Lateral superposed beam and slab structure assembled unbonded prestressed road and construction method

Abstract

The invention provides a lateral superposed beam and slab structure assembled unbonded prestressed road and a construction method. According to the overall technical scheme, a lateral stiffening superposed beam supporting system is constructed, an upper truss rib and a lower truss rib are designed in an anti-shearing and bearing mode, double-layer steel bar meshes are hoisted in place in sections, modules and sections, the lateral stiffening superposed beam in the transverse middle of a road is designed in a mirror image double-superposed mode, and joints serve as structural settlement joints. Additional steel bars are additionally arranged in the settlement joint to be combined with bituminous concrete treatment, horizontal steel bar sleeves of the segmented lateral stiffening superposed beams are connected in a grouting mode, secondary bedding auxiliary components of a gravel cushion layer are hoisted, and hidden beam steel reinforcement cages reinforce segmented connecting joints of the lateral stiffening superposed beams. The unbonded prestressed tendons are symmetrically tensioned and anchored by taking each construction section as an independent unit as a principle, the structural design is innovated, the process method is optimized, a matched technical standard is expected to be formed, high-level development of the technical field of fabricated roads in China is jointly boosted, and the unbonded prestressed tendons are worthy of industrial popularization and application.

Description

Technical Field

[0001] This invention relates to the field of prefabricated road technology, and in particular to a lateral composite beam-slab structure prefabricated unbonded prestressed road and its construction method. Background Technology

[0002] Traditional wet construction methods can no longer meet the basic requirements of the national development of building industrialization and green construction. Innovating structural design and optimizing process methods to continuously develop new structures, processes and methods suitable for different complex working conditions are key issues that the industry urgently needs to solve. Existing prefabricated road construction technologies still lack systematic complete sets of technologies and standards in engineering applications. There are still segmental inconsistencies in structural bearing capacity and load transfer. There is still no better solution to the problem of resisting uneven settlement of different geological soil layers. There is still much room for optimization in the dry and wet mixed operation process of hoisting various prefabricated components, such as process connection and improvement of clear load transfer paths. Currently, the research and application of prefabricated road construction technology in China is still in its early stages, and the supporting technical system is not perfect. The existing road structure system mainly uses a compressive load-bearing mode formed by prefabricated component assembly combined with partial grouting process. This is similar to the traditional wet construction integral cast-in-place stress form, and neither can better form an overall stress-bearing form. Therefore, the key to improving the durability of road structures lies in building a more effective structural technology system on the basis of strengthening the roadbed load-bearing capacity and clarifying the load transfer path, so as to form a new roadbed-structure collaborative load-bearing mode, solve technical problems such as large local stress and uneven roadbed settlement during road use, and avoid serious structural damage and short service life of road structures during use.

[0003] Therefore, in order to solve the above-mentioned technical problems, the present invention provides an unbonded prestressed road and construction method for lateral composite beam-slab structure assembly. Summary of the Invention

[0004] The purpose of this invention is to provide an unbonded prestressed road with a lateral composite beam-slab structure and a construction method therefor, in order to solve the problems raised in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a lateral composite beam-slab structure assembled unbonded prestressed road, comprising a roadbed soil layer, laterally stiffened composite beams, upper truss ribs, lower truss ribs, upper steel mesh, lower steel mesh, cast-in-place concrete layer, unbonded prestressed tendons, anchorages, and asphalt concrete surface layer.

[0006] Laterally stiffened composite beams are provided at both ends and the middle of the road. The laterally stiffened composite beams at both ends of the road are independent composite beams, while the laterally stiffened composite beams in the middle of the road are mirror-image double composite beams. Each laterally stiffened composite beam has an upper truss rib and a lower truss rib at its vertical overlapping part. An upper steel mesh and a lower steel mesh are respectively provided between the upper and lower truss ribs of the adjacent laterally stiffened composite beams in the road. Both the upper and lower steel meshes are double-layered bidirectional steel meshes, and the upper and lower truss ribs are fixed to the upper and lower steel meshes by welding.

[0007] Each of the lateral stiffening composite beams is provided with a reserved channel inside. Unbonded prestressing tendons are arranged transversely along the inside of the road and pass through the reserved channel inside each lateral stiffening composite beam. The two ends of each unbonded prestressing tendon are anchored to the outer end face of the lateral stiffening composite beam at both ends of the road.

[0008] A cast-in-place concrete layer is also provided between the lateral stiffening composite beams of the road, and the cast-in-place concrete layer is poured to the top surface elevation of each lateral stiffening composite beam. After the main structure of the road is hoisted and constructed, an asphalt concrete surface layer is also provided on the top surface of the entire road structure. The asphalt concrete surface layer is appropriately adjusted according to the road alignment.

[0009] Preferably, the lateral stiffening composite beam, upper truss rib, lower truss rib, upper steel mesh, and lower steel mesh are all prefabricated in a prefabricated PC factory. Each lateral stiffening composite beam is 6000mm~9000mm long and has a cross-sectional dimension of not less than 150mm×300mm. The upper and lower truss ribs are integrally formed during the prefabrication of the lateral stiffening composite beam. The upper and lower truss ribs are arranged parallel to each other along the length of the lateral stiffening composite beam. The upper truss rib is arranged 50mm below the top surface of the lateral stiffening composite beam, and the lower truss rib is arranged at least 120mm below the top surface of the lateral stiffening composite beam. It should also be able to provide sufficient space for laying unbonded prestressed tendons between the upper and lower steel meshes. To ensure that the unbonded prestressing tendons can traverse the interior of each laterally stiffened composite beam, pre-embedded ducts are installed in the laterally stiffened composite beams during the prefabrication process in the precast PC factory using a galvanized steel pipe method. These ducts are located inside the laterally stiffened composite beams between the upper and lower truss ribs, with the inner diameter of the ducts being 2mm-3mm larger than the designed outer diameter of the unbonded prestressing tendons. The upper and lower truss ribs are made of high-strength manganese steel with a cross-sectional dimension of not less than 30mm × 120mm, and the flange and web thicknesses are both not less than 10mm. The upper and lower truss ribs are embedded at least 60mm into the laterally stiffened composite beams.

[0010] Preferably, in order to strengthen the joint design of the strong bearing capacity between the composite part and the cast-in-place concrete layer inside the overall road structure, the width of the vertical composite part of the lateral stiffening composite beam shall not be less than 1 / 3 of the width of the precast part of the composite beam and not less than 70mm. The exposed steel bars of the vertical composite part of the lateral stiffening composite beam include stirrups and two longitudinal reinforcing bars at the corners of the stirrups. The upper truss rib and the lower truss rib are located on the inner side of the composite part. The distance between the inner surface of the exposed stirrups of the vertical composite part of the lateral stiffening composite beam and the flange surface of the upper truss rib and the lower truss rib shall not be less than 30mm. Meanwhile, in order to strengthen the bond between the precast laterally stiffened composite beam and the cast-in-place concrete layer, the concrete surface of the vertical overlapping part of the laterally stiffened composite beam is roughened during the prefabrication process in the PC factory. This is achieved by spraying a retarder and using a high-pressure water jet flushing process. Specifically, during the prefabrication process in the PC factory, after the concrete in the mold is poured and before it initially sets, a layer of retarder is sprayed onto the concrete surface of the vertical overlapping part of the laterally stiffened composite beam. After the concrete in the mold has finally set, a high-pressure water jet is immediately used to flush the overlapping part, so that the slurry on the concrete surface of the vertical overlapping part of the laterally stiffened composite beam can be removed and the aggregate exposed. The roughness rate is not less than 85%, and the height difference of the exposed aggregate on the rough surface is not less than 4mm.

[0011] Preferably, in order to improve the overall load-bearing capacity of the prefabricated beam-slab structure technology system, the segmented laterally stiffened composite beams adopt the horizontal steel bar sleeve grouting connection technology. That is, the adjacent laterally stiffened composite beams are connected by no less than 6 horizontal steel bar grouting sleeves. Both ends of the laterally stiffened composite beam are respectively equipped with horizontal steel bar grouting sleeves and outward reinforcing bars. The steel bar grouting sleeves are arranged in two rows. The steel bar grouting sleeves are pre-embedded in the prefabrication process of the laterally stiffened composite beam. The positional relationship between the steel bar grouting sleeves and the outward reinforcing bars is one-to-one. The outward reinforcing bars at one end of the laterally stiffened composite beam are precisely aligned and inserted into the steel bar grouting sleeve of the adjacent laterally stiffened composite beam. The length of the outward reinforcing bars at one end of the laterally stiffened composite beam is not less than 150mm. The segmented connection design of the laterally stiffened composite beam is completed by high-pressure grouting in the steel bar grouting sleeve. According to the design plan, in order to improve the overall load-bearing capacity of the prefabricated beam-slab structure technology system, the focus is on strengthening the resistance of the joints of the laterally stiffened composite beams to uneven settlement of the roadbed. Hidden beam reinforcement cages are set on the inner side of the joints of the adjacent laterally stiffened composite beams. The construction of the hidden beam reinforcement cages is synchronized with the pouring of the cast-in-place reinforced concrete layer. The diameter of the longitudinal reinforcing bars of the hidden beam reinforcement cages is not less than 16mm, and the cutting length of the hidden beam reinforcement cages is not less than 1200mm. All longitudinal reinforcing bars of the hidden beam reinforcement cages on the side closest to the composite beam are arranged inside the stirrups of the composite part of the composite beam and are arranged along the entire length.

