High-speed maglev railway tunnel portal buffer structure and construction method thereof

Abstract

The application discloses a kind of high-speed magnetic levitation railway tunnel entrance buffer structure and its construction method, its buffer structure is arranged at tunnel entrance, including arched plate and gap set in the outer wall of arched plate, the axis of arched plate coincides with tunnel axis arrangement, arched plate and outer wall are butted to form the decompression zone of outer end opening, inner end closure, in the decompression zone, several arched efficiency plates are successively set from inside to outside along its radial direction, the arched plate and efficiency plate, between adjacent efficiency plates, between efficiency plate and outer wall are gap arrangement, a plurality of through holes are opened in arched plate and communicated with decompression zone, a plurality of efficiency holes are opened in each efficiency plate and communicated with both sides inside and outside it. The pressure wave generated after magnetic levitation train enters the application occurs multiple reflection phenomena under the hindering action of arched plate and outer wall, so that the initial compression wave gradient is greatly reduced, the compression wave energy is dissipated to a greater extent, so as to more efficiently relieve tunnel exit microbaro-wave.

Description

Technical Field

[0001] This invention relates to the field of aerodynamics of high-speed maglev railway tunnels, and in particular to a buffer structure at the entrance of a high-speed maglev railway tunnel and its construction method. Background Technology

[0002] When a maglev train enters a tunnel, it generates a series of severe aerodynamic effects both inside and at the tunnel entrance. Typical effects include micro-pressure wave effects at the tunnel entrance and transient pressure effects inside the tunnel. As the train's speed increases, the vehicle / tunnel coupling aerodynamic effects become more pronounced, leading to more intense micro-pressure wave bursts at the tunnel entrance and vibrations of auxiliary facilities inside the tunnel.

[0003] Existing research indicates that the amplitude of the micro-pressure wave at the tunnel exit is directly proportional to the pressure gradient of the initial compression wave. Therefore, the most effective measure to mitigate micro-pressure waves is to reduce the pressure gradient of the initial compression wave. Installing a buffer structure at the tunnel entrance increases the pressure rise time of the compression wave, thus effectively mitigating the pressure gradient. However, for high-speed trains, traditional buffer structures are not as efficient at mitigating micro-pressure waves at the tunnel exit. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a buffer structure and its construction method that can effectively improve the buffering effect at the entrance of a high-speed maglev railway tunnel.

[0005] The high-speed maglev railway tunnel entrance buffer structure provided by this invention is installed at the tunnel entrance and includes an arched plate and an outer wall with gaps around the arched plate. The axis of the arched plate is arranged to coincide with the tunnel axis. The arched plate and the outer wall are in contact with the outer end face of the tunnel to form a pressure relief zone with an open outer end and a closed inner end. In the pressure relief zone, a number of arched enhancement plates are arranged in sequence from the inside to the outside along its radial direction. There are gaps between the arched plates and the enhancement plates, between adjacent enhancement plates, and between the enhancement plates and the outer wall. Multiple through holes connected to the pressure relief zone are opened on the arched plate, and multiple enhancement holes connecting its inner and outer sides are opened on each enhancement plate.

[0006] The cross-sectional area of ​​the outer wall is twice the cross-sectional area of ​​the tunnel.

[0007] The through-hole is square or round.

[0008] The through holes are arranged in multiple rows along the axial direction of the arched plate, and the through holes in the same row are arranged at equal intervals along the axial direction of the arched plate.

[0009] The through holes are arranged in four rows along the axial direction of the arch plate, with two rows symmetrically arranged on the upper left and right sides of the arch plate and two rows symmetrically arranged on the lower left and right sides of the arch plate.

[0010] The enhancement holes and through holes are arranged in a corresponding and interconnected manner.

[0011] The enhancement holes and through holes are arranged in a staggered manner.

[0012] The ratio of the area of ​​the through hole per unit length to the area of ​​the arched plate gradually decreases from the outer end to the inner end of the decompression zone.

[0013] The construction method for the buffer structure at the entrance of a high-speed maglev railway tunnel provided by this invention includes the following steps:

[0014] S1. Based on the inner contour line of the tunnel, formulate the design parameters for the inner contour line of the arch slab, so that the inner contour line of the arch slab is not smaller than the inner contour line of the tunnel.

