Prefabricated road with bracket superposed beam plate bearing bonded prestress and construction method

Abstract

The invention relates to the technical field of fabricated roads, in particular to a bonded prestress-bearing fabricated road with a bracket superposed beam slab, which structurally comprises a roadbed reinforcing layer, a bracket superposed beam, a steel truss, a superposed slab, a prestressed tendon duct, a prestressed tendon and an asphalt concrete surface layer, according to the overall technical scheme, the method follows the steps of laminated beam end supporting with brackets, steel truss combined bearing, reverse laminated slab prefabrication and assembly, micro-expansion low-shrinkage fiber anti-crack fine aggregate concrete high-pressure grouting, post-tensioning method prestressed tendon symmetric tensioning, EPS plate partition and expansion joint treatment and asphalt concrete surface layer comprehensive paving. The prefabricated integrally-formed composite beam with the bracket is adopted as an end support of the road structure, a load transmission path is clear after traffic is open, cooperative bearing is conducted in combination with the internal steel truss, the anti-pressure ability of the road structure and the foundation soil anti-arch effect are improved, the prefabricated reverse composite plate is spliced on the prefabricated integrally-formed composite beam with the bracket, and the construction efficiency is improved. And an effective beam-slab structure bearing frame is formed.

Description

Technical Field

[0001] This invention relates to the field of prefabricated road technology, specifically to a prefabricated road with bonded prestressed concrete beams supported by corbels and its construction method. Background Technology

[0002] Traditional wet-laying road construction involves multiple stages, including subgrade treatment, base course paving, surface layer spreading, compaction, and maintenance. This process is complex, time-consuming, lengthy, causes significant traffic disruption, fluctuates quality, relies on labor and weather, results in severe pollution, is environmentally unfriendly, difficult to maintain, and costly. In contrast, the new prefabricated road technology system features rapid construction, significantly reduced road occupancy time, factory prefabrication, stable and excellent quality, green manufacturing, energy saving and waste reduction, rapid replacement, and low total life-cycle cost. This construction method represents not only a technological upgrade in construction techniques but also a revolution in construction philosophy, signifying the inevitable trend of future transportation infrastructure construction towards industrialization, intelligence, and green development. However, my country's prefabricated road construction level is still not perfect. Considering the different regions, geological environments, and soil layer distributions in my country, developing a complete series of new prefabricated road structures, processes, and methods will have a significant forward-looking role in the high-quality development of my country's highway engineering construction technology field. Summary of the Invention

[0003] The purpose of this invention is to provide a precast road with bonded prestressed concrete beams and slabs supported by corbels and a construction method therefor, in order to solve the problems raised in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a precast prestressed road supported by a composite beam-slab with corbels, comprising a roadbed reinforcement layer, composite beams with corbels, a steel truss, a composite slab, prestressing tendon ducts, prestressing tendons, and an asphalt concrete surface layer. The roadbed reinforcement layer is disposed above the roadbed, and the composite beams with corbels are provided at both ends of the roadbed reinforcement layer. The composite beams with corbels include a composite beam and corbels. The composite beams are disposed at both ends of the roadbed reinforcement layer, and the corbels are located on the inner side of the composite beams. The top is provided with a composite beam with additional side plates; the two ends of the steel truss rest on the top surface of the corbel, the prestressing tendon ducts and the prestressing tendons pass through the interior of the steel truss, the prestressing tendons are located in the prestressing tendon ducts, and the ends are fixed to the outer side of the composite beam with corbel by anchors; the two ends of the composite slab rest on the top surface of the composite beam, and the exposed steel bars at the ends of the composite slab extend into the composite part of the composite beam with corbel, the interior of the composite slab is provided with grouting holes and grout outlet holes, and the upper part of the composite slab is provided with the asphalt concrete surface layer.

[0005] Preferably, the roadbed reinforcement layer is treated by mechanically enlarging holes using the soil displacement method and then filling with a solidified crushed stone and slag mixture. The solidified crushed stone and slag mixture is formed by pre-mixing crushed stone, slag, cement, and water in a certain proportion. The mechanically enlarged holes in the roadbed reinforcement layer have a diameter of not less than 150 mm and a depth of not less than 300 mm. The distance between each mechanically enlarged hole does not exceed 800 mm. For complex geological environments such as sandy soil, silty soil, and silty clay with high water content, the distance between each mechanically enlarged hole does not exceed 500 mm.

[0006] Preferably, the composite beam with corbel is prefabricated in a PC factory. The corbel and the composite beam are designed as an integral whole using the same mold and process. The corbel is the same length as the composite beam, and the width of the corbel is not less than 100mm. The additional side plate of the composite beam is pre-formed and reserved in the upper part of the composite beam with corbel. Its thickness is not less than 20mm, and its top surface elevation is equal to the top surface elevation of the uppermost asphalt concrete surface layer of the overall prefabricated road.

[0007] Preferably, the composite slab is prefabricated in a PC factory. The truss reinforcement of the composite slab faces downward and the flat bottom surface faces upward. The exposed steel bars at the ends of the composite slab are anchored into the interior of the composite part of the top surface of the composite beam with corbel for a length of not less than 70mm. The thickness of the composite slab is not less than 60mm. The truss reinforcement is arranged in a bidirectional staggered manner along the surface of the composite slab. A 120mm post-cast section is left between two adjacent composite slabs. In order to meet the lateral force requirements of the assembly road, no less than two Φ8 continuous steel bars are set in the post-cast section. The cutting length of the continuous steel bars should meet the anchorage length requirements between the exposed steel bars of the composite slab and the steel bars of the composite beam with corbel.

[0008] Preferably, all members of the steel truss are made of small-sized T-shaped steel beams of 30mm×50mm×5mm, welded in the factory. The transverse width of the overall steel truss is the net distance between two overlapping beams with corbels minus 60mm. The longitudinal length of the steel truss is controlled at 3.0m, and the height of the steel truss is not less than 160mm. Each steel truss is placed on corbels at both ends and fixed by pre-embedded bolts on the top surface of the corbels. The number of bolts used to fix each steel truss to the corbels is not less than 6.

[0009] Preferably, the two ends of the prestressing tendon pass through the reserved holes inside the composite beam with corbel, and the inner diameter of the reserved holes is 6mm larger than the outer diameter of the prestressing tendon; the prestressing tendon is only arranged laterally along the road driving direction, and the distance between adjacent prestressing tendons does not exceed 1800mm; the prestressing tendon ducts are freely arranged inside the steel truss, and there must be no collision between the prestressing tendon ducts and the steel truss members.

[0010] Preferably, the support length of the composite slab resting on the composite beam with corbels at both ends is not less than 30mm on each side, and the spacing between the exposed reinforcing bars at the ends of the composite slab does not exceed 150mm; each composite slab is provided with 2 grouting holes and 1 grouting outlet hole, with the two grouting holes respectively located at the diagonal parts of the composite slab, and the grouting outlet hole located at the center of the composite slab, and the diameter of both the grouting holes and the grouting outlet hole is 60mm.