[0012] Preferably, upper and lower reinforcing meshes are respectively provided between the upper and lower truss ribs of the cross-section stiffened composite beams on both sides of the road. The upper and lower reinforcing meshes are made of double-layer bidirectional reinforcing bars with a diameter of not less than 8mm. The lower part of the reinforcing mesh is laid out horizontally, and its two ends are supported on the top of the upper or lower truss ribs respectively. The longitudinal reinforcing bars are supported on the horizontal reinforcing bars. At the same time, in order to facilitate the on-site construction of the upper and lower reinforcing meshes, after the upper and lower reinforcing meshes are fabricated off-site, they are hoisted into place by section, module, and segment using mechanical equipment. The two ends of the horizontal reinforcing bars at the bottom of the reinforcing mesh are welded to the top of the upper or lower truss ribs to achieve a rigid connection node between the upper and lower reinforcing meshes.

[0013] Preferably, the lateral stiffening composite beams in the middle of the road are arranged in a mirror double composite beam design. The joint between the two lateral stiffening composite beams also serves as the road structure settlement joint. The width of the settlement joint in the middle is not less than 60mm, and asphalt concrete is poured into the settlement joint. The asphalt concrete filling the joint is designed with the same mix proportion as the asphalt concrete surface layer at the top of the road structure.

[0014] This invention also proposes a construction method for an unbonded prestressed road with a lateral composite beam-slab structure. The construction process is as follows: S1. Surveying and setting out the road alignment, trench excavation; S2. Elevation verification, laying of sand and gravel cushion layer; S3. Grouting the trench bottom, segmented hoisting of the laterally stiffened composite beam; S4. Installation of the lower layer steel mesh, perforated laying of unbonded prestressing tendons; S5. Grouting and sleeve connection of steel bars at the joints of the laterally stiffened composite beam, installation of the hidden beam steel cage; S6. Installation of the upper layer steel mesh, construction of the cast-in-place concrete layer; S7. Treatment of settlement joints between the two laterally stiffened composite beams in the middle of the road; S8. Tensioning and anchoring of unbonded prestressing tendons, and full paving of the asphalt concrete surface layer.

[0015] The preferred technical solution steps are as follows: S1: Surveying and setting out road alignment, trench excavation First, a total station was used to survey and mark the road alignment in sections. The site was then leveled and excavated. Pre-defined positioning piles were driven in sections and spans to mark the specific locations of each construction section. The length of each construction section was generally 300m to 400m. Three pre-defined positioning piles were driven every 20m in each construction section, one on each side of the road and one in the middle of the road span. The design dimensions of the pre-defined positioning piles were not less than 200mm in cross-section and not less than 800mm in length. They were equipped with no less than 4Φ12 threaded steel bars. Each pre-defined positioning pile was prefabricated in a prefabricated PC factory and transported to the site for driving one by one. The driving of each pre-designated positioning pile employs a two-step pile driving process. First, based on total station measurements, the pre-designated positioning piles are driven to a depth of at least 500mm. This process distributes the road alignment through the installation of these pre-designated positioning piles. Then, based on the trench bottom elevation marked on the pile top, each pile is driven to its designated elevation. The overall design of the pre-designated positioning piles aims to determine the basic road alignment, control the on-site construction elevation of each section, and improve the bearing capacity of the subgrade soil—a triple effect. Specifically, the positioning pile elevation is measured at the top of each pile, and the overall layout is based on the principle that the pile top elevation is equal to the trench bottom elevation. Each pre-designated positioning pile is then driven to its designated trench excavation position. A cross-flow construction organization method is adopted. After the pre-positioned piles in each construction section are driven to the design elevation, the trench excavation work can be carried out. The trench excavation width on both sides of the road should be more than 160mm larger than the width of the lateral stiffening composite beam. The trench excavation width in the middle of the road is equal to the width of the lateral stiffening composite beam × 2 + 200mm to leave sufficient working surface. The trench excavation depth is based on the top elevation of each pre-positioned pile and is arranged in a coordinated manner. On-site procedures are carried out strictly in accordance with the construction organization design requirements, and process acceptance and recording are done well.

[0016] S2: Elevation verification, laying of gravel bedding layer After all trenches in each construction section have been excavated, manual cleaning and elevation verification of the trench bottom and walls are carried out to ensure that the top elevation of each pre-positioned pile is less than or equal to the designed trench excavation elevation, with the height difference controlled within 50mm. To further enhance the load-bearing capacity of the unbonded prestressed prefabricated road technology system with lateral stiffened composite beam-slab structure, a 60mm~90mm sand and gravel cushion layer is installed on the top of the trench. That is, a sand and gravel cushion layer is laid on the top surface of each trench after excavation as a bearing layer. This forms a structure that further improves the load-bearing capacity of the overall road structure system based on the pre-positioned pile-reinforced subgrade soil layer combined with the sand and gravel cushion layer as a bearing layer. After the trenches are excavated, the top surface of the sand and gravel cushion layer is made of 8mm~12mm diameter graded gravel and coarse sand. After the sand and gravel cushion layer in each construction section is laid, it is appropriately compacted and strengthened. Special attention is paid to the quality of the sand and gravel cushion layer at the subsequent hoisting position of the lateral stiffening composite beam. During the on-site construction, a total station is used to check and record the thickness of the sand and gravel cushion layer. Dedicated personnel are assigned to supervise the work on-site to control the construction quality of each process and to do a good job in process acceptance and recording.

[0017] S3: Grouting at the bottom of the trench, sectional hoisting of the lateral stiffening composite beam. Before the sectional hoisting of the laterally stiffened composite beams, the already laid sand and gravel cushion layer in the trench is grouted. The sand and gravel cushion layer is reinforced using a two-stage grooving technique. First, a layer of fiber-reinforced waterproof mortar is laid on top of the sand and gravel cushion layer, according to the bottom elevation of each laterally stiffened composite beam. Then, the fiber-reinforced waterproof mortar is smoothed according to the road alignment and elevations at various points. The smoothed surface elevation is 5mm-10mm lower than the bottom elevation of the laterally stiffened composite beam, thus strengthening the curing of the first grooving layer. After the first grooving layer has cured to 100% of its design strength, a second grooving layer is laid before the laterally stiffened composite beams are hoisted. The loose thickness of the second grooving layer should be 3mm-5mm greater than that of the laterally stiffened composite beams. Then, the laterally stiffened composite beams are hoisted into place in one go. During on-site construction, the "horizontal steel bar sleeve grouting connection technology, segmented hoisting, segmented connection, and segmented high-pressure grouting" technical solution was adopted for the hoisting of the laterally stiffened composite beams. Specifically, adjacent precast laterally stiffened composite beams were connected in segments using a steel bar sleeve grouting connection method. First, the extended steel bars at the ends of the hoisted laterally stiffened composite beams were inserted into the steel bar sleeves at the bottom of the subsequently hoisted laterally stiffened composite beams. Then, high-pressure grouting was used to inject micro-expansion, low-shrinkage fiber-reinforced grout. The segmented hoisting, positioning, and connection of all laterally stiffened composite beams were completed one by one. After the segmented hoisting of the laterally stiffened composite beams in each construction section was completed, fine aggregate concrete with a strength of not less than C30 was injected into the working surface between the laterally stiffened composite beams and the trench. The fine aggregate concrete was poured to 100mm below the designed prestressed tendon anchorages, and relevant concealed works acceptance and recording were carried out.

