Tunnel capable of weakening electromagnetic radiation at portal

Abstract

The utility model relates to the technical field of rail transit, in particular to a tunnel capable of weakening electromagnetic radiation at a portal, which comprises a tunnel portal and a shielding wall, the shielding wall is arranged at the tunnel portal and is of a reinforced concrete structure, an electromagnetic shielding coating is arranged on the surface of the shielding wall, and the side wall, close to the tunnel portal, of the shielding wall is obliquely arranged. And the distance from the side wall to the tunnel portal is gradually increased from the bottom of the shielding wall to the shielding wall. Aggregate and cement in the concrete can absorb and reflect electromagnetic waves; the reinforcing mesh in the reinforced concrete can play a conductive role and is beneficial to reflecting electromagnetic waves, so that the shielding wall is of a reinforced concrete structure. The electromagnetic shielding coating can prevent electromagnetic radiation from penetrating through the shielding wall as much as possible by absorbing or reflecting the electromagnetic radiation. The higher the plane where the side wall of the shielding wall is located is, the larger the distance to the tunnel portal is, unshielded electromagnetic radiation is made to spread in the air above instead of the two sides as much as possible, and the electromagnetic shielding effect of the shielding wall is enhanced.

Description

Technical Field

[0001] This utility model relates to the technical field of rail transit, and in particular to a tunnel that can reduce electromagnetic radiation at the tunnel entrance. Background Technology

[0002] With the rapid development of urban rail transit, the frequency of trains entering and exiting tunnels is constantly increasing, and the problem of electromagnetic radiation at tunnel entrances and exits is becoming increasingly prominent. The traction system and signaling system of trains generate electromagnetic radiation. Especially in densely populated areas such as transfer hubs, electromagnetic radiation may have adverse effects on human health and surrounding sensitive equipment.

[0003] The existing measures to protect against electromagnetic radiation at tunnel entrances are not yet perfect and may have adverse effects on human health. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies, such as the imperfect measures for protecting tunnel entrances from electromagnetic radiation, which can have adverse effects on human health, and to provide a tunnel that can reduce electromagnetic radiation at the entrance.

[0005] In a first aspect, the present invention provides a tunnel capable of reducing electromagnetic radiation at the tunnel entrance, comprising a tunnel entrance, and further comprising:

[0006] A shielding wall is installed at the tunnel entrance. The shielding wall is a reinforced concrete structure and has an electromagnetic shielding coating on its surface. The shielding wall is inclined near the side wall of the tunnel entrance, and the distance from the side wall to the tunnel entrance gradually increases from the bottom of the shielding wall to the tunnel entrance.

[0007] The height of the shielding wall is determined according to the design specifications.

[0008] Because the electromagnetic radiation from the train's onboard electrical, signaling, power supply, and information systems can be transmitted through the tunnel entrance, a shielding wall is installed at the tunnel entrance. The aggregate and cement in concrete can absorb electromagnetic waves; the steel mesh in reinforced concrete can conduct electricity to some extent, helping to reflect electromagnetic waves. Therefore, the shielding wall is a reinforced concrete structure, which helps improve its shielding performance. The electromagnetic shielding coating can absorb or reflect electromagnetic radiation, minimizing its transmission through the shielding wall to the outside. Sidewalls are installed at the ends of the shielding wall; the higher the plane containing the sidewalls, the greater the distance to the tunnel entrance, ensuring that unshielded electromagnetic radiation propagates upwards rather than laterally, thus enhancing the electromagnetic shielding effect of the shielding wall.

[0009] Preferably, the shielding wall includes a steel mesh with a mesh size greater than or equal to 30*30mm and less than or equal to 50*50mm.

[0010] The smaller mesh size of the reinforcing mesh compared to existing mesh sizes leads to a larger number of meshes within the same area, resulting in more gaps in the mesh. Observations in the contour plot show that the electric field energy decays more rapidly at these gaps as electric field lines diffuse outwards. Therefore, a smaller mesh size increases the energy decay of the battery. Furthermore, considering construction costs, the mesh size is set to be larger than 30*30mm and smaller than 50*50mm, minimizing construction costs while increasing the mesh density.

