Shield tunnel under-rail vibration isolation structure and construction method thereof

Abstract

The invention relates to the technical field of shield tunnel vibration control, in particular to a shield tunnel under-rail vibration isolation structure and a construction method thereof.The shield tunnel under-rail vibration isolation structure comprises a prefabricated rail foundation arranged in the longitudinal direction of a tunnel and prefabricated buttresses arranged in the longitudinal direction of the tunnel at intervals; the bottom of the prefabricated track foundation is provided with receding spaces for receding the prefabricated buttresses, the prefabricated buttresses are arranged in the receding spaces, the bottoms of the prefabricated buttresses are connected with the tunnel lining, and vertical vibration isolation supports are arranged between the tops of the prefabricated buttresses and the top of the prefabricated track foundation. The side faces of the prefabricated buttresses are connected with the prefabricated track foundation through compression-shear rigidity decoupling limiters. The prefabricated track foundation provides an inertia reference, the compression-shear rigidity decoupling limiter restrains horizontal displacement and allows vertical vibration at the same time, the vertical vibration isolation support regulates and controls the vertical vibration, through the synergistic effect of all the assemblies, a three-dimensional vibration isolation system is formed, efficient attenuation of vibration energy of the high-speed rail at the specific frequency band of 20-80 Hz is achieved, and the high-speed rail vibration energy attenuation effect is improved. The vibration damping performance of 15-20 dB is guaranteed, meanwhile, the dynamic displacement of the track is within the standard limit value range of the high-speed railway track, the balance of vibration control and track smoothness is achieved, and the requirement for running of the high-speed railway at 350 km / h is comprehensively met.

Description

Technical Field

[0001] The present invention relates to the technical field of shield tunnel vibration control, and in particular to a shield tunnel under-track vibration isolation structure and a construction method thereof, especially for high-speed railway shield tunnels. Background Art

[0002] With the rapid development of high-speed rail and rising public expectations for living and riding environments, the vibration and noise generated by high-speed rail operation has become a crucial component of vibration isolation design within high-speed rail structures. Floating steel spring plates are currently used to isolate and attenuate the characteristic vibration frequency range of 20-80 Hz generated by high-speed rail operating at speeds ≥350 km / h. To achieve a vibration reduction effect of 15-20 dB, the stiffness of the floating plates must be reduced to approximately 10 Hz. However, due to the low mass of the floating plates and the resulting reduced support stiffness, the peak dynamic displacement of the track exceeds the standard limit (≤2 mm) for high-speed rail tracks under 350 km / h operating conditions, impacting train smoothness. Summary of the Invention

[0003] The object of the present invention is to provide a shield tunnel under-track vibration isolation structure and a construction method thereof, which can at least solve some of the defects in the prior art.

[0004] To achieve the above-mentioned purpose, the technical solution of the present invention is a shield tunnel track under-vibration isolation structure, comprising a prefabricated track foundation arranged along the longitudinal direction of the tunnel and prefabricated piers arranged at intervals along the longitudinal direction of the tunnel; the bottom of the prefabricated track foundation is provided with an avoidance space for avoiding each of the prefabricated piers, the prefabricated piers are arranged in the avoidance space, and the bottom of the prefabricated piers is connected to the tunnel lining, a vertical vibration isolation support is provided between the top of the prefabricated pier and the top of the prefabricated track foundation, and the side of the prefabricated pier is connected to the prefabricated track foundation via a compression-shear stiffness decoupling limiter.

[0005] As one of the embodiments, the prefabricated 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 enclosed to form a cavity, a partition is provided in the cavity, and the partition is connected to the side of the prefabricated pier through the compression-shear stiffness decoupling limiter.

[0006] As one of the implementation modes, the cross section of the prefabricated pier is a U-shaped structure, and the vertical vibration isolation supports are provided between the tops of the two arms of the prefabricated pier and the top plate.