[0018] S4: Installation of lower layer steel mesh, and perforation laying of unbonded prestressed tendons. Because the upper and lower truss ribs of the stiffened composite beams on both sides of the road are respectively equipped with upper and lower steel mesh, and both upper and lower steel mesh are double-layered bidirectional steel mesh, from the perspective of coordinated bearing and effective load transfer, the upper and lower steel mesh are supported on the upper and lower truss ribs respectively and fixed by welding. During on-site construction, the installation of the upper and lower steel mesh adopts the technical solution of "prefabrication, segmented hoisting, node welding, bottom-to-top, and reasonable overlap". That is, the upper and lower steel mesh are prefabricated on the construction site or in the prefabricated PC factory, transported to the design position, and then mechanically hoisted into place in segments. The lower steel mesh is hoisted first, followed by the upper steel mesh. The connection nodes of the upper and lower steel mesh and the upper and lower truss ribs are firmly welded, and the overlap length of the distributed steel bars between adjacent steel meshes in the longitudinal direction of the road is not less than 120mm. After the lower layer of steel mesh is installed in each construction section, the unbonded prestressing tendons can be laid out on-site. The unbonded prestressing tendons are laid out using the following technical solution: "First, pass through the pre-embedded ducts in the mirror double composite beam in the middle of the road, accurately lay out the line of the prestressing tendons, and then pass through the pre-embedded ducts inside the composite beams on both sides of the road for temporary anchoring." The construction quality of each process should be well controlled, and process acceptance and recording should be done well.

[0019] S5: Grouting sleeve connection at the joint of the lateral stiffened composite beam, and installation of the hidden beam reinforcement cage. After the lower layer of reinforcing mesh and unbonded prestressed tendons in each construction section are laid, the segmented connection construction of the laterally stiffened composite beams can begin. The segmented connection of the laterally stiffened composite beams adopts a technical solution of "horizontal grouting sleeve connection, segmented alignment, sealing strip treatment, and high-pressure grouting." During on-site construction, since both ends of the laterally stiffened composite beams are equipped with horizontal reinforcing steel grouting sleeves and extended reinforcing bars, the extended reinforcing bars at one end of the laterally stiffened composite beam are first hoisted, precisely aligned, and inserted. Then, the grouting sleeves of the adjacent laterally stiffened composite beams are hoisted, and high-pressure grouting is used to reliably connect each segment of the laterally stiffened composite beams. To prevent grout leakage in the horizontal reinforcing steel sleeves, weather-resistant flexible sealing strips are embedded in the joints of adjacent laterally stiffened composite beams before high-pressure grouting. These sealing strips do not need to be removed after grouting. Meanwhile, in order to further enhance the strength of the segmental connection nodes of each lateral stiffened composite beam and the overall structural bearing capacity, a hidden beam steel cage is installed on the inner side of the road at the joint of the adjacent lateral stiffened composite beams. The two longitudinal steel bars of the hidden beam steel cage near one end of the lateral stiffened composite beam are spot welded to the upper truss rib and the lower truss rib respectively, and the process acceptance and recording work is carried out.

[0020] S6: Installation of upper steel mesh and construction of cast-in-place concrete layer. After the grouting sleeves for the reinforcing bars at the joints of the laterally stiffened composite beams in each construction section are connected and the reinforcing cages for the concealed beams are installed in place, the installation of the upper layer of reinforcing mesh can begin. The installation of the upper layer of reinforcing mesh follows the same technical scheme as the installation of the lower layer of reinforcing mesh in step S4. During on-site construction, the installation of the upper layer of reinforcing mesh must not disturb the positional relationship between the already positioned lower layer of reinforcing mesh and the unbonded prestressed tendons. After all precast components are hoisted into place, the cast-in-place concrete layer is poured in sections and intervals using fine aggregate concrete with a strength not lower than the design strength of the laterally stiffened composite beam. Vibration of the cast-in-place concrete layer within 300mm of each laterally stiffened composite beam and at the joints is intensified. Vibration work must not interfere with the positional relationship of the upper truss ribs, lower truss ribs, unbonded prestressed tendons, and reinforcing mesh. Relevant concealed works acceptance and recording should be completed.

[0021] S7: Settlement joint treatment between the reinforcing composite beams on both sides of the transverse middle section of the road. After the cast-in-place concrete layer reaches more than 85% of its design strength, the settlement joint between the two lateral stiffening composite beams in the middle of the road is treated by "adding additional steel bars + pouring asphalt concrete". The asphalt concrete construction in the settlement joint adopts the two-stage pouring method. That is, the first pouring is at the elevation of the unbonded prestressing tendons. Then, additional steel bars are laid in the settlement joint. The diameter of the additional steel bars is not less than 16mm. The additional steel bars are erected along the entire length on the unbonded prestressing tendons in the settlement joint. After the additional steel bars in each construction section are laid, the second pouring process of asphalt concrete in the settlement joint is carried out. The second pouring of asphalt concrete is carried out to 30mm~50mm below the top surface of the lateral stiffening composite beam. The remaining part is treated together with the subsequent asphalt concrete paving. The process acceptance and recording work should be done well.

[0022] S8: Unbonded prestressed tendon tensioning and anchoring, full asphalt concrete surface paving. Once the overall concrete strength of the road structure reaches 100% of the design strength, the tensioning and anchoring of the unbonded prestressed tendons can begin. During on-site construction, the unbonded prestressed tendons adopt a technical solution of "treating each construction section as an independent unit, tensioning from the middle of the construction section to both ends, using a 1.03σcon over-tensioning method, symmetrical tensioning, and anchoring as tensioning progresses." As can be seen from step S3 of the technical solution, since fine aggregate concrete with a strength of not less than C30 is injected into the working surface between the laterally stiffened composite beam and the trench, and the fine aggregate concrete is poured to 100mm below the designed prestressing tendon anchor, the working surface above the anchor between the laterally stiffened composite beam and the trench after the unbonded prestressing tendons in each construction section are tensioned and anchored still needs to be grouted a second time. The second grouting not only stabilizes the road cut slope and improves the overall load-bearing capacity of the road structure, but also takes into account the sealing and anchoring effect after the prestressing tendons are tensioned. Finally, the asphalt concrete surface layer is fully paved, and steps S1 to S8 are repeated to carry out the overall segmented flow construction organization until the on-site construction of the road structure is completed, and the project acceptance and data archiving are organized. Attached Figure Description

[0023] Figure 1 This is a structural schematic diagram of a preferred embodiment of the unbonded prestressed prefabricated road with a laterally stiffened composite beam-slab structure provided by the present invention. Figure 2 for Figure 1 A three-dimensional view of the laterally stiffened composite beam shown; Figure 3 for Figure 1 The cross-sectional view of the laterally stiffened composite beam is shown. Figure 4 The construction process flow diagram of the unbonded prestressed prefabricated road with lateral stiffened composite beam-slab structure provided by the present invention.

[0024] The following are the labels in the diagram: 1. Laterally stiffened composite beam; 2. Upper truss rib; 3. Lower truss rib; 4. Upper steel mesh; 5. Lower steel mesh; 6. Unbonded prestressed tendon; 7. Anchorage; 8. Asphalt concrete surface layer; 9. Embedded duct; 10. Grouting sleeve for steel reinforcement; 11. Outwardly extending steel bar; 12. Longitudinal reinforcing bar of the composite section; 13. Stirrups of the composite section. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] Please refer to the following: Figure 1 , Figure 2 , Figure 3 , Figure 4 ,in, Figure 1 A schematic diagram of an unbonded prestressed prefabricated road structure with lateral stiffened composite beam-slab structure; Figure 2This is a three-dimensional view of a laterally stiffened composite beam; Figure 3 This is a cross-sectional view of a laterally stiffened composite beam; Figure 4 This is a construction process flow diagram for unbonded prestressed prefabricated roads with lateral stiffened composite beam-slab structures.

[0027] The present invention discloses an integral structure for an unbonded prestressed prefabricated road with a laterally stiffened composite beam-slab structure, as shown in the figure. Figures 1 to 4 As shown, the overall technical solution follows the principle of "constructing a laterally stiffened composite beam support system, designing upper and lower truss ribs for shear bearing capacity, hoisting and positioning double-layer steel mesh in sections, modules, and segments, mirroring the double-layer design of the laterally stiffened composite beam in the middle of the road transverse direction with the joints also serving as structural settlement joints, adding additional steel bars in the settlement joints and treating them with asphalt concrete, grouting the horizontal steel bar sleeves of the segmented laterally stiffened composite beams, using the secondary grouting of the sand and gravel cushion layer to assist in the hoisting of components, reinforcing the segmented connection nodes of each laterally stiffened composite beam with the hidden beam steel cage, and symmetrically tensioning and anchoring the unbonded prestressed tendons with each construction segment as an independent unit".

