Mountain ridge large-span highway tunnel inverted arch assembly type construction method based on prefabricated parts

Abstract

The invention discloses an inverted arch assembly type construction method for a mountain large-span highway tunnel based on prefabricated parts, and belongs to the technical field of tunnel engineering construction. The method comprises the core processes of factory prefabricated part preparation, tunnel base treatment, on-site hoisting and positioning, component connection and fastening, waterproof grouting construction and monitoring, tracing and deployment. According to the method, factory standardized prefabricated parts ensure stable quality, base treatment and hoisting positioning guarantee accurate installation of the parts, reliable connection is achieved through annular embedded steel bar bonding and longitudinal steel plate bolt fastening, and the problems of base settlement and joint leakage are solved through a waterproof grouting technology; and full-life-cycle management and control are realized through monitoring and tracing deployment. The blank of the matched construction method for the prefabricated inverted arch of the mountain ridge large-span highway tunnel is filled, the construction efficiency and the structural safety and durability are improved, and the requirements for industrialization and green construction of the infrastructure industry are met.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering construction technology, specifically to a prefabricated construction method for the invert arch of a long-span highway tunnel in mountainous terrain based on prefabricated components. Background Technology

[0002] The invert arch of a long-span highway tunnel in mountainous areas is a core component of the tunnel lining structure. It directly bears the load of the tunnel foundation, transmits the pressure of the surrounding rock, and works in conjunction with the arch wall to form a closed lining system. Its construction quality and efficiency have a decisive impact on the tunnel's structural safety, durability, and overall construction progress. Currently, the construction technology for invert arches of long-span highway tunnels in mountainous areas still has significant limitations, making it difficult to adapt to the needs of green construction and industrialization. Specific technical status and problems are as follows: Currently, the construction of invert arches for mountain tunnels is mainly divided into two categories: traditional cast-in-place concrete construction and precast assembly construction. Traditional cast-in-place concrete construction is the mainstream method for constructing the invert arch of long-span highway tunnels in mountainous areas. It requires on-site formwork erection, concrete mixing and pouring, and curing inside the tunnel. However, this construction method has significant shortcomings: Firstly, cast-in-place construction is a labor-intensive operation, requiring a large number of people to participate in formwork erection, concrete vibration, and other processes. The average construction efficiency per person is only about 0.5 rings per day, and the carbon emissions from on-site concrete mixing and curing are high. Secondly, the construction environment inside the tunnel is complex, with large fluctuations in temperature and humidity. Cast-in-place concrete is prone to deviations from the design requirements in terms of invert arch depth and shape, resulting in unreasonable overall stress on the lining. At the same time, it is difficult to clean the loose debris at the invert arch base, and the residual loose debris can easily cause uneven settlement in the later stage. Furthermore, the concrete needs to wait for more than 12 hours for initial setting before the lining can be closed into a ring. The long strength equalization time means that the initial support of the tunnel lacks complete constraint, and the physical and mechanical parameters of the base rock are easily weakened by the release of the surrounding rock load. In addition, cast-in-place concrete has almost no special curing measures, and the construction quality is affected by many factors such as process operation and material properties, resulting in poor stability.

[0003] While existing prefabricated assembly construction methods have been applied in small-section tunnels, such as railway tunnels built using the shield tunneling or TBM method, employing slab or box culvert prefabricated invert arches for assembly, this technology has serious limitations: First, it lacks adaptability; existing prefabricated invert arches are mostly designed for small-section scenarios with a top width of 4-6m, and their structural form and block size cannot meet the cross-sectional requirements of large-span highway tunnels in mountainous areas (with the widest part of the inner profile reaching 11.8m and the highest part reaching 8.9m); second, the load-bearing performance is mismatched, as existing prefabricated invert arch connections mainly rely on simple bolt connections. The tunnels are difficult to withstand the Class I vehicle loads of mountain tunnels (such as the full load weight of muck trucks during construction reaching 150kN) and the complex surrounding rock pressure (the vertical pressure of Class V surrounding rock can reach 360.74kN / m²). Thirdly, there is a lack of technology. For mountain tunnels constructed using the mining method, due to the complex terrain and variable bedrock conditions, there is no mature solution for suitable precast invert arch structures and supporting construction technologies. Related engineering practices are still lacking, which leads to such tunnels relying on traditional cast-in-place processes for a long time, resulting in problems such as low construction efficiency, difficulty in quality control, and prominent safety risks.

[0004] Therefore, there is an urgent need for a prefabricated construction method that can adapt to the working conditions of long-span highway tunnels in mountainous areas, solve the problems of poor quality and low efficiency of traditional cast-in-place invert arches, as well as the insufficient adaptability of existing prefabrication technologies and unsystematic construction processes, and promote the transformation of invert arch construction of long-span highway tunnels in mountainous areas towards industrialization, greening, and high efficiency. Summary of the Invention

[0005] In view of this, the purpose of this invention is to overcome the shortcomings of existing related technologies and provide a prefabricated construction method for invert arches of long-span highway tunnels in mountainous areas based on prefabricated components. This method is adapted to the prefabricated invert arch structure (including an integral hollow prefabricated invert arch body, circumferential connecting components, longitudinal connecting components, waterproofing and grouting structures, and monitoring and traceability structures) of long-span highway tunnels in mountainous areas. It solves the problems of insufficient adaptability of existing invert arch construction, poor connection reliability, quality hazards such as foundation settlement and joint leakage, lack of full life cycle management, and low efficiency of traditional cast-in-place construction. It promotes the transformation of invert arch construction towards industrialization and greening, improves construction quality and efficiency, and fills the gap in supporting construction methods for prefabricated invert arches of long-span highway tunnels in mountainous areas.

