An embedded floating raft structure track slab damping system

Abstract

The application discloses a built-in floating raft structure track slab damping system, which comprises upper track slabs, upper vibration isolation layers, floating raft slabs, lower vibration isolation layers and lower track slabs which are sequentially stacked from top to bottom. The upper vibration isolation layers elastically support the upper track slabs, and the lower vibration isolation layers elastically support the floating raft slabs. The floating raft slabs are elastically coupled between the upper and lower track slabs as intermediate mass bodies, and form a multi-stage mass-spring series vibration isolation system. The floating raft slabs and double-layer elastic interfaces are introduced into the vibration transmission path, twice impedance adaptation is formed, and the attenuation capacity for medium and low frequency vibrations is significantly improved. The stiffness and damping parameters of the upper and lower vibration isolation layers can be independently configured to adapt to the damping requirements of different sections. The layered assembly type structure is convenient for layered maintenance and component replacement. The overall structure of the system is stable, and the system can be widely applied to vibration and noise reduction engineering of rail transit lines.

Description

Technical Field

[0001] This invention relates to vibration reduction and noise reduction technology for rail transit, and more particularly to a multi-layer elastic support track slab vibration reduction system with an intermediate mass layer. Background Technology

[0002] With the rapid development of urban rail transit, the environmental vibration and noise problems caused by train operation are becoming increasingly prominent. In order to prevent the propagation of wheel-rail vibration to the tunnel structure and surrounding soil, advanced vibration-damping track technology has been widely used in sensitive sections. At present, the mainstream solution is the floating slab track system, which forms a "mass-spring" system by laying an elastic pad (such as rubber or polyurethane pad) between the concrete track slab and the foundation, and using the mass inertia of the track slab for vibration isolation.

[0003] However, traditional floating slab systems have significant limitations: First, their vibration isolation performance is poor in the low-frequency range (typically <20Hz) because the system's natural frequency is constrained by the slab weight and the stiffness of the subbase, making it difficult to further reduce; in fact, vibrations near the natural frequency are amplified. Second, traditional systems are passive vibration isolation systems with fixed stiffness and damping parameters, making them unable to adapt to the complex excitation spectrum caused by changes in train load (empty, fully loaded) and speed, resulting in unstable vibration isolation under varying operating conditions. Furthermore, maintenance of existing floating slabs, especially the replacement of the subbase, is extremely difficult, almost requiring destructive construction of the track structure, resulting in poor maintainability.

[0004] Based on the above realities, it is necessary to propose a new type of track vibration reduction structure to systematically solve the problem of unsatisfactory vibration reduction effect. Summary of the Invention

[0005] The purpose of this invention is to provide a built-in floating raft structure track slab vibration reduction system, comprising, from top to bottom, an upper track slab, an upper vibration isolation layer, a floating raft slab, a lower vibration isolation layer, and a lower track slab stacked in sequence. The upper vibration isolation layer elastically supports the upper track slab, and the lower vibration isolation layer elastically supports the floating raft slab. The floating raft slab, as an intermediate mass, is elastically coupled between the upper and lower track slabs, forming a multi-stage mass-spring series vibration isolation system. By introducing the floating raft slab and the double-layer elastic interface into the vibration transmission path, two impedance adaptations are formed, significantly improving the attenuation capability for mid-to-low frequency vibrations. The stiffness and damping parameters of the upper and lower vibration isolation layers can be independently configured to adapt to the vibration reduction requirements of different sections. The layered prefabricated structure facilitates layered maintenance and component replacement. The overall system structure is stable and can be widely applied to vibration reduction and noise reduction projects in rail transit lines, thus completing this invention.

[0006] Specifically, the present invention provides a built-in floating raft structure track slab vibration reduction system, the system comprising: Upper track slab 1, which is used to support the steel rails; Lower track slab 2, which is used to fix it to the foundation structure; The floating raft 3 is an independently arranged rigid mass body disposed between the upper track 1 and the lower track 2; The upper vibration isolation layer 4 is disposed between the upper track plate 1 and the floating raft plate 3 to elastically support the upper track plate 1. The lower vibration isolation layer 5 is disposed between the floating raft 3 and the lower track slab 2 to elastically support the floating raft 3.

[0007] The planar projected area of ​​the floating raft 3 is equal to the planar projected area of ​​the upper track 1 and the lower track 2.

[0008] Among them, at least one of the upper track slab 1, the floating raft slab 3 and the lower track slab 2 is a precast reinforced concrete component or a cast-in-place reinforced concrete component.

