Solid-liquid radial metamaterial structure arranged in subway tunnel ballast bed

Abstract

The utility model discloses a solid-liquid radial metamaterial structure arranged inside a subway tunnel ballast bed, which comprises a concrete base body and a coating layer, the liquid layer and the coating layer are both of a radial annular structure along the inner wall of a tunnel lining, the concrete base body is in a solid circular ring shape, the coating layer is in a hollow circular ring shape, the liquid layer is arranged in an inner cavity of the coating layer, and the liquid layer is arranged in the inner cavity of the coating layer. The concrete base body is attached to a tunnel bottom lining, the lower layer of the coating layer is attached to the concrete base body, the concrete base body and the coating layer form a plurality of unit cell structures. The structure can generate a band gap in a low-frequency range, is used for controlling low-frequency vibration caused by a subway, is arranged in a subway tunnel ballast bed, and realizes vibration control from a vibration source.

Description

Technical Field

[0001] The utility model belongs to the technical field of subway vibration reduction and isolation, and specifically relates to a solid-liquid radial metamaterial structure arranged inside a subway tunnel roadbed. Background Art

[0002] With the expansion of urban scale and the increase of urban population, while subway operation brings convenience to people, the environmental vibration problem caused by train operation is becoming increasingly serious. While the subway solves urban congestion and improves traffic capacity, the environmental vibration hazards caused by it are becoming increasingly serious. Subway vibration not only affects the safety of building structures and the use of precision instruments, but also affects people's daily lives and even human health. However, subway vibration has the characteristics of low frequency and long duration, making subway vibration reduction and isolation relatively difficult. How to effectively reduce or eliminate the hazards of subway vibration has become a hot and difficult issue that has attracted widespread attention from scholars at home and abroad.

[0003] At present, the commonly used subway vibration reduction and isolation measures can be divided into vibration source reduction, transmission path isolation and vibration isolation of the vibrated body. Although the existing track vibration isolation means (such as elastic sleepers, fasteners, floating plate tracks, vibration reduction plates, etc.) have achieved certain vibration reduction effects in the field of subway vibration reduction, the frequency below 20Hz is limited by the inherent frequency of the track vibration reduction measures themselves, and the effect in isolating low-frequency vibration is poor. Therefore, the mitigation of low-frequency vibration is still a difficult problem to solve for track measures. Therefore, the study of new vibration isolation measures for ground vibration caused by subways has important engineering significance and social value. Summary of the invention

[0004] In order to overcome the above technical problems, the purpose of the utility model is to provide a solid-liquid radial metamaterial structure placed inside the subway tunnel roadbed, which can generate a band gap in the low-frequency range for controlling the low-frequency vibration caused by the subway. The structure is placed inside the subway tunnel roadbed to achieve vibration control from the vibration source.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A solid-liquid radial metamaterial structure placed inside a subway tunnel roadbed comprises a concrete matrix and a coating layer, wherein both the liquid layer and the coating layer are radial annular structures along the inner wall of the tunnel lining, the concrete matrix is ​​a solid annular shape, the coating layer is a hollow annular shape, the liquid layer is located in the internal cavity of the coating layer, the concrete matrix is ​​bonded to the tunnel bottom lining, the lower layer of the coating layer is bonded to the concrete matrix, the concrete matrix and the coating layer constitute a unit cell structure, and a plurality of the unit cell structures are provided.

[0007] The unit cell structures are bonded to each other, and the coating layer in the unit cell structure at the lower layer is bonded to the concrete matrix at the upper layer.

[0008] The unit cell structures are arranged inside the semi-infinite tunnel ballast in the Z-axis direction to form an elastic wave barrier.

[0009] The concrete matrix and the coating layer are arranged in a three-periodic manner in the Z-axis direction and in a semi-infinite period in the axial direction.

[0010] The concrete base has an axial thickness of 0.1 m in the Z axis and an axial length of 1.2 m in the X axis.

[0011] The liquid layer has an axial thickness of 0.1 m in the Z axis and an axial length of 1.2 m in the X axis.

[0012] The cladding layer has an axial thickness of 0.12 m in the Z-axis and an axial length of 1.2 m in the X-axis.

[0013] Beneficial effects of the utility model:

[0014] The utility model drives the vibration of the upper and lower plates of the coating layer and the torsional vibration of the left and right plates through the liquid inside the coating layer, generates the coupling of the Bragg mechanism and the local resonance mechanism, and obtains two low-frequency strong attenuation bending wave band gaps. The first bending wave band gap ranges from 2.4845 to 12.412 Hz, and the second bending wave band gap (main band gap) ranges from 14.836 to 92.04 Hz. The occupancy rate of the bending wave band gap below 100 Hz is 91.04%, and the maximum attenuation can reach 137 dB. This shows that the solid-liquid radial metamaterial can effectively expand the band gap without the need for multiple cycles. This is beneficial to the application of solid-liquid radial metamaterials in the field of subway vibration reduction. The utility model solid-liquid radial metamaterial has certain application value in the field of subway vibration reduction and can effectively control the elastic waves generated by the subway. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the unit cell structure of the utility model.

