Beam end telescopic device of embedded track

Abstract

The beam end telescopic device comprises a movable rail base, a fixed rail base, a horizontal telescopic assembly, a rail embedding face and a plurality of longitudinal buffering assemblies, the movable rail base and the fixed rail base are installed on beam end structures on the two sides of an expansion joint respectively, and the rail embedding face is laid above the movable rail base and the fixed rail base; a noise reduction assembly and a water stop assembly are sequentially laid between the movable rail base and the rail embedding face and between the fixed rail base and the rail embedding face from bottom to top. The horizontal telescopic assembly comprises a sliding embedded block fixed to one side of the fixed rail base, and a sliding groove allowing the sliding embedded block to be horizontally inserted is formed in the movable rail base. Each longitudinal buffering assembly comprises an elastic piece and a guide cylinder, the elastic pieces are installed in the beam end structures on the two sides in a telescopic mode respectively, the upper ends of the guide cylinders are connected with the movable rail base or the fixed rail base, and the lower ends of the guide cylinders are connected with the elastic pieces. The problems of structural conflict and longitudinal vibration stress concentration of the embedded track and the road expansion joint can be solved.

Description

Technical Field

[0001] This invention belongs to the field of beam end expansion technology, specifically relating to a beam end expansion device with an embedded track. Background Technology

[0002] Currently, modern trams generally adopt embedded track structures to improve road resource utilization, with the top surface of the track flush with the road surface structure. In the reconstruction of existing highway bridges, the embedded track is rigidly connected to the beam structure through pre-embedded steel bars and directly integrated into the cast-in-place concrete layer of the bridge deck. However, the expansion joints at the beam ends of newly built tram bridges typically follow the design of highway expansion joints, requiring the track structure to be partially raised to cross the expansion joint. The core contradiction lies in the conflict between the flush design of embedded tracks in the reconstruction of existing bridges and the structural space requirements of the original highway expansion joints, resulting in incompatibility between track continuity and expansion joint function.

[0003] In the prior art, Chinese patent publication number CN110055888B discloses an embedded track beam-end expansion joint device and its construction method. This embedded track beam-end expansion joint device involves inserting a second component at the top of the left beam-end structure into the opening of the first component at the top of the right beam-end structure. An elastic body between the two components enables expansion and contraction deformation. Waterproof material is added between the elastic body and the first component. By utilizing the spacing between the bottom of the opening groove and the second component to accommodate the maximum expansion and contraction, and through the synergistic effect of component sliding and elastic deformation, the structural conflict between traditional tracks and highway expansion joints is resolved. This also ensures the continuity of the bridge deck in the track area and the waterproof durability of the beam end.

[0004] In practical applications, the longitudinal impact forces generated during train startup, braking, and operation are transmitted to the track structure through wheel-rail contact, causing periodic relative displacement between the rails and the bridge beam. Because the embedded track is rigidly connected to the bridge deck via pre-embedded reinforcing bars, vibration stress easily accumulates in weak points such as beam-end expansion joints and anchorage nodes. Over long-term action, this can lead to fatigue cracking of components, failure of waterproofing materials, and deviations in track geometry, thereby affecting operational safety and structural durability. The aforementioned technologies focus on lateral expansion and contraction compensation and waterproofing, without designing a buffer mechanism for longitudinal vibration characteristics, making it difficult to effectively alleviate stress concentration problems.

[0005] Therefore, a new technology is needed to solve the problem that longitudinal vibration can easily lead to stress concentration in beam end expansion joints and anchorage nodes in existing technologies. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention provides a beam-end expansion joint for an embedded track. By designing horizontal expansion, longitudinal buffer components, and waterproofing and noise reduction functions, it collaboratively resolves the structural conflicts between the embedded track and the highway expansion joint, as well as the problem of longitudinal vibration stress concentration.

[0007] The present invention adopts the following technical solution: An embedded track beam-end telescopic device includes a movable rail seat, a fixed rail seat, a horizontal telescopic component, a track embedding surface, and several longitudinal buffer components. The upper surfaces of the movable rail seat and the fixed rail seat are located on the same horizontal plane and are respectively installed on the beam-end structure on both sides of the expansion joint. The track embedding surface is laid above the movable rail seat and the fixed rail seat. Noise reduction components and water-stopping components are laid sequentially from bottom to top above the movable rail seat and the fixed rail seat and below the track embedding surface. The horizontal telescopic component includes a sliding fitting block, which is fixed to the side of the fixed rail seat near the movable rail seat. The movable rail seat has a groove for horizontal insertion of the sliding fitting block. The lower end of the fixed rail seat has a fixed protrusion, which is embedded downward into the corresponding beam-end structure. Each of the longitudinal buffer components includes an elastic element and a guide cylinder. Several elastic elements are telescopically installed in the beam-end structures on both sides. The lower end of the guide cylinder is connected to the elastic element, and the upper end protrudes from the upper surface of the beam-end structure and is connected to the movable rail seat or the fixed rail seat.