[0006] To achieve the above objectives, this invention provides a prefabricated construction method for the invert arch of a long-span highway tunnel in mountainous areas based on prefabricated components, characterized by the following steps: S1: Prefabricated component preparation, obtaining prefabricated invert arch components adapted to mountainous long-span highway tunnels. The prefabricated invert arch components include an integral hollow prefabricated invert arch body, circumferential connection components, longitudinal connection components, waterproof and grouting structures, and monitoring and traceability structures. S2: Tunnel foundation treatment, pre-treatment of the foundation in the tunnel invert construction area to ensure that the foundation meets the installation conditions of the precast invert components; S3: Precast component hoisting and positioning. The precast invert arch component from step S1 is hoisted to the construction area of ​​the tunnel foundation and the component position is adjusted to the design reference. S4: Component connection and fastening: The circumferential connection component enables the rigid connection between the precast invert arch component and the cast-in-place tunnel arch wall, while the longitudinal connection component enables the fastening connection between adjacent precast invert arch components. S5: Waterproof grouting construction, using the waterproof and grouting structure to seal and fill the gap between the precast invert arch component and the base, and the joints of adjacent components; S6: Monitoring and tracing deployment, activate the monitoring and tracing structure, and complete the debugging and information entry of monitoring functions during the construction and operation phases.

[0007] Furthermore, the preparation of prefabricated components in step S1 specifically includes: completing the casting and molding of the integral hollow prefabricated inverted arch body in the factory according to the design parameters, simultaneously pre-embedding the adapter parts of the circumferential connection components, the connecting parts of the longitudinal connection components, the pre-set components of the waterproof and grouting structure, and the sensing and storage components of the monitoring and traceability structure. After the prefabrication is completed, the components are subjected to appearance inspection, size verification and mechanical performance sampling inspection, and after passing the inspection, they are transported to the construction site.

[0008] Furthermore, the tunnel foundation treatment in step S2 specifically includes: removing loose debris, impurities, and accumulated water from the tunnel invert arch foundation; using leveling materials to level the foundation surface to form a flat installation base; if there are local depressions or loose areas in the foundation, filling and compacting the depressions and reinforcing the loose areas; after treatment, testing the flatness and bearing capacity of the foundation to ensure that the flatness deviation does not exceed the design allowable range and the bearing capacity meets the load requirements of the precast invert arch components.

[0009] Furthermore, step S3, the hoisting and positioning of the precast components, specifically includes: connecting the hoisting equipment to the embedded lifting rods of the components according to the pre-set hoisting point positioning marks on the top of the precast invert arch components; starting the hoisting equipment to slowly hoist the components to the area above the foundation construction area, adjusting the horizontal posture and vertical height of the components to align the axis of the components with the design axis of the tunnel invert arch; gradually lowering the components to the foundation installation surface, monitoring the positional deviation of the components in real time using a level and a total station, adjusting the components until the positioning deviation meets the design requirements, and then temporarily fixing the components.

[0010] Furthermore, step S4, which achieves a rigid connection between the precast invert arch component and the cast-in-place tunnel arch wall through the circumferential connection assembly, specifically includes: cleaning the inner wall of the anchoring hole of the circumferential connection assembly at the end of the precast invert arch component; filling the pre-embedded tapered plastic sleeve in the anchoring hole with modified epoxy resin adhesive; after the adhesive reaches the preset curing strength, inserting the reinforcing bar into the anchoring hole, so that one end of the reinforcing bar is anchored to the tapered plastic sleeve, and the other end extends to the casting area of ​​the cast-in-place tunnel arch wall; and pouring the cast-in-place arch wall concrete, so that the reinforcing bar and the cast-in-place arch wall concrete form an integral whole, thereby achieving a rigid connection between the precast invert arch component and the cast-in-place arch wall.

[0011] Furthermore, step S4, which involves achieving a tight connection between adjacent precast invert arch components using the longitudinal connection assembly, specifically includes: cleaning the surface of the weathering steel plate embedded in the longitudinal end face of the adjacent precast invert arch components, removing rust and impurities from the steel plate surface; aligning and fitting the weathering steel plates of the adjacent components, inserting high-strength bolts into the bolt holes of the steel plates; and tightening the high-strength bolts with a torque wrench according to a preset torque value to ensure that the preload of the bolts meets the design requirements, thereby achieving a tight connection between the adjacent precast invert arch components.

[0012] Furthermore, step S5, which utilizes the waterproofing and grouting structure to fill the gap between the precast invert arch component and the base, specifically includes: connecting the grouting equipment and the pre-embedded grouting steel pipe through the grouting holes of the waterproofing and grouting structure on the bottom surface of the precast invert arch component; injecting grouting material into the pre-embedded grouting steel pipe, the grouting material flowing through the steel pipe into the base grouting strip between the component and the base, filling the gap between the component and the base; during the grouting process, air in the strip is discharged through the vent hole; when the grouting material overflows from the vent hole or the grouting pressure reaches the preset value, grouting is stopped, the grouting hole and the vent hole are sealed, and the grouting material is allowed to solidify.

[0013] Furthermore, in step S5, sealing the joints of adjacent components using the waterproofing and grouting structure specifically includes: embedding a water-swellable strip with a grouting pipe into the groove of the water-stop strip at the longitudinal joint of the adjacent precast invert arch component; filling the joint gap outside the water-stop strip with sealing material to form a sealing layer; and after the sealing layer has cured, applying a waterproof coating to the top surface of the joint so that the waterproof coating covers the top surface of the joint and is flush with the top surface of the concrete panel at the top of the precast invert arch component, while also covering the panel joint of the concrete panel.