[0028] The prefabricated road of the present invention mainly consists of a roadbed soil layer, a lateral stiffening composite beam 1, an upper truss rib 2, a lower truss rib 3, an upper steel mesh 4, a lower steel mesh 5, a cast-in-place concrete layer, unbonded prestressed tendons 6, anchorages 7, and an asphalt concrete surface layer 8. Laterally stiffened composite beams 1 are provided at both ends and the middle of the road. The laterally stiffened composite beams 1 at both ends of the road are independent composite beams, while the laterally stiffened composite beams 1 in the middle of the road are mirror double composite beams. Each laterally stiffened composite beam 1 has an upper truss rib 2 and a lower truss rib 3 at its vertical overlapping part. Between the upper truss rib 2 and the lower truss rib 3 of the adjacent laterally stiffened composite beams 1 on both sides of the road, there are upper steel mesh 4 and lower steel mesh 5 respectively. Both the upper steel mesh 4 and the lower steel mesh 5 are double-layer bidirectional steel meshes, and the upper truss rib 2 and the lower truss rib 3 are fixed to the upper steel mesh 4 and the lower steel mesh 5 by welding. Each laterally stiffened composite beam 1 has a pre-reserved duct 9 inside. Unbonded prestressed tendons 6 are arranged transversely along the interior of the road, and the unbonded prestressed tendons 6 pass through the pre-reserved duct 9 inside each laterally stiffened composite beam 1. The two ends of each unbonded prestressed tendon 6 are anchored to the outer end face of the laterally stiffened composite beam 1 at both ends of the road transversely using anchors 7. A cast-in-place concrete layer is also provided between the two adjacent laterally stiffened composite beams 1 in the transverse direction of the road, and the cast-in-place concrete layer is poured to the top surface elevation of each laterally stiffened composite beam 1. After the hoisting construction of the entire main road structure is completed, an asphalt concrete surface layer 8 is also provided on the top surface of the entire road structure. The asphalt concrete surface layer 8 is appropriately adjusted according to the road alignment.

[0029] The lateral stiffening composite beam 1, upper truss rib 2, lower truss rib 3, upper steel mesh 4, and lower steel mesh 5 are all prefabricated in a prefabricated PC factory. Each lateral stiffening composite beam 1 has a length of 6000mm~9000mm and a cross-sectional dimension of not less than 150mm×300mm. The upper truss rib 2 and lower truss rib 3 are integrally formed during the prefabrication of the lateral stiffening composite beam 1. The upper truss rib 2 and lower truss rib 3 are arranged parallel to each other along the length of the lateral stiffening composite beam 1. The upper truss rib 2 is arranged 50mm below the top surface of the lateral stiffening composite beam 1, and the lower truss rib 3 is arranged at least 120mm below the top surface of the lateral stiffening composite beam 1. It should also be able to provide space for the laying of unbonded prestressed tendons 6 between the upper steel mesh 4 and the lower steel mesh 5. To ensure that the unbonded prestressing tendons 6 can traverse the interior of each lateral stiffening composite beam 1, pre-embedded ducts 9 are installed in the lateral stiffening composite beam 1 during the prefabrication process in the precast PC factory using a galvanized steel pipe method. The pre-embedded ducts 9 are located inside the lateral stiffening composite beam 1 between the upper truss rib 2 and the lower truss rib 3. The inner diameter of the pre-embedded duct 9 is 2mm to 3mm larger than the designed outer diameter of the unbonded prestressing tendons 6. The upper truss rib 2 and the lower truss rib 3 are made of high-strength manganese steel with a cross-sectional dimension of not less than 30mm × 120mm, and the flange and web thicknesses are both not less than 10mm. The upper truss rib 2 and the lower truss rib 3 are embedded at least 60mm inside the lateral stiffening composite beam 1.

[0030] To strengthen the design of the joint bearing capacity between the composite section and the cast-in-place concrete layer inside the overall road structure, the width of the vertical composite section of the lateral stiffening composite beam 1 shall not be less than 1 / 3 of the width of the precast part of the lateral stiffening composite beam 1 and shall not be less than 70mm. The exposed steel bars of the vertical composite section of the lateral stiffening composite beam 1 include stirrups 13 and two longitudinal reinforcing bars 12 at the corners of the stirrups. The upper truss rib 2 and the lower truss rib 3 are located on the inner side of the composite section. The distance between the inner surface of the exposed stirrups 13 of the vertical composite section of the lateral stiffening composite beam 1 and the flange surface of the upper truss rib 2 and the lower truss rib 3 shall not be less than 30mm. Meanwhile, in order to strengthen the bond between the precast laterally stiffened composite beam 1 and the cast-in-place concrete layer, the concrete surface of the vertically overlapping part of the laterally stiffened composite beam 1 is roughened during the prefabrication process in the PC factory. This is achieved by using a "spraying retarder + high-pressure water jet flushing process". That is, during the prefabrication process in the PC factory, after the concrete in the mold is poured and before it has initially set, a layer of retarder is sprayed on the concrete surface of the vertically overlapping part of the laterally stiffened composite beam 1. After the concrete in the mold has finally set, a high-pressure water jet is immediately used to flush the overlapping part, so that the slurry on the concrete surface of the vertically overlapping part of the laterally stiffened composite beam 1 can be removed and the aggregate exposed. The roughness rate is not less than 85%, and the height difference of the exposed aggregate on the rough surface is not less than 4mm.

[0031] To enhance the overall load-bearing capacity of the prefabricated beam-slab structure system, a horizontal steel bar sleeve grouting connection technology is adopted between the segmented laterally stiffened composite beams 1. This means that adjacent laterally stiffened composite beams 1 are connected by at least six horizontal steel bar grouting sleeves 10. Both ends of the laterally stiffened composite beam 1 are respectively equipped with horizontal steel bar grouting sleeves 10 and extended steel bars 11. The steel bar grouting sleeves 10 are arranged in two rows and are pre-embedded during the prefabrication process of the laterally stiffened composite beam 1. The positions of the steel bar grouting sleeves 10 and the extended steel bars 11 correspond one-to-one. The extended steel bars 11 at one end of the laterally stiffened composite beam 1 are precisely aligned and inserted into the steel bar grouting sleeves 10 of the adjacent laterally stiffened composite beam 1. The length of the extended steel bars 11 at one end of the laterally stiffened composite beam 1 is not less than 150mm. High-pressure grouting is used within the steel bar grouting sleeves 10 to complete the segmented connection design of the laterally stiffened composite beam 1. According to the design scheme, in order to improve the overall load-bearing capacity of the prefabricated beam-slab structure technology system, the focus is on strengthening the resistance of the joint of the lateral stiffened composite beam 1 to the problem of uneven settlement of the roadbed. A hidden beam reinforcement cage is set on the inner side of the joint of the adjacent lateral stiffened composite beam 1. The construction of the hidden beam reinforcement cage is synchronized with the pouring of the cast-in-place reinforced concrete layer. The diameter of the longitudinal reinforcing bars of the hidden beam reinforcement cage is not less than 16mm, and the cutting length of the hidden beam reinforcement cage is not less than 1200mm. All longitudinal reinforcing bars of the hidden beam reinforcement cage on the side close to the lateral stiffened composite beam 1 are arranged inside the stirrups of the composite part of the lateral stiffened composite beam 1 and are arranged along the entire length.

[0032] According to the design scheme, upper steel mesh 4 and lower steel mesh 5 are respectively installed between the upper truss rib 2 and lower truss rib 3 of the stiffening composite beam 1 on both sides of the road in the transverse direction. The upper steel mesh 4 and lower steel mesh 5 are made of double-layer bidirectional steel bars with a diameter of not less than 8mm. The lower part of the steel mesh is arranged transversely, and its two ends are supported on the top of the upper truss rib 2 or lower truss rib 3 respectively. The longitudinal distributed steel bars are supported on the transverse distributed steel bars. At the same time, in order to facilitate the on-site construction of the upper steel mesh 4 and lower steel mesh 5, after the upper steel mesh 4 and lower steel mesh 5 are fabricated off-site, they are hoisted into place by mechanical equipment in sections, modules, and segments. The two ends of the transverse distributed steel bars at the bottom of the steel mesh are welded to the top of the upper truss rib 2 or lower truss rib 3 to realize the rigid connection node of the upper steel mesh 4 and lower steel mesh 5.

[0033] The lateral stiffening composite beam 1 in the middle of the road is designed as a mirror double composite beam. The joint between the two lateral stiffening composite beams 1 also serves as the road structure settlement joint. The width of the settlement joint in the middle is not less than 60mm, and asphalt concrete is poured into the settlement joint. The asphalt concrete filling the joint is designed with the same mix proportion as the asphalt concrete surface layer 8 at the top of the road structure.

