Concrete floating structure with weight pressing and vibration isolation functions and construction method thereof

Abstract

The application provides a concrete floating structure with weight pressing and vibration isolation functions and a construction method thereof. The structure comprises a concrete floating plate, a steel spring support, a plate connection structure and a waterproof and drainage system. The floating plate is elastically supported above a tunnel floor through the grid-shaped steel spring support, and the self weight of the floating plate is determined according to the anti-floating requirement of the tunnel. The self weight of the floating plate serves as an anti-floating permanent load, and the floating plate and the support constitute a mass-spring-damping system, so as to reduce the transmission of vehicle vibration to the tunnel body. A steel shear hinge composed of upper and lower connecting plates, shear reinforcement and elastic filling material is arranged at the end of adjacent plates, and UHPC local reinforcement of a non-penetrating flexible plate joint is additionally provided. Side drainage ditches are arranged on both sides of the plate, and drainage holes, drainage pipelines and a water collecting well are arranged under the plate to prevent water accumulation and corrosion of the support. During construction, the base treatment and support anchoring, floating plate hoisting and multi-point synchronous jacking, shear hinge installation and plate joint sealing, drainage system construction and system quality acceptance are sequentially completed.

Description

Technical Field

[0001] This invention relates to the field of road and tunnel engineering technology, and more specifically, to a concrete floating structure with ballast and vibration isolation functions and its construction method. Background Technology

[0002] Existing floating slab technology is mainly used for vibration isolation in rail transit. The slab dimensions, mass, and elastic support parameters are usually determined based on the load of rail vehicles and the wheel-rail vibration characteristics. However, in road tunnels, the types of vehicles, axle loads, speeds, and driving conditions vary greatly. Vehicle braking, acceleration, and passage over uneven road surfaces also generate significant impact loads. Directly using existing floating slab structures makes it difficult to simultaneously meet the requirements of heavy load bearing, vibration control, and tunnel anti-buoyancy.

[0003] Considering the stress characteristics and operating environment of road tunnels, existing anti-buoyancy counterweight structures and vehicle vibration reduction structures are usually set up separately. When the groundwater level is high, a concrete counterweight layer or block is often added to the bottom of the tunnel to increase the structure's self-weight and resist the buoyancy of groundwater. However, this part of the concrete mainly serves the anti-buoyancy function and cannot be used for vehicle vibration control at the same time. This not only increases the amount of material used, but also occupies internal space in the tunnel.

[0004] Furthermore, a working space for elastic support needs to be maintained between the floating slab and the tunnel floor slab. Surface water may enter the area beneath the slab along the joints between the slabs and the edges of the slab. If drainage under the slab is inadequate, water can easily stagnate around the steel spring supports, support bases, and connecting components, thereby affecting the durability of the steel components and the normal operation of the elastic support system. Existing solutions still do not adequately consider aspects such as surface water interception, slab edge sealing, collection of seepage water under the slab, and support maintenance.

[0005] Therefore, it is necessary to propose a road tunnel composite structure with a large self-weight concrete floating slab as the main body, so that the floating slab can serve as the inertial mass of the road load-bearing component and vibration isolation system, and also use its self-weight as the permanent anti-buoyancy load of the tunnel. Through elastic support, inter-slab connection and waterproofing structure, it can meet the requirements of heavy road load, vehicle vibration reduction and long-term use. Summary of the Invention

[0006] To address the problem that existing road tunnels require separate anti-buoyancy ballast and vehicle vibration reduction measures, which are difficult to achieve simultaneously, this invention proposes a concrete floating structure with both ballast and vibration isolation functions. The structure employs concrete floating slabs, which are elastically supported above the tunnel floor. Their self-weight serves two purposes: as ballast for tunnel anti-buoyancy and as inertial mass for the vibration isolation system. Together with the elastic supports, they reduce the transmission of vehicle vibration to the main tunnel structure. Force-transferring connections are established between adjacent floating slabs, and corresponding seepage prevention and drainage measures are implemented on both sides and the bottom of the slabs to ensure the long-term normal operation of the structure.

[0007] To achieve the above objectives, the present invention proposes the following technical solution: A concrete floating structure with counterweight and vibration isolation functions is installed above the tunnel floor slab, comprising: A floating concrete slab is elastically supported above the tunnel floor by spaced elastic support members. Space is provided between the bottom of the floating concrete slab and the tunnel floor for support installation, drainage, and maintenance. The dimensions and self-weight of the floating concrete slab are determined according to the tunnel's anti-buoyancy requirements. Its self-weight is transferred to the tunnel floor via the elastic support members, serving as part of the tunnel's permanent anti-buoyancy load. Simultaneously, the floating concrete slab acts as the inertial mass of the vibration isolation system, forming a vibration isolation system together with the elastic support members to reduce the transmission of vibrations generated by vehicle loads to the main tunnel structure. The inter-slab connection structure is set between adjacent concrete floating slabs and includes a steel shear hinge and a flexible slab joint. The steel shear hinge is used to transfer the shear force at the slab end and limit the vertical misalignment on both sides of the joint, while allowing the adjacent concrete floating slabs to undergo vertical relative displacement and rotation within the design range. The drainage system includes side drainage ditches on both sides of the concrete floating slab, and bottom drainage holes, drainage pipes and sump pits in the area under the slab. The side drainage ditches are used to collect and discharge surface water, and the bottom drainage holes, drainage pipes and sump pits are used to collect and discharge seepage water entering the space under the slab.