[0011] This invention also provides a construction method for a precast road with bonded prestressed concrete slabs supported by composite beams with corbels. The overall technical solution follows the principle of "end support of composite beams with corbels, joint bearing of steel trusses, prefabrication and assembly of reverse composite slabs, high-pressure grouting of micro-expansion and low-shrinkage fiber-reinforced crack-resistant fine aggregate concrete, symmetrical tensioning of post-tensioned prestressing tendons, EPS board partitions serving as expansion joints, and full paving of asphalt concrete surface layer." The corresponding construction process is as follows: surveying and setting out, excavation of composite beam trenches, segmented hoisting of composite beams with corbels, filling of joints with fine aggregate concrete, preparation of mixture, roadbed reinforcement, hoisting and fixing of steel trusses, laying and temporary anchoring of prestressing tendon ducts, prestressing tendon, hoisting of reverse composite slabs, treatment of beam-slab joints, grouting and sealing of holes, tensioning and anchoring of prestressing tendons, grouting of ducts, and full paving of asphalt concrete surface layer.

[0012] The preferred technical solution is as follows:

[0013] Step S1: Measurement and layout, excavation of composite beam trench:

[0014] According to the construction plan, the site was leveled mechanically, the basic alignment of the road was initially determined using a total station, and the roadbed was compacted using compaction machinery. During on-site construction, a segmented excavation method was adopted for the excavation of the composite beam trench, using an "enlarged variable cross-section" excavation scheme. Each excavation segment was 12m long, and excavation and hoisting were carried out immediately. The width of the composite beam trench excavation was 200mm wider than the designed width of the composite beam with corbels, leaving approximately 100mm of working surface on each side for the subsequent hoisting of the composite beam with corbels. The excavation depth of the composite beam trench should be based on the overall road design requirements and should be sufficient to accommodate the top of the additional side plates of the top composite beam after it has been hoisted into place. The surface elevation is the road structure design elevation. When excavating the composite beam trench, the cross-section of the composite beam trench above the corbel should be enlarged to ensure accurate hoisting and positioning of the composite beam with corbel after excavation. The excavation of the composite beam trench in each construction section should be symmetrical. After excavation, a reinforced trench of not less than 50mm of crushed stone and coarse sand should be laid at the bottom of the composite beam trench. Finally, the bottom elevation of the composite beam trench and the positional relationship between the two composite beams with corbel in the same construction section should be accurately checked. The excavation of the composite beam trench should avoid the rainy season. The excavated composite beam trench should not be washed by rainwater for a long time. A dedicated person should be assigned to supervise the site and keep records.

[0015] Step S2: Segmented hoisting of the composite beam with corbels, and grouting with fine aggregate concrete:

[0016] After each section of the composite beam trench is excavated using the enlarged variable cross-section method, the composite beams with corbels are promptly hoisted and positioned in segments. The composite beams with corbels at both ends of the road within each construction section are hoisted and positioned symmetrically. During the hoisting of adjacent composite beams with corbels, the axial distance between the two beams after positioning should be carefully controlled. The planar position and elevation of the positioned composite beams with corbels should be accurately checked, with the planar position error controlled within 10mm and the positioning elevation error controlled within 3mm. During the segmented hoisting of the composite beams with corbels, the additional side plates at the top of the composite beams with corbels should be carefully protected. The additional side plate of the corbel composite beam serves as the side formwork for the post-cast concrete part of the entire prefabricated road structure, which is a formwork-free design for the entire prefabricated road construction process, greatly improving the efficiency of hoisting work. After the composite beam with corbel is hoisted and positioned in sections, and the plane position and positioning elevation are controlled correctly, fine stone concrete is immediately used to fill the gap between the composite beam groove and the positioned composite beam with corbel to strengthen the compactness of the fine stone concrete after filling the joint. Vibration and curing are strengthened. The strength of the fine stone concrete is not less than C25. The height of the fine stone concrete filling joint is 10mm below the corbel surface. It is filled in one go without leaving a construction joint.

[0017] Step S3: Mixture preparation and roadbed reinforcement:

[0018] The subgrade reinforcement layer is designed using a method of mechanically enlarging holes using the displacement method and then filling them with a solidified crushed stone and slag mixture. This involves pre-mixing crushed stone, slag, cement, and water in a specific ratio to form the solidified mixture. This solidified mixture should be prepared beforehand for subgrade reinforcement layer construction. After the composite beams with corbels are installed in sections, a continuous construction method is used to perform mechanically enlarging holes and filling the mixture in sections using the displacement method. The most significant feature of this method is that it strengthens the subgrade through the displacement effect of mechanically enlarging and forming holes. This method is most effective for silty soil, sandy soil, and silty mud foundations with high moisture content. The mechanically enlarging holes using the displacement method follows the technical principle of "enlarging holes sequentially from the middle of the road towards both ends, and immediately filling the holes after enlargement." The case involves the following: During the roadbed reinforcement process, since the composite beams with corbels at both ends of the road have been hoisted into place, the soil inside the road will experience displacement during mechanical hole enlargement. This will result in significant displacement between the roadbed soils, creating a mutual squeezing effect to achieve the purpose of roadbed reinforcement. For the use of the mixed and solidified crushed stone and slag mixture, it should be used immediately after mixing. For roadbeds using the soil displacement method for mechanical hole enlargement, the crushed stone and slag mixture should be used to fill the holes promptly. The interval between hole enlargement and hole filling should not exceed 3 hours, and construction should be avoided during the rainy season. If it is rainy, roadbed hole enlargement should be stopped, and a drainage slope of not less than 0.3% should be set in the middle of the roadbed to promptly drain rainwater from the roadbed area, preventing prolonged soaking of the roadbed. For the roadbed soil layer at the composite beams with corbels at both ends of the road, when using the soil displacement method for mechanical hole enlargement, the hole position closest to the composite beam with corbels should be 200mm to 300mm away from the corbel position.

[0019] Step S4: Steel truss hoisting and fixing:

[0020] According to the construction organization plan, the steel truss hoisting operation can proceed after the segmented construction of the roadbed reinforcement layer is completed. As one of the important load-bearing components inside the prefabricated road, the steel truss is particularly effective in resisting the arching effect of the foundation soil, thus improving the overall load-bearing capacity and service life of the structure. The steel truss hoisting is located on the top surface of the corbels with overlapping beams at both ends of the road. The steel truss and corbels are flexibly fixed using pre-embedded bolts, with two scenarios: for geological environments with minimal arching or vibration, the connection between the steel truss and corbels uses a "fixed at both ends" method; for geological environments with significant arching or vibration, the connection between the steel truss and corbels uses a different method. The connection method is "fixed at one end and hinged at the other end"; during on-site construction, a post-cast section of not less than 120mm is left between the steel trusses in two adjacent construction sections. A negative reinforcement bar with a cutting length of not less than 400m is set between the two steel trusses in the post-cast section. The negative reinforcement bar is made of grade II steel with a diameter of not less than 10mm and a spacing of not more than 150mm. Each negative reinforcement bar has a 90-degree hook at both ends; when the EPS board partition is used as an expansion joint in road construction, an additional baffle should be set on the end face of the steel truss on both sides of the expansion joint. The partition is made by setting an additional baffle on the end face of the steel truss. A protective layer concrete pad is set between the additional baffle and the EPS board. Each concrete pad has a thickness of not less than 35mm.