[0034] This invention also provides a construction method for the aforementioned prefabricated road, see reference. Figure 4 The construction process is as follows: S1 Surveying and setting out the road alignment, trench excavation; S2 Elevation verification, laying of sand and gravel cushion layer; S3 Grouting at the bottom of the trench, segmented hoisting of the lateral stiffening composite beam; S4 Installation of the lower layer steel mesh, perforated laying of unbonded prestressed tendons; S5 Grouting and sleeve connection of steel bars at the joints of the lateral stiffening composite beam, installation of the hidden beam steel cage; S6 Installation of the upper layer steel mesh, construction of cast-in-place concrete layer; S7 Treatment of settlement joints between the lateral stiffening composite beams on both sides of the road transverse center; S8 Tensioning and anchoring of unbonded prestressed tendons, and full paving of the asphalt concrete surface layer.

[0035] The specific technical steps of the above process flow are as follows: S1: Surveying and setting out road alignment, trench excavation According to the technical plan, the road alignment and elevation marking are first carried out in sections using a total station. The site is then initially leveled and earthwork excavated. Pre-defined positioning piles are driven in sections and spans to mark the specific locations of each construction section. The length of a construction section is generally 300m to 400m. Three pre-defined positioning piles are driven every 20m in each construction section, namely one on each side of the road and one in the middle of the road span. The design dimensions of the pre-defined positioning pile cross-section are not less than 200mm, the pile length is not less than 800mm, and there are not less than 4Φ12 threaded steel bars inside. Each pre-defined positioning pile is prefabricated in the prefabricated PC factory and transported to the site for driving one by one. The driving of each pre-designated positioning pile employs a two-step pile driving process. First, based on total station measurements, the pre-designated positioning piles are driven to a depth of at least 500mm. This process distributes the road alignment through the installation of these pre-designated positioning piles. Then, based on the trench bottom elevation marked on the pile top, each pile is driven to its designated elevation. The overall design of the pre-designated positioning piles aims to determine the basic road alignment, control the on-site construction elevation of each section, and improve the bearing capacity of the subgrade soil—a triple effect. Specifically, the positioning pile elevation is measured at the top of each pile, and the overall layout is based on the principle that the pile top elevation is equal to the trench bottom elevation. Each pre-designated positioning pile is then driven to its designated trench excavation position. A cross-flow construction organization method is adopted. After the pre-positioned piles in each construction section are driven to the design elevation, the trench excavation work can be carried out. The trench excavation width on both sides of the road should be more than 160mm larger than the width of the lateral stiffening composite beam. The trench excavation width in the middle of the road is equal to the width of the lateral stiffening composite beam × 2 + 200mm to leave sufficient working surface. The trench excavation depth is based on the top elevation of each pre-positioned pile and is arranged in a coordinated manner. On-site procedures are carried out strictly in accordance with the construction organization design requirements, and process acceptance and recording are done well.

[0036] S2: Elevation verification, laying of gravel bedding layer According to the technical plan, after all trenches in each construction section have been excavated, manual cleaning and elevation verification of the trench bottom and walls will be carried out to ensure that the top elevation of each pre-positioned pile is less than or equal to the designed trench excavation elevation, with the height difference controlled within 50mm. To further enhance the load-bearing capacity of the unbonded prestressed prefabricated road technology system with lateral stiffened composite beam-slab structure, a 60mm-90mm sand and gravel cushion layer is installed on the upper part of the trench. This means that a sand and gravel cushion layer is laid on the top surface of each trench after excavation as a bearing layer. This forms a structure that, based on the pre-positioned pile-reinforced subgrade soil layer, further improves the overall load-bearing capacity of the road structure system by combining the sand and gravel cushion layer as a bearing layer. After the trenches are excavated, the top surface of the sand and gravel cushion layer is made of 8mm~12mm diameter graded gravel and coarse sand. After the sand and gravel cushion layer in each construction section is laid, it is appropriately compacted and strengthened. Special attention is paid to the quality of the sand and gravel cushion layer at the subsequent hoisting position of the lateral stiffening composite beam. During the on-site construction, a total station is used to check and record the thickness of the sand and gravel cushion layer. Dedicated personnel are assigned to supervise the work on-site to control the construction quality of each process and to do a good job in process acceptance and recording.

[0037] S3: Grouting at the bottom of the trench, sectional hoisting of the lateral stiffening composite beam. According to the technical plan, before the lateral stiffening composite beams are hoisted in sections, the already laid sand and gravel cushion layer in the trench is grouted. The sand and gravel cushion layer is reinforced using a two-stage grooving technique. First, based on the bottom elevation of each lateral stiffening composite beam, a layer of fiber-reinforced waterproof mortar is laid on top of the sand and gravel cushion layer. Then, according to the road alignment and elevations at various points, the fiber-reinforced waterproof mortar is troweled smooth, with the smoothed surface elevation 5mm-10mm lower than the bottom elevation of the lateral stiffening composite beam, to enhance the curing of the first grooving layer. After the first grooving layer has cured to 100% of its design strength, a second grooving layer is laid before the lateral stiffening composite beams are hoisted. The loose thickness of the second grooving layer should be 3mm-5mm greater than that of the lateral stiffening composite beams. Then, the lateral stiffening composite beams are hoisted in sections in one go. During on-site construction, the "horizontal steel bar sleeve grouting connection technology, segmented hoisting, segmented connection, and segmented high-pressure grouting" technical solution was adopted for the hoisting of the laterally stiffened composite beams. Specifically, adjacent precast laterally stiffened composite beams were connected in segments using a steel bar sleeve grouting connection method. First, the extended steel bars at the ends of the hoisted laterally stiffened composite beams were inserted into the steel bar sleeves at the bottom of the subsequently hoisted laterally stiffened composite beams. Then, high-pressure grouting was used to inject micro-expansion, low-shrinkage fiber-reinforced grout. The segmented hoisting, positioning, and connection of all laterally stiffened composite beams were completed one by one. After the segmented hoisting of the laterally stiffened composite beams in each construction section was completed, fine aggregate concrete with a strength of not less than C30 was injected into the working surface between the laterally stiffened composite beams and the trench. The fine aggregate concrete was poured to 100mm below the designed prestressed tendon anchorages, and relevant concealed works acceptance and recording were carried out.

[0038] S4: Installation of lower layer steel mesh, and perforation laying of unbonded prestressed tendons. According to the technical solution, since the upper and lower truss ribs of the cross-section stiffened composite beams on both sides of the road are respectively provided with upper and lower steel mesh, and both the upper and lower steel mesh are double-layer bidirectional steel mesh, from the perspective of coordinated bearing and effective load transfer, the upper and lower steel mesh are supported on the upper and lower truss ribs respectively and fixed by welding. During on-site construction, the installation of the upper and lower steel mesh adopts the technical solution of "prefabrication, segmented hoisting, node welding, bottom-to-top, and reasonable overlap". That is, the upper and lower steel mesh are prefabricated on the construction site or in the prefabricated PC factory, transported to the design position, and then mechanically hoisted into place in segments. The lower steel mesh is hoisted first, followed by the upper steel mesh. The connection nodes of the upper and lower steel mesh and the upper and lower truss ribs are firmly welded. The overlap length of the distributed steel bars between adjacent steel meshes in the longitudinal direction of the road is not less than 120mm. After the lower layer of steel mesh is installed in each construction section, the unbonded prestressing tendons can be laid out on-site. The unbonded prestressing tendons are laid out using the following technical solution: "First, pass through the pre-embedded ducts in the mirror double composite beam in the middle of the road, accurately lay out the line of the prestressing tendons, and then pass through the pre-embedded ducts inside the composite beams on both sides of the road for temporary anchoring." The construction quality of each process should be well controlled, and process acceptance and recording should be done well.

[0039] S5: Grouting sleeve connection at the joint of the lateral stiffened composite beam, and installation of the hidden beam reinforcement cage. According to the technical plan, after the lower layer of reinforcing mesh and unbonded prestressed tendons in each construction section are laid, the segmented connection construction of the laterally stiffened composite beams can begin. The segmented connection of the laterally stiffened composite beams adopts a technical solution of "horizontal grouting sleeve connection, segmented alignment, sealing strip treatment, and high-pressure grouting." During on-site construction, since both ends of the laterally stiffened composite beams are equipped with horizontal reinforcing steel grouting sleeves and extended reinforcing bars, the extended reinforcing bars at one end of the laterally stiffened composite beam are first hoisted, precisely aligned, and inserted. Then, the grouting sleeves of the adjacent laterally stiffened composite beams are hoisted, and high-pressure grouting is used to reliably connect each segment of the laterally stiffened composite beams. To prevent grout leakage in the horizontal reinforcing steel sleeves, weather-resistant flexible sealing strips are embedded in the joints of adjacent laterally stiffened composite beams before high-pressure grouting. These sealing strips do not need to be removed after grouting is completed. Meanwhile, in order to further enhance the strength of the segmental connection nodes of each lateral stiffened composite beam and the overall structural bearing capacity, a hidden beam steel cage is installed on the inner side of the road at the joint of the adjacent lateral stiffened composite beams. The two longitudinal steel bars of the hidden beam steel cage near one end of the lateral stiffened composite beam are spot welded to the upper truss rib and the lower truss rib respectively, and the process acceptance and recording work is carried out.