[0015] S2. Starting from the outer end face of the tunnel, along the tunnel axis, according to the design parameters in step S1, erect a formwork outside the tunnel entrance and cast an arched plate with pre-reserved through holes. The inner end face of the arched plate is sealed to the outer end face of the tunnel.

[0016] S3. Based on the outer contour of the arched plate and the cross-sectional area of ​​the tunnel, formulate the design parameters of the outer wall and the design parameters of the enhancement plate to ensure that there are gaps between the arched plate and the enhancement plate, between adjacent enhancement plates, and between the enhancement plate and the outer wall, and to ensure that the cross-sectional area of ​​the outer wall is twice the cross-sectional area of ​​the tunnel.

[0017] S4. Starting from the outer end face of the tunnel, along the tunnel axis, according to the design parameters in step S3, erect formwork and cast the enhancement plate with reserved enhancement holes around the arch plate.

[0018] S5. Starting from the outer end face of the tunnel, along the tunnel axis, according to the design parameters in step S3, erect a formwork and cast the outer wall around the efficiency enhancement plate. The inner end face of the outer wall is sealed to the outer end face of the tunnel, so that the arched plate, the outer wall and the outer end face of the tunnel enclose a pressure relief zone with an open outer end and a closed inner end.

[0019] This invention utilizes an arched plate, an enhancement plate, and an outer wall arranged with internal and external gaps at the tunnel entrance. Through holes in the arched plate and enhancement holes in the enhancement plate, the running cavity of the maglev train inside the arched plate is connected to the decompression zone outside the arched plate. This allows the pressure wave generated by the maglev train entering the invention to enter the decompression zone through the through holes. The pressure wave entering the decompression zone undergoes multiple reflections and dissipation due to the back-and-forth blocking effect between the inner surface of the outer wall and the outer surface of the arched plate. This significantly reduces the initial compression wave gradient and dissipates the compression wave energy to a greater extent, thereby more effectively mitigating the micro-pressure wave at the tunnel exit. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the isometric structure of the present invention.

[0021] Figure 2 for Figure 1Enlarged cross-sectional view of section AA.

[0022] Figure 3 for Figure 1 Enlarged cross-sectional view of the structure at point BB.

[0023] Figure 4 for Figure 1 A schematic diagram comparing the micro-pressure wave at 20m from the tunnel exit with that of the existing buffer structure.

[0024] Figure 5 for Figure 1 A schematic diagram comparing the micro-pressure wave at 50m from the tunnel exit with that of the existing buffer structure.

[0025] The markings shown in the diagram and their corresponding component names are as follows:

[0026] 1. Outer wall;

[0027] 2. Arched plate; 21. Through hole;

[0028] 3. Decompression zone;

[0029] 4. Enhancement plate; 41. Enhancement hole;

[0030] a. Outer face of the tunnel; b. Inner outline of the tunnel. Detailed Implementation

[0031] from Figures 1 to 3 As can be seen, the high-speed maglev railway tunnel entrance buffer structure of this invention, located at the tunnel entrance, includes an outer wall 1 and an arched plate 2. The arched plate 2 is laid on the road surface along the tunnel's running direction, with its axis coinciding with the tunnel's axis. The inner contour line of the arched plate 2 is not smaller than the tunnel's inner contour line b. The outer wall 1 is fitted around the arched plate 2 with a gap. The inner end face of the arched plate 2 is tightly joined to the outer end face a of the tunnel.

[0032] The outer wall 1, the arched plate 2, and the outer end face a of the tunnel together form a pressure relief zone 3 with an open outer end and a closed inner end;

[0033] Multiple square through holes 21 connected to the pressure relief chamber 3 are opened on the arch plate 2. The through holes 21 are arranged in multiple rows along the axial direction of the arch plate 2, and the through holes 21 in the same row are arranged at equal intervals along the axial direction of the arch plate 2.

