A kind of reinforced bed of track imitated root system memory type flexible fiber grid and ballast track

Abstract

The utility model discloses a kind of imitative root system memory type flexible fiber grid of reinforced ballast bed, comprising: accessory body A, main body and accessory body B, using strip-shaped grid, grid trunk, grid node, annular grid and grid root system etc. to realize the embedding of ballast, set up fiber bragg grating strain sensor, main node stress and acceleration sensor, realize the real-time detection evaluation of ballast bed mechanical state. The memory function of the flexible fiber grid is to obtain the ballast bed settlement characteristics by fiber bragg grating strain sensor, and to obtain the long-term service performance of ballast bed by main node stress and acceleration sensor. The utility model structure is suitable for high-speed, heavy-load and urban rail transit and other ballasted track, while strengthening the integrity of ballasted track, it can real-time detect and feedback evaluate the vibration level, stress and settlement characteristics of ballasted bed, and provide effective reference for ballasted track maintenance.

Description

Technical Field

[0001] This utility model relates to the field of railway engineering track technology, and in particular to a root-like memory type flexible fiber grid and ballasted track for reinforcing the track bed. Background Technology

[0002] Ballasted track is one of the most commonly used track structures in railways. Multi-layered heterogeneous ballast track consists of rails, fasteners, sleepers, and the ballast bed from top to bottom. The ballast bed is composed of granular materials, and under the reciprocating load of trains, it inevitably undergoes cumulative deformation. As the main structure directly bearing the load of the superstructure trains, the ballast bed accounts for more than 70% of the total settlement of the ballast track. Currently, controlling ballast bed settlement requires frequent daily track maintenance, using a combination of large-scale mechanical tamping and manual tamping to restore the track's geometry.

[0003] To control track bed settlement and deformation during railway operation and reduce maintenance costs, many railway lines employ geogrids laid between the ballast and subballast layers. However, geogrids are relatively rigid, which can lead to loose contact between ballast particles during installation, creating local voids or stress concentration points. Furthermore, the rigidity of geogrids limits their own deformation capacity, making it difficult to effectively adapt to the particle redistribution and dynamic deformation of the track bed under cyclic loading. They lack the ability to "follow" the deformation of the ballast particles, potentially weakening their long-term reinforcement effect and their ability to suppress cumulative settlement. In addition, the internal stress and vibration characteristics of the track bed change drastically under train loads. Existing geogrids can only control track bed settlement but cannot provide real-time sensing of track bed vibration and settlement conditions, making it impossible to know the service status of the track bed under high-speed traffic conditions. Utility Model Content

[0004] Purpose of the utility model: The purpose of this utility model is to provide a root-like memory type flexible fiber grid and ballasted track for reinforcing the track bed, which solves the problems of ballast breakage, wear and structural deterioration under the complex operating conditions of ballasted track in high-speed and heavy-haul railways, as well as the key issues such as the difficulty in long-term assessment and perception of the internal stress characteristics of loose track beds.

[0005] Technical solution: The present invention describes a root-like memory type flexible fiber grid for reinforcing roadbeds, comprising: a unit body composed of an appendage A, a main body, and an appendage B; wherein, the appendage A, the main body, and the appendage B are radial and annular nested structures composed of strip grids, grid trunks, annular grids, and grid roots.

[0006] Furthermore, the main trunk of the grid is connected to the annular grid through the main nodes, and the strip grids are connected to the fixed nodes and grid nodes respectively; the grid nodes are connected to the grid root system.

[0007] Furthermore, the grid root system exhibits a radially dispersed structure.

[0008] Furthermore, the annular grid is configured with 3 layers, with fiber optic grating sensors evenly distributed between the first and second layers; the annular grids of appendages A and B have a diameter of 1.8m, and the main annular grid is elliptical in shape with a major axis length of 2.4m and a minor axis length of 1.8m.

[0009] Furthermore, the fiber optic grating sensor consists of a resin sleeve, an epoxy resin coating, a fiber optic grating, and basalt fiber grid ribs; wherein, the fiber optic grating, which is wrapped in epoxy resin coating, is covered with a resin sleeve and fixed to the basalt fiber ribs.

[0010] Furthermore, a three-dimensional acceleration sensor is installed in the middle of the main node; and track bed stress test sensors are evenly distributed around the perimeter (18).

[0011] Furthermore, the longitudinal structure is designed as a spliced ​​structure, with the strip grid being 5-7m long and 3.4-3.8m wide, the main unit being 2-3m long, and the auxiliary units A and B each being 1.6-2m long.

[0012] Furthermore, basalt fiber material is used, with a radial tensile stiffness of 210 kN / m and a flexural stiffness of 4.5 × 10⁻⁶ kN / m. 5 mg·cm.