[0008] The above design of this scheme uses fixed rail seats and movable rail seats at the bottom of the track embedded surface to be anchored to the beam end structures on both sides of the expansion joint. The horizontal expansion component is used to realize the relative displacement between the rail seats to adapt to the horizontal deformation of the bridge. The anchoring cylinder and the buffer component work together to reduce the impact of longitudinal stress. The water-stopping component and the noise reduction component realize waterproof leakage and vibration noise control through sealing and energy dissipation mechanisms, respectively. The components work together to form an integrated functional system of expansion compensation, stress buffering and waterproofing and noise reduction.

[0009] This solution utilizes a combination of fixed and movable horizontal expansion joint components to replace the function of traditional highway expansion joints, resolving structural conflicts between the track and expansion joints. It achieves compatibility between the flush-mounted embedded track design and beam-end expansion, avoiding the contradiction between track continuity and expansion functionality. The buffer component, through elastic material deformation, alleviates the accumulation of longitudinal vibration stress, attenuates the periodic longitudinal stress caused by train dynamic loads, and reduces the risk of fatigue cracking in weak areas such as beam-end expansion devices and anchoring nodes. The water-stop component, through a sealing structure, blocks rainwater infiltration, preventing steel corrosion and concrete deterioration. Combined with the vibration energy absorption of the noise reduction component, it extends the service life of the track system. The noise reduction component dissipates vibration energy through gradient materials, reducing wheel-rail impact noise. Simultaneously, the rigid constraint of the horizontal expansion joint ensures track geometric stability, preventing safety hazards caused by track gauge deviations.

[0010] As a further improvement to the technical solution of the present invention, several anchoring cylinders are embedded at intervals in the beam end structure on both sides of the expansion joint, the upper surfaces of the beam end structure on both sides of the expansion joint are flush, the elastic element and the guide cylinder are installed in the anchoring cylinder, and the upper end of the guide cylinder extends out of the upper surface of the beam end structure.

[0011] As a further improvement to the technical solution of the present invention, it also includes a plurality of bidirectional bolt rods, the upper part of each bolt rod being inserted into the fixed rail seat and the lower part being inserted into an anchoring cylinder; each bidirectional bolt rod is equipped with a nut, and the nut is embedded in the upper surface of the fixed rail seat.

[0012] As a further improvement to the technical solution of the present invention, each of the longitudinal buffer components further includes an elastic block, and each of the elastic blocks is located between the anchoring cylinder and the guide cylinder.

[0013] As a further improvement to the technical solution of the present invention, each of the elastic blocks is sleeved on the outside of the guide cylinder in a cylindrical shape.

[0014] As a further improvement to the technical solution of the present invention, the elastic element is a disc spring.

[0015] As a further improvement to the technical solution of the present invention, the noise reduction component includes a shock-absorbing pad, which synchronously covers the upper surfaces of the fixed rail and the movable rail.

[0016] As a further improvement to the technical solution of the present invention, the noise reduction component further includes a foam board, which is located between the shock-absorbing pad and the water-stopping component.

[0017] As a further improvement to the technical solution of the present invention, the water-stopping component includes a water-stopping strip, which is located between the foam board and the track embedding surface.

[0018] As a further improvement to the technical solution of the present invention, the longitudinal cross-section of the sliding interlocking block is an inverted T-shape.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: The beam-end expansion joint of the embedded track in this solution, through the design of horizontal expansion, longitudinal buffer components and waterproof and noise-reducing structure, can collaboratively solve the structural conflict between the embedded track and the highway expansion joint and the problem of longitudinal vibration stress concentration. Attached Figure Description

[0020] The technology of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 This is a front sectional view of an embodiment of the beam-end telescopic device for the embedded track of the present invention. Figure 2This is a schematic diagram of the overall structure of an embodiment of the beam end telescopic device for the embedded track of the present invention; Figure 3 This is a schematic diagram showing the connection between the fixed rail seat and the movable rail seat in an embodiment of the beam end telescopic device of the embedded rail of the present invention. Figure 4 This is an embodiment of the beam end telescopic device for the embedded track of the present invention. Figure 3 A cross-sectional view of the connection between the fixed rail seat and the anchor cylinder at point A in the middle.

