinal and lateral directions to form a "cross" or "grid" sliding network. The pulley assemblies are installed at the bottom of the turnout or the bottom of the rigid frame reinforcement device to ensure smooth movement of the turnout on the slide rails.

[0051] In this embodiment, there are three slide rails, and the length of each slide rail is set in segments according to the movement path. When moving laterally, the two ends of the slide rail are placed on the existing steel rails, and the middle position is set as a sleeper block as a support point to ensure the stability and load-bearing capacity of the slide rail.

[0052] VI. Three-segment combined sliding (step S5) In this embodiment, since there are existing lines and tunnel clearances between the storage area and the target installation location, it is impossible to complete the positioning by moving longitudinally or laterally in a single direction. Therefore, a three-stage combined movement path of "first longitudinal movement → lateral movement → then longitudinal movement" is adopted.

[0053] First longitudinal movement section: The new turnout, which is in the state of an integral rigid frame, is pulled and moved 4.9m longitudinally along the first direction (longitudinal axis direction, i.e. tunnel extension direction), so that the turnout is moved from the storage area to the starting position of the transverse movement.

[0054] Lateral movement section: Switch the traction direction to the second direction (perpendicular to the first direction in the horizontal plane), move laterally by 4.1m, so that the turnout crosses the existing temporary line and moves to the longitudinal extension line of the target installation position.

[0055] Second longitudinal movement segment: Move longitudinally again along the first direction for 8.8m, so that the entire turnout is directly above the target position.

[0056] Detailed procedure for sliding operations: In actual operation, it is carried out in the following order: Remove the temporary track connecting wires and move the old components longitudinally out; Remove the steel supports of the temporary track and install longitudinal and transverse sliding rails on the track bed; The new turnout, which is in a state of overall rigid frame, is first moved longitudinally 4.9m along the first direction to the first position; Then move laterally for 4.1m along the second direction to the second position; Then move longitudinally 8.8m along the first direction to the target position; The transverse sliding rails and temporary track rails were then removed, allowing the new turnout to be lowered into its original position. Finally, all anti-deformation fixing fixtures were removed and the circuit was finely adjusted.

[0057] In this embodiment, the sliding operation is powered by a hand-operated hoist or a hydraulic traction device, and the traction speed is controlled within 0.5m / min to ensure smoothness and precision.

[0058] VII. Fine-tuning Positioning (Step S6) After the turnout is lowered into its original position, it is leveled and positioned using fine-tuning fixtures. These fixtures include a total station, level, track gauge, track offset gauge, chord line, and steel ruler. The specific operation is as follows: Use a total station to measure the planar position of the turnout and adjust the overall orientation of the turnout to align it with the design axis. The rail top elevation is measured using a level and a steel ruler. The rail surface elevation is adjusted to the design value by adjusting the height adjustment shims (1, 2, 4, 5, 10 mm) set under the iron shims. Use a gauge rod to check the track gauge (standard 1435mm). The allowable deviation is +3 or -2mm, and the rate of change is not greater than 1‰. Use a distance gauge to measure the guide curve distance; allowable deviation ±2mm. Using a chord to measure the elevation and direction of the track, the error of the chord measurement over 10m should not exceed 4mm.

[0059] During the fine-tuning process, priority is given to ensuring that the track alignment and gauge of the straight track (Line 1 main line up) meet the acceptance standards in order to ensure that the main line opens the next day.

[0060] 8. Anchoring and Grouting Curing (Step S7) After fine-tuning, the turnout is anchored and grouted for solidification.

[0061] Anchoring Operation: High-strength anchoring agent is used to anchor the pre-embedded plastic sleeve. In this embodiment, the pre-embedded sleeve has already been drilled and pre-embedded during the previous sleeper adaptation modification. The anchoring agent is a modified epoxy resin anchoring adhesive with a pull-out strength of not less than 80kN (sampling test values ​​on site are between 85-95kN). During anchoring, the anchoring agent is injected into the sleeve, the anchor bolts are inserted, and after curing, the design torque (200-220N·m) is applied.