[0008] Furthermore, the floating concrete slab is cast with impermeable concrete, the concrete strength grade is C40, and the impermeability grade is P8; the thickness of the floating concrete slab is 400-600mm, the width is 8-12m, and the length is 6-10m; the slab is equipped with a double-layer bidirectional steel mesh, the bottom layer of steel bars is Φ16-20@150, and the top layer of steel bars is Φ16@200.

[0009] Furthermore, the elastic support component is a steel spring bearing, which is arranged in a grid pattern along the bottom of the concrete floating slab with a standard section spacing of 2.0m × 2.0m. The bearings are densely arranged at the slab ends, heavy-duty lanes, and locations with large bearing reaction forces. The upper part of the steel spring bearing is connected to the pre-embedded component in the concrete floating slab, and the lower part is installed on the concrete leveling layer above the tunnel floor. The base is fixed with anchors and leveled and compacted with non-shrink grout.

[0010] Furthermore, the concrete floating slab is provided with horizontal limiting members at its ends or sides to transmit horizontal loads generated by vehicle braking and lateral action; a gap is maintained between the horizontal limiting members and the concrete floating slab to meet the requirements for vertical vibration isolation, so as to avoid forming a vertical rigid connection; a local reinforcement zone or reinforced concrete support base is provided at the corresponding position of the steel spring support, and the support reaction force is transmitted to the main tunnel structure through the support base and the tunnel floor slab.

[0011] Furthermore, the steel shear hinge includes an upper connecting plate, a lower connecting plate, shear reinforcement, and elastic filler material respectively embedded in the ends of adjacent concrete floating slabs; the upper connecting plate and the lower connecting plate are connected to the steel mesh in the corresponding concrete floating slabs through anchoring members; the shear reinforcement spans the flexible slab joint and passes through reserved holes in the upper connecting plate and the lower connecting plate; the elastic filler material is provided between the shear reinforcement and the wall of the reserved hole.

[0012] Furthermore, a UHPC local reinforcement zone is provided at the end of each adjacent concrete floating slab. The UHPC local reinforcement zone is only poured into the local anchoring groove provided at the end of each adjacent concrete floating slab, which is used to strengthen the anchoring area of ​​the connecting plate and improve the local bearing capacity of the plate end, and does not continuously penetrate the flexible plate joint between adjacent plates; a compressible waterproof sealant is provided in the flexible plate joint.

[0013] Furthermore, the side drainage ditch is constructed of reinforced concrete, with a longitudinal slope at the bottom along the tunnel drainage direction and a waterproof coating on the inner wall; the bottom drainage holes and the inlet of the drainage pipe are equipped with detachable stainless steel filters or sedimentation structures; the water collection wells are arranged at intervals along the longitudinal direction of the tunnel, and the water collection wells and pipe junctions are provided with space for inspection, cleaning and dredging.

[0014] Furthermore, when the longitudinal slope of the tunnel cannot meet the gravity drainage requirements, a submersible pump is installed in the water collection well to discharge the accumulated water into the main drainage network of the tunnel; the bottom drainage hole is arranged in the leveling layer or special drainage layer, and when the bottom drainage hole passes through the main tunnel floor slab, a water-stop sleeve is installed, and the area around the hole is waterproofed, sealed, and locally reinforced.