[0011] Preferably, the reinforcing mesh is a corrugated reinforcing mesh.

[0012] Using corrugated steel mesh can increase the structural stability of the shielding wall, improve its seismic performance, and enhance its fatigue resistance.

[0013] Preferably, the height of the top surface of the shielding wall decreases in the direction away from the tunnel entrance.

[0014] The top surface of the shielding wall near the tunnel entrance is higher than that of the shielding wall away from the tunnel entrance, so that electromagnetic radiation is reflected or absorbed by the shielding wall as much as possible.

[0015] Preferably, the top surface of the shielding wall has a smooth height variation.

[0016] A smooth change in the height of the top surface of the shielding wall can smooth the airflow changes at the tunnel entrance, reduce the micro-pressure wave noise at the tunnel entrance, and help alleviate the sonic boom phenomenon.

[0017] Preferably, the shielding wall is made of cement with a strength of C20-C30.

[0018] Cement with a strength of C20-C30 should be used to ensure that the shielding wall has sufficient strength and shielding performance.

[0019] Preferably, the electromagnetic shielding coating is a nano-lead selenide coating.

[0020] Nano-lead selenide has a narrow bandgap, giving it excellent optical absorption properties in the near-infrared to far-infrared range. Furthermore, nano-lead selenide is a common semiconductor material with certain electrical conductivity, which is beneficial for improving electromagnetic radiation shielding performance.

[0021] Preferably, the extension direction of the shielding wall is perpendicular to the axis of the tunnel entrance.

[0022] The direction in which the shielding wall extends is the width of the shielding wall.

[0023] Preferably, the angle between the extension direction of the shielding wall and the axis of the tunnel entrance is 45°.

[0024] The direction in which the shielding wall extends is the width of the shielding wall.

[0025] Preferably, the tunnel entrance is angled upwards.

[0026] The tunnel entrance is angled upwards to allow unshielded electromagnetic radiation to propagate along the air above rather than to the sides, thus minimizing its impact on the surrounding environment.

[0027] Compared with existing technologies, the advantages of this utility model are as follows:

[0028] This invention provides a tunnel design capable of reducing electromagnetic radiation at the tunnel entrance, comprising a shielding wall installed at the tunnel entrance. Since electromagnetic radiation from the train's onboard electrical, signaling, power supply, and information systems is transmitted through the tunnel entrance, the shielding wall is placed there. The aggregates and cement in concrete can absorb and reflect electromagnetic waves; the steel mesh in reinforced concrete provides conductivity, further aiding in electromagnetic wave reflection. Therefore, the shielding wall is a reinforced concrete structure, which enhances its shielding performance. The electromagnetic shielding coating absorbs or reflects electromagnetic radiation, minimizing its transmission through the shielding wall to the outside. Sidewalls are provided at the ends of the shielding wall; the higher the plane containing the sidewalls, the greater the distance to the tunnel entrance, ensuring that unshielded electromagnetic radiation propagates upwards rather than laterally, thus enhancing the shielding effect. This device overcomes the shortcomings of existing technologies where tunnel entrance electromagnetic radiation protection measures are inadequate and may adversely affect human health. Attached Figure Description

[0029] Figure 1 This is a front view schematic diagram of a tunnel that can reduce electromagnetic radiation at the entrance of a tunnel according to this utility model;

[0030] Figure 2 This is a cross-sectional schematic diagram of the shielding wall;

[0031] Figure 3 The electromagnetic radiation was measured by simulation in the software. Figure 1 ;

[0032] Figure 4 The electromagnetic radiation was measured by simulation in the software. Figure 2 ;

[0033] Icons: 1-Tunnel entrance, 101-Anchor bolt, 2-Shielding wall, 201-Reinforcing mesh, 202-Concrete, 203-Electromagnetic shielding coating, 204-Side wall. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0035] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of the present invention is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0036] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but that it can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0037] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0038] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as 2, 3, 4, 5, 6, 7, 8, or 9, and can even exceed nine.