[0014] Furthermore, step S6 specifically includes the following steps for monitoring and tracing deployment: connecting the signal lines of the strain gauges in the monitoring and tracing structure to external monitoring equipment; adjusting the monitoring accuracy of the strain gauges to ensure that the strain gauges can collect strain data of the precast invert arch components in real time; writing the production parameters, installation parameters, and design parameters of the components to the information storage chip of the monitoring and tracing structure through a dedicated reading and writing device; and connecting the monitoring equipment and the chip reading and writing device to the tunnel operation and maintenance management system to realize the real-time uploading and traceability query of component construction data and operation monitoring data.

[0015] Furthermore, the casting and forming of the integral hollow precast invert arch body in step S1 specifically includes: forming by combining a steel reinforcement skeleton with a template, the steel reinforcement skeleton including main reinforcement bars arranged in the longitudinal and transverse directions of the body, stirrups surrounding the main reinforcement bars, and reinforcement rings surrounding the hollow holes of the body; after the template is installed, concrete is poured, vibrated and compacted, and then cured according to the preset curing system; after curing, the template is removed to form the integral precast invert arch body with hollow areas.

[0016] The present invention, by adopting the above technical solution, has at least the following beneficial effects: In this invention, the integrated construction process design, which includes factory prefabrication of components, tunnel foundation treatment, and on-site hoisting and positioning, can precisely adapt to the overall hollow shape of the prefabricated invert arch components, completely covering the invert arch area of ​​the mountainous long-span highway tunnel laterally. Furthermore, by avoiding the underground ditches on the left and right sides of the tunnel, it adapts to the tunnel's original drainage system, effectively solving the problem that the existing small-section prefabricated invert arch construction method cannot be adapted to the working conditions of long-span highway tunnels. At the same time, standardized factory prefabrication replaces the cumbersome process of traditional cast-in-place invert arch construction, which involves "in-tunnel formwork, concrete vibration, and long-term curing," significantly reducing the amount of manual labor inside the tunnel, lowering on-site carbon emissions, and significantly improving construction efficiency.

[0017] In this invention, relying on the connection process of circumferential rebar bonding and longitudinal steel plate bolt fastening, a reliable and coordinated force-bearing system is formed with the connection structure of the precast invert arch component: circumferentially, by cleaning the rebar holes, filling the bonding material, and then casting the cast-in-place arch wall after rebar installation, the force continuity between the precast invert arch and the cast-in-place arch wall is achieved; longitudinally, by cleaning the embedded steel plates, aligning and fitting them, and tightening the high-strength bolts according to specifications, a tight connection between adjacent precast components is achieved. Compared with the existing precast construction method with simple bolt connections, the overall connection reliability is significantly improved, which can effectively withstand the highway vehicle load and complex surrounding rock pressure of the mountain long-span highway tunnel, and avoid the problem of unreasonable force distribution in the lining structure due to connection failure.

[0018] In this invention, during the factory casting stage of precast invert arch components, the standardized binding of the steel reinforcement cage and the standardized pouring and curing of concrete ensure the precise placement of reinforcement and the compliance of concrete density. The steel reinforcement cage consists of longitudinal and transverse main bars, stirrups surrounding the main bars, and reinforcing rings surrounding the perforated holes. Combined with formwork casting and curing, it effectively controls stress concentration in the perforated areas of the components. Compared with the problems of easy on-site reinforcement displacement and concrete quality interference from the tunnel environment in traditional cast-in-place invert arches, this invention ensures the production quality of precast components from the source of construction and avoids potential structural stress hazards.

[0019] In this invention, based on the positioning marks of the lifting points on the top of the precast invert arch components, the hoisting process, which involves connecting the lifting rods, adjusting the horizontal posture, monitoring the position deviation in real time, and temporarily fixing the components, ensures that the deviation between the lifting points and the center of gravity of the components meets the requirements of force balance, thus significantly reducing the risk of component overturning during hoisting. At the same time, it eliminates the traditional steps of erecting and dismantling formwork inside the invert arch tunnel, significantly shortening the construction time of a single-ring invert arch. Furthermore, the hoisting operation does not require setting up a large number of temporary supports inside the tunnel, reducing the occupation of working space inside the tunnel and lowering the safety risks during construction.

[0020] In this invention, a waterproofing process involving base cleaning, leveling and reinforcement, grouting and filling the gaps between components and the base, and joint sealing can fully fill the voids formed by residual slag in the tunnel invert base, preventing uneven settlement of the invert arch in the later stages of tunnel operation. At the same time, through a multi-seal design of embedding waterstop strips at the joints, filling with sealing layers, and applying a waterproof coating to the top surface, rainwater or groundwater can be effectively blocked from seeping into the base through the component joints, solving the problem of leakage points that are prone to occur in traditional cast-in-place invert arch waterproofing construction, and significantly improving the overall durability of the tunnel structure.