[0015] To address the aforementioned structure, this invention proposes a construction method for a floating concrete structure with counterweight and vibration isolation functions, comprising the following steps: S1. Remove laitance, oil stains, and loose concrete from the surface of the tunnel floor slab, and roughen the area that needs to be connected to the leveling layer; pour a concrete leveling layer on top of the tunnel floor slab, and control the elevation and slope of the top surface of the leveling layer according to the support layout and drainage requirements under the slab; after the leveling layer reaches the specified strength, measure and mark the position of the elastic support components, install the support base, which is fixed with anchors, and use non-shrink grout for leveling and grouting after installation. S2. Transport the prefabricated concrete floating slab to the construction site, lift it using symmetrical lifting points, center it using guide components during positioning, and set up temporary supports to control the center position of the slab, the spacing between the slab ends, and the top elevation; install steel spring supports, ensuring that the upper part of the steel spring supports connects to the embedded components of the concrete floating slab, and the lower part reliably contacts the already installed support base; use multi-point synchronous jacking equipment to gradually adjust the elevation of the concrete floating slab and the stress state of each support, monitoring the elevation difference between adjacent measuring points during the jacking process; after the concrete floating slab reaches the design elevation and the support stress is stable, gradually remove the temporary supports; S3. Inspect the upper and lower connecting plates embedded at the ends of adjacent plates, pass the shear reinforcement through the reserved holes in the connecting plates so that it spans the flexible joint between the plates, and fill the space between the shear reinforcement and the reserved hole wall with elastic material, maintaining the vertical movement gap required by the design during installation; roughen, clean and pour the UHPC local anchoring grooves at the ends of the concrete floating plates on both sides, and the UHPC does not continuously fill the flexible plate joint between the adjacent concrete floating plates; after the UHPC reaches the design strength, install compressible waterproof filler, waterstop strip and surface sealing material in the flexible plate joint; S4. Construct side drainage ditches on both sides of the concrete floating slab, and apply a waterproof coating to the inner wall of the side drainage ditches; when prefabricating the concrete floating slab, embed drainage pipes inside the slab, the drainage pipes are arranged according to the design slope, the inlet end of the drainage pipes is connected to the drain outlet at the bottom of the side drainage ditches, and the confluence point is connected to the drainage hole at the bottom of the concrete floating slab; the surface water collected by the side drainage ditches and the seepage water entering the drainage channel inside the slab are collected by the drainage pipes and introduced into the collection well through the bottom drainage hole and the outlet pipe, and then connected to the existing drainage system of the tunnel; after the drainage system is completed, conduct a water flow test; S5. Check the position, top elevation, joints between slabs and misalignment of adjacent slabs of the concrete floating slab; verify the compression, working height and stress state of each steel spring support; verify the overall anti-buoyancy stability of the tunnel based on the weight contribution of the concrete floating slab and the design groundwater buoyancy; conduct water spraying and water flow checks on the joint sealing and drainage system to confirm that there is no obvious water accumulation under the slab.

[0016] Further, in step S1, the roughening depth of the roughening treatment is not less than 5mm, and the concrete leveling layer is made of C30 concrete with a thickness of 150mm; the support base is fixed with pre-embedded anchors. When post-installed anchoring is used, the diameter of the anchor bar, the anchoring depth and the arrangement position are determined according to the support reaction force and the tunnel floor conditions. In step S3, the elastic material is polyurethane; in step S4, a removable filter screen is provided at the inlet of the drainage pipe and the bottom drainage hole, and the water collection well and the pipe junction are provided with conditions for inspection, cleaning and dredging.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention elastically supports a large self-weight concrete floating slab above the tunnel floor using steel spring supports. This allows the same slab to simultaneously bear the road load, provide anti-buoyancy pressure, and isolate vibration inertial mass, achieving integrated pressure reduction and vibration damping. This effectively weakens the transmission of random impact vibrations from heavy vehicles within a wide frequency range of 10–200 Hz to the tunnel structure and surrounding environment. Combined with a slab connection structure integrating steel shear hinges and local UHPC reinforcement, it transmits shear force at the slab ends, limits joint misalignment, and ensures smooth driving while preserving the ability for slight vertical relative displacement between adjacent slabs, avoiding rigid locking and ensuring independent vibration isolation for each slab. Furthermore, a drainage system combining edge water-stopping seals with drainage holes and sump pits, along with anti-corrosion sealing measures for the supports, prevents water accumulation and corrosion of the supports and connectors, ensuring the long-term load-bearing and vibration reduction performance of the vibration isolation system in humid environments. This invention simultaneously solves the problems of anti-buoyancy stability, wide-frequency vibration reduction, and long-term durability in road tunnels with high groundwater levels with fewer structural layers. It boasts advantages such as simple structure, convenient construction, and easy maintenance. Attached Figure Description

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. In the drawings: Figure 1 This is a front view of the concrete floating structure with counterweight and vibration isolation functions of the present invention; Figure 2 This is a schematic diagram of the steel bar shear hinge connection structure in an embodiment of the present invention; Figure 3 This is a schematic diagram of the drainage system structure in an embodiment of the present invention; Among them, 1-main tunnel structure, 2-concrete floating slab, 3-steel spring support, 4-side drainage ditch, 5-pavement structure layer, 6-waterproof coating, 7-tunnel bottom slab, 8-upper connecting plate, 9-lower connecting plate, 10-shear reinforcement, 11-elastic filling material, 12-UHPC local reinforcement area, 13-bottom drainage hole, 14-sump well, 15-drainage pipe. Detailed Implementation

[0019] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] This embodiment proposes a floating concrete structure with both counterweight and vibration isolation functions, such as... Figure 1 As shown, the structure includes the main tunnel structure 1, concrete floating slabs 2, an elastic support system, inter-slab connection structures, and a drainage system. The concrete floating slabs 2 are supported above the tunnel floor slab 7 by elastic supports. Their self-weight serves as ballast for tunnel anti-buoyancy and also as inertial mass for the vibration isolation system, working together with the elastic supports to reduce the transmission of vehicle vibrations to the main tunnel structure 1. Force-transmitting connection structures are provided between adjacent floating slabs, and corresponding seepage prevention and drainage measures are implemented on both sides and the bottom of the slabs to ensure the long-term normal operation of the structure.

