Foundation-fixing anti-seepage pad for railway ballast track, track bed structure and reinforcing and repairing method

Abstract

The invention discloses a foundation fixing anti-seepage pad for reinforcing and repairing a railway ballast track, a ballast bed structure and a ballast bed reinforcing and repairing method. The foundation fixing anti-seepage pad is of a micro-arch structure with the middle higher than the two sides in the track direction and comprises a bottom surface anti-seepage layer, a middle grid layer and a surface protection layer, and the bottom surface anti-seepage layer and the surface protection layer are compounded on the lower surface and the upper surface of the middle grid layer through a binding agent. And the middle grid layer is a fiber reinforced composite material grid. The foundation-fixing anti-seepage pad provided by the invention is combined with the actual condition of a railway, integrates reinforcement and seepage prevention, has better mechanical properties, high elongation and excellent long-term corrosion resistance, fatigue resistance and seepage resistance, has a stronger horizontal constraint effect on ballast particles, can obviously enhance the bearing capacity of a ballast layer, effectively slows down settlement, reduces the problems of frost boiling and the like, and has a good application prospect. The repair frequency is reduced, and reliable guarantee is provided for the safety and the stability of a railway system.

Description

Technical Field

[0001] The invention relates to the technical field of ballasted track bed maintenance and reinforcement, and in particular to a fast-constructed anti-seepage pad for railway ballasted track reinforcement and repair and a construction method thereof. Background Art

[0002] Since the 1950s, my country's railways have experienced rapid development and continuous expansion, becoming one of the longest and busiest railway networks in the world. The total mileage of my country's railways has increased significantly in the past few decades. According to the latest data, by the end of 2021, the total mileage of China's railways exceeded 140,000 kilometers, including different types of railway lines such as high-speed railways, conventional railways and mining railways.

[0003] Among them, ballasted track is widely used in conventional railways, mining railways and other fields. It refers to the railway track that uses ballast (crushed stone) as the track-laying layer on the railway line. It has the advantages of good shock absorption, low price, easy maintenance, energy absorption and noise reduction. However, under the action of high-speed, heavy-loaded trains and groundwater infiltration, the roadbed is prone to mud bubbling, vertical cumulative settlement and lateral displacement, which causes the roadbed to deteriorate. As a natural bulk material, the cohesion between ballast particles is almost zero and the tensile performance is very poor. In order to improve the overall shear strength and stability of the roadbed and reduce lateral deformation, there have been studies and applications in engineering to reinforce the track bed by laying geogrids. However, practical applications have shown that geogrids, as geotechnical materials for reinforcing railway track beds, can reduce roadbed deformation and extend maintenance cycles, but the strength and stiffness of geogrids cannot meet the needs of railway foundation consolidation. Especially in sections with high groundwater levels, mud and slurry overflow cause serious overall deterioration of the roadbed structure. Conventional replacement and grouting treatments are labor-intensive and time-consuming, and have poor results. Therefore, there is an urgent need for a new material and technology with long life and high durability that can both improve the overall stiffness of the roadbed structure and prevent groundwater from infiltrating upward. Summary of the invention

[0004] In view of these problems of the prior art, the present invention proposes a fast-construction anti-seepage pad for reinforcing and repairing railway ballasted track, a ballast bed structure and a ballast bed reinforcement and repair method.

[0005] In order to achieve the above object, the present invention provides the following technical solutions: The present invention first provides a solid foundation anti-seepage pad for reinforcing and repairing railway ballasted tracks. The solid foundation anti-seepage pad presents a micro-arch structure with a high middle and low sides along the track direction, comprising a bottom surface anti-seepage layer, a middle grid layer and a surface protective layer. The bottom surface anti-seepage layer and the surface protective layer are composited on the lower surface and the upper surface of the middle grid layer by an adhesive; the middle grid layer is a fiber-reinforced composite material grid.

