A vibration isolation structure under the rail of a shield tunnel and its construction method

Abstract

This invention relates to the field of shield tunnel vibration control technology, specifically to a shield tunnel track-under vibration isolation structure and its construction method, including a precast track foundation arranged along the longitudinal direction of the tunnel and precast supports arranged at intervals along the longitudinal direction of the tunnel; the bottom of the precast track foundation is provided with a clearance space to avoid each precast support, the precast supports are set in the clearance space, and the bottom of the precast supports is connected to the tunnel lining; a vertical vibration isolation support is provided between the top of the precast supports and the top of the precast track foundation; the side of the precast supports and the precast track foundation are connected by a compression-shear stiffness decoupling limiter. This invention provides an inertial reference through a prefabricated track foundation, a compression-shear stiffness decoupling limiter constrains horizontal displacement while allowing vertical vibration, and a vertical vibration isolation support regulates vertical vibration. Through the synergistic effect of these components, a three-dimensional vibration isolation system is formed, achieving efficient attenuation of vibration energy in the specific frequency band of 20-80Hz for high-speed rail. While ensuring a vibration reduction performance of 15-20dB, it keeps the dynamic displacement of the track within the limits specified in high-speed railway track specifications, achieving a balance between vibration control and track smoothness, and fully meeting the 350km / h operating requirements of high-speed rail.

Description

Technical Field

[0001] This invention relates to the field of shield tunnel vibration control technology, specifically to a vibration isolation structure under the rails of a shield tunnel and its construction method, particularly for high-speed railway shield tunnels. Background Technology

[0002] With the rapid development of high-speed railways and the increasing demands of people for living and travel environments, the vibration and noise generated by high-speed railway operation has become a crucial aspect of vibration reduction and isolation design in the field of high-speed railway structures. Currently, steel spring floating plates are used to isolate and attenuate the vibrations generated by train operation in the 20-80Hz characteristic vibration frequency band generated when high-speed trains operate at speeds ≥350km / h. To achieve a vibration reduction effect of 15-20dB, the stiffness of the floating plate needs to be reduced to around 10Hz. However, due to the small mass of the floating plate and the forced reduction in support stiffness, the peak dynamic displacement of the track exceeds the limit specified in the high-speed railway track specifications (≤2mm) under operating conditions at 350km / h, affecting the stability of train operation. Summary of the Invention

[0003] The purpose of this invention is to provide a vibration isolation structure under the rail of a shield tunnel and its construction method, which can at least solve some of the defects in the prior art.

[0004] To achieve the above objectives, the technical solution of the present invention is a vibration isolation structure under the rail of a shield tunnel, comprising a precast track foundation arranged longitudinally along the tunnel and precast supports arranged at intervals longitudinally along the tunnel; the bottom of the precast track foundation is provided with a clearance space to avoid each of the precast supports, the precast supports are disposed in the clearance space, and the bottom of the precast supports is connected to the tunnel lining; a vertical vibration isolation support is provided between the top of the precast supports and the top of the precast track foundation; the side of the precast supports is connected to the precast track foundation by a compression-shear stiffness decoupling limiter.

[0005] As one implementation method, the precast track foundation includes an arc-shaped bottom plate and a top plate. The two ends of the top plate are respectively connected to the two ends of the arc-shaped bottom plate and enclose a cavity. A partition is provided in the cavity. The partition is connected to the side of the precast support through the compression-shear stiffness decoupling limiter.

[0006] As one implementation method, the precast support has a U-shaped cross-section, and the top of each of the two arms of the precast support is provided with a vertical vibration isolation support between the top plate and the top plate.

[0007] As one embodiment, two partitions are provided in the cavity and are located on the inner sides of the two arms of the prefabricated support, respectively. Each partition is connected to the outer arm of the support through the compression-shear stiffness decoupling limiter.