[0021] 1. Concrete floating slab design The concrete floating slab 2 is the main load-bearing and counterweight component of this invention. Its dimensions and reinforcement should be determined comprehensively based on the tunnel's anti-buoyancy requirements, vehicle loads, support layout, and transportation and hoisting conditions. The floating slab uses C40 impermeable concrete with an impermeability grade of P8 to meet the strength requirements under road loads and the durability requirements in humid environments. The main design parameters of the floating slab are shown in Table 1.

[0022] Table 1

[0023] Key details: The concrete floating slab 2 is installed above the tunnel floor slab 7. A pavement structure layer 5 is laid on top of the slab, and the pavement, according to the designed cross slope, drains surface water to the side drainage ditches 4 on both sides. The floating slab is supported by spaced steel spring supports 3, with space left between the slab bottom and the tunnel floor slab 7 for support installation, drainage, and maintenance. A waterproof coating 6 is applied to the inner surface of the tunnel and the connection points of the side drainage ditches 4 to reduce the impact of groundwater and surface water on the components beneath the slab. The required counterweight for the floating slab is determined based on the buoyancy force corresponding to the design groundwater level, the self-weight of the tunnel main structure 1, and the weight of other components that can be included in the permanent load. Under the specified load combination, the sum of the self-weight of the tunnel main structure 1, the self-weight of the floating slab, and other permanent loads should meet the overall anti-buoyancy stability requirements. If the self-weight of the floating slab is insufficient, it can be supplemented by increasing the slab thickness, expanding the coverage area of ​​the counterweight plate, using higher density materials, or adding additional counterweight structures.

[0024] 2. Details of the elastic support system Steel spring bearings 3 are installed between the concrete floating slab 2 and the tunnel floor slab 7, serving as elastic support components for the floating slab and bearing the weight of the slab itself, the pavement structure layer 5, and vehicle loads. The large mass of the floating slab, together with the elasticity and damping of the steel spring bearings 3, forms a mass-spring-damping system. The impact and vibration generated by vehicle operation are first dispersed by the floating slab and then transmitted to the tunnel floor slab 7 via the bearings, thereby reducing the propagation of vibration to the tunnel body and the surrounding environment. The upper part of the bearing is connected to the pre-embedded components in the floating slab, and the lower part is installed on the concrete leveling layer above the tunnel floor slab 7. The base is fixed with anchors and leveled and compacted with non-shrink grout. The bearings are arranged in a grid pattern along the bottom of the floating slab, with a standard section spacing of 2.0m × 2.0m. The spacing can be appropriately increased at the slab ends, heavy-load lanes, and locations with large bearing reactions, depending on the stress conditions. The steel spring bearing 3 can be a readily available mature product. Its bearing capacity, vertical stiffness, working stroke and damping parameters are determined by combining the self-weight of the floating plate, vehicle load, number of bearings and dynamic calculation results, so as to avoid excessive stress on individual bearings or uneven deformation of the plate.

[0025] During installation, the center position, top elevation, and initial compression state of the bearings should be controlled, and necessary space for jacking, leveling, and maintenance should be reserved under the slab. The surfaces of the bearings and connecting steel components should be treated with anti-corrosion measures, and exposed parts should be sealed or protected to reduce the impact of humid environments on the long-term operation of the bearings. Horizontal limiting components should be installed at the ends or sides of the floating slab to transfer horizontal loads generated by vehicle braking and lateral forces. A clearance sufficient for normal vertical vibration isolation should be maintained between the limiting components and the slab to avoid forming a rigid vertical connection. Locally reinforced zones or reinforced concrete bearing bases should be provided at the bearing locations. The bearing reaction force is transferred to the main tunnel structure 1 via the base and the tunnel floor slab 7. The local bearing capacity, punching shear capacity, and anchorage bearing capacity below the bearings should be verified.

[0026] 3. Reinforcing steel shear hinges and UHPC joints like Figure 2 As shown, a reinforced shear hinge, a flexible joint, and a UHPC local reinforcement zone 12 are installed between adjacent concrete floating slabs 2 to transfer shear force at the slab ends. This allows for minor vertical relative displacement and rotation of adjacent slabs within the design range while limiting excessive vertical misalignment when vehicles pass through the joint, ensuring smooth driving. The reinforced shear hinge mainly consists of an upper connecting plate 8, a lower connecting plate 9, shear reinforcement 10, and elastic filler material 11, all pre-embedded at the ends of adjacent floating slabs. The upper and lower connecting plates 9 are connected to the reinforcing mesh within the corresponding floating slabs via anchoring members. The shear reinforcement 10 spans the flexible joint between the slabs and passes through pre-drilled holes in the connecting plates. Elastic filler material 11 is placed between the shear reinforcement 10 and the wall of the pre-drilled hole.