[0039] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0040] Example 1

[0041] like Figures 1 to 2 As shown, a tunnel capable of reducing electromagnetic radiation at its entrance includes a tunnel entrance 1 and further includes:

[0042] The shielding wall 2 is located at the tunnel entrance 1. The shielding wall 2 is a reinforced concrete structure. The surface of the shielding wall 2 is provided with an electromagnetic shielding coating 203. The shielding wall 2 is inclined to the side wall 204 near the tunnel entrance 1. The distance from the side wall 204 to the tunnel entrance 1 gradually increases from the bottom of the shielding wall 2 to the tunnel entrance 1.

[0043] Because the electromagnetic radiation from the train's onboard electrical system, signaling system, power supply system, and onboard information system will be transmitted through tunnel entrance 1, shielding wall 2 is installed at the tunnel entrance. The aggregate and cement in concrete 202 can absorb electromagnetic waves; the steel mesh 201 in reinforced concrete can provide some conductivity, which helps reflect electromagnetic waves. Therefore, shielding wall 2 is a reinforced concrete structure, which improves its shielding performance. The electromagnetic shielding coating 203 can absorb or reflect electromagnetic radiation, minimizing its transmission through shielding wall 2 to the outside. Sidewalls 204 are provided at the ends of shielding wall 2. The higher the plane containing the sidewalls 204, the greater the distance to tunnel entrance 1, ensuring that unshielded electromagnetic radiation propagates upwards rather than laterally, thus enhancing the electromagnetic shielding effect of shielding wall 2. Shielding wall 2 achieves a better electromagnetic shielding effect through a combination of reflection and absorption.

[0044] Shielding wall 2 is installed starting 3-5 meters from the tunnel. The height of shielding wall 2 is determined based on the actual situation, ensuring that it covers the train's roof and its main radiation systems, such as the onboard electrical system. The thickness of shielding wall 2 is typically 30-50 cm.

[0045] The location of shielding wall 2 is determined based on the actual situation. If there is equipment or personnel that need electromagnetic protection, shielding wall 2 is set up along the propagation path between the radiation source and the target area that needs electromagnetic protection. Therefore, shielding wall 2 may be set on one side of the opening or on both sides of the opening.

[0046] An electromagnetic shielding layer is positioned directly opposite to the propagation path of radiation, thus maximizing the absorption or reflection of electromagnetic radiation in that direction.

[0047] like Figure 2 As shown, the shielding wall 2 includes a steel mesh 201 with a mesh size greater than or equal to 30*30mm and less than or equal to 50*50mm. The smaller mesh size compared to existing steel meshes results in a larger number of meshes within the same area, leading to more gaps in the mesh. Because observations in the contour map show that the electric field energy decays faster at the gaps when electric field lines diffuse outwards from them, a smaller mesh size is used to increase the energy decay of the battery. Furthermore, considering construction costs, the mesh size is greater than 30*30mm and less than 50*50mm to minimize construction costs while increasing the mesh size.

[0048] The reinforcing mesh 201 is a corrugated reinforcing mesh 201. Using the corrugated reinforcing mesh 201 can increase the structural stability of the shielding wall 2, improve the seismic performance of the shielding wall 2, and enhance the fatigue resistance of the shielding wall 2.

[0049] like Figure 1 As shown, the height of the top surface of the shielding wall 2 decreases along the direction away from the tunnel entrance 1, so as to maximize the reflection or absorption of electromagnetic radiation by the shielding wall 2.

[0050] The top surface of the shielding wall 2 has a smooth height variation, decreasing in height along an arc with a gradually increasing radius from near the tunnel entrance 1 to away from the tunnel entrance 1. This smooth height variation of the top surface of the shielding wall 2 can smooth the airflow changes at the tunnel entrance 1, reduce the micro-pressure wave noise at the tunnel entrance 1, and help alleviate the sonic boom phenomenon when trains enter the station.