[0034] Two enhancement plates 4 with arched cross sections are sequentially installed inside the decompression chamber 3. The enhancement plate 4 on the inner side is spaced apart from the arched plate 2, between the two enhancement plates, and between the enhancement plate 4 on the outer side and the outer wall 1. Each enhancement plate 4 has an enhancement hole 41 that connects its inner and outer sides. Each enhancement hole 41 is connected to the through hole 21.

[0035] from Figures 1 to 3 As can be seen, in this invention, four rows of square through holes 21 are provided on the arch plate 2. Each row of through holes 21 is arranged along the axial direction of the arch plate 2. Two rows of through holes 21 are symmetrically arranged on the upper left and right sides of the arch plate 2, and two rows of through holes 21 are symmetrically arranged on the lower left and right sides of the arch plate 2. The distance between the through holes 21 in the same row is 5m.

[0036] In this invention, the cross-sectional area of ​​the outer wall 1 is 184m². 2 It is twice the cross-sectional area of ​​the tunnel and is 100m long.

[0037] In this invention, the through hole 21 can also be circular.

[0038] In this invention, the enhancement holes 41 and the through holes 21 can also be arranged in a staggered manner.

[0039] In this invention, the arrangement of the through holes 21 on the arched plate 2 can also show a trend of gradually decreasing permeability, that is, the ratio of the area of ​​the through holes 21 to the area of ​​the arched plate 2 per unit length gradually decreases from the outer end to the inner end of the pressure relief zone 3.

[0040] The construction method of this invention for a buffer structure at the entrance of a high-speed maglev railway tunnel includes the following steps:

[0041] S1. Based on the inner contour line b of the tunnel, formulate the design parameters of the inner contour line of the arch plate 2, so that the inner contour line of the arch plate 2 is not less than the inner contour line b of the tunnel; based on the method of computational fluid dynamics, formulate the design parameters of the thickness, length and number of rows of through holes 21 on the arch plate 2 and the number of each row.

[0042] S2. Starting from the outer end face a of the tunnel, along the tunnel axis, according to the design parameters in step S1, cast an arched plate 2 with a reserved through hole 21 in the formwork outside the tunnel entrance, and seal the inner end face of the arched plate 2 with the outer end face a of the tunnel.

[0043] S3. Based on the outer contour line of the arch plate 2 and the cross-sectional area of ​​the tunnel, formulate the design parameters of the outer wall 1 and the design parameters of the enhancement plate 4, and ensure that the arch plate 2 and the adjacent enhancement plate 4, the adjacent enhancement plates 4, and the enhancement plate 4 and the outer wall 1 are all spaced apart, and ensure that the cross-sectional area of ​​the outer wall 1 is twice the cross-sectional area of ​​the tunnel.

[0044] S4. Starting from the outer end face a of the tunnel, along the tunnel axis, according to the design parameters in step S3, formwork is erected and cast around the arch plate 2 to form an enhancement plate 4 with pre-reserved enhancement holes 41.

[0045] S5. Starting from the outer end face a of the tunnel, along the tunnel axis, according to the design parameters in step S3, formwork is erected and the outer wall 1 is poured around the outside of the enhancement plate 4, and the inner end face of the outer wall 1 is sealed and connected to the outer end face a of the tunnel. The arched plate 2, the outer wall 1 and the outer end face a of the tunnel together form a pressure relief zone 3 with an open outer end and a closed inner end.

[0046] go through Figure 4 and Figure 5 The numerical simulation verification shown yields the data presented in Table 1:

[0047] Table 1

[0048]

[0049] As can be seen from Table 1, the data comparison between the present invention and the existing buffer structure is as follows: the present invention achieves a mitigation effect of 14.3% on the micro-pressure wave at 20m from the tunnel exit and a mitigation effect of 13.0% on the micro-pressure wave at 50m from the tunnel exit.

[0050] This invention is applicable not only to high-speed maglev railway tunnel structures, but also to high-speed railway tunnels.