[0021] Figure label: 1- Track embedding surface; 2- Fixed rail seat; 3- Movable rail seat; 4- Sliding clamping block; 5- Slide groove; 6- Anchoring cylinder; 7- Guide cylinder; 8- Elastic block; 9- Disc spring; 10- Waterstop strip; 11- Shock-absorbing pad; 12- Foam board; 13- Two-way bolt rod; 14- Nut. Detailed Implementation

[0022] The following will provide a clear and complete description of the concept, specific structure, and technical effects of the present invention in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, solution, and effects of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The same reference numerals used throughout the accompanying drawings indicate the same or similar parts.

[0023] It should be noted that, unless otherwise specified, when a feature is referred to as "fixed" or "connected" to another feature, it can be directly fixed or connected to the other feature, or indirectly fixed or connected to the other feature. Furthermore, the descriptions of "up," "down," "left," and "right" used in this invention are only relative to the relative positional relationships of the various components of the invention in the accompanying drawings.

[0024] Reference Figures 1 to 4An embedded track beam-end expansion device is disclosed, comprising a movable track seat 3, a fixed track seat 2, a horizontal expansion component, a track embedding surface 1, and several longitudinal buffer components. The upper surfaces of the movable track seat 3 and the fixed track seat 2 are located on the same horizontal plane and are respectively installed on the beam-end structures on both sides of the expansion joint. The track embedding surface 1 is laid above the movable track seat 3 and the fixed track seat 2. A noise reduction component and a water-stopping component are sequentially laid from bottom to top above the movable track seat 3 and the fixed track seat 2 and below the track embedding surface 1. The water-stopping component is used to prevent water leakage, and the noise reduction component is used to reduce vibration noise. A first beam-end structure and a second beam-end structure are respectively provided on both sides of the expansion joint. The horizontal expansion component includes a sliding fitting block protruding from one side of the fixed track seat 2. One side of the movable track seat 3 has a groove 5 for the horizontal insertion of the sliding fitting block. The mutually mating sliding fitting block and the groove 5 together form the horizontal expansion component. A sliding clamping block 4 is fixedly connected to the side of the fixed track seat 2 near the movable track seat 3. The horizontal telescopic component forms a sliding pair structure by nesting the sliding clamping block 4 of the fixed rail seat 2 with the sliding groove 5 of the movable rail seat 3. This allows the horizontal displacement of the beam end caused by temperature, load or settlement to slide freely along the axis of the sliding groove 5. This not only constrains the geometric shape of the track through rigid nesting, but also avoids the accumulation of additional stress.

[0025] The lower end of the fixed rail base 2 is provided with a fixing protrusion, which is embedded downward into the first beam end structure. Each of the longitudinal buffer components includes an elastic element and a guide cylinder 7. The elastic element is telescopically installed in the first beam end structure or the second beam end structure. The lower end of the guide cylinder 7 is connected to the elastic element, and the upper end protrudes from the upper surface of the first beam end structure or the second beam end structure.

[0026] In this design, the bottom of the track embedding surface 1 is fitted with fixed rail seats 2 and movable rail seats 3, which are located on the beam end structures on both sides of the expansion joint. A horizontal expansion joint is provided between the fixed rail seats 2 and the movable rail seats 3 to connect them. Several longitudinal buffer components connected to the corresponding beam end structures are installed at the bottom of both the fixed rail seats 2 and the movable rail seats 3. These longitudinal buffer components are used to reduce the impact of longitudinal stress on the fixed rail seats 2 or the movable rail seats 3. Water-stopping components for waterproofing and leakage prevention, and noise-reducing components for reducing vibration noise are provided between the track embedding surface 1 and the fixed rail seats 2 and the movable rail seats 3. This design, by setting up horizontal expansion joints, longitudinal buffer components, waterproofing components, and noise-reducing components, collaboratively solves the structural conflict between the embedded track and the highway expansion joint, as well as the problem of longitudinal vibration stress concentration.

[0027] Specifically, the fixing protrusion at the lower end of the fixed rail seat 2 makes its cross-section an inverted L-shape. The fixed rail seat 2 is embedded into the corresponding first beam end structure through the fixing protrusion. The fixed rail seat 2 is embedded into the first beam end structure with an inverted L-shaped cross-section. The vertical section is rigidly anchored to the beam of the first beam end structure, and the horizontal section extends to the bottom of the rail embedding surface 1 to form a support limit. By increasing the contact area and pull-out resistance, the fixing efficiency is improved, ensuring that the fixed rail seat 2 does not loosen when the movable rail seat 3 is displaced, and ensuring the stability of the rigid reference of the track system.