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

[0008] As one of the embodiments, the compression-shear stiffness decoupling limiter includes a first limiter and a second limiter, the first limiter is connected to the prefabricated track foundation, the second limiter is connected to the prefabricated pier, and the first limiter semi-surrounds the second limiter, and an elastic material layer is arranged between the first limiter and the second limiter.

[0009] As one of the embodiments, the first limiting member includes a first connecting plate and a first curved plate connected to the first connecting plate at one end; the second limiting member includes a second connecting plate, a second curved plate and a third connecting plate arranged parallel to the first connecting plate, the two ends of the second curved plate are respectively connected to one end of the third connecting plate and the second connecting plate, and the other end of the third connecting plate is vertically connected to one end of the second connecting plate; and the second curved plate and the third connecting plate are located in a semi-enclosed groove surrounded by the first connecting plate and the first curved plate.

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

[0011] As one of the embodiments, the vertical vibration isolation support includes a top connecting plate, a bottom connecting plate, and a plurality 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 prefabricated track foundation, and the bottom connecting plate is connected to the top of the prefabricated pier.

[0012] As one of the implementation modes, 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 further provides a method for constructing the shield tunnel under-track vibration isolation structure as described in any one of the above items, comprising the following steps:

[0014] 1) Construction of tunnel lining;

[0015] 2) Install the prefabricated buttresses at intervals along the longitudinal direction in the tunnel lining, and fix the bottom of the prefabricated buttresses to the tunnel lining;

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

[0017] 4) Fixing compression-shear stiffness decoupling limiters on the sides of the precast piers;

[0018] 5) Hoist the precast track foundation, align the avoidance space of the precast track foundation with the precast pier, lower it into place, and 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] The present 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 various components, a three-dimensional vibration isolation system is formed to achieve efficient attenuation of vibration energy in the high-speed rail's specific frequency band of 20-80Hz. While ensuring 15-20dB vibration reduction performance, the dynamic displacement of the track is within the standard limit range of high-speed railway tracks, achieving a balance between vibration control and track smoothness, and meeting the high-speed rail's 350km / h operating requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A schematic structural diagram of a shield tunnel under-track vibration isolation structure provided by an embodiment of the present invention;

[0023] Figure 2 A schematic structural diagram of a prefabricated buttress provided in an embodiment of the present invention;

[0024] Figure 3 A schematic structural diagram of a prefabricated track foundation at a non-prefabricated pier provided by an embodiment of the present invention;

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

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

[0027] In the figure: 1. Tunnel lining; 2. Precast pier; 21. Support arm; 3. Vertical vibration isolation bearing; 4. Compression-shear stiffness decoupling limiter; 41. First connecting plate; 42. First curved plate; 43. Second connecting plate; 44. Second curved plate; 45. Third connecting plate; 46. Elastic material layer; 5. Precast track foundation; 51. Top plate; 52. Curved bottom plate; 53. Partition; 54. Support platform; 6. Flexible isolation layer; 7. Ancillary structure; 8. Track plate. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0030] The terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include one or more of such features; and in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0031] like Figure 1 As shown, this embodiment provides a shield tunnel track under-vibration isolation structure, comprising a prefabricated track foundation 5 arranged longitudinally along the tunnel and prefabricated piers 2 arranged at intervals longitudinally along the tunnel; an escape space for evading each of the prefabricated piers 2 is provided at the bottom of the prefabricated track foundation 5, the prefabricated piers 2 are arranged in the escape space, and the bottoms of the prefabricated piers 2 are connected to the tunnel lining 1, a vertical vibration isolation support 3 is provided between the tops of the prefabricated piers 2 and the tops of the prefabricated track foundation 5, and the sides of the prefabricated piers 2 are connected to the prefabricated track foundation 5 via compression-shear stiffness decoupling limiters 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 various components, a three-dimensional vibration isolation system is formed to achieve efficient attenuation of vibration energy in the specific frequency band of 20-80Hz of the high-speed rail. While ensuring the 15-20dB vibration reduction performance, the dynamic displacement of the track is within the standard limit range of the high-speed railway track, achieving a balance between vibration control and track smoothness, and meeting the high-speed rail operation requirements of 350km / h.