[0008] As one embodiment, the compression-shear stiffness decoupling limiter includes a first limiting member and a second limiting member. The first limiting member is connected to the precast track foundation, and the second limiting member is connected to the precast support. The first limiting member partially surrounds the second limiting member, and an elastic material layer is provided between the first limiting member and the second limiting member.

[0009] As one embodiment, the first limiting member includes a first connecting plate and a first arc-shaped plate with one end connected to the first connecting plate; the second limiting member includes a second connecting plate, a second arc-shaped plate, and a third connecting plate arranged parallel to the first connecting plate, the two ends of the second arc-shaped plate being connected to one end of the third connecting plate and the second connecting plate respectively, and the other end of the third connecting plate being perpendicularly connected to one end of the second connecting plate; and the second arc-shaped plate and the third connecting plate are located in a semi-enclosed groove formed by the first connecting plate and the first arc-shaped plate.

[0010] As one embodiment, the thickness of the elastic material layer is 15-25mm, and the ratio of compressive stiffness to shear stiffness is ≥10:1.

[0011] As one embodiment, the vertical vibration isolation support includes a top connecting plate, a bottom connecting plate, and multiple sets of disc spring modules arranged in parallel between the top connecting plate and the bottom connecting plate. The top connecting plate is connected to the top of the precast track foundation, and the bottom connecting plate is connected to the top of the precast support pier.

[0012] As one implementation method, an auxiliary structure is provided on the top surface of the prefabricated track foundation, and a flexible isolation layer is provided between the prefabricated track foundation and the auxiliary structure.

[0013] The present invention also provides a construction method for the vibration isolation structure under the rail of a shield tunnel as described in any one of the above claims, comprising the following steps:

[0014] 1) Construction of tunnel lining;

[0015] 2) Install the precast supports at intervals along the longitudinal direction inside the tunnel lining, and fix the bottom of the precast supports to the tunnel lining;

[0016] 3) Install vertical vibration isolation bearings on the top of the precast piers;

[0017] 4) Fix compression-shear stiffness decoupling limiters on the side of the precast support;

[0018] 5) Hoist the precast track foundation, align the clearance space of the precast track foundation with the precast support, and lower it into place. Then connect the compression-shear stiffness decoupling limiter to the precast track foundation.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This invention provides an inertial reference through a prefabricated track foundation, a compression-shear stiffness decoupling limiter constrains horizontal displacement while allowing vertical vibration, and a vertical vibration isolation support regulates vertical vibration. Through the synergistic effect of these components, a three-dimensional vibration isolation system is formed, achieving efficient attenuation of vibration energy in the specific frequency band of 20-80Hz for high-speed rail. While ensuring a vibration reduction performance of 15-20dB, it keeps the dynamic displacement of the track within the limits specified in high-speed railway track specifications, achieving a balance between vibration control and track smoothness, and meeting the 350km / h operating requirements of high-speed rail. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the vibration isolation structure under the shield tunnel rail provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of the prefabricated support pier provided in an embodiment of the present invention;

[0024] Figure 3 A schematic diagram of the structure of a prefabricated track foundation at a non-prefabricated support, provided for an embodiment of the present invention;

[0025] Figure 4 A schematic diagram of the prefabricated track foundation at the prefabricated support pier provided in an embodiment of the present invention;

[0026] Figure 5 This is a top view of the compression-shear stiffness decoupling limiter provided in an embodiment of the present invention;