[0028] Specifically, several anchor cylinders 6 are embedded at intervals within the first beam end structure or the second beam end structure. The upper end of each anchor cylinder 6 is flush with the upper surface of the first beam end structure or the second beam end structure. The elastic element and the guide cylinder 7 are installed inside the anchor cylinder 6. The upper end of the guide cylinder 7 extends beyond the upper end of the anchor cylinder 6, and the upper end of each guide cylinder 7 is connected to the fixed rail seat 2 or the movable rail seat 3. That is, several anchor cylinders 6 fixedly connected to the corresponding beam end structure are installed at the bottom of both the fixed rail seat 2 and the movable rail seat 3. Each anchor cylinder 6 is provided with a buffer assembly to reduce the impact of longitudinal stress on the fixed rail seat 2 or the movable rail seat 3. The elastic element is a disc spring 9. The top end of each guide cylinder 7 is fixedly connected to the corresponding fixed rail seat 2 or the movable rail seat 3, and the bottom of each guide cylinder 7 is provided with a disc spring 9 between it and the inner bottom wall of the corresponding anchor cylinder 6. The two ends of each disc spring are fixedly connected to the bottom end of the guide cylinder 7 and the inner bottom wall of the anchor cylinder 6, respectively.

[0029] The buffer assembly drives the rail seat to move along the axis of the anchoring cylinder 6 through the guide cylinder 7. The elastic block 8 rubs against the inner wall of the anchoring cylinder 6 to dissipate energy, and the disc spring 9 absorbs the impact energy through elastic deformation, forming an effect of elastic buffering and friction damping, attenuating longitudinal stress impact, avoiding bolt loosening and track gauge deviation, and taking into account both shock absorption effect and track positioning accuracy.

[0030] Specifically, the anchoring cylinders 6 corresponding to the positions of the movable rail seats 3 are all connected to the bottom of the movable rail seats 3 by universal ball joints, and the anchoring cylinders 6 corresponding to the positions of the fixed rail seats 2 are all connected to the bottom of the fixed rail seats 2 by bolts. The beam end telescopic device of the embedded rail in this scheme also includes several bidirectional bolt rods 13, the upper part of each bolt rod is inserted into the fixed rail seat 2, and the lower part is inserted into one of the anchoring cylinders 6. Each bidirectional bolt rod 13 is equipped with a nut 14, which is embedded in the upper surface of the fixed rail seat 2, that is, each bidirectional bolt rod 13 is threaded with a nut 14 embedded in the top wall of the fixed rail seat 2.

[0031] In this design, the bidirectional bolt rod 13 penetrates the fixed rail seat 2 and the anchoring cylinder 6, and works in conjunction with the embedded nut 14. The threaded connection allows for fine-tuning of the rail seat height, compensating for elevation deviations caused by construction errors and concrete creep. This ensures that the rail surfaces of the fixed rail seat 2 and the movable rail seat 3 remain on the same plane, improving the continuity and smoothness of train load transfer. The bolted connections between the corresponding anchoring cylinder 6 and the bottom of the fixed rail seat 2 are all achieved through the bidirectional bolt rod 13. Each bidirectional bolt rod 13 penetrates from the top of the corresponding fixed rail seat 2 downwards into the anchoring cylinder 6, and each bidirectional bolt rod 13 is threadedly connected to the corresponding fixed rail seat 2 and anchoring cylinder 6. Specifically, the thread direction of the bidirectional bolt rod 13 connecting to the anchoring cylinder 6 is the same as the thread direction of the bidirectional bolt rod 13 connecting to the fixed rail seat 2, while the thread direction of the bidirectional bolt rod 13 connecting to the anchoring cylinder 6 is opposite to the thread direction of the nut 14 connecting to the bidirectional bolt rod 13. In this design, the bidirectional bolt rod 13 uses the same thread as the anchor cylinder 6 and the fixed rail seat 2, and the reverse thread as the nut 14. When the vibration load causes a loosening tendency, the same thread generates a reverse preload force, and the reverse nut 14 further tightens, forming a double anti-loosening mechanism, which improves the connection node's resistance to loosening and reduces the risk of connection failure under long-term dynamic load.

[0032] In this scheme, the movable rail seat 3 and anchor cylinder 6 are connected by universal ball joints to accommodate multi-directional displacement, and the fixed rail seat 2 is rigidly fixed by bolts, forming a displacement control system of "flexible release at the end of the movable rail seat 3 and rigid constraint at the end of the fixed rail seat 2", which ensures that the movable rail seat 3 can freely move with the deformation of the beam end, while the fixed rail seat 2 remains stationary to maintain the track reference.