[0033] In this embodiment, the prefabricated track foundation 5 and the prefabricated pier 2 are arranged at the bottom of the tunnel lining 1, and a track plate 8 is arranged on the top surface of the prefabricated track foundation 5, and rail fasteners are installed on the track plate 8. The prefabricated track foundation 5 has a large mass, which can form an "inertial anchoring" effect. At the same natural frequency, it allows the use of a vertical vibration isolation support 3 with higher stiffness. Through the mass-stiffness matching relationship between the prefabricated 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. While maintaining the vibration attenuation performance, the dynamic displacement of the track is reduced by 40%, fundamentally solving the long-standing technical contradiction in the field of high-speed railway shield tunnel vibration isolation that "vibration reduction and stability cannot be achieved at the same time."

[0034] Preferably, the transverse span of the precast track foundation 5 matches the tunnel lining 1; the precast track foundation 5 is divided into multiple longitudinal segments, and within each longitudinal segment, two precast buttresses 2 are longitudinally spaced apart. In one embodiment, the longitudinal segment length of the precast track foundation 5 is 2 meters, and the longitudinal spacing between the two precast buttresses 2 within the precast track foundation 5 is 1.2-1.8 meters, achieving a match between the longitudinal length of the precast track foundation 5 and the spacing between the precast buttresses 2.

[0035] In some embodiments, such as Figure 3 As shown, the prefabricated track foundation 5 includes a curved bottom plate 52 and a top plate 51. The two ends of the top plate 51 are respectively connected to the two ends of the curved bottom plate 52 to enclose a cavity. A partition 53 is provided in the cavity. The partition 53 is connected to the side of the prefabricated pier 2 through the compression-shear stiffness decoupling limiter 4. The curvature radius of the curved bottom plate 52 is consistent with the inner diameter of the tunnel lining 1, ensuring that the curved bottom plate 52 is completely fitted with the tunnel lining 1; the roller plate is provided on the top plate 51. Variable cross-section structures are provided at both ends of the prefabricated track foundation 5 to form an avoidance space for avoiding the prefabricated pier 2, and the change rate of the moment of inertia of the variable cross-section area is ≤15%, and the height of the avoidance space is ≥120% of the height of the prefabricated pier 2. In this embodiment, the curved bottom plate 52, the top plate 51 and the partition 53 are prefabricated as a whole.

[0036] In some embodiments, the cross section of the prefabricated buttress 2 is a U-shaped structure, and the vertical vibration isolation supports 3 are provided between the tops of the two arms 21 of the prefabricated buttress 2 and the top plate 51. Figure 1 and Figure 2As shown, the bottom of the precast pier 2 conforms to the contour of the tunnel lining 1, and the tops of the two arms 21 correspond precisely to the positions of the two tracks. Vertical vibration isolation supports 3 are installed 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 vibrations to the tunnel structure. In this embodiment, the bottom of the precast pier 2 and the interior of the two arms 21 are equipped with multiple layers of main reinforcement and reinforced steel to meet the bending and shear load requirements.

[0037] Optimizing the above embodiment, two partitions 53 are provided in the cavity and are respectively located on the inner sides of the two arms 21 of the prefabricated buttress 2. Each partition 53 is connected to the 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, restricting horizontal displacement while allowing vertical vibration.

[0038] In some embodiments, the compression-shear stiffness decoupling limiter 4 includes a first limiter and a second limiter. The first limiter is connected to the prefabricated track foundation 5, and the second limiter is connected to the prefabricated pier 2. The first limiter semi-surrounds the second limiter, and an elastic material layer 46 is provided between the first and second limiters. By semi-surrounding the second limiter in the horizontal direction of the first limiter and providing the elastic material layer 46 therebetween, 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 curved plate 42 connected to the first connecting plate 41 at one end; the second limiting member includes a second connecting plate 43, a second curved plate 44 and a third connecting plate 45 arranged parallel to the first connecting plate 41, the two ends of the second curved 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 vertically connected to one end of the second connecting plate 43; and the second curved plate 44 and the third connecting plate 45 are located in a semi-enclosed groove surrounded by the first connecting plate 41 and the first curved plate 42.