[0021] Step S5: Prestressed tendon ducts, prestressed tendon laying and temporary anchorage:

[0022] According to the construction plan, prestressed tendons are arranged only along the width of the road in one direction. The prestressed tendon ducts and tendons are placed inside the steel truss, with both ends passing through pre-reserved holes inside the composite beam with corbels, and finally anchored to the outer edges of the composite beams with corbels at both ends of the road. During on-site construction, the prestressed tendon placement can be done before the steel truss is hoisted or after the steel truss is in place and fixed, ensuring that the prestressed tendon ducts do not collide with each other inside the steel truss. Bonded prestressing technology is used, and the prestressed tendons are cut... The length should be appropriately extended by 200mm on the basis of meeting the requirements for tensioning and anchoring of prestressing tendons. The prestressing tendon ducts should be laid out using corrugated metal pipes. The prestressing tendon ducts should be laid out before the steel truss is hoisted. The prestressing tendons should be perforated after the steel truss is in place and fixed. That is, the on-site prestressing tendon layout adopts the technical solution of "perforating from the outside of the composite beam with corbel at one end, pulling the steel wire through the inside of the steel truss, and then passing it out through the reserved perforation inside the composite beam with corbel at the other end, and finally temporarily anchoring it on the outside of the composite beam with corbel at both ends".

[0023] Step S6: Reverse composite slab hoisting, beam-slab joint treatment:

[0024] After the prestressed tendons in each construction section are laid, the reverse composite slab hoisting work can begin. The composite slabs are hoisted on-site with the composite section facing downwards to enhance the synergistic load-bearing capacity between the grouted composite slab and the internal steel truss. Four-point hoisting is used for accurate positioning. At the beam-slab composite section, the exposed reinforcing bars at the ends of the composite slab are anchored into the top surface of the corbel composite beam for a length of not less than 70mm inside the composite section. The composite slab thickness is not less than 60mm. The truss reinforcement is arranged alternately in both longitudinal and transverse directions along the surface of the composite slab. A 120mm post-cast section is left between adjacent composite slabs. To meet the lateral load requirements of the assembly road, at least two Φ8 continuous reinforcing bars are installed in the post-cast section. The composite slab and the corbel composite beam should be reliably connected. The exposed reinforcing bars of the composite slab... The reinforcing bars at the overlapping section of the composite beam with corbels are reliably fixed by welding, and both ends of the composite slab rest on the top surface of the composite beam with corbels. The support length of the composite slab resting on the composite beam with corbels on each side is not less than 30mm. To prevent the grouting holes and grout outlet holes from being blocked during the transportation, hoisting, and placement of the composite slab, rubber plugs should be used to seal the grouting holes and grout outlet holes on the composite slab before grouting. After the composite slab is hoisted, fine aggregate concrete of not less than C30 is poured to the beam-slab joint until it is flush with the top surface of the composite slab. Throughout the entire process of hoisting and fixing the composite slab, a dedicated person should be present to supervise and control each key node, ensuring the accuracy and reliability of the hoisting and placement of the composite slab and the connection nodes, and to properly inspect and record the process of concealed works.

[0025] Step S7: Grouting and Sealing:

[0026] After the composite slab is hoisted into place in sections, intervals, and modules, grouting can begin. The grout used on site is micro-expansion, low-shrinkage fiber-reinforced fine aggregate concrete grout. Fine aggregate should preferably be pebbles with a diameter not exceeding 10mm. It should be mixed and used immediately. When the temperature exceeds 30 degrees Celsius, the grout should not be used for more than 2 hours. At least two sets of grout test blocks with the same curing conditions should be prepared for each construction section on site, with at least four test blocks in each set. The grouting operation process is as follows: First, remove one rubber plug from each of the grouting holes and grout outlet holes on the composite slab, leaving one rubber plug inside the grouting hole intact. Ensure the inside of the grouting hole and grout outlet hole is clean. The process is smooth and free of debris. High-strength grout is then injected into one of the injection holes on the composite slab using high-pressure grouting. Grouting is stopped once grout is visible at the outlet hole in the middle of the composite slab. The second step involves plugging the injection hole with a rubber stopper. The rubber stopper in the other injection hole is then removed, and high-pressure grouting is continued until grout emerges from the outlet hole in the middle of the composite slab. The third step involves plugging the outlet hole in the middle of the composite slab with a rubber stopper. This high-pressure grouting process is repeated three times. Finally, all injection and outlet holes are sealed, and the grout is fully cured. The process is then inspected and accepted.

[0027] Step S8: Tensioning and anchoring of prestressed tendons, grouting of ducts:

[0028] After the grouting of each section of the composite slab is completed, curing should be strengthened. Prestressing tendons can only be tensioned and anchored after the concrete strength of the test blocks cured under the same conditions as the grout has reached the design strength. For bonded prestressing techniques, first loosen the anchorages at both ends, then use 1.05σcon over-tensioning, symmetrical tensioning, and then grout the prestressing tendon ducts. After strengthening curing and prestressing tendon tensioning and anchoring, the anchorages should be sealed with high-strength, crack-resistant mortar.

[0029] Step S9: Full paving of the asphalt concrete surface layer:

[0030] A reasonable assembly line operation method is adopted, repeating steps S1 to S8 until the prefabricated road main structure hoisting construction site is completed. After the prestressing tendon tensioning and anchoring work is completed, the asphalt concrete pavement can be laid in sections and successively. It is particularly important to note that the additional side plates of the composite beam also serve as the formwork for the prefabricated road construction, so no formwork is required during construction. During the paving and mechanical compaction of the asphalt concrete pavement on site, special attention should be paid to the compaction of the asphalt concrete pavement within 500mm of the additional side plates of the composite beam on both sides of the road, and protection work should be done. After all the construction procedures are completed, the project acceptance and data archiving should be organized in a timely manner.

[0031] Compared with the prior art, the beneficial effects of this invention are as follows:

[0032] 1. The composite beam with corbel, composite slab, and steel truss supported on the corbel used in this invention are the core structural support components. They can transfer the load after the road is opened to traffic to the foundation through the structural frame. In the structural design, the composite beam with corbel is designed and formed as an integrated unit. During on-site hoisting, the steel truss is directly hoisted and supported on the corbel. The hoisting position relationship and placement elevation of each prefabricated component are controllable, and the hoisting efficiency is extremely high. The corbel not only serves as the hoisting support point of the steel truss, but also as an enlarged section of the composite beam, which is beneficial for shear bearing and improves structural durability.

[0033] 2. This invention also incorporates a continuous additional side plate on the top of the composite beam with corbels for a "formwork-free design" of the post-cast concrete joint between the beam and slab. The design elevation of the top surface of the additional side plate is the construction elevation for the full asphalt pavement, reducing the workload of repeated surveying and setting out. This further accelerates the hoisting speed, improves the appearance quality, and provides clear elevation guidance for subsequent construction processes. The structural design is novel, the process methods are consistent, and the application value is high.

[0034] 3. The new prefabricated road structure system developed in this invention adopts a high-pressure grouting process of micro-expansion fiber-reinforced crack-resistant fine stone concrete in its internal cavity, which effectively optimizes the process of prefabricated road assembly. The assembly construction is completed in one grouting. The development of the new structure system has formed a new construction process and a new technical method, realizing the hoisting speed of 100 meters per 4 hours for prefabricated roads. The application of this technical system has significant social benefits in terms of traffic disruption and effectively solving people's livelihood issues. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the prefabricated road structure of the present invention;

[0036] Figure 2 This is a flowchart of the construction process of the present invention. Detailed Implementation

[0037] This invention discloses a precast road with bonded prestressed concrete beams and slabs supported by corbels, as described in the embodiments of the present invention. Figure 1 It includes the roadbed, the roadbed reinforcement layer 1, the composite beam with corbels, the steel truss 5, the composite slab 6, the prestressed tendon duct 13, the prestressed tendon 7, the anchorage 8, and the asphalt concrete surface layer 9. The roadbed reinforcement layer 1 is located above the roadbed. The roadbed reinforcement layer 1 has composite beams with corbels at both ends. The composite beams with corbels include composite beams 2 and corbels 3. The composite beams 2 are located at both ends of the roadbed reinforcement layer 1, and the corbels 3 are located on the inner side of the composite beams 2. The top of the composite beams with corbels has additional side plates 4. The two ends of the steel truss 5 rest on the top surface of the corbels 3. The prestressing tendon ducts 13 and prestressing tendons 7 pass through the interior of the steel truss 5. The prestressing tendons 7 are located in the prestressing tendon ducts 13, and the ends of the prestressing tendons 7 are fixed to the outer side of the composite beams with corbels by anchors 8. The two ends of the composite slab 6 rest on the top surface of the composite beams with corbels, and the exposed steel bars at the ends of the composite slab 6 extend into the composite part of the composite beams with corbels. The interior of the composite slab 6 has grouting holes 10 and grout outlet holes 11. The upper part of the composite slab 6 has an asphalt concrete surface layer 9.