[0040] S6: Installation of upper steel mesh and construction of cast-in-place concrete layer. According to the technical plan, after the grouting sleeves for the reinforcing bars at the joints of the laterally stiffened composite beams in each construction section are connected and the reinforcing cages for the concealed beams are installed in place, the installation of the upper layer of reinforcing mesh can begin. The technical plan for the installation of the upper layer of reinforcing mesh is the same as that for the installation of the lower layer of reinforcing mesh in step S4. During on-site construction, the installation of the upper layer of reinforcing mesh must not disturb the positional relationship between the lower layer of reinforcing mesh and the unbonded prestressed tendons that have already been placed. After all prefabricated components are hoisted into place, the cast-in-place concrete layer will be poured in sections and intervals using fine aggregate concrete with a strength not lower than the design strength of the laterally stiffened composite beams. The vibration of the cast-in-place concrete layer within 300mm of each laterally stiffened composite beam and at the joints should be strengthened. The vibration operation must not interfere with the positional relationship of the upper truss ribs, lower truss ribs, unbonded prestressed tendons, and reinforcing mesh. Relevant concealed works acceptance and recording should be carried out.

[0041] S7: Settlement joint treatment between the reinforcing composite beams on both sides of the transverse middle section of the road. According to the technical plan, after the cast-in-place concrete layer reaches more than 85% of its design strength, the settlement joint between the two lateral stiffening composite beams in the middle of the road will be treated by "adding additional steel bars + pouring asphalt concrete". The asphalt concrete construction in the settlement joint adopts a two-stage pouring method. The first pouring is at the elevation of the unbonded prestressing tendons. Then, additional steel bars are laid in the settlement joint. The diameter of the additional steel bars is not less than 16mm, and the additional steel bars are erected along the entire length on the unbonded prestressing tendons in the settlement joint. After the additional steel bars in each construction section are laid, the second pouring of asphalt concrete in the settlement joint is carried out. The second pouring of asphalt concrete extends to 30mm to 50mm below the top surface of the lateral stiffening composite beam. The remaining part is treated together with the subsequent asphalt concrete paving. Process acceptance and recording are carried out.

[0042] S8: Unbonded prestressed tendon tensioning and anchoring, full asphalt concrete surface paving. According to the technical plan, once the overall concrete strength of the road structure reaches 100% of the design strength, the tensioning and anchoring of the unbonded prestressed tendons can begin. During on-site construction, the unbonded prestressed tendons adopt a technical solution of "treating each construction section as an independent unit, tensioning from the middle of the construction section to both ends, using a 1.03σcon over-tensioning method, symmetrical tensioning, and anchoring immediately after tensioning". As can be seen from step S3 of the technical solution, since fine aggregate concrete with a strength of not less than C30 is injected into the working surface between the laterally stiffened composite beam and the trench, and the fine aggregate concrete is poured to 100mm below the designed prestressing tendon anchor, the working surface above the anchor between the laterally stiffened composite beam and the trench after the unbonded prestressing tendons in each construction section are tensioned and anchored still needs to be grouted a second time. The second grouting not only stabilizes the road cut slope and improves the overall load-bearing capacity of the road structure, but also takes into account the sealing and anchoring effect after the prestressing tendons are tensioned. Finally, the asphalt concrete surface layer is fully paved, and steps S1 to S8 are repeated to carry out the overall segmented flow construction organization until the on-site construction of the road structure is completed, and the project acceptance and data archiving are organized.

[0043] In summary, the lateral composite beam-slab structure assembly unbonded prestressed road technology system formed by this invention is more suitable for situations such as poor original bearing capacity of the subgrade soil layer, severe groundwater erosion, and harsh geological environment. The system constructs a laterally stiffened composite beam support system, with upper and lower truss ribs designed for shear bearing capacity. Double-layer steel mesh is used for segmented, modular, and inter-segmental hoisting. The laterally stiffened composite beam in the middle of the road's transverse direction features a mirrored double-overlap design, with joints also serving as structural settlement joints. Additional steel reinforcement is added within the settlement joints, combined with asphalt concrete treatment. The horizontal steel reinforcement sleeves of the segmented laterally stiffened composite beams are grouted. Grouting connection, secondary grouting of sand and gravel cushion layer auxiliary components hoisting, hidden beam steel cage reinforcement of each lateral stiffening composite beam segment connection node, unbonded prestressed tendons symmetrically tensioned and anchored with each construction section as an independent unit, innovative structural design, optimized process methods, can better achieve the efficiency of road construction, the integrity of structural load-bearing, and the effectiveness of resisting uneven settlement of roadbed. It has formed a new structure, new process and new method of prefabricated road, which can save 25% to 30% of the construction period and reduce construction costs by 11% to 17% under the same conditions, meeting the requirements of national green building standards.

[0044] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A type of unbonded prestressed road constructed using a lateral composite beam-slab structure, characterized in that, include: The road consists of a subgrade soil layer, laterally stiffened composite beams, upper truss ribs, lower truss ribs, upper steel mesh, lower steel mesh, cast-in-place concrete layer, unbonded prestressed tendons, anchorages, and asphalt concrete surface layer. Laterally stiffened composite beams are installed at both ends and the middle section of the road. The laterally stiffened composite beams at both ends are independent composite beams, while the laterally stiffened composite beams in the middle section are mirror-image double composite beams. Each laterally stiffened composite beam has upper and lower truss ribs at its vertical overlapping section. Upper and lower steel meshes are respectively installed between the upper and lower truss ribs of adjacent laterally stiffened composite beams on both sides of the road. Both the upper and lower steel meshes are double-layered, bidirectional steel meshes, and the upper and lower truss ribs are fixed to the upper and lower steel meshes by welding. Each laterally stiffened composite beam has pre-reserved ducts inside. Unbonded prestressed tendons are laid transversely along the road interior, passing through the pre-reserved ducts inside each laterally stiffened composite beam. Both ends of each unbonded prestressed tendon are anchored to the outer end faces of the laterally stiffened composite beams at both ends of the road. A cast-in-place concrete layer is also provided between adjacent laterally stiffened composite beams in the transverse direction of the road, and this layer is poured up to the top elevation of each laterally stiffened composite beam. After the entire main road structure is erected, an asphalt concrete surface layer is laid on top of the entire road structure, with the asphalt concrete surface elevation adjusted appropriately according to the road alignment.

2. The unbonded prestressed road assembled from a lateral composite beam-slab structure according to claim 1, characterized in that, The laterally stiffened composite beams, upper truss ribs, lower truss ribs, upper steel mesh, and lower steel mesh are all prefabricated in a prefabricated PC factory. Each laterally stiffened composite beam is 6000mm~9000mm long and has a cross-sectional dimension of not less than 150mm×300mm. The upper and lower truss ribs are integrally formed during the prefabrication of the laterally stiffened composite beams. The upper and lower truss ribs are arranged parallel to each other along the length of the laterally stiffened composite beam. The upper truss ribs are arranged 50mm below the top surface of the laterally stiffened composite beam, and the lower truss ribs are arranged at least 120mm below the top surface of the laterally stiffened composite beam. They should also provide sufficient space for the laying of unbonded prestressed tendons between the upper and lower steel meshes. To ensure that the unbonded prestressing tendons can traverse the interior of each laterally stiffened composite beam, pre-embedded ducts are installed in the laterally stiffened composite beams during the prefabrication process in the precast PC factory using a galvanized steel pipe method. These ducts are located inside the laterally stiffened composite beams between the upper and lower truss ribs, with the inner diameter of the ducts being 2mm-3mm larger than the designed outer diameter of the unbonded prestressing tendons. The upper and lower truss ribs are made of high-strength manganese steel with a cross-sectional dimension of not less than 30mm × 120mm, and the flange and web thicknesses are both not less than 10mm. The upper and lower truss ribs are embedded at least 60mm into the laterally stiffened composite beams.