[0021] In this invention, the monitoring and traceability functions of precast invert arch components are activated through the deployment process of strain gauge debugging, component parameter writing into storage chips, and monitoring equipment access to the operation and maintenance system: during the construction phase, the installation accuracy and strain changes of the components can be monitored in real time; during the operation phase, the risk of load exceeding the design value can be warned in a timely manner, avoiding structural damage due to overload; at the same time, the entire life cycle traceability from component production and on-site construction to operation and maintenance is realized, which facilitates the later structural maintenance and responsibility traceability, solves the problems of difficult quality traceability of traditional cast-in-place invert arches and lack of later structural stress monitoring, and ensures the long-term operational safety of the tunnel. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the prefabricated invert arch lining structure. Figure 2 This is a schematic diagram of the prefabricated inverted arch structure of the present invention; Figure 3 This is a schematic diagram of the structure of the present invention with main reinforcement and stirrups; Figure 4 This is a schematic diagram of the prefabricated inverted arch structure with grouting structure of the present invention; Figure 5 yes Figure 4 A schematic diagram of the BB direction; Figure 6 This is a schematic diagram of the prefabricated inverted arch structure with a waterstop strip groove according to the present invention. Figure 7 This is a schematic diagram of the prefabricated inverted arch structure with pre-embedded grouting steel pipes of the present invention; Figure 8 yes Figure 7 A top-down view of the structure; Figure 9 This is a schematic diagram of the prefabricated inverted arch structure with strain gauges of the present invention; In the diagram: 1. Precast invert arch main body; 2. Waterstop strip groove; 3. RFID embedded part; 4. Rebar hole; 5. Embedded weathering steel plate; 6. Strain gauge; 7. Concrete panel; 8. Surface layer reserved layer; 9. Roadside culvert empty space; 10. Cement-based penetrating crystalline waterproof coating filling; 11. Main reinforcement; 12. Stirrup; 13. Circular hollow hole reinforcement ring; 14. Chip positioning groove; 15. Embedded hanger; 16. Vent hole; 17. Embedded vent pipe; 18. Base grouting strip; 19. Embedded grouting steel pipe; 20. Grouting hole; 21. Monitoring point. Detailed Implementation

[0024] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0025] This embodiment provides a prefabricated construction method for the invert arch of a long-span highway tunnel in mountainous areas based on prefabricated components, characterized by the following steps: S1: Prefabricated component preparation, obtaining prefabricated invert arch components adapted to mountainous long-span highway tunnels. The prefabricated invert arch components include an integral hollow prefabricated invert arch body, circumferential connection components, longitudinal connection components, waterproof and grouting structures, and monitoring and traceability structures. S2: Tunnel foundation treatment, pre-treatment of the foundation in the tunnel invert construction area to ensure that the foundation meets the installation conditions of the precast invert components; S3: Precast component hoisting and positioning. The precast invert arch component from step S1 is hoisted to the construction area of ​​the tunnel foundation and the component position is adjusted to the design reference. S4: Component connection and fastening: The circumferential connection component enables the rigid connection between the precast invert arch component and the cast-in-place tunnel arch wall, while the longitudinal connection component enables the fastening connection between adjacent precast invert arch components. S5: Waterproof grouting construction, using the waterproof and grouting structure to seal and fill the gap between the precast invert arch component and the base, and the joints of adjacent components; S6: Monitoring and tracing deployment, activate the monitoring and tracing structure, and complete the debugging and information entry of monitoring functions during the construction and operation phases.

[0026] As one implementation method, the preparation of prefabricated components in step S1 of this embodiment specifically includes: completing the casting and molding of the integral hollow prefabricated inverted arch body in the factory according to the design parameters, simultaneously pre-embedding the adapter parts of the circumferential connection components, the connecting parts of the longitudinal connection components, the pre-set components of the waterproof and grouting structure, and the sensing and storage components of the monitoring and traceability structure. After the prefabrication is completed, the components are subjected to appearance inspection, size verification and mechanical performance sampling inspection, and after passing the inspection, they are transported to the construction site.

[0027] As one implementation method, the tunnel foundation treatment in step S2 of this embodiment specifically includes: removing loose debris, impurities, and accumulated water from the tunnel invert arch foundation; using leveling materials to level the foundation surface to form a flat installation base surface; if there are local depressions or loose areas in the foundation, filling and compacting the depressions and reinforcing the loose areas; after treatment, testing the flatness and bearing strength of the foundation to ensure that the flatness deviation of the foundation does not exceed the design allowable range and that the bearing strength meets the load requirements of the precast invert arch components.

[0028] As one implementation method, the precast component hoisting and positioning in step S3 of this embodiment specifically includes: connecting the hoisting equipment to the pre-embedded lifting rods of the component according to the pre-set hoisting point positioning marks on the top of the precast invert arch component; starting the hoisting equipment to slowly hoist the component to the top of the foundation construction area, adjusting the horizontal posture and vertical height of the component to align the axis of the component with the design axis of the tunnel invert arch; gradually lowering the component to the foundation installation surface, monitoring the positional deviation of the component in real time using a level and total station, adjusting the component until the positioning deviation meets the design requirements, and temporarily fixing the component.

[0029] As one implementation method, step S4 of this embodiment, which achieves a rigid connection between the precast invert arch component and the cast-in-place tunnel arch wall through the circumferential connection assembly, specifically includes: cleaning the inner wall of the anchoring hole of the circumferential connection assembly at the end of the precast invert arch component; filling the pre-embedded tapered plastic sleeve in the anchoring hole with modified epoxy resin adhesive; after the adhesive reaches the preset curing strength, inserting the reinforcing bar into the anchoring hole, so that one end of the reinforcing bar is anchored to the tapered plastic sleeve, and the other end extends to the casting area of ​​the cast-in-place tunnel arch wall; and pouring the cast-in-place arch wall concrete, so that the reinforcing bar and the cast-in-place arch wall concrete form an integral whole, thereby achieving a rigid connection between the precast invert arch component and the cast-in-place arch wall.

[0030] As one implementation method, step S4 of this embodiment, which achieves a tight connection between adjacent precast invert arch components through the longitudinal connection assembly, specifically includes: cleaning the surface of the weathering steel plate embedded in the longitudinal end face of the adjacent precast invert arch components, removing rust and impurities from the steel plate surface; aligning and fitting the weathering steel plates of the adjacent components, inserting high-strength bolts into the bolt holes of the steel plates; and tightening the high-strength bolts with a torque wrench according to the preset torque value to ensure that the preload of the bolts meets the design requirements, thereby achieving a tight connection between the adjacent precast invert arch components.

