A ballastless track structure

Abstract

The present invention relates to a ballastless track structure, comprising a base bed surface layer composed of asphalt concrete material, a base plate arranged above the base bed surface layer and cast from reinforced concrete material, and a base bed bottom layer composed of graded crushed stone arranged below the base bed surface layer. The structure is characterized in that it also includes a reinforcement unit for strengthening the connection between the base bed surface layer and the base bed bottom layer, the reinforcement unit including fasteners arranged on both sides of the base bed surface layer corresponding to the joint of the two base plate structures, the fasteners being inserted into the base bed bottom layer, and the fasteners being composed of a material having a stiffness greater than that of the asphalt concrete material and the graded crushed stone material.

Description

Technical Field

[0001] The present invention relates to the technical field of ballastless track, and in particular to a ballastless track structure. Background Art

[0002] With the rapid development of high-speed railways in recent years, the requirements for the smoothness and durability of ballastless tracks used in high-speed railways have become increasingly stringent. As the world's most advanced track technology, ballastless track not only has high precision and excellent stability, but is particularly suitable for high-speed trains traveling at speeds exceeding 200 km / h.

[0003] The existing ballastless track structure, from top to bottom, generally consists of a ballastless track slab, base plate, subgrade surface layer, subgrade bottom layer, and roadbed. To prevent surface water, such as rainwater, from seeping into the roadbed and damaging the stability and bearing capacity of the ballastless track, a functional layer of fiber cement concrete is usually installed between the tracks and on the shoulders for sealing. However, due to the presence of structural joints, this functional layer often cracks, causing atmospheric precipitation to infiltrate. If a full-section asphalt concrete material is used as a waterproof sealing layer, the stability of the ballastless track under different environmental conditions will be greatly challenged due to the fact that the asphalt concrete material itself is subject to significant deformation due to temperature. This poses a significant risk to the operation of high-speed trains.

[0004] Therefore, there is a need for a ballastless track structure that has good waterproof performance and is not easily affected by temperature loads. Summary of the Invention

[0005] The present invention provides a ballastless track structure, comprising a base bed surface layer composed of asphalt concrete material, a base plate arranged above the base bed surface layer and cast from reinforced concrete material, and a base bed bottom layer composed of graded crushed stone arranged below the base bed surface layer. The structure is characterized in that it also includes a reinforcement unit for strengthening the connection between the base bed surface layer and the base bed bottom layer, the reinforcement unit including fasteners arranged on both sides of the joint of the two base plate structures on the base bed surface layer, the fasteners being inserted into the base bed bottom layer, and the fasteners being composed of a material having a stiffness greater than that of the asphalt concrete material and the graded crushed stone material.

[0006] Preferably, the fastener is a T-shaped structure as a whole, including a top and at least one columnar portion connected to the top, the top is arranged below the base bed surface or maintained horizontally with the base bed surface, and the columnar portion passes through the base bed surface and extends into the base bed bottom layer.

[0007] Preferably, it is characterized in that the fastener is arranged below the surface of the base bed, and includes at least one protruding structure integrally formed with the surface of the base bed, and the bottom layer of the base bed is provided with a groove corresponding to the protruding structure, and the protruding structure extends into the groove of the bottom layer of the base bed.

[0008] Preferably, the reinforcement units are arranged on both sides of the structural joint between the two base plates, and at least one reinforcement unit is arranged per square meter of area.

[0009] Preferably, the closer the distance between any two fasteners in the reinforcement unit and the two base plate structural seams is, the smaller the distance between the two fasteners is.

[0010] Preferably, the fasteners are distributed in the reinforcement unit in an X-shape, a M-shape, or a criss-cross shape.

[0011] Preferably, an isolation unit is further included, wherein the isolation unit is arranged between the base plate and the surface layer of the subgrade, and is arranged on both sides of the structural seam between the two base plates on the reinforcing unit.

[0012] Preferably, the laying length of the isolation unit on each side of the structural seam between the two base plates is 1.0m-1.5m.

[0013] Preferably, the isolation unit is made of geocomposite material.

[0014] Preferably, a filling unit is further included, and the filling unit is filled in the connection between the fastener and the base bed surface layer and / or the base bed bottom layer to fill the structural seam at the connection.

