Reinforced concrete stiffening rib pile supporting post-tensioning method pre-stressed road and construction method

Abstract

The invention relates to the technical field of road engineering, in particular to a reinforced concrete stiffening dense rib pile supporting post-tensioning method prestressed road and a construction method. According to the overall technical scheme, dense rib pile multilateral wing beam pile head integrated design is adopted, pile sinking is conducted through a steel casing guide soil squeezing static pressure method, longitudinal and transverse crossed flat and hidden beams cooperatively bear, butt joint steel bars are connected through a full grouting sleeve grouting method, post-tensioning method unbonded prestressed tendon perforation laying is conducted, and double-I-beam pedestal bearing prestress applying and anchoring are conducted; according to the principle of reinforcing the bearing effect of road structure group piles through reinforcing meshes, the rapid mounting and dismounting process of aluminum molds and comprehensive pavement of asphalt concrete surface layers, the bearing capacity of the road structure is improved, the stability and durability are enhanced, meanwhile, the construction efficiency is optimized, and the follow-up maintenance cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of road engineering technology, specifically to a post-tensioned prestressed road supported by reinforced concrete ribbed piles and its construction method. Background Technology

[0002] Traditional wet construction methods consume significant resources such as manpower, materials, and machinery, resulting in low construction efficiency, substantial impact on road traffic, and environmental degradation. Currently, research and application of prefabricated road construction technology in China are still in their early stages, with an incomplete supporting technical system. Existing road structural systems primarily utilize prefabricated component assembly combined with partial grouting to form a compressive load-bearing mode, similar to the traditional wet-construction cast-in-place stress form. Neither approach effectively achieves a comprehensive load-bearing structure. Therefore, the key to improving road structure durability lies in constructing a more effective structural technology system based on strengthening the roadbed's load-bearing capacity, establishing a clear load transfer path, and thus forming a new roadbed-structure collaborative load-bearing mode. This addresses technical issues such as excessive localized stress and uneven roadbed settlement during road use, preventing severe structural damage and short service life. Summary of the Invention

[0003] The purpose of this invention is to provide a post-tensioned prestressed road supported by reinforced concrete ribbed piles 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 post-tensioned prestressed road supported by reinforced concrete ribbed piles, comprising ribbed piles, double I-beam pedestals, steel mesh, and unbonded prestressing tendons. The ribbed piles are driven longitudinally and transversely along the roadbed. Each ribbed pile has an integrally formed wing beam pile head and a double I-beam pedestal at its top. Reinforcing bars are provided between opposite wing beam pile heads. The double I-beam pedestal has unbonded pre-reserved holes for the unbonded prestressing tendons to pass through. The unbonded prestressing tendons are arranged transversely along the road and fixed at both ends to the outer side of the double I-beam pedestal with anchors. The steel mesh is provided at the entire elevation of the top of the double I-beam pedestal. A fine aggregate concrete layer is poured within the ribbed section enclosed by each ribbed pile according to the road design elevation. An asphalt concrete surface layer is also provided on top of the fine aggregate concrete layer.

[0005] Preferably, the ribbed piles are prefabricated in a prefabricated PC factory. The cross-sectional design dimensions of the ribbed piles are not less than 300mm×300mm, the design height is not less than 600mm, and the spacing between the ribbed piles does not exceed 1600mm. The bottom of the ribbed pile is provided with a pile tip, and the top is provided with the double I-beam platform and the wing beam pile head.

[0006] Preferably, the wing beam pile heads at the top of the ribbed piles are divided into three-sided wing beam pile heads and four-sided wing beam pile heads. The ribbed piles with three-sided wing beam pile heads are arranged longitudinally at both ends of the road structure, and the ribbed piles with four-sided wing beam pile heads are arranged longitudinally in the middle of the road structure. The length of each wing beam pile head extending beyond the ribbed pile is not less than 450mm and not less than 1.5 times the maximum side length of the ribbed pile cross-section. The cross-sectional width of the wing beam pile head is equal to the dimension of the corresponding side of the ribbed pile, and its cross-sectional height is not less than 120mm. All surfaces of each wing beam pile head are roughened, with a roughness rate of over 80% as designed.

[0007] Preferably, at least four butt reinforcing bars with a diameter of not less than 16mm are provided at the end of the wing beam pile head between two adjacent closely ribbed piles. The butt reinforcing bars at the wing beam pile head between two adjacent closely ribbed piles in the same span are connected by the "full grouting sleeve grouting method". The four butt reinforcing bars are divided into two rows. The first row of butt reinforcing bars is located 50mm below the top surface of the wing beam pile head, and the second row of butt reinforcing bars is located 100mm below the first row of butt reinforcing bars. The upper and lower rows of butt reinforcing bars form a "flat hidden beam" between two adjacent closely ribbed piles by adding stirrups. Preferably, the web height of the double I-beam platform is not less than 300mm, the flange width is not less than 40mm, and the thickness of both the web and flange is not less than 25mm. The cutting length of the double I-beam platform is calculated as the width of the ribbed pile in the same direction + the length of the wing pile head × 2-60mm. The diameter of the reserved hole on the double I-beam platform is not less than 60mm. There is a working space of not less than 1 / 3 of the cross-sectional length of the ribbed pile and not less than 120mm between the two double I-beam platforms at the top of the same ribbed pile.