[0027] In the diagram: 1. Tunnel lining; 2. Precast support; 21. Support arm; 3. Vertical vibration isolation support; 4. Compression-shear stiffness decoupling limiter; 41. First connecting plate; 42. First arc-shaped plate; 43. Second connecting plate; 44. Second arc-shaped plate; 45. Third connecting plate; 46. Elastic material layer; 5. Precast track foundation; 51. Top slab; 52. Arc-shaped bottom slab; 53. Partition plate; 54. Supporting platform; 6. Flexible isolation layer; 7. Auxiliary structure; 8. Track slab. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0031] like Figure 1 As shown, this embodiment provides a vibration isolation structure under the shield tunnel track, including a precast track foundation 5 arranged along the longitudinal direction of the tunnel and precast supports 2 arranged at intervals along the longitudinal direction of the tunnel; the bottom of the precast track foundation 5 is provided with a clearance space to avoid each of the precast supports 2, the precast supports 2 are set in the clearance space, and the bottom of the precast supports 2 is connected to the tunnel lining 1; a vertical vibration isolation support 3 is provided between the top of the precast supports 2 and the top of the precast track foundation 5; the side of the precast supports 2 is connected to the precast track foundation 5 by a compression-shear stiffness decoupling limiter 4.

[0032] In this embodiment, the prefabricated track foundation 5 provides an inertial reference, the compression-shear stiffness decoupling limiter 4 constrains horizontal displacement while allowing vertical vibration, and the vertical vibration isolation support 3 regulates vertical vibration. Through the synergistic effect of each component, a three-dimensional vibration isolation system is formed, which achieves efficient attenuation of vibration energy in the specific frequency band of 20-80Hz for high-speed rail. While ensuring a vibration reduction performance of 15-20dB, it keeps the dynamic displacement of the track within the limit range of the high-speed rail track specification, achieving a balance between vibration control and track smoothness, and meeting the 350km / h operation requirements of high-speed rail.

[0033] In this embodiment, the precast track foundation 5 and precast support 2 are set at the bottom of the tunnel lining 1. A track slab 8 is set on the top surface of the precast track foundation 5, and rail fasteners are installed on the track slab 8. The precast track foundation 5 has a large mass, which can form an "inertial anchoring" effect, allowing for the use of a vertical vibration isolation support 3 with higher stiffness at the same natural frequency. Through the mass-stiffness matching relationship between the precast track foundation 5 and the vertical vibration isolation support 3, the dynamic displacement of the track can be reduced from 2.5mm to 1.5mm, the horizontal offset at the center of the track is controlled within ±0.3mm, and the horizontal offset at the edge of the track is controlled within ±0.5mm. This achieves a 40% reduction in dynamic displacement of the track while maintaining vibration attenuation performance, fundamentally solving the long-standing technical contradiction in the field of vibration isolation for high-speed railway shield tunnels: "vibration reduction and stability cannot be achieved simultaneously."

[0034] Preferably, the lateral span of the precast track foundation 5 matches that of the tunnel lining 1; the precast track foundation 5 is divided into multiple longitudinal segments, and two precast supports 2 are arranged longitudinally at intervals within each longitudinal segment. In one embodiment, the longitudinal segment length of the precast track foundation 5 is 2m, and the longitudinal distribution spacing between the two precast supports 2 within the range of the precast track foundation 5 is 1.2-1.8m, thereby achieving a match between the longitudinal length of the precast track foundation 5 and the spacing of the precast supports 2.

[0035] In some embodiments, such as Figure 3 As shown, the precast track foundation 5 includes an arc-shaped bottom plate 52 and a top plate 51. The two ends of the top plate 51 are connected to the two ends of the arc-shaped bottom plate 52, forming a cavity. A partition 53 is installed inside the cavity, and the partition 53 is connected to the side of the precast support 2 via a compression-shear stiffness decoupling limiter 4. The radius of curvature of the arc-shaped bottom plate 52 is consistent with the inner diameter of the tunnel lining 1, ensuring complete contact between the arc-shaped bottom plate 52 and the tunnel lining 1. A roller conveyor is installed on the top plate 51. Variable cross-section structures are provided at both ends of the precast track foundation 5, thereby forming a clearance space to avoid the precast support 2. The rate of change of the moment of inertia in the variable cross-section region is ≤15%, and the height of the clearance space is ≥120% of the height of the precast support 2. In this embodiment, the arc-shaped bottom plate 52, the top plate 51, and the partition 53 are precast integrally.