[0051] The shielding wall 2 is made of cement with a strength of C20-C30 to ensure that the shielding wall 2 has sufficient strength and shielding performance as much as possible.

[0052] like Figure 2 As shown, the electromagnetic shielding coating 203 is a nano-lead selenide coating, applied to the exterior of the concrete 202. Nano-lead selenide has a narrow bandgap, giving it excellent optical absorption characteristics in the near-infrared to far-infrared range. Furthermore, nano-lead selenide is a common semiconductor material with certain electrical conductivity, which helps improve the electromagnetic radiation shielding performance.

[0053] Figure 3 and Figure 4This refers to the electromagnetic radiation measured in dB when the vehicle's antenna transmitter port is located on the roof, and the angle between the extension direction of shielding wall 2 and the axis of tunnel entrance 1 is 45° and 90°, respectively, in software simulation. The purple line represents the radiation value measured at the predetermined location without shielding wall 2, and the red line represents the radiation value measured at the predetermined location with shielding wall 2 installed. Figure 3 and Figure 4 It can be concluded that when the angle between the extension direction of the shielding wall 2 and the axis of the tunnel entrance 1 is 90°, the minimum radiation is approximately -44dB; when the angle between the extension direction of the shielding wall 2 and the axis of the tunnel entrance 1 is 45°, the minimum radiation is approximately -29.2dB. The extension direction of the shielding wall 2 is perpendicular to the axis of the tunnel entrance 1, or the angle between the extension direction of the shielding wall 2 and the axis of the tunnel entrance 1 is 45°, to ensure the shielding performance of the shielding wall 2 as much as possible.

[0054] The tunnel entrance 1 is angled upwards. The angled upward orientation of the tunnel entrance 1 allows unshielded electromagnetic radiation to propagate along the upper air rather than along the sides, thus minimizing the impact of electromagnetic radiation on the surrounding environment.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A tunnel capable of reducing electromagnetic radiation at its entrance, comprising a tunnel entrance (1), characterized in that, Also includes: A shielding wall (2) is provided at the tunnel entrance (1). The shielding wall (2) is a reinforced concrete structure. An electromagnetic shielding coating (203) is provided on the surface of the shielding wall (2). The shielding wall (2) is inclined to the side wall (204) near the tunnel entrance (1). The distance from the side wall (204) to the tunnel entrance (1) gradually increases from the bottom of the shielding wall (2) to the shielding wall (2). The shielding wall (2) includes a steel mesh (201), the mesh size of which is greater than or equal to 30*30mm and less than or equal to 50*50mm; The steel mesh (201) is a corrugated steel mesh (201); The height of the top surface of the shielding wall (2) decreases in the direction away from the tunnel opening (1); The height of the top surface of the shielding wall (2) changes smoothly, and the height of the top surface of the shielding wall (2) decreases along an arc with a gradually increasing radius from near the tunnel entrance (1) to away from the tunnel entrance (1). The electromagnetic shielding coating (203) is a nano-lead selenide coating; The tunnel entrance (1) is set at an angle upward; The electromagnetic shielding coating (203) faces the path of radiation propagation and is oriented in the opposite direction to the propagation direction.

2. A tunnel capable of reducing electromagnetic radiation at the entrance, as described in claim 1, is characterized in that, The shielding wall (2) is made of cement with a strength of C20-C30.

3. A tunnel capable of reducing electromagnetic radiation at the entrance, as described in claim 1, is characterized in that... The extension direction of the shielding wall (2) is perpendicular to the axis of the tunnel entrance (1).

4. A tunnel capable of reducing electromagnetic radiation at the entrance, as described in claim 1, characterized in that, The angle between the extension direction of the shielding wall (2) and the axis of the tunnel entrance (1) is 45°.

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