[0013] The present invention provides a ballasted track, which adopts the root-like memory type flexible fiber grid for reinforcing the track bed as described in any one of the claims, and includes, from top to bottom: rails, fastening system, sleepers and track bed; the root-like memory type flexible fiber grid is laid inside the track bed, 100mm away from the bottom of the track bed.

[0014] Beneficial Effects: Compared with existing technologies, this invention has the following advantages: The root-like memory flexible fiber grating of this invention can be intelligently manufactured in factories, assembled on-site, and intelligently inspected under long-term service conditions for ballasted tracks. The root-like memory flexible fiber grating combines the advantages of ballast embedding and ballast inspection, significantly improving the overall performance and maintainability of traditional ballasted tracks, providing key technical support for the construction and maintenance of ballasted railway lines. This structure can also promote the extension of service life and long-term stability of service performance in high-speed and heavy-haul railways. Attached Figure Description

[0015] Figure 1 This is a plan view of the root-like memory type flexible fiber grid of this utility model and its components; Figure 2 This is a dimensional drawing of the root-like memory type flexible fiber grid of this utility model; Figure 3 This is a partial enlarged view of the fiber grid and the arrangement of the fiber optic grating sensor of this utility model. Figure 4 This is a cross-sectional view of the fiber Bragg grating sensor of this utility model; Figure 5 This is a diagram showing the arrangement of the stress and acceleration sensors at the main node positions of this utility model. Figure 6 This is a schematic diagram showing the laying position of the root-like memory type flexible fiber grid of this utility model in a ballast track. Figure 7 Stress measurement at the main node location; Figure 8 The acceleration measurement at the main node position; Figure 9 This describes the fiber optic grating strain measurement. Figure 10 Figure showing the cumulative axle number and track bed settlement monitoring results; Figure 11 This is a graph showing the relationship between cumulative axis order and fiber grating strain. Figure 12 This is a graph showing the relationship between fiber optic grating strain and track bed settlement. Detailed Implementation

[0016] The technical solution of this utility model will be further described below with reference to the accompanying drawings.

[0017] like Figures 1-2 As shown, flexible basalt fiber grids primarily assist crushed stone ballast in enhancing track stability and do not directly bear vertical train loads. The grid structure achieves stress interlocking and constraint on the ballast layer, directly improving its overall stability and alleviating localized stress concentration. This reduces the tendency of ballast deterioration and effectively mitigates subgrade settlement in ballasted track structures.

[0018] Therefore, this utility model embodiment provides a root-like memory type flexible fiber grid for reinforcing track beds, comprising: a unit body composed of an appendage A2, a main body 3, and an appendage B4; wherein, the appendage A2, the main body 3, and the appendage B4 are radial and annular nested structures composed of a strip grid 5, a grid trunk 6, an annular grid 8, and a grid root system 10.

[0019] The grid trunk 6 is connected to the annular grid 8 via the main node 7, and the strip grid 5 is connected to the fixed node (11) and the grid node 12 respectively; the grid node 12 is connected to the grid root system 10. The grid root system 10 has a radially dispersed structure. The annular grid 8 is set in 3 layers, with fiber optic grating sensors 9 evenly distributed between the first and second layers; the diameter of the annular grid 8 of the appendages A and B is 1.8m, the shape of the main annular grid is elliptical, the major axis length is 2.4m, and the minor axis length is 1.8m. The longitudinal direction is set as a spliced ​​structure, the strip grid 5 is 6m long and 3.6m wide, the main unit 3 is 2.4m long, and the appendages A2 and B4 are each 1.8m long. Basalt fiber material is used, with a radial tensile stiffness of 210kN / m and a flexural stiffness of 4.5×10. 5 mg·cm.

[0020] Compared to traditional force sensors such as earth pressure cells, fiber optic grating (FBG) sensing test units offer advantages such as longer service life and simpler deployment. To enable long-term use within ballast layers, the FBG is integrated into the basalt fibers, rather than being laid on the surface of the fiber grid as in traditional methods. This prevents direct impact from the ballast onto the sensor, improving its lifespan and durability. See also... Figure 3 and Figure 4 The fiber optic grating sensor 9 is composed of a resin sleeve 13, an epoxy resin coating 14, a fiber optic grating 15, and basalt fiber grid ribs 16; wherein, the fiber optic grating 15, which is wrapped in epoxy resin coating 14, is covered with a resin sleeve 13 and fixed to the basalt fiber ribs 16.

[0021] Grid nodes are selected as sensor placement locations to acquire the structural stress and vibration response at these nodes under train loads. This clarifies the stress on the nodes, and the structural performance is optimized by controlling the stress-bearing units at each node. Simultaneously, long-term data acquisition and predictive early warning are conducted for the stress conditions of fiber nodes under long-term operational conditions. (See also...) Figure 5 A three-dimensional acceleration sensor 17 is installed in the middle of the main node 7; track bed stress test sensors 18 are evenly distributed around the perimeter.