[0036] In some embodiments, the precast support 2 has a U-shaped cross-section, and the vertical vibration isolation support 3 is provided between the top of the two arms 21 of the precast support 2 and the top plate 51. Figure 1 and Figure 2As shown, the bottom of the precast support 2 is adapted to the contour of the tunnel lining 1, and the tops of the two arms 21 correspond exactly to the positions of the two tracks. Vertical vibration isolation supports 3 are provided between the tops of the two arms 21 and the top plate 51 of the precast track foundation 5 to attenuate the transmission of track vibration to the tunnel structure. In this embodiment, the bottom of the precast support 2 and the interior of the two arms 21 are equipped with multiple layers of main reinforcement and denser reinforcement to meet the requirements for bending and shear bearing capacity.

[0037] In an optimized embodiment, two partitions 53 are provided within the cavity, respectively located inside the two arms 21 of the prefabricated support 2. Each partition 53 is connected to its outer arm 21 via the compression-shear stiffness decoupling limiter 4. Figure 1 As shown, the compression-shear stiffness decoupling limiters 4 are symmetrically arranged on both sides of the precast track foundation 5, which constrain horizontal displacement while allowing vertical vibration.

[0038] In some embodiments, the compression-shear stiffness decoupling limiter 4 includes a first limiting member and a second limiting member. The first limiting member is connected to the precast track foundation 5, and the second limiting member is connected to the precast support 2. The first limiting member partially surrounds the second limiting member, and an elastic material layer 46 is provided between the first limiting member and the second limiting member. By having the first limiting member partially surround the second limiting member in the horizontal direction and providing an elastic material layer 46 between them, horizontal displacement is suppressed while maintaining vertical vibration isolation performance.

[0039] like Figure 5 As shown, the first limiting member includes a first connecting plate 41 and a first arc-shaped plate 42 with one end connected to the first connecting plate 41; the second limiting member includes a second connecting plate 43, a second arc-shaped plate 44, and a third connecting plate 45 arranged parallel to the first connecting plate 41. The two ends of the second arc-shaped plate 44 are respectively connected to one end of the third connecting plate 45 and the second connecting plate 43, and the other end of the third connecting plate 45 is perpendicularly connected to one end of the second connecting plate 43; and the second arc-shaped plate 44 and the third connecting plate 45 are located in a semi-enclosed groove formed by the first connecting plate 41 and the first arc-shaped plate 42.

[0040] In the optimized embodiment, the thickness of the elastic material layer 46 is 15-25 mm, and the ratio of compressive stiffness to shear stiffness is ≥10:1. The compressive stiffness of the elastic material layer 46 is significantly greater than its shear stiffness, ensuring controllable deformation under vertical loads, maintaining track smoothness, and allowing horizontal displacement to be released through the shear deformation of the elastic layer, reducing the lateral force transmission to the pier. Specifically, the elastic material layer 46 can be made of fluororubber, etc. In one embodiment, the thickness of the elastic material layer 46 is 20 mm, with a compressive stiffness ≥50 MN / m and a shear stiffness ≤5 MN / m.

[0041] In some embodiments, the vertical vibration isolation support 3 includes a top connecting plate, a bottom connecting plate, and multiple sets of disc spring modules arranged in parallel between the top and bottom connecting plates. The top connecting plate is connected to the top of the precast track foundation 5, and the bottom connecting plate is connected to the top of the precast support pier 2. Each disc spring module includes multiple disc springs, which are arranged in series in the same direction or in pairs facing each other and arranged in series. In this embodiment, the stiffness of the vertical vibration isolation support 3 matches the mass of the precast track foundation 5, and the support stiffness can be adjusted by changing the number of disc springs. In one embodiment, the mass per unit length of the precast track foundation 5 is ≥20,000 kg / m, and the natural frequency of the vertical vibration isolation support 3 is f_n = 12 ± 2 Hz.