[0040] In an optimization of the above embodiment, the elastic material layer 46 has a thickness of 15-25 mm and a compression to shear stiffness ratio of ≥10:1. The compression stiffness of the elastic material layer 46 is significantly greater than its shear stiffness, ensuring controllable deformation under vertical loads and maintaining track smoothness. This also allows horizontal displacement to be released through shear deformation of the elastic layer, reducing lateral force transmission to the piers. Specifically, the elastic material layer 46 can be made of fluororubber or other materials. In one embodiment, the elastic material layer 46 has a thickness of 20 mm, a compression stiffness of ≥50 MN / m, and a shear stiffness of ≤5 MN / m.

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

[0042] Furthermore, guide rods are provided on the bottom surface of the top connecting plate at locations corresponding to each disc spring module, and limit slots are provided on the top surface of the bottom connecting plate at locations corresponding to each disc spring module. The guide rods extend downward through the center holes of all disc spring leaves in the corresponding disc spring module and into the corresponding limit slots. Optimally, the surface of each disc spring leaf is nitrided to a depth of 0.1-0.2mm.

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

[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 prefabricated track foundation 5 at the position corresponding to the support arm 21 of the prefabricated pier 2. In some embodiments, the top connecting plate is connected to the support platform 54 by bolts, and the bottom connecting plate is connected to the support arm 21 of the prefabricated pier 2 by bolts. At the same time, in order to facilitate the replacement of the vertical vibration isolation support 3, a lubricant is applied to the contact surface between the top connecting plate and the prefabricated track foundation 5 and the contact surface between the bottom plate connecting plate and the prefabricated pier 2. The lubricant can specifically be molybdenum disulfide lubricant or the like. In other embodiments, embedded steel plates are pre-embedded in the top surfaces of the support platform 54 and the support arm 21 of the prefabricated pier 2, and the top connecting plate is welded to the embedded steel plate on the support platform 54, and the bottom plate connecting plate is welded to the embedded steel plate on the top surface of the prefabricated pier 2. The welding is carried out using CO2 gas shielded welding, and the interlayer temperature is controlled to be ≤150°C.

[0045] Furthermore, the bottom of the prefabricated pier 2 is rigidly connected to the tunnel lining 1 through a shear connector. By rigidly connecting the prefabricated pier 2 to the tunnel lining 1, the shear resistance of the prefabricated pier 2 and the tunnel lining 1 can be improved, a reliable system that adapts to high-frequency vibration environments can be established, and the vibration isolation structure and the tunnel lining 1 can be dynamically coupled. In this embodiment, the tunnel lining 1 includes multiple ring segments spliced in sequence along the longitudinal direction, and each ring segment includes multiple shield segments spliced in sequence along the circumferential direction. Furthermore, multiple groups of shear connectors are embedded in the shield segments corresponding to the bottom range of the prefabricated pier 2, and the multiple groups of shear connectors are arranged in a double-row staggered manner in the shield segments. The ends of the shear connectors are provided with shear key grooves and are rigidly connected to the bottom of the prefabricated pier 2 through high-strength bolts, thereby achieving uniform transmission of shear force. In one embodiment, the longitudinal spacing of the shear connectors is 200 mm, the transverse spacing is 150 mm, the implantation depth is ≥120 mm, and the size of the shear keyway is 8 mm deep × 12 mm 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 the track vibration energy and block the vibration from being transmitted to the auxiliary structure 7. Figure 1 As shown, the top surfaces of both ends of the precast track foundation 5 form shoulders that slope downward toward the shield segment. The bottom of the auxiliary structure 7 is wedge-shaped and embedded in the area between the shoulder and the shield segment. A flexible isolation layer 6 is provided between the shoulder and the auxiliary structure 7, with one end extending to the shield segment and the other end extending to the side of the track plate 8. Furthermore, the shoulder of the precast track foundation 5 has an inclination angle of 40-50° and is polished to a flatness of ≤2mm / m, which can form a wedge-shaped lock for the auxiliary structure 7 placed thereon. The auxiliary structure 7 includes a communication cable trough structure, a drainage ditch structure, and the like.