[0033] Specifically, each of the longitudinal buffer components further includes an elastic block 8, which is located between the anchoring cylinder 6 and the guide cylinder 7. The elastic block 8 can be fixedly connected to the outside of the guide cylinder 7. Each elastic block 8 can be cylindrically sleeved on the outside of the guide cylinder 7.

[0034] Specifically, the noise reduction component includes a gradient pad layer located between the waterstop strip 10 and the track embedding surface 1. The gradient pad layer includes a shock-absorbing pad 11 and a foam board 12. The shock-absorbing pad 11 simultaneously covers the upper surfaces of the fixed track seat 2 and the movable track seat 3. Through the synergistic action of the shock-absorbing pad 11 and the foam board 12 in the gradient pad layer, the shock-absorbing pad 11 dissipates vibration mechanical energy through material damping, while the foam board 12 reflects and scatters sound waves through its porous structure. This dual mechanism reduces vibration noise and simultaneously converts impact energy into inelastic deformation energy, avoiding structural fatigue damage caused by resonance.

[0035] Specifically, the noise reduction component also includes a foam board 12, which is located between the shock-absorbing pad 11 and the water-stopping component.

[0036] Specifically, the water-stopping component includes a water-stopping strip 10 covering the fixed rail seat 2 and the movable rail seat 3, the water-stopping strip 10 being located between the foam board 12 and the rail embedding surface 1. This solution covers the rail seat joint with the water-stopping strip 10, utilizing the material's elastic deformation and water-expanding properties to fill the gaps, forming a labyrinthine sealing path. This maintains sealing continuity during beam end displacement, blocking rainwater infiltration channels and protecting the beam structure and anchoring system from erosion.

[0037] Specifically, the longitudinal section of the sliding interlocking block is convex or inverted T-shaped, and the shape of the sliding groove 5 is adapted to the shape of the sliding clamping block 4. The sliding clamping block 4 and the sliding groove 5 are engaged by a T-shaped structure. In the longitudinal direction, the T-shaped head makes rigid contact with the side wall of the sliding groove 5 to restrict lateral misalignment, and in the lateral direction, the load is transferred through the T-shaped web, increasing the contact area to reduce pressure, while preventing the sliding clamping block 4 from dislodging under vibration load, thus ensuring the geometric accuracy and structural stability of the track.

[0038] Example 1 In this embodiment, the beam-end expansion joint of the embedded track includes a track embedding surface 1, with a fixed rail seat 2 and a movable rail seat 3 respectively attached to the bottom of the track embedding surface 1 on the beam-end structure on both sides of the expansion joint. Since the beam-end expansion joint of the embedded track needs to be designed for horizontal expansion to accommodate the horizontal displacement of the bridge caused by temperature changes, vehicle loads, and foundation settlement, and to avoid excessive additional stress between the track structure and the beam body leading to cracking or deformation failure, this embodiment provides a horizontal expansion component between the fixed rail seat 2 and the movable rail seat 3 to connect them. The horizontal expansion component includes a sliding clamping block 4 welded to the side of the fixed rail seat 2 near the movable rail seat 3. The movable rail seat 3 has a groove 5 corresponding to the position and shape of the sliding clamping block 4. The sliding clamping block 4 and the groove 5 form a nested sliding pair. When the beam end experiences horizontal displacement due to temperature deformation, load, or foundation settlement, the sliding clamping block 4 can slide freely along the axial direction of the groove 5. This design ensures the stability of the track geometry through rigid nesting while allowing relative displacement of the beam end, avoiding the accumulation of additional stress.

[0039] Furthermore, the sliding clamping block 4 has a T-shaped structure, and the shape of the sliding groove 5 corresponds to the shape of the sliding clamping block 4, both being T-shaped groove structures. The T-shaped structure design uses a top-wide and bottom-narrowing method to geometrically engage the sliding clamping block 4 and the sliding groove 5. During horizontal displacement, in the longitudinal direction (perpendicular to the track displacement direction), the rigid contact between the T-shaped head of the sliding clamping block 4 and the side wall of the sliding groove 5 restricts the relative misalignment between the fixed rail seat 2 and the movable rail seat 3, avoiding deviations in track geometry caused by lateral offset. In the lateral direction (track displacement direction), the load is transferred through the contact between the T-shaped web of the sliding clamping block 4 and the top surface of the sliding groove 5. This increases the contact area compared to the conventional rectangular structure, reduces the pressure per unit area, and prevents the sliding clamping block 4 from dislodging from the sliding groove 5 under vibration load.