[0038] The roadbed reinforcement layer 1 is treated by mechanically enlarging holes using the soil displacement method and then filling it with a solidified crushed stone and slag mixture. The solidified crushed stone and slag mixture is formed by pre-mixing crushed stone, slag, cement and water in a certain proportion. The mechanically enlarged holes in the roadbed reinforcement layer 1 have a diameter of not less than 150 mm and a depth of not less than 300 mm. The distance between each mechanically enlarged hole does not exceed 800 mm. For complex geological environments such as sandy soil, silty soil and silty soil with high water content, the distance between each mechanically enlarged hole does not exceed 500 mm.

[0039] The composite beam with corbel and the composite slab 6 are prefabricated in the PC factory. The corbel 3 on the composite beam with corbel is designed as an integral unit with the main component composite beam 2, using the same mold and process. The corbel 3 is designed to be the same length as the composite beam 2, and the width of the corbel 3 is not less than 100mm. To achieve integrated molding of the composite beam with corbel in the PC factory, the steel mold at the end of the corbel 3 is customized separately according to the position, size, and slope angle of the corbel 3, or a combination assembly method can be used to customize the steel mold. The internal steel bars of the composite beam with corbel extend from the top surface of the composite beam 6 and form the overlapping part of the composite beam with corbel. The thickness of the additional side plate 4 of the composite beam with corbel, which is reserved in the integrated molding of the upper part of the composite beam with corbel, is not less than 20mm. The top surface elevation of the additional side plate 4 of the composite beam is equal to the top surface elevation of the uppermost asphalt concrete surface layer 9 of the overall prefabricated road.

[0040] To achieve modular overall hoisting of prefabricated roads, simplify the construction process, and eliminate the need for leveling the top surface of the structural layer, the truss reinforcement of the composite slab 6 is designed with the bottom flat part of the composite slab 6 facing downwards. The exposed steel bars at the ends of the composite slab 6 are anchored into the interior of the composite part of the top surface of the composite beam with corbels for a length of not less than 70mm. The thickness of the composite slab 6 is not less than 60mm. The truss reinforcement is arranged in a bidirectional staggered arrangement along the surface of the composite slab 6. A 120mm post-cast section is left between two adjacent composite slabs 6. In order to meet the lateral stress requirements of the prefabricated road, no less than two Φ8 continuous steel bars are set in the post-cast section. The cutting length of the continuous steel bars should meet the anchorage length requirements between the exposed steel bars of the composite slab 6 and the steel bars of the composite beam with corbels.

[0041] As an important component of the overall load-bearing system, the steel truss 5 consists of small-sized T-shaped steel beams of 30mm×50mm×5mm welded in the factory. The transverse width of the steel truss 5 is the net distance between the two corbels of the composite beams - 60mm. The longitudinal length of the steel truss 5 is controlled at 3.0m, and the height of the steel truss 5 is not less than 160mm. Each steel truss 5 rests on the corbels 3 of the composite beam 2 at both ends. The steel truss 5 is fixed by pre-embedding bolts on the top surface of the corbels 3. The number of bolts used to fix each steel truss 5 to the corbels 3 is not less than 6.

[0042] Prestressing tendons 7 are installed inside the steel truss 5, passing through pre-drilled holes 12 at both ends, which are prefabricated integrally with the corbel-supported composite beam in the PC factory. They are ultimately anchored to the outer edges of the corbel-supported composite beam at both ends of the road. Based on the structural stress characteristics, the prestressing tendons 7 are only arranged laterally along the road's driving direction, with a distance of no more than 1800mm between adjacent prestressing tendons 7. The prestressing tendon ducts 13 are freely arranged inside the steel truss 5, and collisions between the prestressing tendon ducts 13 and the steel truss 5 members must be avoided. Therefore, the placement of the prestressing tendon ducts 13 should be fully considered during the design of the steel truss 5. The prestressing tendons 7 pass through pre-drilled holes 12 inside the corbel-supported composite beam at both ends, with the inner diameter of the pre-drilled holes 12 being 6mm larger than the outer diameter of the prestressing tendon 7.

[0043] The composite slab 6 rests on the top surface of the composite beam with corbels at both ends. The support length of the composite slab 6 resting on the composite beam with corbels on each side is not less than 30mm, and the spacing between the exposed reinforcing bars at the ends of the composite slab 6 does not exceed 150mm. Each composite slab 6 is provided with two grouting holes 10 and one grout outlet hole 11. The two grouting holes 10 are respectively located at the diagonal parts of the composite slab 6, and the grout outlet hole 11 is located at the center of the composite slab 6. The diameter of both the grouting holes 10 and the grout outlet hole 11 is 60mm.

[0044] This invention also proposes a construction method for the aforementioned prefabricated road structure. The overall technical solution is based on the principles of "end support of composite beams with corbels, joint load-bearing of steel trusses, prefabrication and assembly of reverse composite slabs, high-pressure grouting of micro-expansion and low-shrinkage fiber-reinforced crack-resistant fine aggregate concrete, symmetrical tensioning of post-tensioned prestressed tendons, EPS board partitions serving as expansion joints, and full paving of asphalt concrete surface layer." (See reference...) Figure 2 The construction process is as follows: surveying and setting out, excavation of composite beam trenches, segmented hoisting of composite beams with corbels, fine stone concrete filling, mixture preparation, roadbed reinforcement, hoisting and fixing of steel trusses, prestressed tendon ducts, laying and temporary anchoring of prestressed tendons, hoisting of reverse composite slabs, treatment of beam-slab joints, grouting and sealing of holes, tensioning and anchoring of prestressed tendons, duct grouting, and full paving of asphalt concrete surface layer.

[0045] Based on the above principles and process flow, the specific technical solution is as follows:

[0046] Step S1: Measurement and layout, excavation of composite beam trench.

[0047] According to the construction plan, the site was mechanically leveled, and the basic alignment of the road was initially determined using a total station. The roadbed was then compacted using compaction machinery. During on-site construction, a segmented excavation method was adopted for the excavation of the composite beam trenches, using an "enlarged variable cross-section" excavation scheme. Each excavation segment was 12m long, with immediate hoisting after excavation. The width of the composite beam trench excavation was 200mm wider than the designed width of the composite beam with corbels, leaving approximately 100mm of working surface on each side for subsequent hoisting of the composite beam with corbels. The excavation depth of the composite beam trenches should comprehensively meet the overall road design requirements, ensuring that the top elevation of the additional side plate of the top composite beam after hoisting and positioning with corbels is the road structure design elevation. During the excavation of the composite beam trenches, the cross-section of the composite beam trenches above the corbels was enlarged to ensure accurate hoisting and positioning of the composite beam with corbels after excavation. The excavation of the composite beam trench within each construction section should be symmetrical. After excavation, a reinforced trench of at least 50mm thick gravel and coarse sand should be laid at the bottom of the composite beam trench. Finally, the elevation of the bottom of the composite beam trench and the positional relationship between the two composite beams with corbels in the same construction section should be accurately checked. The excavation of the composite beam trench should avoid the rainy season to prevent the excavated composite beam trench from being washed away by rainwater for a long time. A dedicated person should be assigned to supervise the site and keep records.