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

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

[0049] 1) Construction of tunnel lining 1;

[0050] 2) Install the prefabricated buttresses 2 in the tunnel lining 1 at intervals along the longitudinal direction, and fix the bottoms of the prefabricated buttresses 2 to the tunnel lining 1;

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

[0052] 4) Fixing the compression-shear stiffness decoupling limiter 4 on the side of the prefabricated pier 2;

[0053] 5) Hoist the prefabricated track foundation 5, align the avoidance space of the prefabricated track foundation 5 with the prefabricated pier 2, and lower it into place, and connect the compression-shear stiffness decoupling limiter 4 to the prefabricated track foundation 5.

[0054] In step 1), the construction method for tunnel lining 1 is to prefabricate the shield segments, then assemble them longitudinally and annularly to form tunnel lining 1. During prefabrication of the shield segments, double rows of shear connectors are implanted using 3D laser positioning technology. After curing, shear keyways are milled into the exposed ends to facilitate connection with prefabricated buttresses 2.

[0055] During step 2), precast pier 2 was installed using a total station for positioning, with a center-to-center deviation of ≤±5mm. M24 high-strength bolts were used to secure the precast pier 2 to the tunnel lining 1 in diagonal order, with a torque of 900N·m±5%. The precast pier 2 was prefabricated using a removable steel formwork, the inner surface of which was polished (Ra ≤ 3.2μm). Concrete was poured in two layers, with the lower layer vibrated and compacted before the upper layer was poured. The formwork was then removed after steam curing (60°C for 24 hours).

[0056] In step 3), the vertical vibration isolation support 3 is installed by connecting the bottom connecting plate to the top of the prefabricated pier 2, arranging multiple sets of disc spring modules in parallel on the bottom connecting plate, and then installing the top connecting plate.

[0057] In step 4), the second connecting plate 43 of the compression-shear decoupling stopper 4 is connected to a transverse side surface of the buttress. During installation, the inclination angle is calibrated using a laser goniometer, and a hydraulic jack is used to pre-compress the flexible layer to a designed thickness of 20 mm. The first and second stoppers of the compression-shear decoupling stopper 4 are co-vulcanized with the elastic material layer 46 between them. The compressive stiffness gradient of the elastic material layer 46 is controlled to be 70±5 Shore A in the center and 60±5 Shore A at the edges.

[0058] In step 5), before installing the precast track foundation 5, the BIM model was used to rehearse the installation path to avoid interference with the precast support piers 2. Once the precast track foundation 5 was in place, a vibrating wire displacement meter was used to monitor its position, with an adjustment accuracy of ≤ 0.2 mm. The top connecting plate of the vertical vibration isolation support 3 was then connected to the precast track foundation 5.

[0059] The shoulder of the precast track foundation 5 is then polished to a flatness of ≤2 mm / m. A flexible insulation layer 6 is then laid on top, with one end extending to the shield segment and the other to the top surface of the precast track foundation 5. The auxiliary structure 7 is then installed. The base of the auxiliary structure 7 is wedge-shaped and embedded in the area between the shoulder and the shield segment. A preload of 50 kN / m is then applied. The joints of the flexible insulation layer 6 are welded using hot melt welding (temperature 230°C ± 10°C).