[0031] As one implementation method, step S5 of this embodiment, which utilizes the waterproofing and grouting structure to fill the gap between the precast invert arch component and the base, specifically includes: connecting the grouting equipment and the pre-embedded grouting steel pipe through the grouting holes of the waterproofing and grouting structure on the bottom surface of the precast invert arch component; injecting grouting material into the pre-embedded grouting steel pipe, the grouting material flowing into the base grouting strip between the component and the base through the steel pipe, filling the gap between the component and the base; during the grouting process, air in the strip is discharged through the vent hole; when the grouting material overflows from the vent hole or the grouting pressure reaches the preset value, grouting is stopped, the grouting hole and the vent hole are sealed, and the grouting material is allowed to solidify.

[0032] As one implementation method, the sealing of the joints of adjacent components using the waterproofing and grouting structure in step S5 of this embodiment specifically includes: embedding a water-swellable water-stop strip with a grouting pipe into the groove of the water-stop strip of the longitudinal joint of the adjacent precast invert arch component; filling the joint gap outside the water-stop strip with sealing material to form a sealing layer; after the sealing layer has cured, applying a waterproof coating to the top surface of the joint so that the waterproof coating covers the top surface of the joint and is flush with the top surface of the concrete panel of the precast invert arch component, while also covering the panel joint of the concrete panel.

[0033] As one implementation method, the monitoring and traceability deployment in step S6 of this embodiment specifically includes: connecting the signal line of the strain gauge in the monitoring and traceability structure to the external monitoring equipment, adjusting the monitoring accuracy of the strain gauge to ensure that the strain gauge can collect strain data of the precast invert arch component in real time; writing the production parameters, installation parameters and design parameters of the component to the information storage chip of the monitoring and traceability structure through a dedicated reading and writing device; connecting the monitoring equipment and the chip reading and writing device to the tunnel operation and maintenance management system to realize the real-time uploading and traceability query of component construction data and operation monitoring data.

[0034] As one implementation method, the casting and forming of the integral hollow precast invert arch body in step S1 of this embodiment specifically includes: forming by combining a steel reinforcement skeleton with a template, wherein the steel reinforcement skeleton includes main reinforcement bars arranged in the longitudinal and transverse directions of the body, stirrups surrounding the main reinforcement bars, and reinforcement rings surrounding the hollow holes of the body; after the template is installed, concrete is poured, vibrated and compacted, and then cured according to the preset curing system; after curing, the template is removed to form an integral precast invert arch body with a hollow area.

[0035] To further elaborate on this embodiment, such as Figures 1 to 9 As shown, the prefabricated invert arch structure of a long-span highway tunnel in mountainous areas will be further explained, which includes the main load-bearing structure and the connecting structure. The main load-bearing structure is an integral hollow prefabricated inverted arch body 1. The integral hollow prefabricated inverted arch body 1 horizontally covers the tunnel inverted arch area and avoids the dark ditches on the left and right sides of the tunnel, and vertically extends from the bottom surface of the outer side of the inverted arch to the bottom surface of the tunnel road surface base bearing foundation, with a hollow area inside. This integrated hollow design can reduce the weight of components while ensuring the structural load-bearing strength. Compared with solid structures, it reduces the amount of materials used and the lifting weight is reduced to match the lifting capacity of the tunnel. The lateral coverage area is perfectly matched with the tunnel invert area, and by avoiding the roadside culverts, it avoids interference with the original drainage system of the tunnel, eliminating the need for additional modifications to the drainage system and simplifying the construction process.

[0036] The connection structure includes a circumferential connection component and a longitudinal connection component: The circumferential connecting component is located at the end of the integral hollow precast invert arch body 1 and corresponds to the connection position of the cast-in-place tunnel arch wall. It includes a tapered plastic sleeve pre-embedded at the end of the integral hollow precast invert arch body 1, a modified epoxy resin adhesive filled in the tapered plastic sleeve, and a rebar hole 4 coaxially arranged with the tapered plastic sleeve. The tapered plastic sleeve is used to adapt the rebar, the modified epoxy resin adhesive is used to enhance the anchoring strength between the rebar and the tapered plastic sleeve, and the rebar hole 4 is used to insert rebar to achieve a rigid connection between the integral hollow precast invert arch body 1 and the cast-in-place arch wall. The longitudinal connection component is located on the longitudinal end face of the integral hollow precast inverted arch body 1, including a pre-embedded weathering steel plate 5 embedded in the longitudinal end face, and high-strength bolts penetrating the pre-embedded weathering steel plates 5 of adjacent integral hollow precast inverted arch bodies 1; the pre-embedded weathering steel plate 5 is used to provide the installation foundation for the high-strength bolts, and the high-strength bolts are used to fasten adjacent integral hollow precast inverted arch bodies 1.

[0037] The tapered plastic sleeve adopts a gradually tapering structure that is thicker at the top and thinner at the bottom, which can improve the compatibility with the rebar and the anchoring stability. With the addition of modified epoxy resin adhesive, it can further enhance the bonding force between the rebar and the sleeve and prevent the connection node from loosening. The longitudinally embedded weathering steel plate can increase the stress area of ​​the high-strength bolts, prevent local squeezing damage to the end face of the precast main body when the bolts are tightened, and ensure the overall stress continuity after the connection of adjacent precast blocks.