[0008] Preferably, the steel mesh has a bidirectional structure, with the diameter of the distributed steel bars not less than 10mm and the spacing not exceeding 150mm. At least two continuous distributed steel bars are erected perpendicular to the upper part of the double I-beam platform, and the ends of the continuous distributed steel bars are provided with 180° hooks with the hooks facing downwards.

[0009] This invention also provides a construction method for post-tensioned prestressed roads supported by reinforced concrete ribbed piles, comprising: Step S1: Surveying, setting out, and determining stake positions; roadbed treatment. Step S2: Ribbed piles arrive on site, soil is squeezed and piles are driven in; Step S3: Verify the pile top elevation and adjust the wing beam pile head; Step S4: Adjust the double I-beam platform and grout the steel reinforcement sleeves. Step S5: Install the steel mesh and lay the unbonded prestressed tendons through holes; Step S6: Install aluminum formwork in sections, pour and cure fine aggregate concrete; Step S7: Remove aluminum formwork, tension and anchor unbonded prestressing tendons; Step S8: Repeat steps S1 to S7 until the main structure construction is completed and the asphalt concrete surface layer is fully paved.

[0010] The preferred technical solution is as follows: Step S1: Measurement, layout, and stakeout; roadbed treatment: First, the roadbed is leveled and reinforced, and all obstacles affecting road construction are cleared. An elevation control line is set every 3km along the road's direction of travel to assist in the leveling and reinforcement of the roadbed in each construction section. For complex conditions such as complex original terrain, road design lengths exceeding 10km, or limited construction space, a plan of the ribbed pile layout is drawn in advance. The ribbed piles at each location are numbered and marked on the plan. The road alignment and the planar position of each ribbed pile are accurately measured using a total station in each section. The "steel rod driving method" is used to accurately locate and mark the ribbed pile positions. Sectional work is carried out, and the overall positional relationship and mutual positional relationship of each ribbed pile position are accurately measured and verified. The longitudinal error within each construction section is controlled within 20mm, the lateral error within 5mm, and the positional error between adjacent pile positions within 2mm. Process acceptance is carried out, with particular emphasis on protecting each pile position, assigning dedicated personnel, and keeping records. Step S2: Ribbed piles arrive on site, soil displacement and pile driving: A continuous construction approach is adopted. Once the pile locations within each construction section are determined, the driving of ribbed piles can begin. Before on-site construction, strict quality control is implemented for all precast ribbed piles upon arrival. Piles damaged, with severe appearance defects, improper wing beam pile heads, or insufficient or severely deformed / broken butt reinforcement bars due to improper handling during precast component production, transportation, or storage are strictly prohibited from entering the site. The quality of finished products is rigorously controlled. On-site ribbed pile driving primarily focuses on pile top elevation control, supplemented by soil penetration depth control. The "steel casing guidance + soil squeezing static pressure method" is employed, meaning that during hoisting, the pile top elevation is first... A steel casing is accurately placed at the pile location of the ribbed pile as a guide for the soil displacement pile driving operation. The steel casing is made of cast iron and has a wall thickness of not less than 50mm. The inner diameter of the steel casing is 5mm to 10mm larger than the diameter of the ribbed pile to be driven. The steel casing is supported by 4 adjustable angle hinge bolts. The bottom of the hinge bolt support is equipped with a steel support, which is driven into the subgrade soil layer by steel anchors. The guiding effect of the steel casing ensures the accuracy of the soil displacement pile driving of the ribbed pile. The on-site soil displacement pile driving construction adopts the method of "first driving the piles on both sides to control the overall road alignment, and then driving the piles in the middle to fully exert the soil displacement effect to strengthen the subgrade". Step S3: Verify pile top elevation and adjust wing beam pile heads: After the ribbed piles are driven in sections, the planar position relationship and pile top elevation of each ribbed pile should be checked in a timely and accurate manner. If there are large errors in the planar position relationship and pile top elevation of the ribbed piles, a plan should be formulated to adjust the pile position. At the same time, the positional relationship between each adjacent ribbed pile should be checked to ensure that the double I-beam platform at the top of the ribbed pile is consistent with the direction of travel after the ribbed pile is driven. When the positional deviation of the ribbed pile is large and affects the construction of subsequent procedures, the pile should be pulled out, filled with sand and gravel mixture, and then re-driven to adjust it. The pile top elevation should be checked a second time according to the positioning elevation marked on the pile top to ensure that each ribbed pile is accurately positioned. For the adjustment of the butt reinforcement at the wing beam pile head, if the butt reinforcement at the pile head is bent, broken, or rusted due to improper operation during the production, transportation, and stacking of the ribbed piles, it should be straightened before the grouting sleeve connection of the butt reinforcement. The length of the butt reinforcement joint should be measured to meet the dimensional requirements of the grouting sleeve connection. Process acceptance and recording should be done well. Step S4: Adjustment of the double I-beam platform, grouting connection of the reinforcing bar sleeve: The double I-beam platforms atop the ribbed piles on both