[0048] Step S2: Segmented hoisting of composite beams with corbels, and grouting with fine aggregate concrete.

[0049] After the excavation of each composite beam section using the enlarged variable cross-section method is completed, the composite beams with corbels are promptly hoisted into place. The composite beams with corbels at both ends of each construction section are hoisted and positioned symmetrically. During the hoisting of adjacent composite beams with corbels, the axial distance between them after positioning should be carefully controlled. The planar position and elevation (especially the corbel surface elevation) of the positioned composite beams with corbels should be accurately checked, with the planar position error controlled within 10mm and the positioning elevation error controlled within 3mm. During the segmented hoisting of the composite beams with corbels, the additional side plates at the top of the composite beams with corbels should be carefully protected. These additional side plates serve as the side formwork for the post-cast concrete portion of the entire prefabricated road structure, representing a formwork-free design throughout the entire prefabricated road construction process, significantly improving the efficiency of the hoisting work. After the composite beams with corbels are hoisted and positioned in sections, and the plane position and positioning elevation are confirmed to be correct, fine aggregate concrete is immediately used to fill the gap (working surface) between the composite beam groove and the positioned composite beams with corbels. This strengthens the compactness of the fine aggregate concrete after filling the gaps, and strengthens vibration and curing. The strength of the fine aggregate concrete should not be lower than C25. The height of the fine aggregate concrete filling should be 10mm below the corbel surface. The filling should be done in one go without leaving any construction joints.

[0050] Step S3: Mixture preparation and roadbed reinforcement

[0051] The subgrade reinforcement layer is designed using a method of mechanically enlarging holes using the soil displacement method and then filling them with a solidified crushed stone and slag mixture. This solidified mixture is prepared by pre-mixing crushed stone, slag, cement, and water in a specific ratio. This solidified mixture should be prepared beforehand for subgrade reinforcement layer construction. After the composite beams with corbels are hoisted into sections, a continuous construction method is used to perform mechanically enlarging holes using the soil displacement method and then filling the mixture into sections of the subgrade. The most significant characteristic of this method is that it strengthens the subgrade through the soil displacement effect of mechanically enlarging and forming holes. This method is most effective for silty soil, sandy soil, and silty clay foundations with high moisture content. The mechanically enlarging holes using the soil displacement method follows a technical scheme of "enlarging holes sequentially from the middle of the road towards both ends, and immediately filling the holes after enlargement." During the roadbed reinforcement process, since the composite beams with corbels at both ends of the road have been hoisted into place, the soil inside the road will shift during mechanical hole enlargement. This will result in significant displacement between the roadbed soil layers, creating a mutual squeezing effect to achieve the purpose of roadbed reinforcement. For the use of the mixed and solidified crushed stone and slag mixture, it should be used immediately after mixing. For roadbeds using the soil displacement method for mechanical hole enlargement, the crushed stone and slag mixture should be used to fill the holes promptly. The interval between hole enlargement and filling should not exceed 3 hours, and construction should be avoided during the rainy season. If it is rainy, roadbed hole enlargement should be stopped, and a drainage slope of not less than 0.3% should be set in the middle of the roadbed to promptly drain rainwater from the roadbed area, preventing prolonged soaking of the roadbed. For the roadbed soil layer at the composite beams with corbels at both ends of the road, when using the soil displacement method for mechanical hole enlargement, the hole position closest to the composite beam with corbel should be 200mm to 300mm away from the corbel position.

[0052] Step S4: Steel truss hoisting and fixing

[0053] According to the construction schedule, the steel truss hoisting operation can begin after the segmented construction of the roadbed reinforcement layer is completed. As one of the important load-bearing components within the prefabricated road, the steel truss is particularly effective in resisting the arching effect of the foundation soil, thus improving the overall load-bearing capacity and service life of the structure. The steel truss hoisting is located on the top surface of the corbels with overlapping beams at both ends of the road. The steel truss is flexibly fixed to the corbels using pre-embedded bolts, with two scenarios: for geological environments with minimal arching or vibration, the connection between the steel truss and the corbel uses a "fixed at both ends" method; for geological environments with significant arching or vibration, the connection uses a "fixed at one end, hinged at the other" method. During on-site construction, a post-cast section of no less than 120mm is left between the steel trusses of adjacent construction sections. A negative reinforcement bar with a cutting length of no less than 400m is installed between the two steel trusses in the post-cast section. The negative reinforcement bar uses grade II steel with a diameter of no less than 10mm, with a spacing of no more than 150mm, and each negative reinforcement bar has a 90-degree hook at both ends. In road construction, where EPS board partitions also serve as expansion joints, additional baffles should be installed on the end faces of the steel trusses on both sides of the expansion joint. The partition is achieved by installing additional baffles on the end faces of the steel trusses, and a protective concrete pad is installed between the additional baffle and the EPS board, with each concrete pad having a thickness of no less than 35mm.

[0054] Step S5: Prestressed tendon ducts, prestressed tendon laying and temporary anchorage

[0055] According to the construction plan, the prestressing tendons are arranged only in one direction along the width of the road. The prestressing tendon ducts and tendons are placed inside the steel truss, with both ends passing through pre-reserved holes inside the composite beam with corbels, and finally anchored to the outer edges of the composite beams with corbels at both ends of the road. During on-site construction, the prestressing tendons can be arranged before the steel truss is hoisted, or after the steel truss is in place and fixed, ensuring that the positional relationship of the prestressing tendon ducts inside the steel truss does not collide. The prestressing technology with bonding is adopted. The cutting length of the prestressing tendons should be appropriately extended by 200mm on the basis of meeting the requirements for tensioning and anchoring of the prestressing tendons. The prestressing tendon ducts are laid out using corrugated metal pipes. The prestressing tendon ducts are laid out before the steel truss is hoisted. The prestressing tendons are perforated after the steel truss is in place and fixed. That is, the on-site layout of the prestressing tendons adopts the technical solution of "perforating from the outside of the composite beam with corbel at one end, pulling the steel wire through the inside of the steel truss, and then passing it out through the reserved perforation inside the composite beam with corbel at the other end, and finally temporarily anchoring it on the outside of the composite beam with corbel at both ends".