[0027] When adjacent floating slabs experience minor vertical relative displacement, the elastic filler material 11 undergoes compressive deformation, and the shear reinforcement 10 undergoes controlled bending, thus accommodating the minor vertical displacement between the slabs. As the relative displacement increases, the shear reinforcement 10 and the connecting plate jointly transmit the shear force at the slab ends, limiting excessive misalignment on both sides of the joint. UHPC is only cast within the local anchorage grooves at the ends of adjacent floating slabs to strengthen the anchorage area of ​​the connecting plate and improve the local bearing capacity at the slab ends. It does not continuously penetrate the flexible joint between adjacent slabs to avoid forming a rigid vertical connection. A compressible waterproof sealant is installed within the flexible joint between the slabs to meet the requirements for minor deformation and joint seepage prevention. The dimensions, quantity, anchorage length, and vertical clearance of the connecting plate and shear reinforcement 10 should be calculated and determined based on the vehicle load, the force at the slab ends, and the allowable misalignment.

[0028] 4. Drainage and waterproofing system design like Figure 3 As shown, the drainage system in this embodiment consists of side drainage ditches 4 on both sides of the concrete floating slab 2, bottom drainage holes 13 in the area under the slab, a collection well 14, and drainage pipes 15. Water accumulated on the top surface of the floating slab is drained into the side drainage ditches 4 via the road cross slope and flows longitudinally along the tunnel towards the existing drainage facilities. Small amounts of seepage water entering the space under the slab along the joints between the slabs and the sealing positions at the edges are collected through the bottom drainage holes 13 and then introduced into the collection well 14 via the drainage pipes 15, preventing water from stagnating around the steel spring supports 3 and their bases for extended periods. The side drainage ditches 4 are constructed of C30 reinforced concrete, with a cross-sectional dimension of 350mm × 250mm. The bottom of the ditch has a longitudinal slope of approximately 0.5% along the tunnel drainage direction, and the inner wall is coated with a waterproof layer 6 according to the engineering waterproofing requirements.

[0029] To reduce the entry of silt and debris into the drainage pipe 15, removable stainless steel filters or sedimentation structures are installed at the bottom drainage holes 13 and pipe inlets. Space is reserved for inspection, cleaning, and dredging at the sump pits 14 and pipe junctions. The sump pits 14 can be arranged at intervals along the tunnel's longitudinal direction, with an initial spacing of 50m. When the tunnel's longitudinal slope cannot meet gravity drainage requirements, submersible pumps can be installed in the sump pits 14 to drain accumulated water into the tunnel's main drainage network. The drainage holes, pipe diameter, sump pit spacing, and pump parameters should be determined based on the catchment area, tunnel longitudinal slope, and design drainage capacity. The bottom drainage holes 13 are generally located within the leveling layer or a dedicated drainage layer. If they must penetrate the tunnel's main floor slab, a water-stop sleeve should be installed, and the area around the hole should be waterproofed, sealed, and locally reinforced to prevent the drainage structure from forming new leakage channels.

[0030] The concrete floating slab road tunnel composite structure of the present invention is constructed according to the following steps: S1. Foundation treatment and support base anchoring: Remove laitance, oil stains, and loose concrete from the surface of tunnel floor slab 7. Roughen the areas that need to connect with the leveling layer to a depth of not less than 5mm. After cleaning, pour a C30 concrete leveling layer with a thickness of approximately 150mm on top of tunnel floor slab 7, controlling its top surface elevation and slope according to the support layout and drainage requirements under the slab. After the leveling layer reaches the specified strength, measure and mark the positions of the steel spring supports 3, and install the support bases. Pre-embedded anchors are recommended for fixing the support bases; when using post-installed anchors, the anchor diameter, anchoring depth, and arrangement should be determined based on the support reaction force and the conditions of tunnel floor slab 7. After the bases are installed, use non-shrink grout for leveling and grouting to ensure that the elevation of each support base meets the installation requirements of the floating slab.

[0031] S2. Floating slab hoisting and synchronous lifting: The prefabricated concrete floating slab 2 is transported to the construction site. After inspecting the slab's appearance, dimensions, embedded connectors, and lifting point status, it is lifted using symmetrical lifting points. During placement, guide components are used for centering, and temporary supports are installed to control the slab's center position, end spacing, and top elevation. Steel spring supports 3 are then installed, ensuring the upper part connects to the embedded components of the floating slab and the lower part reliably contacts the already installed support base. Multi-point synchronous jacking equipment is used to gradually adjust the floating slab's elevation and the stress state of each support. During jacking, the elevation difference between adjacent measuring points is monitored to prevent significant tilting of the slab or overloading of local supports. Once the floating slab reaches the design elevation and the supports are stable, the temporary supports are gradually removed, creating space below the floating slab for the steel spring supports 3 to operate, drain, and for future maintenance.