[0062] Grouting and curing: Resin mortar is used to fill the gap between the sleeper and the track bed. The 28-day compressive strength of the resin mortar is not less than 90 MPa (the measured value in this embodiment is 92-98 MPa), and the 28-day interfacial shear strength is not less than 5.0 MPa. Before grouting, debris in the sleeper pit is cleaned and an interface agent is applied. After grouting, a vibrator is used to compact the mortar, and the surface is smoothed.

[0063] Switch fixing: Due to the presence of a switch pit (recessed space) at the switch location, conventional iron pads cannot be used for direct anchoring. Therefore, steel supports are used as intermediate connecting components. The steel supports are installed on the track bed in the switch pit, with iron pads fixed at the top, and then the switch rails are fixed using a fastening system.

[0064] IX. Subsequent Procedures and Acceptance After completing steps S1-S7 above, the core part of the turnout is installed. Subsequently, the second-end frog and guard rail are replaced during subsequent routine track maintenance windows. After all replacements are completed, the switch system and signal system are integrated and tested. After passing the electric train track test, passenger service is officially resumed.

[0065] In this embodiment, due to the adoption of the overall combined sliding construction method of the present invention, the one-time accurate alignment rate of the core turnout installation reached 100%. The entire sliding and positioning process was successfully completed within the extended 8-hour track window, without any rework caused by frame deformation or misalignment. Compared with the traditional segmented laying method, it saves approximately 30% of the track window time, and the track geometry after construction meets the acceptance requirements of the "Standard for Acceptance of Construction Quality of Underground Railway Engineering" (GB / T 50299-2018) in one go.

[0066] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for integral sliding construction of double-intersection turnouts based on operating subway lines, characterized in that, Includes the following steps: S1. Utilize regular nighttime track maintenance windows for temporary track conversion, including: pre-drilling holes in the existing track bed to pre-embed the first batch of sleeves, removing the double switch and obtuse-angle frog parts in the existing turnouts and then drilling additional holes and pre-embedding sleeves, and installing temporary fastener pads and temporary rails to restore normal train operation. S2. Transport the pre-assembled double-cross turnout as a whole to the storage area of ​​the construction work section; S3. In the storage area, a rigid frame reinforcement device is installed on the entire double-cross turnout to lock the iron pad, rail and its fastening system into an integral rigid frame. S4. Remove the existing temporary line's steel supports and joint plates, and install a sliding device on the resulting translation channel; S5. The entire compound turning turnout is moved longitudinally along the first direction to the first position by the sliding device, then moved laterally along the second direction perpendicular to the first direction to the second position, and then moved longitudinally along the first direction to the target position. S6. Use fine-tuning fixtures to level and position the double-cross turnout; S7. Anchoring and grouting are carried out on the turnout to complete the laying; the switch position is fixed to the track bed by steel supports.

2. The method for integral sliding construction of double-intersection turnouts based on operating subway lines according to claim 1, characterized in that, The on-site operation process for temporary track switching during the regular nighttime track maintenance window in step S1 includes: setting up insulating joints and installing temporary rail connectors at the rail joints of the main line before and after the construction area; cooperating with the power supply professionals to determine the grounding position of the contact rail and perform power outage protection; grinding the existing track bed surface; pre-drilling holes and pre-burying the first batch of sleeves at positions under the existing rails that do not affect train passage; after removing the double switches and obtuse-angle frogs in the existing turnouts, drilling holes and pre-burying sleeves at the remaining un-drilled positions; connecting the temporary fastener iron pads to the pre-buried sleeves with anchor bolts; laying temporary rails and performing joint connections and track fine-tuning to restore normal train operation.

