Sleeper sole for railway track and method for manufacturing the assembly of such sleeper sole and a sleeper

Abstract

A sleeper base for a railway sleeper, the composition of which comprises: - a polymer matrix; - elastomer granules; - rock aggregates with a grain size of between 1 and 20 mm; and a method of manufacturing the assembly of such a sleeper base and a sleeper.

Description

Subject of the invention

[0001] The present invention relates to the field of port railways, and in particular to that of soles intended to be fixed under the sleepers of these port railways. State of the art

[0002] In recent years, the use of ballasted tracks in container port operations has become increasingly common, particularly in the container storage area where ASC (Automated Stacking Crane) or RMG (Rail Mounted Gantry Crane) cranes are operated. These port cranes move on rails, particularly for handling containers. No standard has yet been adopted regarding the design of the sleepers on which the running tracks are installed.

[0003] Generally speaking, the center distance between the two rails on which ASC or RMG cranes are operated is greater than 20 meters. Consequently, the two rails of the ballasted port tracks are independent of each other, and are also supported by independent sleepers (each sleeper only supports a single rail, given the distance between the rails and the load to be supported). Furthermore, the loads applied to the wheels, and therefore to the rails of these tracks, are very high (around 250 kN per wheel for ASC / RMG cranes, whereas for a high-speed train, the loads are around 80 kN per wheel, and for a heavy traffic train, the loads are around 125 kN per wheel). On some port sites, very significant horizontal displacements of the rail sleeper system have been observed, making it impossible to operate these tracks.These deviations can occur on both rails or independently, on only one of the two rails.

[0004] Document WO2019157540 A1 discloses a sole intended to be fixed under a railway sleeper, the sole comprising at least one elastic layer and cork granules. The elastic layer helps to dampen vibrations while the cork granules provide a certain stability.

[0005] Document KR 102363912 discloses a railway sleeper pad that improves ballast durability by uniformly transmitting the load applied to the rails to the asphalt subgrade to avoid stress concentration. This pad also aims to improve friction resistance between the underside of the sleeper and the ballast. The pad is formed from a combination of rubber and non-woven fabric (geotextile) layers, the assembly being hot-pressed to fuse them together.

[0006] To date, no railway sleeper footing provides a sufficiently effective solution for ballasted tracks used in the port sector, which involves very high loads, particularly with regard to the movement of ASC or RMG cranes. Aims of the invention

[0007] The present invention aims to overcome the disadvantages of the state of the art, and in particular to provide a sleeper base capable of transmitting forces in the context of port-type ballasted tracks. Indeed, in this context of port tracks, the sleepers are subjected to very high stresses, in particular resulting from horizontal forces. In view of the significant loads supported, the ballasted bed suffers and requires numerous maintenance operations.

[0008] One of the aims of the invention is to provide a sole under the sleeper which makes it possible to increase the resistance to horizontal movements of the sleepers.

[0009] Another aim of the invention is to provide a solution that improves the distribution of loads on the ballast and reduces the level of stress in the latter. This increases the service life of the ballast and reduces maintenance operations.

[0010] Another object of the invention is to provide a sleeper sole which reduces the vibrations transmitted between the sleeper and the ballasted bed.

[0011] The present invention offers the advantage of allowing an assembly between the sole and the crosspiece which is simple and easy to implement, and does not require the addition of heat. Summary of the invention

[0012] The present invention discloses a sleeper sole whose composition comprises: a polymer matrix; elastomer granules; rock aggregates with a grain size between 1 and 20 mm.

[0013] According to particular embodiments, the invention comprises one or more of the following characteristics: the polymer matrix comprises an aromatic polyurethane resin; the elastomer granules are composed of rubber; said granules have a diameter of between 0.5 and 15 mm; the polymer matrix is comprised at least 5 percent, preferably at least 8 percent, more preferably at least 10 percent in the composition of the sole; the elastomer granules are comprised at least 20 percent, preferably at least 40 percent and particularly preferably at least 50 percent in the composition of the sole; the rock aggregates are comprised at least 10 percent, preferably at least 20 percent and particularly preferably at least 50 percent in the composition of the sole; the diameter of the elastomer granules is between 1 and 4 mm; the rock aggregates have a particle size of between 5 and 11 mm; the composition includes long fibers.

[0014] The present invention also discloses an assembly formed of a cross member sole and a cross member.

[0015] According to particular execution methods, the sole under sleeper / sleeper assembly includes one or more of the following characteristics: the sleeper is a port sleeper; the interface between the sole and the sleeper preferably comprises polymer matrix; the assembly is placed on a ballasted bed.

[0016] The present invention also discloses a method of manufacturing the assembly of a sleeper sole and a sleeper, comprising the following steps: application of a layer of polymer matrix to the interface between a sleeper sole and a sleeper; cold pressing of the assembly comprising the sleeper sole and the sleeper. Brief description of the figures

[0017] There Figure 1represents a three-dimensional view of an example of a sole under a sleeper according to the invention, on the one hand the sole being disassembled from the sleeper, and on the other hand the sole being assembled with the sleeper.

[0018] There Figure 2 represents the sole under the crosspiece with an enlargement of its composition.

[0019] There Figure 3 represents the horizontal movements applied to the sleeper, which are reduced thanks to the under-sleeper sole of the invention.

[0020] There Figure 4 represents a diagram of the horizontal displacement of the sleeper (in mm) according to the horizontal force applied to the rail (in kN), the results being compared between a conventional sole of the prior art and a sole of the invention. List of reference symbols

[0021] 1: Sleeper footing 2: rock aggregate 3: elastomer granules 4: polymer matrix 5: fiber 6: sleeper Detailed description of the invention

[0022] The sole 1 according to the present invention is intended to be placed under a track sleeper 6 for a port crane. The assembly of the sole under the sleeper is illustrated in Figure 1 .