[0040] To accommodate longitudinal displacement of the bridge caused by temperature gradients, vehicle centrifugal force, or uneven foundation settlement, and to prevent lateral additional stress between the track structure and the beam from causing gauge deviation or structural damage, this embodiment includes several anchoring cylinders 6 at the bottom of both the fixed rail seat 2 and the movable rail seat 33. Each anchoring cylinder 6 is fixedly connected to the corresponding beam end structure via a beam end embedded plate and bolts. Inside each anchoring cylinder 6 is a buffer assembly to mitigate the impact of longitudinal stress on the fixed rail seat 2 or the movable rail seat 3. Each buffer assembly includes a guide cylinder 7, the top of which is integrally formed with the corresponding fixed rail seat 2 or the movable rail seat 3. An elastic block 8 is fixedly connected to the outside of each guide cylinder 7 via a snap-fit. A disc spring 9 is provided between the bottom of each guide cylinder 7 and the inner bottom wall of the corresponding anchoring cylinder 6. Both ends of the disc spring are welded and fixed to the inner bottom walls of the guide cylinder 7 and the anchoring cylinder 6, respectively. When stress perpendicular to the direction of track movement is generated at the beam end, the guide cylinder 7 will drive the fixed rail seat 2 or the movable rail seat 3 to move up and down along the axis of the anchor cylinder 6. The vibration energy is absorbed by the elastic deformation of the disc spring 9, and the energy is dissipated by the friction between the outer elastic block 8 and the inner wall of the anchor cylinder 6. This forms a dual energy dissipation and vibration reduction mechanism of elastic buffer and friction damping, which attenuates the strain acceleration of the track caused by longitudinal displacement stress and avoids the problems of bolt loosening or track deformation caused by instantaneous impact load. At the same time, the rigid constraint of the guide cylinder 7 ensures that the probability of track gauge deviation is reduced during the occurrence of longitudinal displacement stress, thus balancing the vibration reduction effect and track geometric accuracy.

[0041] To prevent rainwater and moisture from seeping into the expansion joints at the beam ends, which could lead to steel corrosion, concrete deterioration, or electrical equipment malfunctions, and to ensure the durability and operational safety of the track system, this embodiment includes a water-stopping component between the track embedding surface 1 and the fixed rail seat 2. This component comprises a water-stopping strip 10 covering the fixed rail seat 2 and the movable rail seat 3. The water-stopping strip 10 is preferably made of water-swellable rubber. During installation, it is pre-compressed to fit tightly against the joint between the track embedding surface 1 and the rail seat. When rainwater seeps in, the water-stopping strip 10 expands upon contact with moisture, filling the gaps between the beam end structures and generating continuous sealing pressure. Simultaneously, its corrugated surface forms a labyrinthine sealing path with the fixed rail seat 2 and the movable rail seat 3, slowing down the seepage rate. When longitudinal displacement occurs at the beam end, the elastic deformation capacity of the water-stopping strip 10 can stretch or compress with the relative movement of the rail seat, maintaining the continuity of the sealing surface and achieving a dynamic water-stopping effect that is flexible, adaptable, and reinforced by water.

[0042] To reduce vibration and impact noise at the expansion joints when trains pass, and to improve passenger comfort, this embodiment includes a noise reduction component between the track embedding surface 1 and the fixed rail seat 2. This component comprises a gradient pad layer between the waterstop strip 10 and the track embedding surface 1, consisting of a shock-absorbing pad 11 and a foam board 12. The shock-absorbing pad 11 is preferably supported by highly elastic butyl rubber, which dissipates vibrational mechanical energy into heat energy through friction of the internal molecular chains. Simultaneously, the closed-cell porous structure of the foam board 12 creates multiple reflections and scattering of sound waves, attenuating airborne noise. When train loads cause beam end vibration, the dynamic stiffness of the shock-absorbing pad 11 absorbs high-frequency vibrations, while the foam board 12 buffers low-frequency impacts through plastic deformation. This reduces noise generated by beam end structure vibration and converts impact energy into inelastic deformation energy, preventing fatigue damage to the beam end structure caused by resonance.

[0043] The following experiments were conducted on the beam-end telescopic device of the embedded track based on this embodiment: Experimental objective: To verify whether the device proposed in this embodiment can attenuate the longitudinal vibration stress caused by the dynamic load of the train and reduce the risk of fatigue cracking in weak parts.