3. The unbonded prestressed road assembled from a lateral composite beam-slab structure according to claim 1, characterized in that, To strengthen the design of the joint bearing capacity between the composite section and the cast-in-place concrete layer inside the overall road structure, the width of the vertical composite section of the lateral stiffened composite beam shall not be less than 1 / 3 of the width of the precast part of the composite beam and not less than 70mm. The exposed steel bars of the vertical composite section of the lateral stiffened composite beam include stirrups and two longitudinal reinforcing bars at the corners of the stirrups. The upper truss rib and the lower truss rib are located on the inner side of the composite section. The distance between the inner surface of the exposed stirrups of the vertical composite section of the lateral stiffened composite beam and the flange surface of the upper truss rib and the lower truss rib shall not be less than 30mm. Meanwhile, in order to strengthen the bond between the precast laterally stiffened composite beam and the cast-in-place concrete layer, the concrete surface of the vertical overlapping part of the laterally stiffened composite beam is roughened during the prefabrication process in the PC factory. This is achieved by spraying a retarder and using a high-pressure water jet flushing process. Specifically, during the prefabrication process in the PC factory, after the concrete in the mold is poured and before it initially sets, a layer of retarder is sprayed onto the concrete surface of the vertical overlapping part of the laterally stiffened composite beam. After the concrete in the mold has finally set, a high-pressure water jet is immediately used to flush the overlapping part, so that the slurry on the concrete surface of the vertical overlapping part of the laterally stiffened composite beam can be removed and the aggregate exposed. The roughness rate is not less than 85%, and the height difference of the exposed aggregate on the rough surface is not less than 4mm.

4. The unbonded prestressed road assembled from a lateral composite beam-slab structure according to claim 1, characterized in that, To enhance the overall load-bearing capacity of the prefabricated beam-slab structure system, a horizontal steel bar sleeve grouting connection technology is adopted between the segmented laterally stiffened composite beams. This involves connecting adjacent laterally stiffened composite beams with at least six horizontal steel bar grouting sleeves. Both ends of the laterally stiffened composite beam are equipped with horizontal steel bar grouting sleeves and extended steel bars, arranged in two rows. These sleeves are pre-embedded during the prefabrication of the laterally stiffened composite beams. The positions of the grouting sleeves and the extended steel bars correspond one-to-one. The extended steel bars at one end of the laterally stiffened composite beam are precisely aligned and inserted into the grouting sleeve of the adjacent laterally stiffened composite beam. The length of the extended steel bars at one end of the laterally stiffened composite beam is not less than 150mm. High-pressure grouting is used to complete the segmented connection design of the laterally stiffened composite beams within the grouting sleeves. According to the design plan, in order to improve the overall load-bearing capacity of the prefabricated beam-slab structure technology system, the focus is on strengthening the resistance of the joints of the laterally stiffened composite beams to uneven settlement of the roadbed. Hidden beam reinforcement cages are set on the inner side of the joints of the adjacent laterally stiffened composite beams. The construction of the hidden beam reinforcement cages is synchronized with the pouring of the cast-in-place reinforced concrete layer. The diameter of the longitudinal reinforcing bars of the hidden beam reinforcement cages is not less than 16mm, and the cutting length of the hidden beam reinforcement cages is not less than 1200mm. All longitudinal reinforcing bars of the hidden beam reinforcement cages on the side closest to the composite beam are arranged inside the stirrups of the composite part of the composite beam and are arranged along the entire length.

5. The unbonded prestressed road constructed using a lateral composite beam-slab structure according to claim 1, characterized in that, The road's transversely adjacent stiffened composite beams are equipped with upper and lower reinforcing meshes, respectively. Both the upper and lower reinforcing meshes utilize double-layered, bidirectional reinforcing bars with a diameter of at least 8mm. The lower portion of the mesh has transversely distributed reinforcing bars, with both ends supported on the top of the upper or lower truss ribs. The longitudinal reinforcing bars are supported on the transverse reinforcing bars. To facilitate on-site construction, the upper and lower reinforcing meshes are fabricated off-site and then hoisted into place using mechanical equipment in sections, modules, and segments. The transverse reinforcing bars at the bottom of the mesh are welded to the top of the upper or lower truss ribs to achieve a rigid connection between the upper and lower reinforcing meshes.

6. The unbonded prestressed road assembled from a lateral composite beam-slab structure according to claim 1, characterized in that, The lateral stiffening composite beams in the transverse middle of the road are arranged in a mirror double composite beam design. The joint between the two lateral stiffening composite beams also serves as the road structure settlement joint. The width of the settlement joint in the middle is not less than 60mm, and asphalt concrete is poured into the settlement joint. The asphalt concrete filling the joint is designed with the same mix proportion as the asphalt concrete surface layer at the top of the road structure.

7. A construction method for an unbonded prestressed road constructed using a lateral composite beam-slab structure, characterized in that, The construction process is as follows: S1 Surveying and setting out the road alignment, trench excavation; S2 Elevation verification, laying of sand and gravel cushion layer; S3 Grouting at the bottom of the trench, segmented hoisting of the lateral stiffening composite beam; S4 Installation of the lower layer steel mesh, perforated laying of unbonded prestressed tendons; S5 Grouting and sleeve connection of steel bars at the joints of the lateral stiffening composite beam, installation of the hidden beam steel cage; S6 Installation of the upper layer steel mesh, construction of cast-in-place concrete layer; S7 Treatment of settlement joints between the lateral stiffening composite beams on both sides of the road transverse center; S8 Tensioning and anchoring of unbonded prestressed tendons, full paving of asphalt concrete surface layer.