[0056] Step S6: Reverse composite slab hoisting and beam-slab joint treatment

[0057] Once the prestressed tendons in each construction section are laid, the reverse composite slab hoisting work can begin. The on-site hoisting of the composite slabs utilizes a downward-facing arrangement of the composite section to enhance the coordinated load-bearing capacity between the grouted composite slabs and the internal steel trusses. The on-site hoisting of the composite slabs employs a four-point hoisting method for accurate positioning. At the beam-slab composite section, the exposed reinforcing bars at the ends of the composite slab are anchored into the top surface of the composite beam with corbels for a length of not less than 70mm within the composite section. The composite slab thickness is not less than 60mm. The truss reinforcement is arranged in a staggered, bi-directional pattern along the surface of the composite slab. A 120mm post-cast section is left between adjacent composite slabs, and to meet the lateral load requirements of the assembly road, at least two Φ8 continuous reinforcing bars are installed within the post-cast section. The composite slab and the composite beam with corbels should be reliably connected. The exposed reinforcing bars of the composite slab and the reinforcing bars at the overlapping part of the composite beam with corbels should be reliably fixed by welding. Both ends of the composite slab should rest on the top surface of the composite beam with corbels, and the support length of the composite slab resting on the composite beam with corbels should be no less than 30mm on each side. To prevent clogging of the grouting holes and grout outlet holes during the transportation, hoisting, and placement of the composite slab, rubber plugs should be used to seal the grouting holes and grout outlet holes on the composite slab before grouting. After the composite slab is hoisted, fine aggregate concrete of no less than C30 should be poured into the beam-slab joint until it is flush with the top surface of the composite slab. Throughout the entire process of hoisting and fixing the composite slab, a dedicated person should be present to supervise and control each key node, ensuring the accuracy and reliability of the hoisting, placement, and connection of the composite slab, and to properly inspect and record the concealed works.

[0058] Step S7: Grouting and Sealing

[0059] After the composite slab is hoisted into place in sections, intervals, and modules, grouting can begin. The grout used on-site is micro-expansion, low-shrinkage fiber-reinforced fine aggregate concrete grout. The fine aggregate should ideally be pebbles with a diameter not exceeding 10mm. It should be mixed and used immediately. When the temperature exceeds 30 degrees Celsius, the grout should not be used for more than 2 hours. At least two sets of grout test blocks with at least four blocks per set should be prepared for each construction section under the same curing conditions. The grouting operation process is as follows: First, remove one rubber plug from each of the grouting holes and outlet holes on the composite slab, leaving one plug in the grouting hole. Ensure that the grouting hole and outlet hole are clean, unobstructed, and free of debris. Then, inject high-strength grout through one of the grouting holes on the composite slab using high-pressure injection. Stop grouting when grout is visible in the outlet hole in the middle of the composite slab, and then re-plug the grouting hole with the rubber plug. The second step is to remove the rubber plug from the other grouting hole and continue to pressurize and grout using high-pressure grouting. Stop grouting when grout emerges from the grout outlet in the middle of the composite slab. The third step is to plug the grout outlet in the middle of the composite slab with the rubber plug and repeat the high-pressure grouting operation. Repeat the pressurization and grouting three times. Finally, keep all grouting holes and grout outlets sealed, allow for sufficient curing, and complete the process acceptance.

[0060] Step S8: Tensioning and anchoring of prestressed tendons, and grouting of ducts.

[0061] After grouting of each section of the composite slab is completed, curing should be strengthened. Prestressing tendons can only be tensioned and anchored after the concrete strength of the grout-cured test blocks reaches the design strength. For bonded prestressing techniques, the anchorages at both ends should be loosened first, and symmetrical tensioning with 1.05σcon over-tensioning should be performed. Then, grouting should be carried out on the prestressing tendon ducts, followed by strengthened curing. After the prestressing tendons are tensioned and anchored, the anchorages should be sealed with high-strength, crack-resistant mortar.

[0062] Step S9: Full paving of asphalt concrete surface layer

[0063] A reasonable assembly line operation method will be adopted, repeating steps S1 to S8 until the hoisting and construction of the prefabricated road main structure is completed. After the prestressing tendon tensioning and anchoring work is completed on-site, the asphalt concrete pavement can be laid in sections and sequentially. It is particularly important to note that the additional side plates of the composite beams also serve as formwork for the prefabricated road construction; therefore, no formwork is required during construction. During the paving and mechanical compaction of the asphalt concrete pavement on-site, special attention should be paid to the compaction of the asphalt concrete pavement within 500mm of the additional side plates of the composite beams on both sides of the road, and proper protection measures should be taken. After all construction procedures are completed, project acceptance and document archiving should be organized promptly.

[0064] In summary, this invention employs precast integrated composite beams with corbels as end supports for the road structure. After opening to traffic, the load transfer path is clearly defined. Combined with internal steel trusses for synergistic load bearing, it improves the road structure's compressive strength and the arching effect of the foundation soil. Furthermore, precast reverse composite slabs are assembled onto the precast integrated composite beams with corbels, forming an effective beam-slab structural load-bearing frame. This invention focuses on innovative structural design, optimized process flow, improved durability, reduced costs, shortened construction period, and environmental protection. It constructs a novel prefabricated road technology system with corbel composite beam-slab structures, effectively solving the technical challenges of traditional wet construction methods, such as numerous procedures, long maintenance periods, significant traffic disruption neglecting public welfare, high labor costs, low levels of green construction, environmental pollution, and difficult maintenance.

[0065] 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 precast road with bonded prestressed concrete beams and slabs supported by corbels, characterized in that: The system includes a roadbed reinforcement layer, composite beams with corbels, a steel truss, composite slabs, prestressed tendon ducts, prestressed tendons, and an asphalt concrete surface layer. The roadbed reinforcement layer is located above the roadbed. The composite beams with corbels are located at both ends of the roadbed reinforcement layer. Each composite beam includes a composite beam and corbels. The composite beams are located at both ends of the roadbed reinforcement layer, and the corbels are located inside the composite beams. Additional side plates are provided at the top of the composite beams with corbels. The steel truss is supported at both ends. On the top surface of the corbel, the prestressing tendon duct and the prestressing tendon pass through the interior of the steel truss. The prestressing tendon is located in the prestressing tendon duct and its end is fixed to the outer side of the composite beam with corbel by an anchor. The two ends of the composite slab rest on the top surface of the composite beam, and the exposed steel bars at the ends of the composite slab extend into the composite part of the composite beam with corbel. The composite slab is provided with grouting holes and grout outlet holes inside, and the asphalt concrete surface layer is provided on the upper part of the composite slab.

2. The prefabricated road according to claim 1, characterized in that: The roadbed reinforcement layer is treated by mechanically enlarging holes using the soil displacement method and then filling them with a solidified crushed stone and slag mixture. The solidified crushed stone and slag mixture is formed by pre-mixing crushed stone, slag, cement, and water in a certain proportion. The mechanically enlarged holes in the roadbed reinforcement layer have a diameter of not less than 150 mm and a depth of not less than 300 mm. The distance between each mechanically enlarged hole does not exceed 800 mm. For complex geological environments such as sandy soil, silty soil, and silty mud with high water content, the distance between each mechanically enlarged hole does not exceed 500 mm.

3. The prefabricated road according to claim 1, characterized in that: The composite beam with corbel is prefabricated in a PC factory. The corbel and the composite beam are designed as an integral whole using the same mold and process. The corbel is the same length as the composite beam, and the width of the corbel is not less than 100mm. The additional side plate of the composite beam is pre-formed and reserved in the upper part of the composite beam with corbel. Its thickness is not less than 20mm, and its top surface elevation is equal to the top surface elevation of the uppermost asphalt concrete surface layer of the overall prefabricated road.