[0042] Furthermore, guide rods are provided on the bottom surface of the top connecting plate corresponding to the positions of each disc spring module, and limit grooves are provided on the top surface of the bottom connecting plate corresponding to the positions of each disc spring module. The guide rods pass downward through the center holes of all disc springs in the corresponding disc spring module and extend into the corresponding limit grooves. Optimally, the surface of each disc spring is nitrided, and the nitriding layer depth is 0.1-0.2mm.

[0043] In one embodiment, eight sets of disc spring modules are arranged in parallel between the top connecting plate and the bottom connecting plate, and the flatness error is ≤0.1mm / m; each set of disc spring modules is composed of six disc springs stacked in the same direction, and the preload of the guide rod is controlled at 50kN.

[0044] like Figure 4 As shown, a downwardly protruding support platform 54 is provided on the bottom surface of the top plate 51 of the precast track foundation 5 at the position corresponding to the support arm 21 of the precast support pier 2. In some embodiments, the top connecting plate is bolted to the support platform 54, and the bottom connecting plate is bolted to the support arm 21 of the precast support pier 2. To facilitate the replacement of the vertical vibration isolation bearing 3, a lubricant is applied to the contact surfaces of the top connecting plate and the precast track foundation 5, and the contact surfaces of the bottom connecting plate and the precast support pier 2. The lubricant can be molybdenum disulfide lubricant, etc. In other embodiments, embedded steel plates are pre-embedded on the top surfaces of the support platform 54 and the support arm 21 of the precast support pier 2. The top connecting plate is welded to the embedded steel plate on the support platform 54, and the bottom connecting plate is welded to the embedded steel plate on the top surface of the precast support pier 2. The welding is performed using CO2 gas shielded welding, with the interpass temperature controlled ≤150℃.

[0045] Furthermore, the bottom of the precast support 2 is rigidly connected to the tunnel lining 1 via shear-resistant connectors. By rigidly connecting the precast support 2 to the tunnel lining 1, the shear resistance of both the precast support 2 and the tunnel lining 1 can be improved, establishing a reliable system adapted to high-frequency vibration environments, and enabling dynamic coupling between the vibration isolation structure and the tunnel lining 1. In this embodiment, the tunnel lining 1 includes multiple ring segments spliced ​​longitudinally, each ring segment including multiple shield segments spliced ​​circumferentially. Further, multiple sets of shear-resistant connectors are pre-embedded within the shield segments corresponding to the bottom range of the precast support 2, and these connectors are arranged in a double-row staggered manner within the shield segments. The ends of the shear-resistant connectors are provided with shear keyways and are rigidly connected to the bottom of the precast support 2 via high-strength bolts, thereby achieving uniform transmission of shear force. In one embodiment, the longitudinal spacing of the shear connectors is 200mm, the transverse spacing is 150mm, the implantation depth is ≥120mm, and the dimensions of the shear keyway are 8mm deep × 12mm wide.

[0046] In this embodiment, an auxiliary structure 7 is provided on the top surface of the prefabricated track foundation 5, and a flexible isolation layer 6 is provided between the prefabricated track foundation 5 and the auxiliary structure 7. The flexible isolation layer 6 can absorb track vibration energy and block the transmission of vibration to the auxiliary structure 7. Further, as... Figure 1 As shown, the top surfaces at both ends of the prefabricated track foundation 5 form shoulders that slope downwards towards the shield tunnel segment. The bottom of the auxiliary structure 7 is wedge-shaped and embedded in the area between the shoulder and the shield tunnel segment. A flexible isolation layer 6 is disposed between the shoulder and the auxiliary structure 7, with one end extending to the shield tunnel segment and the other end extending to the side of the track slab 8. Furthermore, the inclination angle of the shoulder of the prefabricated track foundation 5 is 40-50°, and the surface is ground to a flatness of ≤2mm / m, which can form a wedge-shaped locking for the auxiliary structure 7 installed on it. The auxiliary structure 7 includes a communication cable trough structure, a drainage ditch structure, etc.