[0009] The floating raft 3 is a precast reinforced concrete component or a cast-in-place reinforced concrete component.

[0010] The overall stiffness of the upper vibration isolation layer 4 is set to a different value than that of the lower vibration isolation layer 5.

[0011] The upper vibration isolation layer 4 and the lower vibration isolation layer 5 both include multiple discretely arranged elastic support units. The elastic support unit is made of polyurethane, rubber, or composite elastic material.

[0012] The upper vibration isolation layer 4 and the lower vibration isolation layer 5 each have preset stiffness parameters and damping parameters.

[0013] The elastic support units of the upper vibration isolation layer 4 and the elastic support units of the lower vibration isolation layer 5 have different arrangement densities.

[0014] In the upper vibration isolation layer 4, sound-absorbing material or damping material is filled between the discretely arranged elastic support units. In the lower vibration isolation layer 5, sound-absorbing material or damping material is filled between the discretely arranged elastic support units.

[0015] Among them, an elastic limiting member is also provided on the side of the floating raft plate 3, which does not exceed the height position of the upper track plate 1 and the lower track plate 2 in the vertical direction.

[0016] The built-in floating raft structure track slab vibration reduction system provided by this invention has the following beneficial effects: (1) Excellent vibration reduction performance: Through the synergistic effect of the built-in intermediate mass block of the "floating raft plate" and the upper and lower vibration isolation layers, a highly efficient dual vibration isolation system is formed, which has a significant attenuation effect on low and medium frequency vibrations, a wider vibration reduction frequency band, and a vibration reduction performance that is much better than traditional single-layer floating slab tracks and comprehensively better than steel spring floating slabs.

[0017] (2) Strong adaptability: By adjusting the dynamic parameters of the upper and lower vibration isolation layers respectively, the overall vibration isolation frequency of the system can be finely tuned, flexibly adapting to different levels of requirements from general vibration reduction to special ultra-high vibration reduction, as well as sensitive areas with different geological conditions.

[0018] (3) High system stability and reliability: The floating raft plate, as a built-in large counterweight, increases the system's inertia, effectively suppresses the resonance amplitude of the track plate, and improves the smoothness of operation. The multi-layer structure also disperses the stress and improves the long-term durability of the system.

[0019] (4) Convenience of maintenance: Each level of the structure is relatively independent. When necessary, the vibration isolation elements of a specific level can be inspected, replaced or their parameters adjusted without disturbing the entire track superstructure, thus reducing the maintenance cost throughout the entire life cycle. Attached Figure Description

[0020] Figure 1 A three-dimensional structural schematic diagram of the built-in floating raft structure track plate vibration reduction system provided in this application is shown. Figure 2 A cross-sectional schematic diagram of the built-in floating raft structure track plate vibration reduction system provided in this application is shown. Figure 3 Show Figure 2 A magnified view of a portion of the image.

[0021] Explanation of reference numerals in the attached figures 1-Upper track slab, 2-Lower track slab, 3-Floating raft slab, 4-Upper vibration isolation layer, 5-Lower vibration isolation layer. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present invention will become clearer and more apparent.

[0023] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0024] This invention provides a built-in floating raft structure track slab vibration reduction system, such as... Figure 1 , Figure 2 and Figure 3 As shown, this vibration reduction system is applied to underground lines, especially those located in special sections such as tunnels and bridges.

[0025] The system consists of, from top to bottom, an upper track slab 1, an upper vibration isolation layer 4, a floating raft slab 3, a lower vibration isolation layer 5, and a lower track slab 2, which together form a multi-level mass-spring series vibration isolation system.

[0026] The upper track plate 1 is used to support the steel rails; The lower track slab 2 is used to fix it to the foundation structure; The floating raft 3 is an independently arranged rigid mass body disposed between the upper track 1 and the lower track 2; The upper vibration isolation layer 4 is disposed between the upper track plate 1 and the floating raft plate 3 to elastically support the upper track plate 1; The lower vibration isolation layer 5 is disposed between the floating raft 3 and the lower track slab 2 to elastically support the floating raft 3.

[0027] At least one of the upper track slab 1, the floating raft slab 3, and the lower track slab 2 is a steel-concrete composite component, which can be a precast reinforced concrete component or a cast-in-place reinforced concrete component.