4. The prefabricated road according to claim 1, characterized in that: The composite slab is prefabricated in a PC factory. The truss reinforcement of the composite slab faces downward and the flat bottom surface faces upward. The exposed steel bars at the ends of the composite slab are anchored into the interior of the composite part of the top surface of the composite beam with corbel for a length of not less than 70mm. The thickness of the composite slab is not less than 60mm. The truss reinforcement is arranged in a bidirectional staggered manner along the surface of the composite slab. A 120mm post-cast section is left between two adjacent composite slabs. In order to meet the lateral force requirements of the assembly road, no less than two Φ8 continuous steel bars are set in the post-cast section. The cutting length of the continuous steel bars should meet the anchorage length requirements between the exposed steel bars of the composite slab and the steel bars of the composite beam with corbel.

5. The prefabricated road according to claim 1, characterized in that: All members of the steel truss are made of small-sized T-shaped steel beams of 30mm×50mm×5mm, welded in the factory. The transverse width of the overall steel truss is the net distance between two overlapping beams with corbels minus 60mm. The longitudinal length of the steel truss is controlled at 3.0m, and the height of the steel truss is not less than 160mm. Each steel truss is placed on corbels at both ends and fixed by pre-embedded bolts on the top surface of the corbels. The number of bolts used to fix each steel truss to the corbels is not less than 6.

6. The prefabricated road according to claim 5, characterized in that: The two ends of the prestressed tendons pass through the reserved holes inside the composite beam with corbels. The inner diameter of the reserved holes is 6mm larger than the outer diameter of the prestressed tendons. The prestressed tendons are arranged only laterally along the road traffic direction, and the distance between adjacent prestressed tendons does not exceed 1800mm. The prestressed tendon ducts are freely arranged inside the steel truss, and there must be no collision between the prestressed tendon ducts and the steel truss members.

7. The prefabricated road according to claim 1, characterized in that: The support length of the composite slab resting on the composite beam with corbels at both ends is not less than 30mm on each side, and the spacing between the exposed steel bars at the ends of the composite slab does not exceed 150mm; each composite slab is provided with 2 grouting holes and 1 grout outlet hole, with the two grouting holes located at opposite corners of the composite slab and the grout outlet hole located at the center of the composite slab, and the diameter of both the grouting holes and the grout outlet hole is 60mm.

8. A construction method for bonded prestressed precast roads supported by composite beams with corbels, characterized in that: The overall technical solution follows the principle of "end support of composite beams with corbels, joint load-bearing of steel trusses, prefabrication and assembly of reverse composite slabs, high-pressure grouting of micro-expansion and low-shrinkage fiber-reinforced crack-resistant fine aggregate concrete, symmetrical tensioning of post-tensioned prestressing tendons, EPS board partitions serving as expansion joints, and full paving of asphalt concrete surface layer." The corresponding construction process is as follows: surveying and setting out, excavation of composite beam trenches, segmental hoisting of composite beams with corbels, grouting of fine aggregate concrete joints, preparation of mixture, roadbed reinforcement, hoisting and fixing of steel trusses, prestressing tendon ducts, laying and temporary anchoring of prestressing tendons, hoisting of reverse composite slabs, beam-slab joint treatment, grouting and sealing of holes, tensioning and anchoring of prestressing tendons, duct grouting, and full paving of asphalt concrete surface layer.