[0023] The sole is composed of a polymer matrix 4, elastomer granules 3 and rock aggregates 2 as shown in the Figure 2 . Generally, the thickness of the sole is between 10 and 100mm and does not exceed ¼ of the thickness of the sleeper to which it is associated. Generally, the thickness of the sleeper is between 250 and 400mm.

[0024] The polymer matrix is for example of the aromatic polyurethane resin type 95 (PU95). This matrix is present at least 5 percent, preferably at least 8 percent and even more preferably at least 10 percent in the composition of the sole.

[0025] The elastomer granules are formed from rubber, preferably recycled. The granules have a diameter preferably between 0.5 and 15 mm, particularly preferably between 1 and 4 mm. Preferably, the composition of the sole of the invention comprises at least 20 percent, particularly preferably at least 40 percent and even more preferably at least 50 percent of rubber granules.

[0026] The presence of rock aggregate provides resistance to the movement of the sleeper on the ballast bed. Preferably, the gravel has a grain size of between 1 and 20 mm, particularly preferably between 5 and 11 mm. Preferably, the composition of the sole of the invention comprises at least 10 percent, particularly preferably at least 20 percent and even more preferably at least 50 percent of gravel.

[0027] Thanks to the composition of the undersleeper pad of the invention, the contact surface between the lower part of the sleeper comprising the pad and the ballasted bed is increased. Consequently, the loads applied to the rails and the sleeper, which are transmitted to the ballast, are distributed over a larger surface area, reducing the stresses experienced by the ballast. This is a consequence of the interpenetration of the ballast in the pad, and in particular in the mixture of the polymer matrix with the elastomer beads and the gravel, which makes it possible to increase the contact surface between the pad and the ballast.

[0028] In a particular embodiment of the invention, it is possible to insert fibers, for example of the carbon fiber type, preferably long to reinforce the sole. Preferably, the length of the fibers is at least 1 / 3 of the length of the sole under the crosspiece.

[0029] The sole is produced by casting in a mold at room temperature. The mixture that makes up the sole has very good adhesion to steel and concrete. To bond the sole to the underside of the concrete sleeper, a layer of polymer matrix is applied to the interface between the sole and the sleeper. The assembly of the sole of the invention and the sleeper can be done at room temperature under the pressure of the sleeper's own weight. The use of a higher temperature or a catalyst can accelerate adhesion.

[0030] There Figure 4represents a diagram of the horizontal displacement of the sleeper (in millimeters) according to the horizontal force applied to the rail (in kN). The diagram compares the results of a sleeper equipped with a conventional commercial pad of the prior art used in railways with those of a sleeper equipped with a pad of the invention. The results show that to move by one millimeter the sleeper equipped with a pad according to the invention, it is necessary to apply a force 58% greater than for the sleeper equipped with a pad commercialized in the railway industry. The resistance to horizontal forces is significantly improved, which makes it possible to prevent the sleepers and rails of the tracks from undergoing significant horizontal displacements as is currently the case, making it impossible to operate these tracks.

Claims

1. Sleeper base (1) for railway sleeper (6) whose composition comprises: - a polymer matrix (4); - elastomer granules (3); - rock aggregates (2) with a grain size between 1 and 20 mm.

2. Under-sleeper sole (1) according to any one of the preceding claims, characterized in that the polymer matrix (4) comprises an aromatic polyurethane resin.

3. Under-sleeper sole (1) according to any one of the preceding claims, characterized in that the elastomer granules (3) are composed of rubber.

4. Under-sleeper sole (1) according to any one of the preceding claims, characterized in that said granules (3) have a diameter between 0.5 and 15 mm.

5. Under-sleeper sole (1) according to any one of the preceding claims, characterized in thatthe polymer matrix (4) is comprised at least 5 percent, preferably at least 8 percent, more preferably at least 10 percent in the composition of the sole (1).

6. Under-sleeper sole (1) according to any one of the preceding claims, characterized in that the elastomer granules (3) are included at least 20 percent, preferably at least 40 percent and particularly preferably at least 50 percent in the composition of the sole (1).

7. Under-sleeper sole (1) according to any one of the preceding claims, characterized in that the rock aggregates (2) are included at least 10 percent, preferably at least 20 percent and particularly preferably at least 50 percent in the composition of the sole (1).

8. Under-sleeper sole (1) according to any one of the preceding claims, characterized in thatthe diameter of the elastomer granules (3) is between 1 and 4 mm.

9. Under-sleeper sole (1) according to any one of the preceding claims, characterized in that rock aggregates (2) have a grain size between 5 and 11 mm.

10. Under-sleeper sole (1) according to any one of the preceding claims, characterized in that the composition includes long fibers (5).

11. Assembly of a cross member sole (1) according to any one of the preceding claims and of a cross member (6).

12. Assembly of a sole under sleeper (1) according to claim 11, the sleeper (6) being a port sleeper.

13. Assembly according to one of claims 11 or 12, the interface between the sole (1) and the crosspiece (6) comprising polymer matrix.

14. Assembly according to one of claims 11 to 12, placed on a ballasted bed.

15. Method for manufacturing the assembly of a sleeper sole according to one of claims 1 to 10 and a sleeper, comprising the following steps: - application of a layer of polymer matrix to the interface between a sleeper sole (1) according to one of claims 1 to 10 and a sleeper (6); - cold pressing of the assembly comprising the sleeper sole (1) and the sleeper (6).

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