[0016] Figure 2 It is a three-dimensional arrangement diagram of the utility model.

[0017] Figure 3 This is the energy band diagram of the solid-liquid radial metamaterial structure of the utility model.

[0018] Figure 4 This is a frequency response function curve of the solid-liquid radial metamaterial structure of the utility model. DETAILED DESCRIPTION

[0019] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0020] like Figure 1 , Figure 2As shown, an implementation method of the solid-liquid radial metamaterial structure of the utility model, the solid-liquid radial metamaterial is arranged in three periods along the z direction and arranged semi-wirelessly along the tunnel in the x direction. The solid-liquid radial metamaterial structure consists of a concrete matrix 1, a liquid layer 2, and a coating layer 3. The concrete matrix 1 is bonded to the coating layer 3, the liquid layer 2 is located inside the coating layer 3, the lower part of the concrete matrix 1 is bonded to the subway tunnel lining, and the uppermost part of the coating layer is connected to the tunnel roadbed concrete. The materials used are C40 concrete, PVC coating layer, and water liquid layer. The specific material parameters are as follows:

[0021] Material <![CDATA[Density kg / m 3 > Young's modulus μ / Pa Poisson's ratio Speed ​​of sound C40 Concrete 2450 <![CDATA[3.45x10 10 ]]> 0.2 Pvc 1204.8 <![CDATA[3.5x10 6 ]]> 0.319 water 1000 1500

[0022] from Figure 3 It can be seen from the energy band diagram that the solid-liquid radial metamaterial of the utility model has two bending wave band gaps, the first bending wave band gap ranges from 2.48 to 12.4 Hz, and the second bending wave band gap (main band gap) ranges from 14.83 to 92.04 Hz. The band gap frequency is low and the band gap is wide.

[0023] from Figure 4 From the frequency response function curve, it can be seen that the transmission characteristic curve has two attenuation domains at 2.4845~12.412Hz and 14.836~92.04Hz. Figure 3 The energy band diagram matches.

[0024] The mechanism of the solid-liquid radial metamaterial of the utility model is that the elastic wave propagates in the liquid and couples with the local resonance mode of the cladding layer 3, and the energy is continuously exchanged to the middle position of the upper and lower sides of the cladding layer 3 and is localized, thereby affecting the forward propagation of the elastic wave.

[0025] It can be seen that the solid-liquid radial metamaterial structure of the utility model can generate bending wave gaps in the low-frequency range, thereby effectively reducing the elastic waves generated by the subway in terms of structure.

[0026] Therefore, the solid-liquid radial metamaterial structure of the utility model can be applied to the fields of subway vibration reduction, and the new solid-liquid radial metamaterial can be arranged inside the subway tunnel roadbed to reduce the impact of the elastic waves generated by the subway on the ground buildings. The solid-liquid radial metamaterial structure of the utility model provides a new option for the fields of subway and low-frequency vibration reduction.

Claims

1. A solid-liquid radial metamaterial structure placed inside a subway tunnel ballast, characterized in that: The invention comprises a concrete base (1) and a coating layer (3), wherein the liquid layer (2) and the coating layer (3) are both radial annular structures along the inner wall of the tunnel lining, the concrete base (1) is a solid annular shape, the coating layer (3) is a hollow annular shape, the liquid layer (2) is located in the inner cavity of the coating layer (3), the concrete base (1) is bonded to the tunnel bottom lining, the lower layer of the coating layer (3) is bonded to the concrete base (1), the concrete base (1) and the coating layer (3) form a unit cell structure, and a plurality of the unit cell structures are provided.

2. The solid-liquid radial metamaterial structure placed inside the subway tunnel ballast according to claim 1, characterized in that: The unit cell structures are bonded to each other, and the coating layer (3) in the unit cell structure at the lower layer is bonded to the concrete matrix (1) at the upper layer.

3. The solid-liquid radial metamaterial structure placed inside the subway tunnel ballast according to claim 1, characterized in that: The unit cell structures are arranged inside the semi-infinite tunnel ballast in the Z-axis direction to form an elastic wave barrier.

4. The solid-liquid radial metamaterial structure placed inside the subway tunnel ballast according to claim 1, characterized in that: The concrete base (1) and the coating layer (3) are arranged in a three-period arrangement in the Z-axis direction and in a semi-infinite period in the axial direction.

5. The solid-liquid radial metamaterial structure placed inside the subway tunnel ballast according to claim 1, characterized in that: The concrete base (1) has a Z-axis axial thickness of 0.1 m and an X-axis axial length of 1.2 m.

6. The solid-liquid radial metamaterial structure placed inside the subway tunnel ballast according to claim 1, characterized in that: The liquid layer (2) has a Z-axis axial thickness of 0.1 m and an X-axis axial length of 1.2 m.

7. The solid-liquid radial metamaterial structure placed inside the subway tunnel ballast according to claim 1, characterized in that: The coating layer (3) has a Z-axis axial thickness of 0.12 m and an X-axis axial length of 1.2 m.

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