[0038] In one embodiment, the hollow area of ​​the integral hollow precast inverted arch body 1 is a circular hollow hole, forming an integral circular hollow precast inverted arch body 1; the main body load-bearing structure also includes a concrete panel 7, a surface reserved layer 8, and a roadside culvert space 9; The concrete panel 7 is prefabricated on the top of the integral circular hollow prefabricated inverted arch body 1, and is the same width as the integral circular hollow prefabricated inverted arch body 1 in the horizontal direction. The top of the panel forms a panel joint corresponding to the adjacent prefabricated structure. The surface layer 8 is set on top of the concrete panel 7 and is used for on-site paving of road surface material. The roadside culvert space 9 is a reserved space on the left and right sides of the integral circular hollow prefabricated invert arch body 1. Its size matches the original design of the roadside culvert in the tunnel, avoiding interference with the tunnel drainage system.

[0039] Compared to other shaped perforated structures, circular perforations distribute stress more evenly, reducing stress concentration around the perforated area and lowering the risk of structural cracking. The prefabricated concrete panel 7 eliminates the need for on-site pouring, shortening the road base construction time. The surface layer 8 provides space for on-site paving of the road surface layer, allowing for flexible selection of surface materials based on actual road design requirements, thus improving structural adaptability. The dimensions of the roadside culvert openings 9 precisely match the original culvert design, ensuring smooth drainage and preventing drainage obstruction due to prefabricated structures.

[0040] like Figure 3 As shown, in one embodiment, this embodiment also includes a reinforcement structure; the reinforcement structure includes main bars 11, stirrups 12, and circular hollow reinforcement rings 13; The main reinforcing bars 11 are arranged at intervals along the longitudinal and transverse directions of the integral circular hollow prefabricated inverted arch body 1, and are the main load-bearing reinforcing bars of the structure. The stirrups 12 are arranged at intervals around the main reinforcement 11 along the length of the main reinforcement 11 to fix the position of the main reinforcement 11. The circular hollow hole reinforcement ring 13 surrounds the outside of the circular hollow hole of the integral circular hollow prefabricated inverted arch body 1 and is connected to the main reinforcement 11, which is used to strengthen the weak parts of the structure around the circular hollow hole. The longitudinally and transversely spaced main reinforcement bars 11 can fully bear the load borne by the structure and evenly transfer the force to the entire precast main body; the stirrups 12 are arranged around the main reinforcement bars, which can effectively fix the position of the main reinforcement bars and prevent the main reinforcement bars from shifting during precast production or stress, thus preventing the reinforcement skeleton from deforming; the circular hollow hole reinforcement rings 13 specifically strengthen the weak areas around the hollow holes, make up for the local strength deficiency that may be caused by the hollow design, and ensure that the entire precast main body is subjected to balanced forces.

[0041] like Figure 8 As shown, in one embodiment, this embodiment also includes a hoisting structure; the hoisting structure includes a pre-embedded hoisting rod 15, a pre-embedded sleeve for the hoisting rod, and hoisting point positioning marks; The pre-embedded sleeve of the hanger is pre-embedded in the top of the integral hollow precast inverted arch body 1 and on the side close to the concrete panel 7, and is symmetrically distributed in the transverse direction along the integral hollow precast inverted arch body 1. The pre-embedded lifting rod 15 is inserted into the pre-embedded sleeve of the lifting rod and is used for hoisting the integral hollow prefabricated inverted arch body 1; The lifting point positioning mark is set on the top surface of the integral hollow precast inverted arch body 1 to indicate the installation position of the pre-embedded sleeve of the lifting rod, ensuring that the deviation between the lifting point and the center of mass of the integral hollow precast inverted arch body 1 meets the requirements of balanced lifting force.

[0042] The pre-embedded sleeves of the lifting rods are symmetrically distributed along the transverse direction, which ensures that the components are subjected to uniform force during lifting and avoids tilting or damage caused by unilateral force. The lifting point positioning marks can quickly indicate the position of the sleeves, which facilitates precise docking of on-site lifting equipment, reduces the time for finding the lifting point, and improves lifting efficiency. The combined design of the pre-embedded lifting rods and sleeves eliminates the need to weld additional lifting lugs to the surface of the prefabricated main body, avoiding damage to the main structure. At the same time, the lifting rods can be removed after lifting without affecting subsequent construction.

[0043] like Figure 4 and Figure 7 As shown, in one embodiment, this embodiment also includes a waterproofing and grouting structure; the waterproofing and grouting structure includes a base grouting strip 18, a pre-embedded grouting steel pipe 19, and grouting holes 20; The base grouting strip 18 is located between the bottom surface of the integral hollow precast inverted arch body 1 and the tunnel base, and is used to accommodate grouting material to fill the gap between the body and the base. The pre-embedded grouting steel pipe 19 is pre-embedded in the base grouting strip 18 and is arranged longitudinally at intervals along the integral hollow prefabricated inverted arch body 1, and is used to inject grouting material into the base grouting strip 18. The grouting hole 20 is located on the bottom surface of the integral hollow prefabricated inverted arch body 1 and is used to indicate the installation position of the pre-embedded grouting steel pipe 19.

[0044] like Figure 4 and Figure 5 As shown, this embodiment also includes vent holes 16 and pre-embedded vent pipes 17. The base grouting strip 18 can accommodate grouting material to fill the gap between the precast body and the tunnel base, avoiding uneven stress on the precast body due to incomplete cleaning of base debris or voids formed by base settlement; the pre-embedded grouting steel pipes are arranged longitudinally at intervals to ensure that the grouting material uniformly fills the entire base grouting strip without grouting blind spots; the vent holes 16 and pre-embedded vent pipes 17 can discharge air in the strip during the grouting process, preventing air from accumulating and forming bubbles that affect the grouting density, and improving the adhesion between the precast body and the base.