[0044] Experimental principle: Based on the proportional model of the expansion joint proposed in this embodiment, the horizontal displacement and longitudinal vibration of the bridge beam end under temperature deformation and train load are simulated to test the horizontal expansion performance, stress buffering effect, waterproof sealing and noise reduction capability of the device. The performance difference of the device is compared with that of traditional highway expansion joint devices to verify the effectiveness of the collaborative solution of the device.

[0045] Experimental steps: 1. Experimental Preparation Specimen preparation: In the experimental group, based on the structure of the beam end expansion joint of the embedded track in this scheme, a 1:1 scale beam end structure model (including expansion joint, with an adjustable joint width of 0~50mm) was made. The fixed rail seat 2 (inverted L-shape) and the movable rail seat 3 (including T-shaped slide groove 5) of the device were installed on both sides respectively. The horizontal expansion component (sliding clamping block 4 + slide groove 5), the buffer component (guide cylinder 7 + elastic block 8 + disc spring 9), the water-stop component (water-swellable water-stop strip 10) and the noise reduction component (gradient pad: shock-absorbing pad 11 + foam board 12) were assembled.

[0046] Control group: Traditional highway expansion joint devices (such as modular expansion joints) were used, and the track structure was locally raised.

[0047] Testing instruments: Displacement sensor (accuracy 0.01mm), stress sensor (range 0~200MPa), accelerometer, waterproof leakage detector, noise meter (range 30~130dB), hydraulic servo loading system (simulating train load).

[0048] 2. Horizontal expansion and contraction performance test Working condition simulation: Horizontal displacement (0~50mm, simulating bridge temperature deformation / settlement) is applied by a hydraulic device at a rate of 0.5mm / min, and the cycle is repeated 30 times.

[0049] Data collection: Record the sliding resistance (N) and maximum displacement (mm) of the sliding clamping block 4 in the groove 5. The flatness deviation (mm / m) of the track embedding surface 1 was detected using a laser level.

[0050] 3. Longitudinal stress buffer test Working condition simulation: Longitudinal periodic impact force (simulating train starting / braking load, frequency 1~10Hz, amplitude 0.1~1mm) is applied through a vibration table for 1 hour.

[0051] Data collection: Stress sensors are arranged at the bottom of the anchoring cylinder 6 and at the connection node between the fixed rail seat 2 and the movable rail seat 3 to record the input stress (σ) and the output stress (σ) and calculate the stress attenuation rate.

[0052] The vibration acceleration (m / s²) of the buffer assembly was measured using an accelerometer.

[0053] (4) The experimental data are shown in Table 1 below:

[0054] Table 1 (5) Experimental conclusion: The stress attenuation rate of the experimental group reached 65%, and the vibration acceleration was reduced to 2.5 m / s², which was far better than the control group (20% attenuation rate, 8 m / s² acceleration). This shows that the longitudinal stress at the beam end was attenuated by elastic deformation and friction energy dissipation, which reduced the risk of fatigue cracking of the anchorage node.

[0055] Example 2 In this embodiment, the difference from embodiment 1 is that the fixed rail seat 2 has an inverted L-shaped cross section and is embedded in the corresponding beam end structure. The fixed rail seat 2 adopts an inverted L-shaped cross section design. Its vertical section is rigidly anchored to the beam end structure through rebar, and its horizontal section extends to the bottom of the rail embedding surface 1 to form a composite constraint of support and limitation, which increases the contact area with the concrete matrix and reduces the probability of the fixed rail seat 2 detaching from the beam end structure.

[0056] Example 3 In this embodiment, the difference from embodiment 2 is that the connection between the anchoring cylinders 6 corresponding to the positions of the movable rail seats 3 and the bottom of the movable rail seats 3 is a universal ball joint connection, and the connection between the anchoring cylinders 6 corresponding to the positions of the fixed rail seats 2 and the bottom of the fixed rail seats 2 is a bolt connection. This design allows the movable rail seats 3 to rotate and move freely along the center of the ball joint when the beam end expands and contracts, so as to realize the displacement control effect of the beam end structure on one side of the movable rail seat 3 to flexibly release stress fluctuations.

[0057] The bolted connections between the anchoring cylinder 6 and the bottom of the fixed rail seat 2 all include bidirectional bolt rods 13. Each bidirectional bolt rod 13 extends from the top of the corresponding fixed rail seat 2 into the anchoring cylinder 6, and is threadedly connected to both the fixed rail seat 2 and the anchoring cylinder 6. Nuts 14, embedded in the top wall of the fixed rail seat 2, are threaded onto each bidirectional bolt rod 13. This design ensures that the rail surfaces of the fixed rail seat 2 and the movable rail seat 3 remain on the same plane, avoiding wheel-rail impact noise caused by the height difference between the two sides of the fixed rail seat 2 and the movable rail seat 3. It also ensures the continuity of train load transmission, compensates for elevation deviations caused by construction errors and concrete creep, and improves the long-term smoothness of the track system.