8. A construction method for an unbonded prestressed road with a lateral composite beam-slab structure, characterized in that, The specific technical steps are as follows: S1: Surveying and setting out road alignment, trench excavation First, a total station was used to survey and mark the road alignment in sections. The site was then leveled and excavated. Pre-defined positioning piles were driven in sections and spans to mark the specific locations of each construction section. The length of each construction section was generally 300m to 400m. Three pre-defined positioning piles were driven every 20m in each construction section, one on each side of the road and one in the middle of the road span. The design dimensions of the pre-defined positioning piles were not less than 200mm in cross-section and not less than 800mm in length. They were equipped with no less than 4Φ12 threaded steel bars. Each pre-defined positioning pile was prefabricated in a prefabricated PC factory and transported to the site for driving one by one. The driving of each pre-designated positioning pile employs a two-step pile driving process. First, based on total station measurements, the pre-designated positioning piles are driven to a depth of at least 500mm. This process distributes the road alignment through the installation of these pre-designated positioning piles. Then, based on the trench bottom elevation marked on the pile top, each pile is driven to its designated elevation. The overall design of the pre-designated positioning piles aims to determine the basic road alignment, control the on-site construction elevation of each section, and improve the bearing capacity of the subgrade soil—a triple effect. Specifically, the positioning pile elevation is measured at the top of each pile, and the overall layout is based on the principle that the pile top elevation is equal to the trench bottom elevation. Each pre-designated positioning pile is then driven to its designated trench excavation position. The cross-flow construction organization method is adopted. After the pre-positioned piles in each construction section are driven to the design elevation, the trench excavation work can be carried out. The trench excavation width on both sides of the road should be more than 160mm larger than the width of the lateral stiffening composite beam. The trench excavation width in the middle of the road is equal to the width of the lateral stiffening composite beam × 2 + 200mm, so as to leave enough construction working surface. The trench excavation depth is based on the top elevation of each pre-positioned pile and is arranged in a coordinated manner. The on-site procedures are carried out in strict accordance with the construction organization design requirements, and process acceptance and recording are done well. S2: Elevation verification, laying of gravel bedding layer After all trenches in each construction section have been excavated, manual cleaning and elevation verification of the trench bottom and walls are carried out to ensure that the top elevation of each pre-positioned pile is less than or equal to the designed trench excavation elevation, with the height difference controlled within 50mm. To further enhance the load-bearing capacity of the unbonded prestressed prefabricated road technology system with lateral stiffened composite beam-slab structure, a 60mm~90mm sand and gravel cushion layer is installed on the top of the trench. That is, a sand and gravel cushion layer is laid on the top surface of each trench after excavation as a bearing layer. This forms a structure that further improves the load-bearing capacity of the overall road structure system based on the pre-positioned pile-reinforced subgrade soil layer combined with the sand and gravel cushion layer as a bearing layer. After the trenches are excavated, the top surface of the sand and gravel cushion layer is made of 8mm~12mm diameter graded gravel and coarse sand. After the sand and gravel cushion layer in each construction section is laid, the sand and gravel cushion layer is appropriately compacted and strengthened. Special attention is paid to the quality of the sand and gravel cushion layer at the subsequent hoisting position of the lateral stiffening composite beam. During the on-site construction, a total station is used to check and record the thickness of the sand and gravel cushion layer. Dedicated personnel are assigned to supervise the work on-site to control the construction quality of each process and to do a good job in process acceptance and recording. S3: Grouting at the bottom of the trench, sectional hoisting of the lateral stiffening composite beam. Before the sectional hoisting of the laterally stiffened composite beams, the already laid sand and gravel cushion layer in the trench is grouted. The sand and gravel cushion layer is reinforced using a two-stage grooving technique. First, a layer of fiber-reinforced waterproof mortar is laid on top of the sand and gravel cushion layer, according to the bottom elevation of each laterally stiffened composite beam. Then, the fiber-reinforced waterproof mortar is smoothed according to the road alignment and elevations at various points. The smoothed surface elevation is 5mm-10mm lower than the bottom elevation of the laterally stiffened composite beam, thus strengthening the curing of the first grooving layer. After the first grooving layer has cured to 100% of its design strength, a second grooving layer is laid before the laterally stiffened composite beams are hoisted. The loose thickness of the second grooving layer should be 3mm-5mm greater than that of the laterally stiffened composite beams. Then, the laterally stiffened composite beams are hoisted into place in one go. During on-site construction, the "horizontal steel bar sleeve grouting connection technology, segmented hoisting, segmented connection, and segmented high-pressure grouting" technical solution was adopted for the hoisting of the laterally stiffened composite beams. Specifically, adjacent precast laterally stiffened composite beams were connected in segments using a steel bar sleeve grouting connection method. That is, the protruding steel bars at the ends of the first hoisted laterally stiffened composite beam were inserted into the steel bar sleeves at the bottom of the second hoisted laterally stiffened composite beam. Then, high-pressure grouting was used to inject micro-expansion, low-shrinkage fiber-reinforced grout. The segmented hoisting, positioning, and connection of all laterally stiffened composite beams were completed one by one. After the segmented hoisting of the laterally stiffened composite beams in each construction section was completed, fine aggregate concrete with a strength of not less than C30 was injected into the working surface between the laterally stiffened composite beam and the trench. The fine aggregate concrete was poured to 100mm below the designed prestressed tendon anchorage, and relevant concealed works acceptance and recording were carried out. S4: Installation of lower layer steel mesh, and perforation laying of unbonded prestressed tendons. Because the upper and lower truss ribs of the stiffened composite beams on both sides of the road are respectively equipped with upper and lower steel mesh, and both upper and lower steel mesh are double-layered bidirectional steel mesh, from the perspective of coordinated bearing and effective load transfer, the upper and lower steel mesh are supported on the upper and lower truss ribs respectively and fixed by welding. During on-site construction, the installation of the upper and lower steel mesh adopts the technical solution of "prefabrication, segmented hoisting, node welding, bottom-up, and reasonable overlap". That is, the upper and lower steel mesh are prefabricated on the construction site or in the prefabricated PC factory, transported to the design position, and then mechanically hoisted into place in segments. The lower steel mesh is hoisted first, followed by the upper steel mesh. The connection nodes of the upper and lower steel mesh and the upper and lower truss ribs are firmly welded, and the overlap length of the distributed steel bars between adjacent steel meshes in the longitudinal direction of the road is not less than 120mm. After the lower layer of steel mesh in each construction section is installed, the on-site perforation and laying of unbonded prestressed tendons can be carried out. The perforation and laying of unbonded prestressed tendons adopts the technical solution of "first passing through the pre-embedded ducts in the mirror double composite beam in the middle of the road, accurately laying out the line shape of the prestressed tendons, and then passing through the pre-embedded ducts inside the composite beams on both sides of the road for temporary anchoring". The construction quality of each process should be well controlled, and the process acceptance and recording should be done well. S5: Grouting sleeve connection at the joint of the lateral stiffened composite beam, and installation of the hidden beam reinforcement cage. After the lower layer of reinforcing mesh and unbonded prestressed tendons in each construction section are laid, the segmented connection construction of the laterally stiffened composite beams can begin. The segmented connection of the laterally stiffened composite beams adopts a technical solution of "horizontal grouting sleeve connection, segmental alignment, sealing strip treatment, and high-pressure grouting." During on-site construction, since both ends of the laterally stiffened composite beams are equipped with horizontal reinforcing steel grouting sleeves and extended reinforcing bars, the extended reinforcing bars at one end of the laterally stiffened composite beam are first hoisted, precisely aligned, and inserted. Then, the grouting sleeves of the adjacent laterally stiffened composite beams are hoisted, and high-pressure grouting is used to reliably connect each segment of the laterally stiffened composite beams. To prevent grout leakage in the horizontal reinforcing steel sleeves, weather-resistant flexible sealing strips are embedded in the joints of adjacent laterally stiffened composite beams before high-pressure grouting. These sealing strips do not need to be removed after grouting is completed. Meanwhile, in order to further enhance the strength of the segmented connection nodes of each lateral stiffened composite beam and the overall load-bearing effect of the structure, a hidden beam steel cage is installed on the inner side of the road at the joint of the adjacent lateral stiffened composite beams. The two longitudinal steel bars of the hidden beam steel cage near one end of the lateral stiffened composite beam are spot welded to the upper truss rib and the lower truss rib respectively, and the process acceptance and recording work is carried out. S6: Installation of upper steel mesh and construction of cast-in-place concrete layer After the grouting sleeves for the reinforcing bars at the joints of the laterally stiffened composite beams in each construction section are connected and the reinforcing cages for the concealed beams are installed in place, the installation of the upper layer of reinforcing mesh can begin. The installation of the upper layer of reinforcing mesh follows the same technical scheme as the installation of the lower layer of reinforcing mesh in step S4. During on-site construction, the installation of the upper layer of reinforcing mesh must not disturb the positional relationship between the already positioned lower layer of reinforcing mesh and the unbonded prestressed tendons. After all prefabricated components are hoisted into place, the cast-in-place concrete layer is poured in sections and intervals using fine aggregate concrete with a strength not lower than the design strength of the laterally stiffened composite beam. Vibration of the cast-in-place concrete layer within 300mm of each laterally stiffened composite beam and at the joints is intensified. Vibration must not interfere with the positional relationship of the upper truss ribs, lower truss ribs, unbonded prestressed tendons, and reinforcing mesh. Relevant concealed works acceptance and recording should be completed. S7: Settlement joint treatment between the reinforcing composite beams on both sides of the transverse middle section of the road. After the cast-in-place concrete layer reaches more than 85% of the design strength, the settlement joint between the two sides of the lateral stiffening composite beam in the middle of the road is treated by "adding additional steel bars + pouring asphalt concrete". The asphalt concrete construction in the settlement joint adopts the two-stage pouring method. That is, the first pouring is at the elevation of the unbonded prestressing tendon. Then, additional steel bars are laid in the settlement joint. The diameter of the additional steel bars is not less than 16mm. The additional steel bars are erected on the unbonded prestressing tendon in the settlement joint. After the additional steel bars in each construction section are laid, the second pouring process of asphalt concrete in the settlement joint is carried out. The second pouring of asphalt concrete is 30mm to 50mm below the top surface of the lateral stiffening composite beam. The remaining part is treated together with the subsequent asphalt concrete paving. The process acceptance and recording work should be done well. S8: Unbonded prestressed tendon tensioning and anchoring, full asphalt concrete surface paving. Once the overall concrete strength of the road structure reaches 100% of the design strength, the tensioning and anchoring of the unbonded prestressed tendons can begin. During on-site construction, the unbonded prestressed tendons adopt a technical solution of "treating each construction section as an independent unit, tensioning from the middle of the construction section to both ends, 1.03σcon over-tensioning method, symmetrical tensioning, and anchoring as tensioning progresses". As can be seen from step S3 of the technical solution, since fine aggregate concrete with a strength of not less than C30 is injected into the working surface between the laterally stiffened composite beam and the trench, and the fine aggregate concrete is poured to 100mm below the designed prestressing tendon anchor, the working surface above the anchor between the laterally stiffened composite beam and the trench after the unbonded prestressing tendons in each construction section are tensioned and anchored still needs to be grouted a second time. The second grouting not only stabilizes the road cut slope and improves the overall load-bearing capacity of the road structure, but also takes into account the sealing and anchoring effect after the prestressing tendons are tensioned. Finally, the asphalt concrete surface layer is fully paved, and steps S1 to S8 are repeated to carry out the overall segmented flow construction organization until the on-site construction of the road structure is completed, and the project acceptance and data archiving are organized.

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