[0032] S3. Shear hinge installation and plate joint sealing: After the floating slabs are hoisted and leveled, inspect the upper connecting plates 8 and lower connecting plates 9 embedded at the ends of adjacent slabs. Pass the shear reinforcement 10 through the pre-drilled holes in the connecting plates, allowing it to span the flexible joint between the slabs. Fill the space between the shear reinforcement 10 and the wall of the pre-drilled hole with elastic material such as polyurethane. During installation, the vertical clearance required by the design should be maintained to allow the shear hinge to transfer the shear force at the slab ends, while allowing for slight vertical relative displacement between adjacent floating slabs. Subsequently, roughen, clean, and pour the UHPC local anchoring grooves at the ends of the floating slabs on both sides. The UHPC should not continuously fill the flexible joint between adjacent floating slabs to avoid forming a rigid connection that runs through both sides of the slabs. After the UHPC reaches its design strength, install compressible waterproof filler, waterstop strips, and surface sealing material in the central flexible joint.

[0033] S4. Drainage system construction: C30 reinforced concrete side drainage ditches 4 are constructed on both sides of the concrete floating slab 2, and a waterproof coating 6 is applied to the inner wall of the drainage ditches. During the precasting of the concrete floating slab 2, transverse drainage pipes 15 are pre-embedded inside the slab. The pipes are arranged according to the designed slope, with their inlet ends connected to the drain outlets at the bottom of the side drainage ditches 4, and their confluence points connected to the drainage holes at the bottom of the floating slab. Surface water collected by the side drainage ditches 4, as well as a small amount of seepage water entering the drainage channels within the slab, is collected by the pre-embedded drainage pipes 15 and then introduced into the collection well 14 through the bottom drainage holes 13 and the outlet pipe, before being connected to the existing tunnel drainage system. Removable filters are installed at the inlet of the drainage pipes 15 and at the bottom drainage holes 13. The collection well 14 and the pipe junctions are designed to allow for inspection, cleaning, and dredging. After the drainage system construction is completed, a water flow test is conducted to check the pipe slope, joint sealing, and drainage smoothness.

[0034] S5. System Quality Acceptance: After the structural construction is completed, check the position, top elevation, joints between slabs, and misalignment of adjacent slabs of the floating slab. Also, verify the compression, working height, and stress state of each steel spring support 3. Calculate the weight contribution of the floating slab based on its actual dimensions, concrete density, and other permanent loads, and compare it with the designed groundwater buoyancy to verify the overall anti-buoyancy stability of the tunnel. Subsequently, conduct water spray and flow checks on the joint sealing and drainage system to confirm that there is no significant water accumulation under the slab. Once loading conditions are met, conduct on-site vibration tests using representative vehicles to measure the vibration response of the floating slab and tunnel floor slab 7, and compare it with the design calculation results or a control section to verify the vibration reduction performance of the composite structure.

[0035] In summary, the main technical features of the embodiments of the present invention are reflected in the following three aspects: A concrete floating slab structure integrating counterweight and vibration damping. The dimensions and self-weight of the concrete floating slab 2 are determined according to the tunnel's anti-buoyancy requirements. The slab's self-weight is transferred to the tunnel floor slab 7 via elastic supports, serving as part of the tunnel's permanent anti-buoyancy load. Simultaneously, the large self-weight floating slab acts as the inertial mass of the vibration isolation system, forming an elastic support system together with the steel spring supports 3, reducing the transmission of vibrations generated by vehicle loads to the main tunnel structure 1. This structure integrates the road load-bearing slab, anti-buoyancy counterweight components, and vibration isolation mass, allowing the same concrete slab to simultaneously bear the road load, anti-buoyancy counterweight, and vehicle vibration damping functions.

[0036] A slab connection structure combining reinforced shear hinges and localized UHPC reinforcement. The reinforced shear hinges transfer shear force at the slab ends through connecting plates and shear reinforcement 10. Elastic filler material 11 and vertical movable gaps allow adjacent floating slabs to undergo minor vertical relative displacement and rotation within the design range, preventing complete locking of adjacent slabs and limiting excessive misalignment when vehicles pass through the joint. UHPC is only used for localized reinforcement in the anchorage area of ​​the slab end connecting plates and does not penetrate the central flexible slab joint, thus balancing the requirements for slab end load-bearing capacity, shear force transfer, joint deformation, and independent vibration isolation of the floating slabs.