[0006] The thickness of the fiber reinforced composite material grid is 1-5mm, and is distributed along the track direction with high in the middle and low on both sides; the thickness of the bottom surface anti-seepage layer is 0.5-0.6mm; the thickness of the surface protection layer is not less than 3.5mm.

[0007] The mesh of the fiber reinforced composite material grid is square, and the side length of the mesh is 50-100 mm.

[0008] The tensile strength of the fiber reinforced composite material grid is not less than 2000MPa, and the tensile strength of the fiber reinforced composite material grid nodes is not less than 6kN.

[0009] The fiber reinforced composite material grid is a carbon fiber reinforced composite material grid, a glass fiber reinforced composite material grid, a basalt fiber reinforced composite material grid and a mixed fiber reinforced composite material grid.

[0010] The bottom surface anti-seepage layer is a waterproof geomembrane; the surface of the bottom surface anti-seepage layer is provided with anti-slip granular protrusions.

[0011] The surface protection layer is a flexible geotextile with anti-seepage and drainage functions, with a breaking strength of not less than 14.0 kN / m and a tearing strength of not less than 0.5 kN.

[0012] The solid foundation anti-seepage pad provided by the present invention combines the actual situation of the railway, takes into account both reinforcement and anti-seepage, has better mechanical properties, high elongation and excellent long-term corrosion resistance, fatigue resistance and impermeability, has a stronger horizontal constraint effect on ballast particles, can significantly enhance the bearing capacity of the ballast layer, effectively slow down settlement, reduce slurry overflow and other problems, reduce the frequency of repair, and provide reliable guarantee for the safety and stability of the railway system.

[0013] The present invention also provides a railway ballasted track ballast bed structure, comprising: a roadbed layer, a base bed, a ballast layer and a solid foundation anti-seepage pad; the roadbed layer, the base bed, the solid foundation anti-seepage pad and the ballast layer are laid in sequence from bottom to top.

[0014] The present invention also provides a method for reinforcing and repairing a railway ballasted track bed, in which a base-fixing and anti-seepage pad is arranged between the base bed and the ballast layer.

[0015] The railway ballasted track bed reinforcement and repair method specifically includes the following steps: A. Remove rails and sleepers), excavate the deteriorated ballast layer, and remove the aged, damaged and deteriorated ballast layer; B. Treat the roadbed subgrade, mainly including cleaning the debris, loose particles and gravel on the surface of the subgrade, and replacing and compacting it; C. Backfill the base bed to the designed elevation, and backfill a 3~5cm sand cushion layer on the top of the base bed; D. Arrange the foundation-fixing and anti-seepage pad on the sand cushion layer and lay it continuously along the long side; E. Use clean ballast particles to cover and backfill the solid base anti-seepage pad until the ballast particles are filled to the thickness required by the design to ensure the consistency and uniformity of the ballast layer.

[0016] The present invention provides an anti-seepage pad for reinforcing and repairing a railway ballasted track, which is composed of a fiber-reinforced composite material grid. The solid-base anti-seepage pad has a micro-arch structure with a high middle and low sides along the track direction, including a bottom surface anti-seepage layer, a middle grid layer and a surface protective layer, and the composite molding of each material layer is performed by an adhesive. The bottom surface anti-seepage layer is a waterproof geomembrane, which has good mechanical strength and excellent puncture resistance, and a granular protrusion is provided on the surface to prevent the pad material from sliding or dislocating; the middle grid layer is a fiber-reinforced composite material grid, including but not limited to carbon fiber, glass fiber, basalt fiber and its mixed fiber grid, which can be bent for easy construction, has a high strength of not less than 2000MPa, a rigid node, a node tensile force of not less than 6kN, and excellent corrosion resistance; the surface protective layer is a flexible geotextile, which not only has high tensile strength and tear resistance, but also integrates anti-seepage and drainage functions, and is not easily damaged by ballast stone extrusion. The adhesive is a high-viscosity hot-melt adhesive particle with a fast curing speed. It can quickly melt and penetrate into the membrane layer and the fiber layer in a short time. It has elasticity and can effectively resist external pressure and vibration.