[0028] Preferably, the lower track slab 2 is a cast-in-place reinforced concrete structure, directly cast onto the tunnel foundation or the reinforced foundation, serving as the installation base for the entire vibration reduction system. Its thickness can be 50-70mm, and its width is determined according to the tunnel cross-section.

[0029] Preferably, the lower vibration isolation layer 5 is laid on the top surface of the lower track slab 2. The lower vibration isolation layer 5 includes multiple discretely arranged elastic support units, which are arranged in a predetermined array. Each elastic support unit is fixedly connected to the lower track slab 2 by a structural adhesive. The material of the elastic support unit can be polyurethane elastomer or rubber, and the thickness of a single layer is 20mm to 30mm.

[0030] Preferably, the floating raft slab 3 is a prefabricated thick reinforced concrete slab installed on the lower vibration isolation layer 5. The floating raft slab 3 is an independent rigid slab with a thickness of 150mm to 200mm, serving as a crucial intermediate mass block in the system. The planar profile of the floating raft slab 3 is consistent with the planar profile of the lower track slab 2, and the two are vertically aligned, meaning the planar projected area of ​​the floating raft slab 3 is equal to the planar projected area of ​​the upper track slab 1 and the lower track slab 2. The entire self-weight of the floating raft slab 3 and the upper load are transferred to the lower track slab 2 through the lower vibration isolation layer 5. As a concentrated mass element, the floating raft slab's inertial effect plays a role in energy absorption and phase adjustment in the vibration transmission path.

[0031] Furthermore, the floating raft 3 can adopt a steel-concrete composite structure, that is, concrete is poured inside a steel box to obtain greater mass while controlling the thickness, which is suitable for occasions with high requirements for vibration reduction quality but limited space. This steel-concrete composite structure can be prefabricated or cast on site.

[0032] Preferably, an elastic limiting member is also provided on the side of the floating raft plate 3. The elastic limiting member does not exceed the height position of the upper track plate 1 and the lower track plate 2 in the vertical direction, so as to prevent the floating raft plate 3 from moving in the horizontal direction and avoid damage.

[0033] Preferably, the upper vibration isolation layer 4 is laid on the top surface of the floating raft plate 3. The upper vibration isolation layer 4 also includes multiple discretely arranged elastic support units, which are arranged in a predetermined array. The elastic support units of the upper vibration isolation layer 4 and the lower vibration isolation layer 5 can use the same standard material, that is, materials with the same stiffness and damping parameters. By adjusting the number of elastic support units or the geometric dimensions of the units themselves, a difference can be made between the overall stiffness of the upper vibration isolation layer 4 and the overall stiffness of the lower vibration isolation layer 5. For example, if the elastic support unit is a standard steel spring, the spacing between the elastic support units on the upper vibration isolation layer 4 is set to 1.2m, and the spacing between the elastic support units on the lower vibration isolation layer 5 is set to 1.8m, thereby achieving a difference in the overall stiffness of the upper and lower layers. This difference in stiffness helps to disrupt the impedance continuity of the vibration transmission path and suppress the penetration of vibration energy in a specific frequency band.

[0034] In addition, the upper vibration isolation layer 4 can also be made of an elastic material with a different stiffness coefficient and additional viscous damping than the lower vibration isolation layer 5. For example, the elastic support unit in the upper vibration isolation layer 4 can be made of polyurethane padding, and the elastic support unit in the lower vibration isolation layer 5 can be made of rubber, so that the stiffness value of the upper vibration isolation layer 4 is different from that of the lower vibration isolation layer 5, so as to achieve frequency coordination of the system.

[0035] Furthermore, in the upper vibration isolation layer 4, sound-absorbing material or damping material is filled between the discretely arranged elastic support units; in the lower vibration isolation layer 5, sound-absorbing material or damping material is filled between the discretely arranged elastic support units.

[0036] Preferably, the upper track slab 1 is installed on top of the upper vibration isolation layer 4. The upper track slab 1 is a precast reinforced concrete component used to directly bear the rail and train loads, and its top surface has a pre-set connection structure for installing rail fasteners. The bottom of the upper track slab 1 has a connection structure corresponding to the upper vibration isolation layer 4. The upper track slab 1 is hoisted into place, so that it sits on all the upper vibration isolation layers 4, and is finally fixed by grouting or bolts. After the upper track slab 1, upper vibration isolation layer 4, floating raft slab 3, lower vibration isolation layer 5, and lower track slab 2 are assembled, they form an overall constraint through prestressing or limiting devices to prevent relative displacement between the layers from exceeding the design allowable range.