[0015] Compared with the prior art, the present invention has achieved the following beneficial technical effects: the ballastless track structure provided by the present invention adopts asphalt concrete material as a waterproof and closed surface layer, and utilizes reinforcement units to strengthen the connection performance between the surface layer and the bottom layer, so that the asphalt concrete surface layer, which is originally susceptible to deformation due to temperature, can withstand a greater temperature load, while ensuring the waterproof performance of the ballastless track, and improving the temperature tolerance of the ballastless track; and when arranging the reinforcement units, targeted reinforcement is carried out, especially at the positions of the structural joints between the base plates that are more affected by the temperature load, so as to save the laying cost and effectively reduce the strain of the ballastless track structure under the action of the temperature load; the ballastless track structure provided by the present invention has a flexible construction method, improves the durability and stability of the ballastless track under various environmental conditions, is highly practical and is conducive to popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the cross-sectional structure of the ballastless track structure provided by the present invention.

[0017] Figure 2 It is a schematic diagram of the top view of the ballastless track structure provided by the present invention.

[0018] Figure 3It is a schematic diagram of the fastener structure provided by another embodiment of the present invention.

[0019] Figure 4 It is a schematic diagram of a temperature load test provided by a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] The typical design service life of ballastless track is no less than 60 years. However, ballastless track structures exposed to the atmospheric environment are extremely susceptible to deformation due to temperature loads. Based on the principles of thermal engineering, environmental conditions typically include solar radiation, temperature, wind speed, rainfall, and other environmental factors. Therefore, overcoming environmental factors, especially the impact of temperature loads on the ballastless track structure to improve stability, is a major challenge in ballastless track structure design.

[0022] Based on years of experience in ballastless track construction, the inventors discovered that the impact of temperature loads is more pronounced at the base plate joints than at other structural locations. Based on this discovery, the inventors proposed a ballastless track structure with reinforcement units. These reinforcement units effectively improve the connection strength between the top and bottom layers of the ballastless track subgrade, helping to resist the effects of temperature loads.

[0023] Figure 1 This is a schematic diagram of the cross-sectional structure of the ballastless track structure provided by the present invention, such as Figure 1 As shown, the ballastless track structure includes a subgrade surface layer 2 (i.e., a waterproof sealing layer) made of asphalt concrete, a plurality of base plates 1 cast from reinforced concrete material above the subgrade surface layer 2, a subgrade bottom layer 3 made of graded crushed stone material below the subgrade surface layer 2, and a reinforcement unit 4 provided on the subgrade surface layer 2. The reinforcement unit 4 is provided on the subgrade surface layer 2 corresponding to the structural joint 10 between the two base plates 1 (see FIG. Figure 2 ) position and extends into the base bed bottom layer 3, so as to reduce the strain between the base bed surface layer 2 and the base bed bottom layer 3 caused by the temperature load.

[0024] Figure 2 Schematic diagram of the top view of the ballastless track provided by the present invention, as shown in FIG. Figure 2As shown, three reinforcement units 4 are symmetrically arranged on either side of the structural seam 10 of the base plate 2. Each reinforcement unit 4 includes five fasteners 40 arranged in an X-shape. Preferably, each reinforcement unit 4 occupies an area of 1 square meter. For example, for a 3400mm wide base plate 1, three 800mm wide reinforcement units 4 can be arranged on either side of the structural seam 10, with a spacing of 200mm between each reinforcement unit 4 and a distance of 300mm between each reinforcement unit 4 and the edge of the subgrade surface layer 2.

[0025] The ballastless track structure provided by the present invention also includes a filling unit (not shown) for filling the gap between the reinforcement unit 4 and the subgrade surface layer 2 and / or the subgrade bottom layer 3. This filling unit is primarily used to fill the gap between the reinforcement unit 4 and the subgrade surface layer 2 and / or the subgrade bottom layer 3. Preferably, the filling unit can be a construction adhesive, such as a mortar made from a certain proportion of sand and a binder (cement, lime paste, clay, etc.) mixed with water. This filling unit is used to fill the gap in the subgrade surface layer 2 and / or the subgrade bottom layer 3 created when installing the fasteners 40.