[0017] Preferably, the waterproof geomembrane is a high-density polyethylene film; the fiber-reinforced composite material grid includes but is not limited to carbon fiber, glass fiber, basalt fiber and mixed fibers thereof; the flexible geotextile is a geotextile composite membrane; and the high-viscosity hot melt adhesive particles include but are not limited to EVA and TPU hot melt adhesive particles.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. The solid foundation anti-seepage pad of the present invention has a three-layer structure, the middle layer is a grid, and the upper and lower layers are film layers, and the film layers are directly formed on the middle grid; the grid is the main force-bearing structure, which can effectively control the overall settlement of the track. At the same time, the large mesh area of ​​the grid provides deformation space for the upper and lower film layers, so that the upper and lower film layers are deformed when impacted from the upper and lower parts without being directly damaged. At the same time, it can also play a good buffering role and better protect the main structure. The entire upper surface of the solid foundation anti-seepage pad is slightly arched, which is convenient for drainage of the upper surface layer.

[0019] 2. Bottom surface anti-seepage layer - high-density polyethylene film can prevent the upwelling of mud. In some railway sections with high groundwater levels or high soil permeability, mud will break through the roadbed and upwell to the ballast layer through cracks and gaps. By placing a high-density polyethylene film, the upwelling of mud can be effectively prevented, maintaining the stability and drainage performance of the ballast layer. In addition, the granular protrusions on the surface can increase the anti-slip ability of the mat material.

[0020] 3. Middle grid layer - The fiber reinforced composite grid is the main load-bearing material, which can effectively control the overall settlement of the track. The grid has the characteristics of large node stiffness and high strength, which can enhance the bearing capacity of the ballast layer. By embedding the grid into the ballast layer, it provides uniform restraint and support, prevents the settlement and deformation of the ballast layer, and disperses the impact of train load on the ballast layer, thereby improving the service life and operation safety of the railway.

[0021] 4. Surface protection layer - geotextile composite membrane can prevent ballast blocks from damaging the grid. The ballast blocks in the ballast layer may produce impact and pressure on the grid, and the geotextile composite membrane as a protective layer can effectively disperse and reduce this part of the impact force, and cooperate with the middle grid layer to present a micro-arch structure with high in the middle and low on both sides along the track direction. The surface protection layer integrates anti-seepage and drainage functions, which can improve the overall service life and stability of the material.

[0022] 5. The integrated solid foundation anti-seepage pad proposed by the present invention is light and high-strength, and is easy to load and unload and operate directly by manual labor; it has a simple structure, is convenient and efficient to construct, can effectively reduce labor intensity, and is suitable for railway ballast layers of different types and conditions. At the same time, the material uses high-performance fiber-reinforced composite materials, which have high durability and corrosion resistance, and can play a long-term and stable role under high groundwater levels or other acid, alkali, and salt environmental conditions, and its service life is greatly improved compared to conventional geogrids or steel-plastic grids.

[0023] 6. The present invention proposes a method for reinforcing and repairing the ballast track of a railway. Compared with the traditional replacement scheme, the thickness of the sand cushion layer can be greatly reduced or directly omitted. The solid foundation anti-seepage pad is arranged between the ballast layer and the subgrade, which can form a good "interlocking effect" and "net bag effect", and the overall settlement control effect is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0025] In the attached picture: Figure 1 The invention is a schematic diagram of the main structure of a fast-constructed anti-seepage pad for reinforcing and repairing railway ballasted tracks.

[0026] Figure 2 The invention is a schematic diagram of a side surface of an anti-seepage pad for reinforcing and repairing a railway ballasted track which is constructed quickly according to the present invention.

[0027] Figure 3 The invention is a schematic diagram of the reinforcement of an anti-seepage pad for reinforcing and repairing a railway ballasted track with rapid construction.