[0047] The vibration isolation structure under the shield tunnel in this embodiment can achieve directional dissipation of vibration energy in specific frequency bands of high-speed rail, and is especially suitable for high-speed rail shield tunnels with an outer diameter of D=10-14m, which can reduce the vibration acceleration level of the shield tunnel wall by 8-12dB.

[0048] This embodiment also provides a construction method for the above-described shield tunnel track-under vibration isolation structure, including the following steps:

[0049] 1) Construction of tunnel lining 1;

[0050] 2) Install the precast supports 2 longitudinally at intervals inside the tunnel lining 1, and fix the bottom of the precast supports 2 to the tunnel lining 1;

[0051] 3) Install vertical vibration isolation bearings 3 on the top of the precast support 2;

[0052] 4) Fix the compression-shear stiffness decoupling limiter 4 on the side of the precast support 2;

[0053] 5) Hoist the precast track foundation 5, align the clearance space of the precast track foundation 5 with the precast support 2, and lower it into place. Connect the compression-shear stiffness decoupling limiter 4 to the precast track foundation 5.

[0054] In step 1), the construction method of tunnel lining 1 is as follows: first, the shield tunnel segments are prefabricated, and then the shield tunnel segments are assembled longitudinally and circumferentially to form tunnel lining 1. During the prefabrication of shield tunnel segments, double-row shear connectors are implanted using three-dimensional laser positioning technology. After curing, shear keyways are milled at the exposed ends to facilitate connection with prefabricated supports 2.

[0055] In step 2), when installing the precast support 2, a total station is used for positioning, with the center distance deviation of the support ≤ ±5mm. M24 high-strength bolts are used to fasten the precast support 2 to the tunnel lining 1 in a diagonal sequence, with the torque controlled at 900N·m±5%. The precasting process of the precast support 2 is as follows: the precast support 2 is precast using a detachable steel mold, and the inner surface of the detachable steel mold is polished (Ra≤3.2μm). When pouring concrete, it is poured in two layers. The lower layer is vibrated and compacted before the upper layer is poured. After steam curing (60℃×24h), the mold is removed.

[0056] In step 3), the installation method of the vertical vibration isolation support 3 is as follows: connect the bottom connecting plate to the top of the precast support 2, arrange multiple sets of disc spring modules in parallel on the bottom connecting plate, and then install the top connecting plate.

[0057] In step 4), the second connecting plate 43 of the compression-shear stiffness decoupling limiter 4 is connected to one side of the pier in the lateral direction. During installation, the tilt angle is calibrated using a laser angle measuring instrument, and the flexible layer is pre-compressed to the designed thickness of 20mm using a hydraulic jack. The first and second limiting components of the compression-shear stiffness decoupling limiter 4 are co-vulcanized with the elastic material layer 46 between them, and the compression stiffness gradient of the elastic material layer 46 is controlled as follows: hardness of 70±5 Shore A in the central area and 60±5 Shore A at the edge.

[0058] In step 5), before hoisting the precast track foundation 5, a BIM model is used to simulate the hoisting path to avoid interference with the precast support 2. After the precast track foundation 5 is in place, a vibrating wire displacement gauge is used for monitoring, and the adjustment accuracy is ≤0.2mm. The top connecting plate of the vertical vibration isolation support 3 is then connected to the precast track foundation 5.

[0059] Further, the shoulder of the precast track foundation 5 is ground to a flatness of ≤2mm / m, and then a flexible isolation layer 6 is laid on it. One end of the flexible isolation layer 6 extends to the shield tunnel segment, and the other end extends to the top surface of the precast track foundation 5. Then, the auxiliary structure 7 is installed. The bottom of the auxiliary structure 7 is wedge-shaped and embedded in the area between the shoulder and the shield tunnel segment. A preload of 50kN / m is then applied. The joints of the flexible isolation layer 6 are hot-melt welded (temperature 230℃±10℃).