[0022] During the use of memory fiber grating, stress sensors are placed at the main node locations to test the track bed stress, thereby obtaining the time-domain variation curve of the track bed stress as a vehicle passes. Figure 7 As shown, the stress changes inside the track bed can be assessed, thereby guiding on-site maintenance. Through the triaxial acceleration sensors arranged at the main nodes, the triaxial acceleration changes during train operation can be acquired, including vertical, lateral, and longitudinal accelerations. Figure 8 As shown, this allows for the assessment of ballast movement trends and ballast degradation. Based on fiber optic grating sensors deployed within the annular grid, the strain of the flexible fiber optic grid can be obtained, as shown... Figure 9 As shown, this can serve as a basis for assessing track bed settlement. Combining existing research on the relationship between cumulative axle loads and track bed settlement monitoring data, the correlation between operating axle loads and track bed settlement data can be analyzed, such as... Figure 10 As shown. Simultaneously, the monitoring data from the fiber Bragg grating sensor obtained through field testing and its relationship with the number of operating axes are also presented, as shown below. Figure 11 As shown, the transmission relationship between fiber optic grating strain and track bed settlement can be proposed as follows: Figure 12 As shown.

[0023] like Figure 6 As shown, ballast is an effective structural layer in ballasted tracks for distributing force and improving structural performance. The placement of fiber grating within the ballast layer enhances its service performance. Flexible fiber grating can reduce stress on the ballast, thereby decreasing inter-ballast pressure, reducing ballast running speed to decrease overall ballast layer wear, and increasing interfacial friction. Simultaneously, by improving the overall integrity of the ballast layer, it can effectively reduce stress at the bottom of the track bed and alleviate uneven stress distribution.

[0024] Therefore, embodiments of the present invention provide a ballasted track, which adopts the root-like memory type flexible fiber grid for reinforcing the track bed as described in any one of the claims, and includes, from top to bottom: rails, fastening system, sleepers and track bed; the root-like memory type flexible fiber grid is laid inside the track bed, 100mm away from the bottom of the track bed.

Claims

1. A root-memory type flexible fiber grid for reinforcing track beds, characterized in that, include: The unit is composed of appendage A (2), main body (3) and appendage B (4); wherein appendage A (2), main body (3) and appendage B (4) are radial and annular nested structures composed of strip grid (5), grid trunk (6), ring grid (8) and grid root system (10).

2. The root-memory type flexible fiber grid for reinforcing track beds according to claim 1, characterized in that, The grid trunk (6) is connected to the ring grid (8) through the main node (7), and the strip grid (5) is connected to the fixed node (11) and the grid node (12) respectively; the grid node (12) is connected to the grid root system (10).

3. The root-memory type flexible fiber grid for reinforcing track beds according to claim 2, characterized in that, The root system (10) of the grid has a radially dispersed structure.

4. The root-memory type flexible fiber grid for reinforcing track beds according to claim 2, characterized in that, The annular grid (8) is set to 3 layers, and fiber optic grating sensors (9) are evenly distributed between the first and second layers; the annular grid (8) of appendage A and appendage B has a diameter of 1.8m, the main annular grid is elliptical in shape, the major axis is 2.4m and the minor axis is 1.8m.

5. A root-memory type flexible fiber grid for reinforcing track beds according to claim 4, characterized in that, The fiber grating sensor (9) consists of a resin sleeve (13), an epoxy resin coating (14), a fiber grating (15), and basalt fiber grid ribs (16); wherein the fiber grating (15) wrapped in the epoxy resin coating (14) is covered with a resin sleeve (13) and fixed to the basalt fiber ribs (16).

6. The root-memory type flexible fiber grid for reinforcing track beds according to claim 2, characterized in that, A three-dimensional acceleration sensor (17) is provided in the middle of the main node (7); and track bed stress test sensors (18) are evenly distributed around the perimeter.

7. The root-memory type flexible fiber grid for reinforcing track beds according to claim 1, characterized in that, The longitudinal section is designed as a spliced ​​structure. The strip grid (5) is 5-7m long and 3.4-3.8m wide in the transverse direction. The main body (3) is 2-3m long, and the appendages A (2) and B (4) are each 1.6-2m long.

8. The root-memory type flexible fiber grid for reinforcing track beds according to claim 1, characterized in that, It is made of basalt fiber material, with a radial tensile stiffness of 210kN / m and a flexural stiffness of 4.5×10^5 mg·cm.

9. A ballasted track, employing the root-memory type flexible fiber grid for reinforcing the track bed as described in any one of claims 1-8, characterized in that, From top to bottom, it includes: rail (20), fastening system (19), sleeper (21) and track bed (22); the track bed (22) is internally laid with root-like memory type flexible fiber grid (1), which is 100mm away from the bottom of the track bed.

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