[0028] Numbers in the figure: 1. Solid base anti-seepage pad body, 2. Bottom surface anti-seepage layer, 3. Middle grid layer, 4. Surface protection layer, 5. Hot melt adhesive particles, 6. Roadbed base layer, 7. Base bed, 8. Ballast layer, 9. Rails and sleepers, 10. Sand cushion layer. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. Example 1

[0030] See also Figure 1 and Figure 2 A fast-construction anti-seepage pad for reinforcing and repairing railway ballasted tracks has a micro-arch structure with a high middle and low sides along the track direction. The main body 1 of the solid foundation anti-seepage pad includes a bottom surface anti-seepage layer 2, a middle grid layer 3 and a surface protection layer 4, and the surface materials are composited into an integrated whole by an adhesive.

[0031] The bottom surface anti-seepage layer 2 is a waterproof geomembrane, specifically a high-density polyethylene film with a thickness of 40-80 threads, which ensures that the material has good mechanical strength and excellent puncture resistance. The surface is provided with granular protrusions to prevent the mat material from sliding or dislocating.

[0032] The middle grid layer 3 is a fiber-reinforced composite material grid, including but not limited to carbon fiber, glass fiber, basalt fiber and mixed fiber grids, preferably basalt fiber grids, using an integrated molding process, light and high strength, tensile strength of 2100MPa, with rigid nodes, node tensile force of not less than 6.2kN, and high corrosion resistance. The mesh size is 25mm~50mm, and along the track direction, the thickness of the limbs is distributed with a large thickness in the middle (4~5mm) and a small thickness on both sides (1~2mm).

[0033] The surface protection layer 4 is a flexible geotextile, specifically a geotextile composite membrane, with a weight of 500-1000g / m 2 It not only has high tensile strength and tearing strength to prevent ballast from damaging the grid, but also integrates anti-seepage and drainage functions. Together with the micro-arched middle grid layer, it can effectively drain precipitation to both sides of the track.

[0034] Adhesive 5 is a high-viscosity hot-melt adhesive particle, preferably low-temperature thermoplastic polyurethane rubber, which can be melted at a low temperature of ~50°C, has a fast curing speed, is elastic and can effectively resist external pressure and vibration. A laminating process is used during production and compounding to ensure overall stability and bonding strength. Example 2

[0035] This embodiment provides a railway ballast track track bed structure, including a roadbed subgrade layer 6, a subgrade 7 and a ballast layer 8, and a solid foundation anti-seepage mat 1 is laid in the ballast bed structure, arranged on the bottom surface of the ballast layer 8 and the top surface of the subgrade 7. Compared with the geogrid in the prior art, the solid foundation anti-seepage mat 1 added to the ballast bed structure of the present invention has a stronger horizontal constraint effect on the ballast particles, can enhance the bearing capacity of the ballast layer, slow down settlement, reduce slurry overflow and other problems, reduce the repair frequency, and extend the service life of the railway ballast track, and has a good application effect.

[0036] The foundation-fixing and anti-seepage pad 1 provided by the present invention can be used for laying a new ballasted track, and can also be used for reinforcing an existing ballasted track.

[0037] The reinforcement methods for existing ballasted tracks are: First, remove the rails and sleepers 9, excavate the deteriorated ballast layer 8, and remove the aged, damaged or deteriorated ballast layer; then treat the roadbed sub-layer 6, mainly including cleaning the debris, loose particles and gravel on the surface of the sub-layer, and replace and compact it. By compacting the sub-layer, the density and bearing capacity of the sub-layer can be improved, providing a good foundation for the laying of the railway sub-base anti-seepage pad 1. After the sub-base layer 6 is treated, backfill the sub-bed 7 to the design elevation, and backfill the 3~5cm sand cushion layer 10 on the top of the sub-bed for foundation leveling and elevation adjustment. Finally, lay the railway sub-base anti-seepage pad 1 on the sand cushion layer 10, and cover and backfill it with clean ballast particles until the ballast particles are filled to the thickness required by the design to ensure the consistency and uniformity of the ballast layer 8. Compared with the traditional replacement scheme, the solid foundation anti-seepage pad is arranged between the ballast layer and the subgrade, which can form a good "interlocking effect" and "net bag effect". The thickness of the sand cushion layer can be greatly reduced or directly omitted, and the overall settlement control effect is significantly improved.