[0060] After the construction of the vibration isolation structure under the shield tunnel rails was completed, the track slab 8 and rail fasteners were installed. Then, a vibration test was conducted using 20-80Hz white noise excitation, with a natural frequency of 12±0.5Hz. When a 350km / h EMU train passed by, the dynamic displacement was monitored to be ≤1.5mm. Simultaneously, the interface was inspected, and the torque attenuation rate of the tightening bolts was ≤3%.

[0061] 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, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A vibration isolation structure under the rail of a shield tunnel, characterized in that: The system includes precast track foundations arranged longitudinally along the tunnel and precast supports spaced apart longitudinally along the tunnel. The bottom of each precast track foundation has a clearance space to avoid the precast supports. The precast supports are located within the clearance space, and their bottoms are connected to the tunnel lining. A vertical vibration isolation support is provided between the top of each precast support and the top of the precast track foundation. The sides of each precast support are connected to the precast track foundation via compression-shear stiffness decoupling limiters. Each precast track foundation includes an arc-shaped bottom plate and a top plate. The two ends of the top plate are connected to the two ends of the arc-shaped bottom plate, forming a cavity. A partition is provided within the cavity, and the partition communicates with the sides of the precast supports. The precast support has a U-shaped cross-section, and vertical vibration isolation supports are provided between the top of the two arms of the precast support and the top plate. Two partitions are provided inside the cavity, located on the inner sides of the two arms of the precast support, and each partition is connected to its outer arm via the compression-shear stiffness decoupling limiter. The compression-shear stiffness decoupling limiter includes a first limiting member and a second limiting member. The first limiting member is connected to the precast track foundation, and the second limiting member is connected to the precast support. The first limiting member partially surrounds the second limiting member, and an elastic material layer is provided between the first limiting member and the second limiting member.

2. The shield tunnel track-under vibration isolation structure as described in claim 1, characterized in that: The first limiting member includes a first connecting plate and a first arc-shaped plate with one end connected to the first connecting plate; the second limiting member includes a second connecting plate, a second arc-shaped plate, and a third connecting plate arranged parallel to the first connecting plate, the two ends of the second arc-shaped plate being connected to one end of the third connecting plate and the second connecting plate respectively, and the other end of the third connecting plate being perpendicularly connected to one end of the second connecting plate; and the second arc-shaped plate and the third connecting plate are located in a semi-enclosed groove formed by the first connecting plate and the first arc-shaped plate.

3. The shield tunnel track-under vibration isolation structure as described in claim 1, characterized in that: The thickness of the elastic material layer is 15-25mm, and the ratio of compressive stiffness to shear stiffness is ≥10:

1.

4. The vibration isolation structure under the shield tunnel rail as described in claim 1, characterized in that: The vertical vibration isolation support includes a top connecting plate, a bottom connecting plate, and multiple sets of disc spring modules arranged in parallel between the top connecting plate and the bottom connecting plate. The top connecting plate is connected to the top of the precast track foundation, and the bottom connecting plate is connected to the top of the precast support pier.

5. The vibration isolation structure under the shield tunnel rail as described in claim 1, characterized in that: An auxiliary structure is provided on the top surface of the precast track foundation, and a flexible isolation layer is provided between the precast track foundation and the auxiliary structure.

6. A construction method for a vibration isolation structure under the rail of a shield tunnel as described in any one of claims 1-5, characterized in that, Includes the following steps: 1) Construction of tunnel lining; 2) Install the precast supports at intervals along the longitudinal direction inside the tunnel lining, and fix the bottom of the precast supports to the tunnel lining; 3) Install vertical vibration isolation bearings on the top of the precast piers; 4) Fix compression-shear stiffness decoupling limiters on the side of the precast support; 5) Hoist the precast track foundation, align the clearance space of the precast track foundation with the precast support, and lower it into place. Then connect the compression-shear stiffness decoupling limiter to the precast track foundation.

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