A method for vibration reduction and upgrading of underground rail transit track bed

Abstract

This invention relates to a method for vibration reduction and upgrading of underground rail transit track beds. The method involves segmenting the existing track bed into blocks of a certain length, cutting installation grooves at the bottom of both sides of each block, and installing high-pressure air cushions within these grooves. The air cushions are then pressurized and expanded, causing the track blocks to lift and detach from the tunnel lining segments. Flexible elastic material is injected into the gaps. Once the flexible elastic material reaches its design strength, the high-pressure air cushions are depressurized. The weight of the track blocks and the train load are supported by the vibration-damping layer formed by the flexible elastic material. The advantages of this invention are: it achieves in-situ vibration reduction and upgrading of existing underground rail transit track beds without breaking or shifting rails, effectively ensuring the structural performance and safety of the rails; and it allows for segmented upgrades during the existing rail transit operation window, avoiding disruption to normal operation.

Description

Technical Field

[0001] This invention relates to the field of track bed renovation technology, and in particular to a method for vibration reduction and upgrading of underground rail transit track beds. Background Technology

[0002] With the advancement of urbanization, underground rail transit lines are becoming increasingly abundant in cities. During the operation of rail transit, the vibration of trains will undoubtedly have an adverse effect on tunnel boring machine (TBM) segments, especially for existing older lines with a longer construction history. Long-term and frequent vibrations can further lead to damage to the TBM segments, creating risks. At the same time, based on the technical capabilities or specifications required at the time of construction, existing older lines generally lack vibration reduction capabilities, and even if they do have vibration reduction capabilities, their level often does not meet current requirements.

[0003] Therefore, upgrading existing old lines is an urgent direction that needs to be considered. However, the main problems encountered include the following aspects:

[0004] 1) Due to their early construction dates, existing subway lines are typically located in core urban areas according to urban planning principles. For example, Shanghai Metro Line 1, built in 1995, runs through numerous landmarks, commercial districts, and other areas, resulting in consistently high passenger traffic. Therefore, how to renovate these existing lines while minimizing disruption to people's travel and construction impact is a significant challenge.

[0005] 2) Due to the structural characteristics of existing railway lines during construction, their overall structure, including the track bed, is generally a heavy, monolithic concrete structure with a very large volume. If vibration reduction modifications are to be made, a large amount of concrete must be removed, which is not only a massive undertaking but also extremely time-consuming. Furthermore, since the rails are the primary point of vibration transmission for trains, the area of ​​concrete removal often extends to the rails themselves. Removal work can easily affect the already laid rails, potentially requiring rail realignment, and in extreme cases, depending on the construction method, may even involve rail breakage and rerailing.

[0006] In conclusion, upgrading existing old lines is a pressing technical problem that needs to be solved. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of the prior art by providing a method for vibration reduction and upgrading of underground rail transit track beds. This method involves cutting the existing track bed into sections and using high-pressure air cushions to lift the sections, thereby performing in-situ vibration reduction and upgrading of the existing track bed without affecting the rails. This achieves efficient renovation and construction under conditions of no rail breakage and no rail repositioning.

[0008] The objective of this invention is achieved through the following technical solutions:

[0009] A method for vibration reduction and upgrading of underground rail transit track bed, used to upgrade the existing track bed of an existing underground rail transit line, wherein the existing track bed is installed on shield tunnel segments and the shapes of the two are matched, and the existing track bed has drainage ditches on both sides, characterized in that the upgrade method includes the following steps:

[0010] The existing track bed is divided into sections along the direction of the existing underground rail transit line, so that the existing track bed is divided into several track bed blocks of a certain length, and installation grooves are cut at the bottom positions on both sides of the track bed blocks.

[0011] A high-pressure air cushion is installed in the mounting groove, and the high-pressure air cushion is installed within the bottom range of the track bed block.

[0012] The high-pressure air cushion is pressurized and driven to expand, causing the track bed block to be lifted and separated from the shield tunnel segment under the action of the high-pressure air cushion, forming a certain gap between the track bed block and the shield tunnel segment;

[0013] A flexible elastic material is injected into the gap, and the flexible elastic material serves as a vibration damping pad between the track bed block and the shield tunnel segment.