[0037] The system assembly process is as follows: First, complete the construction and maintenance of the lower track slab 2; then, lay out and position each elastic support unit of the lower vibration isolation layer 5 on the top surface of the lower track slab 2 and fix it; finally, hoist the floating raft slab 3 into place and adjust its plane position and elevation; then, install the elastic support unit of the upper vibration isolation layer 4 on the top surface of the floating raft slab 3; finally, hoist the upper track slab 1 into place and complete the final fine adjustment; and finally, install the rails and fastener system.

[0038] Under train load, the vibration energy generated by wheel-rail contact passes sequentially through the rails and fasteners into the upper track slab 1. The vibration is first attenuated by the upper vibration isolation layer 4 (the first-stage "spring"), and some energy is transferred to the floating raft slab 3 (the intermediate "mass"). The floating raft slab 3, with its large mass inertia, induces phase hysteresis and amplitude attenuation in the incoming vibration, effectively "absorbing" some of the energy. Subsequently, the vibration energy encounters elastic resistance again when passing through the lower vibration isolation layer 5 (the second-stage "spring"), and is further attenuated. After this secondary attenuation, it enters the lower track slab 2 and the foundation. Through the combined action of the two elastic interfaces and the intermediate mass, the vibration energy ultimately transferred to the foundation is significantly reduced compared to traditional single-layer floating slab structures. This "mass-spring-mass-spring-mass" series structure effectively isolates broadband vibrations, and in particular, by tuning the parameters of the two vibration isolation layers, it can specifically suppress difficult-to-handle low-frequency vibrations.

[0039] The present invention has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present invention based on these embodiments, all of which fall within the scope of protection of the present invention.

Claims

1. A built-in floating raft structure track slab vibration reduction system, characterized in that, The system includes: The upper track slab (1) is used to support the rails; The lower track slab (2) is used to fix it to the foundation structure; The floating raft plate (3) is an independently arranged rigid mass body arranged between the upper track plate (1) and the lower track plate (2); The upper vibration isolation layer (4) is disposed between the upper track plate (1) and the floating raft plate (3) to elastically support the upper track plate (1). The lower vibration isolation layer (5) is disposed between the floating raft plate (3) and the lower track plate (2) to elastically support the floating raft plate (3).

2. The built-in floating raft structure track slab vibration reduction system according to claim 1, characterized in that, The planar projected area of ​​the floating raft plate (3) is equal to the planar projected area of ​​the upper track plate (1) and the lower track plate (2).

3. The built-in floating raft structure track slab vibration reduction system according to claim 1, characterized in that, At least one of the upper track slab (1), the floating raft slab (3), and the lower track slab (2) is a precast reinforced concrete component or a cast-in-place reinforced concrete component.

4. The built-in floating raft structure track slab vibration reduction system according to claim 3, characterized in that, The floating raft (3) is a precast reinforced concrete component or a cast-in-place reinforced concrete component.

5. The built-in floating raft structure track slab vibration reduction system according to claim 1, characterized in that, The overall stiffness of the upper vibration isolation layer (4) is set to a different value than that of the lower vibration isolation layer (5).

6. The built-in floating raft structure track slab vibration reduction system according to claim 1, characterized in that, Both the upper vibration isolation layer (4) and the lower vibration isolation layer (5) include multiple discretely arranged elastic support units; The elastic support unit is made of polyurethane, rubber, or composite elastic material.

7. The built-in floating raft structure track slab vibration reduction system according to claim 6, characterized in that, The upper vibration isolation layer (4) and the lower vibration isolation layer (5) each have preset stiffness parameters and damping parameters.

8. The built-in floating raft structure track slab vibration reduction system according to claim 7, characterized in that, The elastic support units of the upper vibration isolation layer (4) and the elastic support units of the lower vibration isolation layer (5) have different arrangement densities.

9. The built-in floating raft structure track slab vibration reduction system according to claim 6, characterized in that, In the upper vibration isolation layer (4), sound-absorbing material or damping material is filled between the discretely arranged elastic support units; In the lower vibration isolation layer (5), sound-absorbing material or damping material is filled between the discretely arranged elastic support units.

10. The built-in floating raft structure track slab vibration reduction system according to claim 1, characterized in that, An elastic limiting member is also provided on the side of the floating raft plate (3), which does not exceed the height position of the upper track plate (1) and the lower track plate (2) in the vertical direction.

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