[0026] In one embodiment of the present invention, Figure 1 As shown, the fastener 40 is made of a material with a stiffness greater than that of asphalt concrete and graded crushed stone, and is capable of penetrating the subgrade surface layer 2 and extending into the subgrade bottom layer 3. Specifically, the fastener 40 includes a top portion 401 disposed below the subgrade surface layer 2, and one or more columnar portions 402 penetrating the subgrade surface layer 2 and inserted into the subgrade bottom layer 3. The top portion 401 may also be arranged to be level with the surface of the subgrade surface layer 2. Preferably, the fastener 40 may be a T-shaped structure as a whole. For example, the fastener 40 may be a penetrating steel nail with a diameter of 18 mm and a length of 400 mm. When the thickness of the subgrade surface layer 2 is 100 mm, the penetrating steel nail may be inserted to 300 mm into the subgrade bottom layer 3.

[0027] In one embodiment of the present invention, Figure 3 FIG. 1 is a schematic diagram of a ballastless track structure provided by another embodiment of the present invention, as shown in FIG. Figure 3 As shown above Figure 1 The difference of the ballastless track structure shown is that the fasteners 50 can be used instead of Figure 1 The fastener 40 is provided below the subgrade surface layer 2 and is a protruding structure integrally formed with the subgrade surface layer 2. Furthermore, a groove 60 is provided in the subgrade bottom layer 3 for use with the fastener 50, so that each protruding structure can extend into the groove 60, thereby strengthening the connection strength between the subgrade surface layer 2 and the subgrade bottom layer 3 and reducing the effect of the temperature load on the subgrade surface layer 2.

[0028] In one embodiment of the present invention, the fasteners 40 (or fasteners 50) included in the reinforcement unit 4 may be distributed in other arrangements within the reinforcement unit 4. For example, they may be evenly distributed in a cross-pattern or a well-pattern; or, if the distance between any two fasteners 40 (or fasteners 50) and the structural joint 10 between the two base plates 1 is closer, the distance between the two fasteners 40 (or fasteners 50) is also closer, so that the distribution of the fasteners 40 (or fasteners 50) within the reinforcement unit 4 can be adjusted according to the intensity of the temperature load.

[0029] In one embodiment of the present invention, the ballastless track structure provided by the present invention further includes an isolation unit provided between the subgrade surface layer 2 and the base plate 1. Specifically, the isolation unit is arranged on both sides of the structural joint 10 between the two base plates 1 and is provided above the above-mentioned reinforcement unit 4. Preferably, the isolation unit is composed of a geocomposite material, for example, two cloths and one membrane with a single layer thickness of not less than 0.25 mm and an elongation of 25%-100%. Preferably, the length of the isolation unit laid on each side of the structural joint 10 is 1.0m-1.5m. By utilizing the isolation unit, the relative displacement strain between the base plate 1 and the asphalt concrete subgrade surface layer 2 caused by the temperature load can be effectively reduced, thereby improving the reinforcement effect of the reinforcement unit 4 on the subgrade surface layer 2 and the subgrade bottom layer 3.

[0030] In order to verify the ballastless track structure provided by the present invention's ability to withstand temperature loads, the inventors conducted temperature load tests on ballastless tracks equipped with the aforementioned reinforcement units 4 and on ballastless tracks without the aforementioned reinforcement units 4 at a ballastless track construction site. The following uses penetrating steel nails arranged in an X pattern as an example for illustration. Figure 4 Schematic diagram of temperature load test provided by the preferred embodiment of the present invention, as shown in FIG. Figure 4 The specific test steps are as follows:

[0031] 1) Divide the three reinforced concrete base plates into five areas, such as Figure 4 As shown, from left to right, base plates 100, 200, and 300 are shown, each measuring 19.2 m x 3.4 m x 0.3 m. The 1 m area on each side of the structural joint 10 between base plates 1 and 2 is Area A1, and the remainder of base plate 1 (excluding Area A1) is Area C1. The 1 m area on each side of the construction joint between base plates 2 and 3 is Area A2, and the remainder of base plate 3 (excluding Area A2) is Area C2. The remainder of base plate 2 (excluding Area A1 and A2) is Area B.

[0032] 2) Two fiber Bragg grating surface strain gauges are placed on the edge of the asphalt concrete subgrade and the base plate to measure the on-site temperature and the strain generated by the ballastless track structure;

[0033] 3) For the shoulder side of the five areas mentioned above, traditional strain gauges are arranged at different densities. For example, for areas A1 and A2, a strain gauge is arranged every 200 mm to centrally monitor the strain caused by temperature loads at the structural joints.