[0014] After the flexible elastic material to be injected reaches the design strength, the high-pressure air cushion is depressurized, and the weight of the track bed block and the train load are supported by the vibration damping pad layer formed by the flexible elastic material.

[0015] Before cutting the existing track bed, the ditches on both sides are broken.

[0016] Once the flexible elastic material reaches its designed strength and the high-pressure air cushion is depressurized, the drainage ditches on both sides of the track bed block are restored and waterproofed.

[0017] The renovation method is carried out in units of the number of track bed blocks, that is, one or more track bed blocks are constructed at a time according to the construction capacity and construction time.

[0018] Within the influence range of the track bed block under construction, height adjustment pads adapted to the height of the vibration damping pad layer formed by flexible elastic material are added to the rail fastening system on the adjacent track bed block to adjust the rail surface height, so that the rail can be connected smoothly without rail breakage or rail shifting.

[0019] Each track bed block is used independently after the grouting construction, and an independent stray circuit drainage terminal and connecting wire are installed on each track bed block.

[0020] The high-pressure air cushions are arranged in multiple pairs at intervals on each of the existing underground rail transit blocks, along the direction of the existing rail transit line.

[0021] The existing track bed is segmented and cut using a circular saw with an arc-shaped guide groove, the curvature of which matches the curvature of the shield tunnel segment.

[0022] The advantages of this invention are: it enables in-situ vibration reduction and upgrading of existing underground rail transit track beds without breaking or shifting rails, thus ensuring the structural performance and safety of the rails; it allows for segmented upgrades during the existing rail transit operation window, avoiding disruption to the normal operation of the existing rail transit; and the construction method is simple and reasonable, allowing for the upgrading of one or more sections within an operation window based on different construction efficiencies, effectively improving construction efficiency. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the existing track bed structure targeted in the embodiments of the present invention;

[0024] Figure 2 Construction steps of the present invention Figure I ;

[0025] Figure 3 Construction steps of the present invention Figure II ;

[0026] Figure 4 Construction steps of the present invention Figure III ;

[0027] Figure 5 Construction steps of the present invention Figure IV ;

[0028] Figure 6 Construction steps of the present invention Figure V ;

[0029] Figure 7 This is a schematic diagram of the arrangement structure of the high-pressure air cushion in this invention. Detailed Implementation

[0030] The features and other related features of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate understanding by those skilled in the art:

[0031] like Figure 1-7 As shown in the figure, the markings 1-10 represent: shield tunnel segment 1, existing track bed 2, sleeper 3, rail 4, drainage ditch 5, high-pressure air cushion 6, gap 7, flexible elastic material 8, waterproof seal 9, track bed block 10.

[0032] Example: Figure 1As shown, the vibration reduction and upgrading method for underground rail transit track bed in this embodiment is used to upgrade the existing track bed 2. The existing track bed 2 is installed on the shield tunnel segment 1, and drainage ditches 5 are set on both sides of the existing track bed 2 for drainage of the underground line. Sleepers 3 are installed on the existing track bed 2 to support the rails 4 used for rail transit line operation. It should be noted that the vibration reduction and upgrading method in this embodiment is not only applicable to the vibration reduction and upgrading of the existing track bed 2, but also, in some cases, such as when the existing track bed 2 needs to be completely renovated, the method in this embodiment can be used to dismantle the existing track bed 2.

[0033] Specifically, the vibration reduction upgrade method in this embodiment includes the following steps:

[0034] 1) such as Figure 2 As shown, the existing track bed 2's drainage ditch 5 section was completely demolished. A certain distance was maintained between the demolition area and the existing sleepers 3, with the primary criterion being to avoid affecting the existing sleepers 3, the rails 4 installed above them, and the internal structural reinforcement of the existing track bed 2. After the drainage ditch 5 was demolished, construction surfaces were formed on both sides of the existing track bed 2. The structure of the existing track bed 2 after the drainage ditch 5 was demolished is as follows. Figure 3 As shown.