[0045] like Figure 6 and Figure 7As shown, in one embodiment, the waterproofing and grouting structure in this embodiment also includes a joint waterproofing component; the joint waterproofing component is provided at the longitudinal joint of the adjacent integral hollow precast inverted arch body 1, and includes a water-swellable waterstop strip with grouting pipe, a waterstop strip groove 2, a sealing layer and a top waterproof coating. The waterstop groove 2 is opened on the inner wall of the longitudinal joint and is used to limit the waterstop strip with grouting pipe that expands when exposed to water; The water-swellable sealing strip with grouting pipe is embedded in the sealing strip groove 2 to seal the inner gap of the longitudinal joint; The sealing layer is filled on the outside of the water-swellable waterstop strip with grouting pipe, and is used for secondary sealing of longitudinal joints; The top waterproof coating covers the top surface of the longitudinal joint and is flush with the top surface of the concrete panel 7, while also covering the panel joint, thus achieving waterproof sealing of the top surface of the joint. In this embodiment, the top waterproof coating uses a cement-based penetrating crystalline waterproof coating filling 10.

[0046] The waterstop groove 2 can precisely limit the water-swellable waterstop strip, preventing it from shifting during construction and causing waterproofing failure. The water-swellable waterstop strip with grouting pipe can expand on its own after contact with water, tightly adhering to the joint sidewall to achieve primary waterproofing. The outer sealing layer forms secondary waterproofing, and the top waterproof coating achieves tertiary waterproofing. This triple waterproofing system can significantly improve the waterproofing performance at the joint, preventing rainwater or groundwater from seeping into the tunnel foundation through the joint. Cement-based penetrating crystalline waterproof coating is used as the top waterproof coating. It has good compatibility with the concrete panel and has penetrating crystalline properties, which can self-repair even at tiny cracks, improving waterproofing durability.

[0047] like Figure 9 As shown, in one embodiment, this embodiment also includes a monitoring and traceability structure; the monitoring and traceability structure includes a strain gauge 6, a strain gauge signal line protection tube, an information storage chip, and a chip positioning slot 14; The chip positioning slot 14 is opened in the internal cavity sidewall of the integral hollow prefabricated arch body 1 and is used to accommodate the information storage chip. The information storage chip is embedded in the chip positioning slot 14. The information storage chip used in this invention uses RFID pre-embedded parts 3 to record the production and structural parameters of the integral hollow prefabricated inverted arch body 1, so as to realize full life cycle traceability. The strain gauges 6 are arranged at intervals along the longitudinal and transverse directions of the integral hollow precast inverted arch body 1, and are used to monitor strain changes during the construction and operation of the structure. The strain gauge signal line protection tube is embedded inside the integral hollow prefabricated arch body 1 and sleeved on the outside of the strain gauge 6 signal line to protect the signal line from being squeezed and damaged by the internal materials of the structure.

[0048] This invention also includes a monitoring point 21. The RFID embedded part 3 can store information such as the production batch, material specifications, and reinforcement parameters of the precast main body, which can be easily read by special equipment at each stage of construction and operation, realizing quality traceability and responsibility traceability of the entire life cycle of the component. The strain gauges 6 arranged longitudinally and laterally can monitor the strain changes of the structure in real time under the action of construction hoisting and operation loads. When the strain value exceeds the design threshold, it can give an early warning in time to avoid damage to the structure due to overload. The strain gauge signal line protection tube can prevent the signal line from being squeezed or broken by concrete pouring during precast production, ensuring stable monitoring data transmission. The monitoring point 21 can be used as a fixed point for on-site manual inspection or equipment monitoring, improving the accuracy and consistency of monitoring data.

[0049] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A prefabricated construction method for the invert arch of a long-span highway tunnel in mountainous areas based on prefabricated components, characterized by: Includes the following steps: S1: Prefabricated component preparation, obtaining prefabricated invert arch components adapted to mountainous long-span highway tunnels. The prefabricated invert arch components include an integral hollow prefabricated invert arch body, circumferential connection components, longitudinal connection components, waterproof and grouting structures, and monitoring and traceability structures. S2: Tunnel foundation treatment, pre-treatment of the foundation in the tunnel invert construction area to ensure that the foundation meets the installation conditions of the precast invert components; S3: Precast component hoisting and positioning. The precast invert arch component from step S1 is hoisted to the construction area of ​​the tunnel foundation and the component position is adjusted to the design reference. S4: Component connection and fastening: The circumferential connection component enables the rigid connection between the precast invert arch component and the cast-in-place tunnel arch wall, while the longitudinal connection component enables the fastening connection between adjacent precast invert arch components. S5: Waterproof grouting construction, using the waterproof and grouting structure to seal and fill the gap between the precast invert arch component and the base, and the joints of adjacent components; S6: Monitoring and tracing deployment, activate the monitoring and tracing structure, and complete the debugging and information entry of monitoring functions during the construction and operation phases.

2. The prefabricated construction method for the invert arch of a long-span highway tunnel in mountainous areas based on prefabricated components according to claim 1, characterized in that: The preparation of prefabricated components in step S1 specifically includes: casting and forming the integral hollow prefabricated inverted arch body in the factory according to the design parameters, simultaneously pre-embedding the adapter parts of the circumferential connection components, the connecting parts of the longitudinal connection components, the pre-set components of the waterproof and grouting structure, and the sensing and storage components of the monitoring and traceability structure. After the prefabrication is completed, the components are subjected to appearance inspection, size verification and mechanical performance sampling inspection. After passing the inspection, they are transported to the construction site.