[0034] 4) The fiber Bragg grating surface strain gauge and the traditional strain gauge are connected to a computer via a collector, and the computer is used to collect and analyze the data obtained by all the strain gauges in real time.

[0035] Tests using the above-mentioned test method revealed that before the reinforcement device provided by the present invention was installed, the maximum bending and tensile strain of the asphalt concrete base bed surface layer at the structural joint 10 between the two base plates 1 was approximately 196.1 με, and the maximum bending and tensile strain of the asphalt concrete base bed surface layer at the shoulder was approximately 184.9 με; after the X-shaped penetrating steel nails provided by the present invention were installed, the maximum bending and tensile strain of the asphalt concrete base bed surface layer at the structural joint 10 between the two base plates 1 was reduced to approximately 154.4 με, with a decrease of approximately 21.2%, and the maximum bending and tensile strain of the asphalt concrete base bed surface layer at the shoulder was reduced to approximately 169.4 με, with a decrease of approximately 8.3%.

[0036] It can be seen from this that by arranging the reinforcement device provided by the present invention on the ballastless track, the strain effect of the temperature load on the ballastless track structure can be greatly reduced, and the closer the ballastless track structure is to the arrangement position of the above-mentioned reinforcement device, the better the reinforcement effect.

[0037] Although in the above embodiment, an X-shaped penetrating steel nail structure is used as an example of a test experiment to illustrate the effect of the reinforcement device provided by the present invention, ordinary technicians in this field should understand that in other embodiments, the reinforcement device provided by the present invention may also include fasteners of other shapes, such as a claw-type structure with a top and multiple columnar parts, and the arrangement of the fasteners may also be adjusted according to the needs of the actual environment. For example, for environmental conditions with relatively high temperature load requirements, the arrangement density of the fasteners may be appropriately increased to obtain a better reinforcement effect.

[0038] Although the present invention has been described through preferred embodiments, the present invention is not limited to the embodiments described herein but includes various changes and modifications that may be made without departing from the scope of the present invention.

Claims

1. A ballastless track structure comprising a subgrade surface layer composed of asphalt concrete, a base plate cast from reinforced concrete above the subgrade surface layer, and a subgrade bottom layer composed of graded crushed stone below the subgrade surface layer, characterized in that: Also includes A reinforcing unit for reinforcing the connection between the base bed surface layer and the base bed bottom layer, the reinforcing unit including fasteners arranged on both sides of the base bed surface layer corresponding to the two base plate structural joints, the fasteners are inserted from the base bed surface layer into the base bed bottom layer, the fasteners are composed of a material with a stiffness greater than that of the asphalt concrete material and the graded crushed stone material; the closer the distance between any two fasteners in the reinforcing unit and the two base plate structural joints, the smaller the distance between the two fasteners; the fasteners are distributed in an X-shape, a M-shape, or a criss-cross shape in the reinforcing unit; and an isolation unit is also included, the isolation unit is arranged between the base plate and the base bed surface layer, and the isolation unit is composed of geocomposite material.

2. The ballastless track structure according to claim 1, characterized in that: The fastener is an overall T-shaped structure, including a top and at least one columnar portion connected to the top, the top is arranged below the base bed surface or kept level with the base bed surface, and the columnar portion passes through the base bed surface and extends into the base bed bottom layer.

3. The ballastless track structure according to claim 1, characterized in that: The fastener is arranged below the surface of the base bed and includes at least one protruding structure integrally formed with the surface of the base bed. The bottom layer of the base bed is provided with a groove corresponding to the protruding structure, and the protruding structure extends into the groove of the bottom layer of the base bed.

4. The ballastless track structure according to any one of claims 2 or 3, characterized in that: The reinforcement units are arranged on both sides of the structural joint between the two base plates, and at least one reinforcement unit is arranged per square meter of area.

5. The ballastless track structure according to claim 1, characterized in that: The isolation unit is arranged on both sides of the structural gap between the two base plates on the reinforcement unit.

6. The ballastless track structure according to claim 5, characterized in that: The laying length of the isolation unit on each side of the structural gap between the two base plates is 1.0m-1.5m.

7. The ballastless track structure according to claim 1, characterized in that: It also includes a filling unit, which is used to fill the connection between the fastener and the base bed surface layer and / or the base bed bottom layer to fill the structural seam at the connection.

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