[0035] 2) Combining Figure 3 and Figure 7 As shown, along the extension direction of the underground rail transit line, the existing track bed 2, at unreinforced locations, is cut into several track bed blocks 10 at certain lengths. The cutting length of each track bed block 10 is determined based on its weight, the lifting capacity of the high-pressure air cushion used for subsequent lifting, and the injection efficiency of the flexible elastic material. Simultaneously, installation grooves are created on both sides of the existing track bed 2 at the construction surface locations. The shape and size of these grooves are appropriately matched to the shape and size of the high-pressure air cushion 6. For example... Figure 7 As shown, three pairs of high-pressure air cushions 6 are arranged at intervals on both sides of the single track bed block 10 to ensure that it can be stably lifted.

[0036] In this embodiment, the cutting and splitting of the existing track bed 2 in step 2) can also be interchanged with the demolition of the ditch 5 in step 1); that is, the existing track bed 2 is cut and split first, and then the ditch 5 on each of the formed track bed blocks 10 is demolished one by one.

[0037] 3) Comparison Figure 2 and Figure 3As shown, each high-pressure air cushion 6 is connected to an external high-pressure pneumatic device to pressurize and drive it to expand. At this time, the track bed block 10, which has a smaller individual weight, is lifted to a certain height under the action of the high-pressure air cushion 6 and separates from the shield tunnel segment 1, so that a certain gap 7 is formed between the track bed block 10 and the shield tunnel segment 1. This gap 7 is the space for subsequent injection of flexible elastic material.

[0038] In this embodiment, the lifting amount of the high-pressure air cushion 6 is controlled by equipment. This lifting amount directly reflects the thickness of the gap 7 formed between the track bed block 10 and the shield tunnel segment 1, and thus also limits the thickness of the subsequently injected flexible elastic material. Therefore, this embodiment can precisely control the thickness of the flexible elastic material by controlling the lifting amount of the high-pressure air cushion 6, and it is easy to adjust, which is beneficial to improving the construction quality.

[0039] 4) such as Figure 5 As shown, flexible elastic material 8 is injected into the gap 7. This flexible elastic material 8 serves as a vibration damping pad between the track bed block 10 and the shield tunnel segment 1. That is, during the operation of the rail transit, the vibration transmitted through the rail 4 will be isolated or absorbed by the flexible elastic material 8, preventing the vibration from being further vertically transmitted to the shield tunnel segment 1 below, thereby achieving the purpose of vibration reduction and upgrading.

[0040] 5) After the flexible elastic material to be injected reaches its design strength, the high-pressure air cushion 6 is depressurized, returning it to a compressed state from its expanded state. At this time, the weight of the track bed block 10 and the train load during operation are supported by the vibration-damping pad layer formed by the flexible elastic material 8. In this embodiment, the high-pressure air cushion 6 does not need to be removed from under the track bed block 10. Moreover, since it needs to expand under pressure, it is generally made of a flexible material with a certain coefficient of expansion, thus it can also play a certain role in vibration damping without causing a decrease in the vibration damping effect. At the same time, in subsequent construction tasks such as modification and maintenance, the track bed can also be lifted by using the high-pressure air cushion 6 remaining in the track bed block 10.

[0041] 6) For example Figure 6 As shown, the track bed blocks 10 are used independently after the grouting construction and the connections are not restored. Based on this, stray circuit drainage sections and connecting wires are installed for each track bed block 10 to meet the stray circuit drainage requirements. At the same time, after the main construction of the track bed block 10 is completed, the drainage ditches 5 are restored on both sides.

[0042] In this embodiment, the vibration reduction upgrade and renovation project is preferably carried out during the maintenance window of the existing underground rail transit line to avoid affecting normal operation. During the renovation and construction process, one or more track bed blocks 10 can be renovated within a maintenance window, depending on the construction capacity. Before the high-pressure air cushion 6 is raised, height adjustment shims are added to the fastening system of the rail 4 to achieve a smooth transition of the rail surface elevation. Specifically, since the modified track bed block 10 is raised by the flexible elastic material 8, the rail surface elevation of its rail 4 is also further raised. At this time, height adjustment shims are added to the rail fastening points within a certain range, so that the rail surface elevation of the rails within the affected range is also raised accordingly, achieving a smooth transition of the rail surface elevation of the rail 4, so as to facilitate normal operation during the operation period. Therefore, the vibration reduction upgrade and renovation method in this embodiment is an in-situ renovation without breaking rails or shifting rails, which does not affect the condition of the rails, ensuring the structural safety of the rail structure.