3. The prefabricated construction method for the invert arch of a long-span highway tunnel in mountainous areas based on prefabricated components according to claim 1, characterized in that: The tunnel foundation treatment in step S2 specifically includes: removing loose debris, impurities, and accumulated water from the tunnel invert arch foundation; using leveling materials to level the foundation surface to form a flat installation base; if there are local depressions or loose areas in the foundation, filling and compacting the depressions and reinforcing the loose areas; after treatment, testing the flatness and bearing strength of the foundation to ensure that the flatness deviation does not exceed the design allowable range and the bearing strength meets the load requirements of the precast invert arch components.

4. The prefabricated construction method for the invert arch of a long-span highway tunnel in mountainous areas based on prefabricated components according to claim 1, characterized in that: Step S3, the hoisting and positioning of precast components, specifically includes: connecting the hoisting equipment to the embedded lifting rods of the component according to the pre-set hoisting point positioning marks on the top of the precast invert arch component; starting the hoisting equipment to slowly hoist the component to the upper part of the foundation construction area, adjusting the horizontal posture and vertical height of the component to align the axis of the component with the design axis of the tunnel invert arch; gradually lowering the component to the foundation installation surface, monitoring the positional deviation of the component in real time using a level and total station, adjusting the component until the positioning deviation meets the design requirements, and temporarily fixing the component.

5. The prefabricated construction method for the invert arch of a long-span highway tunnel in mountainous areas based on prefabricated components according to claim 1, characterized in that: Step S4, which achieves the rigid connection between the precast invert arch component and the cast-in-place tunnel arch wall through the circumferential connection assembly, specifically includes: cleaning the inner wall of the anchoring hole of the circumferential connection assembly at the end of the precast invert arch component; filling the pre-embedded tapered plastic sleeve in the anchoring hole with modified epoxy resin adhesive; after the adhesive reaches the preset curing strength, inserting the reinforcing bar into the anchoring hole, so that one end of the reinforcing bar is anchored to the tapered plastic sleeve, and the other end extends to the casting area of ​​the cast-in-place tunnel arch wall; and pouring the cast-in-place arch wall concrete, so that the reinforcing bar and the cast-in-place arch wall concrete form an integral whole, thereby achieving the rigid connection between the precast invert arch component and the cast-in-place arch wall.

6. The prefabricated construction method for the invert arch of a long-span highway tunnel in mountainous areas based on prefabricated components according to claim 1, characterized in that: Step S4, which involves achieving a tight connection between adjacent precast invert arch components using the longitudinal connection assembly, specifically includes: cleaning the surface of the weathering steel plate embedded in the longitudinal end face of the adjacent precast invert arch components, removing rust and impurities from the steel plate surface; aligning and fitting the weathering steel plates of the adjacent components, inserting high-strength bolts into the bolt holes of the steel plates; and tightening the high-strength bolts with a torque wrench according to the preset torque value to ensure that the preload of the bolts meets the design requirements, thereby achieving a tight connection between the adjacent precast invert arch components.

7. The prefabricated construction method for the invert arch of a long-span highway tunnel in mountainous areas based on prefabricated components according to claim 1, characterized in that: Step S5, which utilizes the waterproofing and grouting structure to fill the gap between the precast invert arch component and the base, specifically includes: connecting the grouting equipment and the pre-embedded grouting steel pipe through the grouting holes of the waterproofing and grouting structure on the bottom surface of the precast invert arch component; injecting grouting material into the pre-embedded grouting steel pipe, the grouting material flowing through the steel pipe into the base grouting strip between the component and the base to fill the gap between the component and the base; during the grouting process, air in the strip is discharged through the vent hole; when the grouting material overflows from the vent hole or the grouting pressure reaches the preset value, grouting is stopped, the grouting hole and the vent hole are sealed, and the grouting material is allowed to solidify.

8. The prefabricated construction method for the invert arch of a long-span highway tunnel in mountainous areas based on prefabricated components according to claim 1, characterized in that: Step S5, which uses the waterproofing and grouting structure to seal the joints of adjacent components, specifically includes: embedding a water-swellable water-stop strip with a grouting pipe into the groove of the water-stop strip of the longitudinal joint of the adjacent precast invert arch component; filling the joint gap outside the water-stop strip with sealing material to form a sealing layer; and after the sealing layer has cured, applying a waterproof coating to the top surface of the joint so that the waterproof coating covers the top surface of the joint and is flush with the top surface of the concrete panel of the precast invert arch component, while also covering the panel joint of the concrete panel.

9. The prefabricated construction method for the invert arch of a long-span highway tunnel in mountainous areas based on prefabricated components according to claim 1, characterized in that: Step S6, the monitoring and traceability deployment, specifically includes: connecting the signal lines of the strain gauges in the monitoring and traceability structure to external monitoring equipment; adjusting the monitoring accuracy of the strain gauges to ensure that the strain gauges can collect strain data of the precast invert arch components in real time; writing the production parameters, installation parameters, and design parameters of the components to the information storage chip of the monitoring and traceability structure through a dedicated reading and writing device; and connecting the monitoring equipment and the chip reading and writing device to the tunnel operation and maintenance management system to realize the real-time uploading and traceability query of component construction data and operation monitoring data.

10. The prefabricated construction method for the invert arch of a long-span highway tunnel in mountainous areas based on prefabricated components according to claim 2, characterized in that: The casting and forming of the integral hollow precast invert arch body in step S1 specifically includes: forming by combining a steel reinforcement skeleton with a template. The steel reinforcement skeleton includes main reinforcement bars arranged in the longitudinal and transverse directions of the main body, stirrups surrounding the main reinforcement bars, and reinforcement rings surrounding the hollow holes of the main body; after the template is installed, concrete is poured, vibrated and compacted, and then cured according to the preset curing system. After curing, the template is removed to form the integral precast invert arch body with hollow areas.

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