[0037] The system employs a combined edge interception and under-slab drainage design for waterproofing and drainage. Surface water on the top surface of the floating slab is drained into longitudinal drainage ditches on both sides via the road's cross slope. Appropriate sealing measures are implemented at the joints between slabs and at the edges to reduce surface water accumulation in the space beneath the slab. Any small amount of seepage that enters the space under the slab is collected and discharged through bottom drainage holes 13, drainage pipes 15, and a collection well 14, preventing water from stagnating around the steel spring supports 3 and connecting components. The drainage outlets are equipped with filters and inspection structures for easy cleaning and maintenance.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A concrete floating structure with counterweight and vibration isolation functions, installed above the tunnel floor slab (7), characterized in that, include: The concrete floating slab (2) is elastically supported above the tunnel floor slab (7) by spaced elastic support members. There is space for support installation, drainage and maintenance between the bottom of the concrete floating slab (2) and the tunnel floor slab (7). The size and self-weight of the concrete floating slab (2) are determined according to the tunnel anti-buoyancy requirements. The self-weight is transferred to the tunnel floor slab (7) through the elastic support members as part of the tunnel anti-buoyancy permanent load. At the same time, the concrete floating slab (2) serves as the inertial mass of the vibration isolation system and together with the elastic support members, forms a vibration isolation system to reduce the transmission of vibration generated by vehicle load to the main tunnel structure (1). The inter-slab connection structure is set between adjacent concrete floating slabs (2), including a steel shear hinge and a flexible slab joint. The steel shear hinge is used to transfer the shear force at the slab end and limit the vertical misalignment on both sides of the joint, while allowing the adjacent concrete floating slabs (2) to undergo vertical relative displacement and rotation within the design range. The drainage system includes side drainage ditches (4) set on both sides of the concrete floating slab (2), and bottom drainage holes (13), drainage pipes (15) and collection wells (14) set in the area under the slab. The side drainage ditches (4) are used to collect and discharge surface water, and the bottom drainage holes (13), drainage pipes (15) and collection wells (14) are used to collect and discharge seepage water entering the space under the slab.

2. The floating concrete structure with counterweight and vibration isolation functions according to claim 1, characterized in that, The concrete floating slab (2) is made of impermeable concrete with a concrete strength grade of C40 and an impermeability grade of P8. The concrete floating slab (2) has a thickness of 400-600mm, a width of 8-12m, and a length of 6-10m. The slab is equipped with a double-layer bidirectional steel mesh, with the bottom layer steel mesh being Φ16-20@150 and the top layer steel mesh being Φ16@200.

3. The floating concrete structure with counterweight and vibration isolation functions according to claim 1, characterized in that, The elastic support component is a steel spring support (3). The steel spring support (3) is arranged in a grid pattern along the bottom of the concrete floating slab (2). The standard section spacing is 2.0m×2.0m. The steel spring support (3) is densely arranged at the slab end, heavy-load lane and the position where the support reaction force is large. The upper part of the steel spring support (3) is connected to the pre-embedded component in the concrete floating slab (2). The lower part is installed on the concrete leveling layer above the tunnel bottom slab (7). The base is fixed with anchors and leveled and compacted by non-shrink grout.

4. The floating concrete structure with counterweight and vibration isolation functions according to claim 3, characterized in that, The concrete floating slab (2) is provided with a horizontal limiting member at the end or side of the slab to transmit the horizontal load generated by vehicle braking and lateral action; a gap is maintained between the horizontal limiting member and the concrete floating slab (2) to meet the vertical vibration isolation requirements, so as to avoid forming a vertical rigid connection; a local reinforcement zone or reinforced concrete support base is provided at the corresponding position of the steel spring support (3), and the support reaction force is transmitted to the tunnel main structure (1) through the support base and the tunnel bottom slab (7).

5. The floating concrete structure with counterweight and vibration isolation functions according to claim 1, characterized in that, The steel shear hinge includes an upper connecting plate (8), a lower connecting plate (9), shear reinforcement (10), and elastic filler material (11) respectively embedded in the ends of adjacent concrete floating slabs (2); the upper connecting plate (8) and the lower connecting plate (9) are connected to the steel mesh in the corresponding concrete floating slabs (2) through anchoring members; the shear reinforcement (10) spans the flexible slab joint and passes through the reserved holes on the upper connecting plate (8) and the lower connecting plate (9); the elastic filler material (11) is provided between the shear reinforcement (10) and the hole wall of the reserved hole.

6. The floating concrete structure with counterweight and vibration isolation functions according to claim 5, characterized in that, The ends of the adjacent concrete floating slabs (2) are provided with UHPC local reinforcement areas (12). The UHPC local reinforcement areas (12) are only poured into the local anchoring grooves provided at the ends of the adjacent concrete floating slabs (2) to strengthen the anchoring area of ​​the connecting plate and improve the local bearing capacity of the plate end. They do not continuously penetrate the flexible plate joint between the adjacent plates. The flexible plate joint is provided with compressible waterproof sealing material.