3. The method for integral sliding construction of double-intersection turnouts based on operating subway lines according to claim 1, characterized in that, In step S3, the rigid frame reinforcement device includes multiple connecting steel plates, multiple gauge tie rods, multiple rail braces, and multiple transverse rigid fixing frames. The connecting steel plates are arranged in the symmetrical areas on the upper and lower sides of the double-spinning turnout, connecting the corresponding iron pads or sleepers. The gauge tie rods are spaced apart along the longitudinal direction of the turnout, and the transverse rigid fixing frames are straddling the rails on both sides of the turnout. By adding gauge tie rods, setting connecting steel plates between the rail braces and the iron pads, and setting transverse rigid fixing frames, the iron pads, rails, and their fastening system are locked into an integral rigid frame.

4. The method for integral combination and sliding construction of double-intersection turnouts based on operating subway lines according to claim 1, characterized in that, The sliding device in step S4 includes multiple sets of slide rails and pulley assemblies. The slide rails are arranged along the longitudinal and transverse directions of the translation channel, and the pulley assemblies are installed at the bottom of the double-cross turnout or the bottom of the rigid frame reinforcement device. There are at least three slide rails. When transversely moving, the two ends of the slide rails are placed on the existing rails, and the middle position is supported by sleeper blocks.

5. The method for integral sliding construction of double-intersection turnouts based on operating subway lines according to claim 1, characterized in that, In step S5, the first direction is the longitudinal axis direction of the double-heading turnout, and the second direction is the direction perpendicular to the first direction in the horizontal plane. The on-site operation process of moving the new turnout through the sliding system specifically includes: removing the rail connecting line of the temporary track and moving the old components longitudinally; removing the temporary track steel support piers and installing the transverse sliding rail and supporting sliding facilities on the track bed; pulling the new turnout in the overall rigid frame state, first moving it longitudinally along the first direction by a first distance to the first position, then moving it laterally along the second direction by a second distance to the second position, and then moving it longitudinally along the first direction by a third distance to the target position; then removing the transverse sliding rail and the temporary track rail, so that the new turnout is lowered into its original position and the anchor is locked; finally, removing all anti-deformation fixing fixtures and performing track fine adjustment.

6. The method for integral sliding construction of double-intersection turnouts based on operating subway lines according to claim 1, characterized in that, The fine-tuning fixtures in step S6 include a total station, a level, a track gauge, a track offset gauge, a chord line, and a steel ruler, which are used to perform three-dimensional fine-tuning of the track gauge, level, elevation, direction, and offset of the turnout.

7. The method for integral sliding construction of double-intersection turnouts based on operating subway lines according to claim 1, characterized in that, The anchoring in step S7 includes anchoring the pre-embedded plastic sleeve with an anchoring agent, and the grouting and curing operation includes grouting the gap between the sleeper and the track bed with resin mortar; the pull-out resistance of the anchoring agent is not less than 80kN, and the 28-day compressive strength of the resin mortar is not less than 90MPa.

8. The method for integral sliding construction of double-intersection turnouts based on operating subway lines according to claim 1, characterized in that, Before step S4, the following steps are included: extending the track maintenance window construction organization steps: shutting down and de-energizing the construction section, setting up four pairs of insulating joints at the rail joint positions before and after the construction area, installing grounding devices outside the construction area, and setting up temporary vehicle stops and speed limit signs at both ends of the construction area; the shutdown range is the section of the subway line where the construction section is located, the power outage range is consistent with the shutdown range, and setting up power disconnection points on adjacent connecting lines.

9. The method for integral sliding construction of double-intersection turnouts based on operating subway lines according to claim 8, characterized in that, The extended track window construction organization steps also include multi-professional collaborative protection operations: cooperating with the power supply professionals to determine the grounding position of the contact rail, and installing temporary rail connection lines at the rail gap positions before and after the construction area to prevent leakage. In coordination with the signaling professionals, electrical poles were dismantled or restored simultaneously, and the signaling software system was used to lock and shield the construction area during the rail break.

10. The method for integral sliding construction of double-intersection turnouts based on operating subway lines according to any one of claims 1 to 9, characterized in that, The operating metro line is a ballastless monolithic track line.

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