[0060] After the shield tunnel's underrail vibration isolation structure was completed, track plate 8 and rail fasteners were installed. A 20-80Hz white noise excitation was then applied for vibration testing, with a natural frequency of 12±0.5Hz. During the passage of a 350km / h EMU, dynamic displacement was monitored to be ≤1.5mm. Interface inspections were also conducted, ensuring that the torque attenuation rate of the connecting bolts during retightening 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 in the scope of protection of the present invention.

Claims

1. A shield tunnel under-track vibration isolation structure, characterized by: It includes a prefabricated track foundation arranged longitudinally along the tunnel and prefabricated piers arranged at intervals longitudinally along the tunnel; the bottom of the prefabricated track foundation is provided with an avoidance space for avoiding each of the prefabricated piers, the prefabricated piers are arranged in the avoidance space, and the bottom of the prefabricated piers is connected to the tunnel lining, a vertical vibration isolation support is provided between the top of the prefabricated pier and the top of the prefabricated track foundation, and the side of the prefabricated pier is connected to the prefabricated track foundation through a compression-shear stiffness decoupling limiter.

2. The shield tunnel under-track vibration isolation structure according to claim 1, characterized in that: The prefabricated 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 to form a cavity. A partition is provided in the cavity. The partition is connected to the side of the prefabricated pier through the compression-shear stiffness decoupling limiter.

3. The shield tunnel under-track vibration isolation structure according to claim 2, characterized in that: The cross section of the prefabricated buttress is U-shaped, and the vertical vibration isolation supports are arranged between the tops of the two arms of the prefabricated buttress and the top plate.

4. The shield tunnel under-track vibration isolation structure according to claim 3, characterized in that: Two partitions are provided in the cavity and are respectively located on the inner sides of the two arms of the prefabricated pier. Each partition is connected to the arm on its outer side via the compression-shear stiffness decoupling limiter.

5. The shield tunnel under-track vibration isolation structure according to claim 1, characterized in that: The compression-shear stiffness decoupling limiter includes a first limiter and a second limiter, the first limiter is connected to the prefabricated track foundation, the second limiter is connected to the prefabricated pier, and the first limiter semi-surrounds the second limiter, and an elastic material layer is provided between the first limiter and the second limiter.

6. The shield tunnel under-track vibration isolation structure according to claim 5, characterized in that: The first limiting member includes a first connecting plate and a first curved plate connected to the first connecting plate at one end; the second limiting member includes a second connecting plate, a second curved plate and a third connecting plate arranged parallel to the first connecting plate, the two ends of the second curved plate are respectively connected to one end of the third connecting plate and the second connecting plate, and the other end of the third connecting plate is perpendicularly connected to one end of the second connecting plate; and the second curved plate and the third connecting plate are located in a semi-enclosed groove surrounded by the first connecting plate and the first curved plate.

7. The shield tunnel under-track vibration isolation structure according to claim 5, characterized in that: The thickness of the elastic material layer is 15-25 mm, and the ratio of compression stiffness to shear stiffness is ≥10:

1.

8. The shield tunnel under-track vibration isolation structure according to claim 1, characterized in that: The vertical vibration isolation support includes a top connecting plate, a bottom connecting plate, and multiple groups 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 prefabricated track foundation, and the bottom connecting plate is connected to the top of the prefabricated pier.

9. The shield tunnel under-track vibration isolation structure according to claim 1, characterized in that: 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.

10. A construction method for a shield tunnel under-track vibration isolation structure according to any one of claims 1 to 9, characterized in that: The steps include: 1) Construction of tunnel lining; 2) Install the prefabricated buttresses at intervals along the longitudinal direction in the tunnel lining, and fix the bottom of the prefabricated buttresses to the tunnel lining; 3) Install vertical vibration isolation bearings on the top of the prefabricated piers; 4) Fixing compression-shear stiffness decoupling limiters on the sides of the precast piers; 5) Hoist the precast track foundation, align the avoidance space of the precast track foundation with the precast pier, lower it into place, and connect the compression-shear stiffness decoupling limiter to the precast track foundation.

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