Claims

1. A foundation-fixing and anti-seepage pad for reinforcing and repairing railway ballasted tracks, characterized in that: The solid-base anti-seepage pad (1) is a micro-arched bendable structure with a high middle and low sides along the track direction, comprising a bottom surface anti-seepage layer (2), a middle grid layer (3) and a surface protection layer (4); the bottom surface anti-seepage layer (2) and the surface protection layer (4) are composited on the lower surface and the upper surface of the middle grid layer (3) by means of an adhesive (5); the middle grid layer (3) is a fiber-reinforced composite material grid.

2. The anti-seepage pad for reinforcing and repairing the railway ballasted track according to claim 1 is characterized by: The thickness of the fiber reinforced composite material grid is 1-5 mm, and is distributed along the track direction with a high middle and low sides; the thickness of the bottom surface anti-seepage layer (2) is 0.5-0.6 mm; and the thickness of the surface protection layer (4) is not less than 3.5 mm.

3. The anti-seepage pad for reinforcing and repairing the railway ballasted track according to claim 2 is characterized in that: The mesh of the fiber reinforced composite material grid is square, and the side length of the mesh is 50-100 mm.

4. The anti-seepage pad for reinforcing and repairing the railway ballasted track according to claim 3 is characterized by: The tensile strength of the fiber reinforced composite material grid is not less than 2000MPa, and the tensile strength of the fiber reinforced composite material grid nodes is not less than 6kN.

5. The anti-seepage pad for reinforcing and repairing a railway ballasted track according to any one of claims 1 to 4, characterized in that: The fiber reinforced composite material grid is a carbon fiber reinforced composite material grid, a glass fiber reinforced composite material grid, a basalt fiber reinforced composite material grid and a mixed fiber reinforced composite material grid.

6. The anti-seepage pad for reinforcing and repairing a railway ballasted track according to any one of claims 1 to 4, characterized in that: The bottom surface anti-seepage layer (2) is a waterproof geomembrane; the surface of the bottom surface anti-seepage layer (2) is provided with anti-slip granular protrusions.

7. The anti-seepage pad for reinforcing and repairing a railway ballasted track according to any one of claims 1 to 4, characterized in that: The surface protection layer (4) is a flexible geotextile with anti-seepage and drainage properties, with a breaking strength of not less than 14.0 kN / m and a tearing strength of not less than 0.5 kN.

8. A railway ballast track ballast track structure, characterized in that: include: A roadbed layer, a subgrade bed, a ballast layer and a solid foundation anti-seepage pad as described in any one of claims 1 to 7; the roadbed layer, the subgrade bed, the solid foundation anti-seepage pad and the ballast layer are laid in sequence from bottom to top.

9. A method for reinforcing and repairing a railway ballasted track bed, characterized in that: A solid foundation anti-seepage pad (1) as claimed in any one of claims 1 to 7 is arranged between the base bed (7) and the ballast layer (8).

10. The method for reinforcing and repairing the railway ballasted track bed according to claim 9, characterized in that: The following steps are involved: A. removing rails and sleepers (9), excavating the deteriorated ballast layer (8), and removing aged, damaged and deteriorated ballast layer; B. Treating the roadbed subgrade (6), mainly including cleaning the debris, loose particles and gravel on the surface of the subgrade, and replacing and compacting it; C. Backfill the base bed (7) to the designed elevation, and backfill a 3-5 cm sand cushion layer (10) on top of the base bed; D. Arranging a base-fixing and anti-seepage pad (1) on the sand cushion layer (10), which can be bent and laid continuously along the long side direction; E. Use clean ballast particles to cover and backfill the solid foundation anti-seepage pad (1) until the ballast particles are filled to the required thickness in the design, ensuring the consistency and uniformity of the ballast layer (8).

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