[0043] In this embodiment, the cutting of the existing track bed 2 can be achieved by a circular saw, and an arc-shaped guide groove is designed to achieve arc-shaped cutting of the circular saw, so as to meet the need that the contact surface between the shield tunnel segment 1 and the existing track bed 2 is an arc-shaped surface; during cutting, the stroke of the circular saw should be controlled to avoid damaging the shield tunnel segment 1 below.

[0044] The existing track bed 2 is generally 12.5m long. In the actual cutting process, it can be divided into track bed blocks of about 3m each (the self-weight of a 3.6m track bed block is generally about 12T). When cutting into track bed blocks of about 3m, it is advisable to arrange three pairs of high-pressure air cushions, and for track bed blocks of about 4m, it is advisable to arrange four pairs of high-pressure air cushions.

[0045] Although the above embodiments have described the concept and embodiments of the present invention in detail with reference to the accompanying drawings, those skilled in the art will recognize that various improvements and modifications can still be made to the present invention without departing from the scope of the claims, and therefore will not be elaborated here.

Claims

1. A method for vibration reduction and upgrading of underground rail transit track bed, used to upgrade the existing track bed of an existing underground rail transit line, wherein the existing track bed is installed on shield tunnel segments and the shapes of the two are matched, and the existing track bed has drainage ditches on both sides, characterized in that: The modification method includes the following steps: The existing track bed is divided into sections along the direction of the existing underground rail transit line, so that the existing track bed is divided into several track bed blocks of a certain length, and installation grooves are cut at the bottom positions on both sides of the track bed blocks. A high-pressure air cushion is installed in the mounting groove, and the high-pressure air cushion is installed within the bottom range of the track bed block. The high-pressure air cushion is pressurized and driven to expand, causing the track bed block to be lifted and separated from the shield tunnel segment under the action of the high-pressure air cushion, forming a certain gap between the track bed block and the shield tunnel segment; A flexible elastic material is injected into the gap, and the flexible elastic material serves as a vibration damping pad between the track bed block and the shield tunnel segment. After the flexible elastic material to be injected reaches the design strength, the high-pressure air cushion is depressurized, and the weight of the track bed block and the train load are supported by the vibration damping pad layer formed by the flexible elastic material.

2. The method for vibration reduction and upgrading of underground rail transit track bed according to claim 1, characterized in that: Before cutting the existing track bed, the ditches on both sides are broken.

3. The method for vibration reduction and upgrading of underground rail transit track bed according to claim 2, characterized in that: Once the flexible elastic material reaches its design strength and the high-pressure air cushion is depressurized, the drainage ditches on both sides of the track bed block are restored and waterproofed.

4. The method for vibration reduction and upgrading of underground rail transit track bed according to claim 1, characterized in that: The renovation method is carried out in units of the number of track bed blocks, that is, one or more track bed blocks are constructed at a time according to the construction capacity and construction time.

5. A method for vibration reduction and upgrading of underground rail transit track bed according to claim 4, characterized in that: Within the influence range of the track bed block under construction, height adjustment pads adapted to the height of the vibration damping pad layer formed by flexible elastic material are added to the rail fastening system on the adjacent track bed block to adjust the rail surface height, so that the rail can be connected smoothly without rail breakage or rail shifting.

6. The method for vibration reduction and upgrading of underground rail transit track bed according to claim 1, characterized in that: Each track bed block is used independently after the grouting construction, and an independent stray circuit drainage terminal and connecting wire are installed on each track bed block.

7. The method for vibration reduction and upgrading of underground rail transit track bed according to claim 1, characterized in that: The high-pressure air cushions are arranged in multiple pairs at intervals on each of the existing underground rail transit blocks, along the direction of the existing rail transit line.

8. The method for vibration reduction and upgrading of underground rail transit track bed according to claim 1, characterized in that: The existing track bed is segmented and cut using a circular saw with an arc-shaped guide groove, the curvature of which matches the curvature of the shield tunnel segment.

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