7. The floating concrete structure with counterweight and vibration isolation functions according to claim 1, characterized in that, The side drainage ditch (4) is made of reinforced concrete, with a longitudinal slope at the bottom of the ditch along the tunnel drainage direction, and a waterproof coating (6) on the inner wall; the bottom drainage hole (13) and the inlet of the drainage pipe (15) are provided with a detachable stainless steel filter or sedimentation structure; the water collection well (14) is arranged at intervals along the longitudinal direction of the tunnel, and the water collection well (14) and the pipe junction position are reserved with space for inspection, cleaning and dredging.

8. The floating concrete structure with counterweight and vibration isolation functions according to claim 7, characterized in that, When the longitudinal slope of the tunnel cannot meet the gravity drainage requirements, a submersible pump is installed in the water collection well (14) to drain the accumulated water into the main drainage network of the tunnel; the bottom drainage hole (13) is arranged in the leveling layer or special drainage layer. When the bottom drainage hole (13) passes through the bottom plate of the tunnel main body, a water-stop sleeve is installed, and the hole is waterproofed and locally reinforced.

9. A construction method for a floating concrete structure with counterweight and vibration isolation functions, used for constructing the floating concrete structure with counterweight and vibration isolation functions as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Remove laitance, oil stains and loose concrete from the surface of the tunnel floor slab (7), and roughen the area that needs to be connected with the leveling layer; pour a concrete leveling layer on top of the tunnel floor slab (7), and control the elevation and slope of the top surface of the leveling layer according to the support arrangement and drainage requirements under the slab. After the leveling layer reaches the specified strength, the position of the elastic support component is measured and marked out, and the support base is installed. The support base is fixed with anchors. After installation, non-shrink grout is used for leveling and grouting. S2. Transport the precast concrete floating slab (2) to the construction site, lift it using symmetrical lifting points, center it using guide components when in place, and set up temporary supports to control the center position of the slab, the spacing between the slab ends and the top elevation; install steel spring supports (3) so that the upper part of the steel spring supports (3) is connected to the embedded components of the concrete floating slab (2) and the lower part is in reliable contact with the already installed support base; use multi-point synchronous jacking equipment to gradually adjust the elevation of the concrete floating slab (2) and the stress state of each support, and monitor the height difference between adjacent measuring points during the jacking process; after the concrete floating slab (2) reaches the design elevation and the support is stable, gradually remove the temporary supports; S3. Inspect the upper connecting plate (8) and lower connecting plate (9) pre-embedded at the adjacent plate ends, pass the shear steel bar (10) through the reserved hole of the connecting plate so that it spans the flexible joint between the plates, and fill the space between the shear steel bar (10) and the reserved hole wall with elastic material, and retain the vertical movement gap required by the design during the installation process; roughen, clean and pour the UHPC local anchoring groove at the ends of the concrete floating plates (2) on both sides respectively, and the UHPC does not continuously fill the flexible plate joint between the adjacent concrete floating plates (2); after the UHPC reaches the design strength, set the compressible waterproof filler, waterstop strip and surface sealing material in the flexible plate joint; S4. Construct side drainage ditches (4) on both sides of the concrete floating slab (2) and install a waterproof coating (6) on the inner wall of the side drainage ditch (4); When prefabricating the concrete floating slab (2), embed drainage pipes (15) inside the slab body. The drainage pipes (15) are arranged according to the design slope. The inlet end of the drainage pipe is connected to the drain outlet at the bottom of the side drainage ditch (4), and the confluence position is connected to the drainage hole at the bottom of the concrete floating slab (2); The surface water collected by the side drainage ditch (4) and the seepage water entering the drainage channel inside the slab are collected by the drainage pipes (15) and introduced into the collection well (14) through the bottom drainage hole (13) and the outlet pipe, and then connected to the existing drainage system of the tunnel; After the drainage system is completed, a water flow test is carried out; S5. Check the position, top elevation, joints between slabs and misalignment of adjacent slabs of the concrete floating slab (2), and verify the compression, working height and stress state of each steel spring support (3); verify the overall anti-buoyancy stability of the tunnel based on the weight contribution of the concrete floating slab (2) and the design groundwater buoyancy; conduct water spraying and water flow checks on the joint sealing and drainage system to confirm that there is no obvious water accumulation under the slab.

10. The construction method of the concrete floating structure with counterweight and vibration isolation functions according to claim 9, characterized in that, In step S1, the roughening depth of the roughening treatment is not less than 5mm, and the concrete leveling layer is made of C30 concrete with a thickness of 150mm; the support base is fixed with pre-embedded anchors. When post-installed anchoring is used, the diameter of the anchor bar, the anchoring depth and the arrangement position are determined according to the support reaction force and the conditions of the tunnel bottom plate (7). In step S3, the elastic material is polyurethane; in step S4, a detachable filter screen is provided at the inlet of the drainage pipe (15) and the bottom drainage hole (13), and the water collection well (14) and the pipe junction are reserved with conditions for inspection, cleaning and dredging.

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