[0058] The thread direction of the bidirectional bolt rod 13 connecting to the anchor cylinder 6 is the same as the thread direction of the bidirectional bolt rod 13 connecting to the fixed rail seat 2. The thread direction of the bidirectional bolt rod 13 connecting to the anchor cylinder 6 is opposite to the thread direction of the nut 14 connecting to the bidirectional bolt rod 13. The thread direction of the bidirectional bolt rod 13 is the same as that of the anchor cylinder 6 and the fixed rail seat 2, both being right-handed. The thread direction of the nut 14 is opposite and left-handed. When the load stress causes the threaded connection between the bidirectional bolt rod 13 and the anchor cylinder 6 or the fixed rail seat 2 to loosen, the same-direction threads of the anchor cylinder 6 and the fixed rail seat 2 will generate a reverse preload force on the bidirectional bolt rod 13, while the left-handed nut 14 will further tighten it, forming a double anti-loosening mechanism, improving the anti-loosening ability of the connection node, and effectively reducing the risk of connection failure under long-term dynamic load.

[0059] Other aspects of the beam end telescopic device for an embedded track described in this invention are available in the prior art and will not be repeated here.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A beam end telescopic device for an embedded track, characterized in that: The system includes a movable rail base, a fixed rail base, a horizontal telescopic assembly, a rail embedding surface, and several longitudinal buffer assemblies. The upper surfaces of the movable rail base and the fixed rail base are located on the same horizontal plane and are respectively installed on the beam end structures on both sides of the expansion joint. The rail embedding surface is laid above the movable rail base and the fixed rail base. Noise reduction components and water-stopping components are laid sequentially from bottom to top above the movable rail base and the fixed rail base and below the rail embedding surface. The horizontal telescopic assembly includes a sliding fitting block, which is fixed to the side of the fixed rail base near the movable rail base. The movable rail base has a groove for horizontal insertion of the sliding fitting block. The lower end of the fixed rail base has a fixed protrusion, which is embedded downward into the corresponding beam end structure. Each of the longitudinal buffer assemblies includes an elastic element and a guide cylinder. Several elastic elements are telescopically installed in the beam end structures on both sides. The lower end of the guide cylinder is connected to the elastic element, and the upper end protrudes from the upper surface of the beam end structure and is connected to the movable rail base or the fixed rail base.

2. The beam end telescopic device for the embedded track according to claim 1, characterized in that: Several anchoring cylinders are embedded at intervals in the beam end structure on both sides of the expansion joint. The upper surfaces of the beam end structure on both sides of the expansion joint are flush. The elastic element and the guide cylinder are installed in the anchoring cylinder. The upper end of the guide cylinder extends out of the upper surface of the beam end structure.

3. The beam end telescopic device for the embedded track according to claim 2, characterized in that: It also includes several bidirectional bolt rods, the upper part of each bolt rod is inserted into the fixed rail seat, and the lower part is inserted into an anchoring cylinder; each bidirectional bolt rod is equipped with a nut, and the nut is embedded in the upper surface of the fixed rail seat.

4. The beam end telescopic device for the embedded track according to claim 3, characterized in that: Each of the longitudinal buffer components further includes an elastic block, and each of the elastic blocks is located between the anchoring cylinder and the guide cylinder.

5. The beam end telescopic device for the embedded track according to claim 4, characterized in that: Each of the elastic blocks is cylindrically sleeved on the outside of the guide cylinder.

6. The beam end telescopic device for the embedded track according to claim 5, characterized in that: The elastic element is a disc spring.

7. The beam end telescopic device for the embedded track according to claim 6, characterized in that: The noise reduction component includes a shock-absorbing pad, which synchronously covers the upper surfaces of the fixed rail and the movable rail.

8. The beam end telescopic device for the embedded track according to claim 7, characterized in that: The noise reduction component also includes a foam board, which is located between the shock-absorbing pad and the water-stopping component.

9. The beam end telescopic device for the embedded track according to claim 8, characterized in that: The water-stopping component includes a water-stopping strip located between the foam board and the track embedding surface.

10. The beam end telescopic device for the embedded track according to claim 1, characterized in that: The longitudinal cross-section of the sliding interlocking block is an inverted T-shape.

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