9. The construction method according to claim 8, characterized in that: The specific technical solution is as follows: Step S1: Measurement and layout, excavation of composite beam trench: According to the construction plan, the site was leveled mechanically, and the basic alignment of the road was initially determined using a total station. The roadbed was then compacted using compaction machinery. During on-site construction, a segmented excavation method was adopted for the excavation of the composite beam trenches, using an "enlarged variable cross-section" excavation scheme. Each excavation segment was 12m long, with immediate excavation and hoisting. The width of the composite beam trench excavation was 200mm wider than the designed width of the composite beam with corbels, leaving approximately 100mm of working surface on each side for subsequent hoisting of the composite beam with corbels. The excavation depth of the composite beam trenches should comprehensively meet the overall road design requirements and should be sufficient to accommodate the top of the additional side plates of the top composite beam after it has been hoisted into place. The surface elevation is the road structure design elevation. When excavating the composite beam trench, the cross-section of the composite beam trench above the corbel should be enlarged to ensure accurate hoisting and positioning of the composite beam with corbel after excavation. The excavation of the composite beam trench in each construction section should be symmetrical. After excavation, a reinforced trench of not less than 50mm of crushed stone and coarse sand should be laid at the bottom of the composite beam trench. Finally, the bottom elevation of the composite beam trench and the positional relationship between the two composite beams with corbel in the same construction section should be accurately checked. The excavation of the composite beam trench should avoid the rainy season. The excavated composite beam trench should not be washed by rainwater for a long time. A dedicated person should be assigned to supervise the site and keep records. Step S2: Segmented hoisting of the composite beam with corbels, and grouting with fine aggregate concrete: After each section of the composite beam trench is excavated using the enlarged variable cross-section method, the composite beams with corbels are promptly hoisted and positioned in segments. The composite beams with corbels at both ends of the road within each construction section are hoisted and positioned symmetrically. During the hoisting of adjacent composite beams with corbels, the axial distance between the two beams after positioning should be carefully controlled. The planar position and elevation of the positioned composite beams with corbels should be accurately checked, with the planar position error controlled within 10mm and the positioning elevation error controlled within 3mm. During the segmented hoisting of the composite beams with corbels, the additional side plates at the top of the composite beams with corbels should be carefully protected. The additional side plate of the corbel composite beam serves as the side formwork for the post-cast concrete part of the entire prefabricated road structure, which is a formwork-free design for the entire prefabricated road construction process, greatly improving the efficiency of hoisting work. After the composite beam with corbel is hoisted and positioned in sections, and the plane position and positioning elevation are controlled correctly, fine stone concrete is immediately used to fill the gap between the composite beam groove and the positioned composite beam with corbel to strengthen the compactness of the fine stone concrete after filling the joint. Vibration and curing are strengthened. The strength of the fine stone concrete is not less than C25. The height of the fine stone concrete filling joint is 10mm below the corbel surface. It is filled in one go without leaving a construction joint. Step S3: Mixture preparation and roadbed reinforcement: The subgrade reinforcement layer is designed using a method of mechanically enlarging holes using the displacement method and then filling them with a solidified crushed stone and slag mixture. This involves pre-mixing crushed stone, slag, cement, and water in a specific ratio to form the solidified mixture. This solidified mixture should be prepared beforehand for subgrade reinforcement layer construction. After the composite beams with corbels are installed in sections, a continuous construction method is used to perform mechanically enlarging holes and filling the mixture in sections using the displacement method. The most significant feature of this method is that it strengthens the subgrade through the displacement effect of mechanically enlarging and forming holes. This method is most effective for silty soil, sandy soil, and muddy soil foundations with high moisture content. The mechanically enlarging holes using the displacement method follows the technical principle of "enlarging holes sequentially from the middle of the road towards both ends, and immediately filling the holes after enlargement." The case involves the following: During the roadbed reinforcement process, since the composite beams with corbels at both ends of the road have been hoisted into place, the soil inside the road will experience displacement during mechanical hole enlargement. This will result in significant displacement between the roadbed soils, creating a mutual squeezing effect to achieve the purpose of roadbed reinforcement. For the use of the mixed and solidified crushed stone and slag mixture, it should be used immediately after mixing. For roadbeds using the soil displacement method for mechanical hole enlargement, the crushed stone and slag mixture should be used to fill the holes promptly. The interval between hole enlargement and hole filling should not exceed 3 hours, and construction should be avoided during the rainy season. If it is rainy, roadbed hole enlargement should be stopped, and a drainage slope of not less than 0.3% should be set in the middle of the roadbed to promptly drain rainwater from the roadbed area, preventing prolonged soaking of the roadbed. For the roadbed soil layer at the composite beams with corbels at both ends of the road, when using the soil displacement method for mechanical hole enlargement, the hole position closest to the composite beam with corbels should be 200mm to 300mm away from the corbel position. Step S4: Steel truss hoisting and fixing: According to the construction organization plan, the steel truss hoisting operation can proceed after the segmented construction of the roadbed reinforcement layer is completed. As one of the important load-bearing components inside the prefabricated road, the steel truss is particularly effective in resisting the arching effect of the foundation soil, thus improving the overall structure's load-bearing capacity and service life. The steel truss hoisting is located on the top surface of the corbels with overlapping beams at both ends of the road. The steel truss and corbels are flexibly fixed using pre-embedded bolts, with two scenarios: for geological environments with minimal arching or vibration, the connection between the steel truss and corbels uses a "fixed at both ends" method; for geological environments with significant arching or vibration, the connection between the steel truss and corbels uses a different method. The connection method is "fixed at one end and hinged at the other end"; during on-site construction, a post-cast section of not less than 120mm is left between the steel trusses in two adjacent construction sections. A negative reinforcement bar with a cutting length of not less than 400m is set between the two steel trusses in the post-cast section. The negative reinforcement bar is made of grade II steel with a diameter of not less than 10mm and a spacing of not more than 150mm. Each negative reinforcement bar has a 90-degree hook at both ends; when EPS board partitions are used as expansion joints in road construction, additional baffles should be set on the end faces of the steel trusses on both sides of the expansion joint. The partition treatment is carried out by setting additional baffles on the end faces of the steel trusses. A protective layer concrete pad is set between the additional baffle and the EPS board. Each concrete pad has a thickness of not less than 35mm. Step S5: Prestressed tendon ducts, prestressed tendon laying and temporary anchorage: According to the construction plan, prestressed tendons are arranged only along the width of the road in one direction. The prestressed tendon ducts and tendons are placed inside the steel truss, with both ends passing through pre-reserved holes inside the composite beam with corbels, and finally anchored to the outer edges of the composite beams with corbels at both ends of the road. During on-site construction, the prestressed tendon placement can be done before the steel truss is hoisted or after the steel truss is in place and fixed, ensuring that the prestressed tendon ducts do not collide with each other inside the steel truss. Bonded prestressing technology is used, and the prestressed tendons are cut... The length should be appropriately extended by 200mm on the basis of meeting the requirements for tensioning and anchoring of prestressing tendons. The prestressing tendon ducts should be laid out using corrugated metal pipes. The prestressing tendon ducts should be laid out before the steel truss is hoisted. The prestressing tendons should be perforated after the steel truss is in place and fixed. That is, the on-site prestressing tendon layout adopts the technical solution of "perforating from the outside of the composite beam with corbel at one end, pulling the steel wire through the inside of the steel truss, and then passing it out through the reserved perforation inside the composite beam with corbel at the other end, and finally temporarily anchoring it on the outside of the composite beam with corbel at both ends". Step S6: Reverse composite slab hoisting, beam-slab joint treatment: After the prestressed tendons in each construction section are laid, the reverse composite slab hoisting work can begin. The composite slabs are hoisted on-site with the composite section facing downwards to enhance the synergistic load-bearing capacity between the grouted composite slab and the internal steel truss. Four-point hoisting is used for accurate positioning. At the beam-slab composite section, the exposed reinforcing bars at the ends of the composite slab are anchored into the top surface of the corbel composite beam for a length of not less than 70mm inside the composite section. The composite slab thickness is not less than 60mm. The truss reinforcement is arranged alternately in both longitudinal and transverse directions along the surface of the composite slab. A 120mm post-cast section is left between adjacent composite slabs. To meet the lateral load requirements of the assembly road, at least two Φ8 continuous reinforcing bars are installed in the post-cast section. The composite slab and the corbel composite beam should be reliably connected. The exposed reinforcing bars of the composite slab... The reinforcing bars at the overlapping section of the composite beam with corbels are reliably fixed by welding, and both ends of the composite slab rest on the top surface of the composite beam with corbels. The support length of the composite slab resting on the composite beam with corbels on each side is not less than 30mm. To prevent the grouting holes and grout outlet holes from being blocked during the transportation, hoisting, and placement of the composite slab, rubber plugs should be used to seal the grouting holes and grout outlet holes on the composite slab before grouting. After the composite slab is hoisted, fine aggregate concrete of not less than C30 is poured to the beam-slab joint until it is flush with the top surface of the composite slab. Throughout the entire process of hoisting and fixing the composite slab, a dedicated person should be present to supervise and control each key node, ensuring the accuracy and reliability of the hoisting and placement of the composite slab and the connection nodes, and to properly inspect and record the process of concealed works. Step S7: Grouting and Sealing: After the composite slab is hoisted into place in sections, intervals, and modules, grouting can begin. The grout used on site is micro-expansion, low-shrinkage fiber-reinforced fine aggregate concrete grout. Fine aggregate should preferably be pebbles with a diameter not exceeding 10mm. It should be mixed and used immediately. When the temperature exceeds 30 degrees Celsius, the grout should not be used for more than 2 hours. At least two sets of grout test blocks with the same curing conditions should be prepared for each construction section on site, with at least four test blocks in each set. The grouting operation process is as follows: First, remove one rubber plug from each of the grouting holes and grout outlet holes on the composite slab, leaving one rubber plug inside the grouting hole intact. Ensure the inside of the grouting hole and grout outlet hole is clean. The process is smooth and free of debris. High-strength grout is then injected into one of the injection holes on the composite slab using high-pressure grouting. Grouting is stopped once grout is visible at the outlet hole in the middle of the composite slab. The second step involves plugging the injection hole with a rubber stopper. The rubber stopper in the other injection hole is then removed, and high-pressure grouting is continued until grout emerges from the outlet hole in the middle of the composite slab. The third step involves plugging the outlet hole in the middle of the composite slab with a rubber stopper. This high-pressure grouting process is repeated three times. Finally, all injection and outlet holes are sealed, and the grout is fully cured. The process is then inspected and accepted. Step S8: Tensioning and anchoring of prestressed tendons, grouting of ducts: After the grouting of each section of the composite slab is completed, curing should be strengthened. Prestressing tendons can only be tensioned and anchored after the concrete strength of the test blocks cured under the same conditions as the grout has reached the design strength. For bonded prestressing techniques, first loosen the anchorages at both ends, then use 1.05σcon over-tensioning, symmetrical tensioning, and then grout the prestressing tendon ducts. After strengthening curing and prestressing tendon tensioning and anchoring, the anchorages should be sealed with high-strength, crack-resistant mortar. Step S9: Full paving of the asphalt concrete surface layer: A reasonable assembly line operation method is adopted, repeating steps S1 to S8 until the prefabricated road main structure hoisting construction site is completed. After the prestressing tendon tensioning and anchoring work is completed, the asphalt concrete pavement can be laid in sections and successively. It is particularly important to note that the additional side plates of the composite beam also serve as the formwork for the prefabricated road construction, so no formwork is required during construction. During the paving and mechanical compaction of the asphalt concrete pavement on site, special attention should be paid to the compaction of the asphalt concrete pavement within 500mm of the additional side plates of the composite beam on both sides of the road, and protection work should be done. After all the construction procedures are completed, the project acceptance and data archiving should be organized in a timely manner.

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