[0051] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this invention. It should be understood that the above descriptions are merely preferred embodiments of this invention and are not intended to limit the scope of protection of this invention. For those skilled in the art, this invention can be modified in various ways. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A buffer structure for the entrance of a high-speed maglev railway tunnel, installed at the tunnel entrance, characterized in that: The structure includes an arched plate (2) and an outer wall (1) with gaps around the arched plate. The axis of the arched plate is arranged to coincide with the tunnel axis. The arched plate and the outer wall are connected to the outer end face of the tunnel to form a pressure relief zone (3) with an open outer end and a closed inner end. Several arched enhancement plates (4) are arranged in sequence from the inside to the outside along the radial direction of the pressure relief zone. There are gaps between the arched plate and the enhancement plates, between adjacent enhancement plates, and between the enhancement plates and the outer wall. Multiple through holes (21) connected to the pressure relief zone are opened on the arched plate. Multiple enhancement holes (41) connecting the inner and outer sides of each enhancement plate are opened on each enhancement plate. This allows the pressure wave generated after the maglev train enters the buffer structure to enter the pressure relief zone through the through holes. The pressure wave entering the pressure relief zone is reflected and consumed multiple times under the back-and-forth blocking effect of the inner surface of the outer wall and the outer surface of the arched plate, thereby reducing the initial compression wave gradient, dissipating the compression wave energy, and alleviating the micro-pressure wave at the tunnel exit.

2. The buffer structure at the entrance of a high-speed maglev railway tunnel according to claim 1, characterized in that: The cross-sectional area of ​​the outer wall is twice the cross-sectional area of ​​the tunnel.

3. The buffer structure at the entrance of a high-speed maglev railway tunnel according to claim 1, characterized in that: The through-hole is square or round.

4. The buffer structure at the entrance of a high-speed maglev railway tunnel according to claim 1, characterized in that: The through holes are arranged in multiple rows along the axial direction of the arched plate, and the through holes in the same row are arranged at equal intervals along the axial direction of the arched plate.

5. The buffer structure at the entrance of a high-speed maglev railway tunnel according to claim 4, characterized in that: The through holes are arranged in four rows along the axial direction of the arch plate, with two rows symmetrically arranged on the upper left and right sides of the arch plate and two rows symmetrically arranged on the lower left and right sides of the arch plate.

6. The buffer structure at the entrance of a high-speed maglev railway tunnel according to claim 1, characterized in that: The enhancement holes and through holes are arranged in a corresponding and interconnected manner.

7. The buffer structure at the entrance of a high-speed maglev railway tunnel according to claim 1, characterized in that: The enhancement holes and through holes are arranged in a staggered manner.

8. The buffer structure at the entrance of a high-speed maglev railway tunnel according to claim 1, characterized in that: The ratio of the area of ​​the through hole per unit length to the area of ​​the arched plate gradually decreases from the outer end to the inner end of the decompression zone.

9. A construction method for a buffer structure at the entrance of a high-speed maglev railway tunnel as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Based on the inner contour line of the tunnel, formulate the design parameters of the inner contour line of the arch plate (2) so that the inner contour line of the arch plate is not less than the inner contour line of the tunnel. S2. Starting from the outer end face of the tunnel, along the tunnel axis, according to the design parameters in step S1, cast an arched plate (2) with a reserved through hole (21) outside the tunnel entrance. The inner end face of the arched plate is sealed to the outer end face of the tunnel. S3. Based on the outer contour line of the arch plate and the cross-sectional area of ​​the tunnel, formulate the design parameters of the outer wall (1) and the design parameters of the enhancement plate (4) to ensure that there are gaps between the arch plate and the enhancement plate, between adjacent enhancement plates, and between the enhancement plate and the outer wall, and to ensure that the cross-sectional area of ​​the outer wall is twice the cross-sectional area of ​​the tunnel. S4. Starting from the outer end face of the tunnel, along the tunnel axis, according to the design parameters in step S3, formwork is erected around the arch plate and the enhancement plate (4) with the enhancement hole (41) is pre-cast. S5. Starting from the outer end face of the tunnel, along the tunnel axis, according to the design parameters in step S3, erect a formwork and cast the outer wall around the enhancement plate. The inner end face of the outer wall is sealed and connected to the outer end face of the tunnel, so that the arch plate, the outer wall and the outer end face of the tunnel enclose a pressure relief zone with an open outer end and a closed inner end (3).

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