sides of the road serve as support points for the tensioning and anchoring of unbonded prestressed tendons. After the elevation of the top of the ribbed piles in each construction section is accurately verified, the double I-beam platforms atop the ribbed piles are effectively adjusted to ensure their integrity and minimal deformation. Then, a high-pressure air gun is used to clean the double I-beam platforms atop the ribbed piles, focusing on cleaning the cavities between the double I-beam platforms and the pre-drilled holes for the unbonded prestressed tendons, ensuring the absence of debris, laitance, and blocked pre-drilled holes. After the adjustment of the double I-beam platforms atop the ribbed piles is completed, the double rows of four butt-jointed reinforcing bars at the ends of the wing beam pile heads between adjacent ribbed piles are fully... The grouting sleeve method is used for on-site connection. First, all the stirrups are put on the butt reinforcement at one end of the wing beam pile head. Then, the full grouting sleeve is installed on the two butt reinforcements to be connected. High-strength, low-shrinkage, micro-expansion fiber-reinforced grouting material is used for grouting. After the strength grade of the grouting material reaches more than 85% of the design strength, the stirrups put on the butt reinforcement at one end of the wing beam pile head are tied to the four butt reinforcements in the double row. This forms a "flat hidden beam reinforcement cage" between the two closely ribbed piles. Finally, a cross-connection support system of longitudinal and transverse flat hidden beams is formed between each closely ribbed pile. This forms a stress form that improves the overall road structure bearing capacity on the basis of strengthening the subgrade. The hidden works are inspected and recorded. Step S5: Installation of steel mesh and laying of unbonded prestressed tendons through holes: After all the butt reinforcement bars between the ribbed piles in each construction section are connected by sleeve grouting and a "flat hidden beam reinforcement cage" is formed, the unbonded prestressing tendon can be laid in the grid area formed by the ribbed piles and the flat hidden beam reinforcement cage. The unbonded prestressing tendons are laid on the top of the ribbed pile group using the post-tensioning method, and the unbonded prestressing tendons pass through the reserved holes on each double I-beam platform. The unbonded prestressing tendons must not interfere with the completed flat hidden beam reinforcement cage during the laying process. The work is carried out in a cross-flow manner. While laying the unbonded prestressing tendons, the installation of the steel mesh is carried out. First, the transverse distribution steel bars are laid on the double I-beam platform by spot welding. The contact parts between the transverse distribution steel bars and the double I-beam platform are spot welded one by one. Then, the longitudinal distribution steel bars are laid and other transverse distribution steel bars are tied as supports using the spot welded and fixed transverse distribution steel bars on the double I-beam platform until the on-site laying of all steel mesh in each section is completed. Step S6: Segmented installation of aluminum formwork, pouring and curing of fine aggregate concrete: After the unbonded prestressed tendons in each construction section are laid, the fine aggregate concrete layer can be poured. Before pouring the fine aggregate concrete, aluminum formwork is used to install the side formwork around each construction section on-site. The aluminum formwork is installed using a direct tightening method with internal threads, eliminating the need for additional supports and facilitating installation and dismantling. A 3mm thick flexible asphalt membrane strip is installed between the aluminum formwork and the positioning piles, with the flexible asphalt membrane strip being at least 100mm wide. After the aluminum formwork in each construction section is installed, the ribbed piles and... Fine aggregate concrete is poured within the lattice space formed by the flat, concealed beam reinforcement cage. The strength grade of the fine aggregate concrete is not lower than C30. The fine aggregate concrete layer in each construction section is poured in one go without leaving construction joints. Special attention is paid to the concrete pouring work at the pile heads of the three-sided and four-sided wing beams at the top of the ribbed piles, and vibration and curing are strengthened. The post-tensioned unbonded prestressed technology is adopted. The cavity in the middle of the double I-beam platform at the top of the ribbed piles is poured together with the fine aggregate concrete layer. Vibration and curing are strengthened, and process acceptance and recording are done well. Step S7: Aluminum formwork removal, tensioning and anchoring of unbonded prestressing tendons: The requirements for removing aluminum formwork as side formwork are relatively low, as long as the appearance of the road concrete is intact after the aluminum formwork is removed. Construction is carried out in sections, and once the fine aggregate concrete has been poured and cured to 100% of its design strength, the tensioning and anchoring of the unbonded prestressing tendons can begin. The anchoring ends of the unbonded prestressing tendons are located on the outer side web of the double I-beam platform at the top of each ribbed pile, providing ample working space for convenient construction. The tensioning of the unbonded prestressing tendons on site is carried out independently for each construction section, proceeding sequentially from the middle to the ends of the section, symmetrically, with immediate anchoring after tensioning. The prestressing tendons are over-tensioned to 1.05σcon, and proper acceptance and recording of concealed works are ensured. Step S8: Repeat steps S1 to S7 until the main structure construction is completed and the asphalt concrete surface layer is fully paved. After the unbonded prestressed tendons and anchors in each construction section are tensioned and the anchors are installed, sulfur mortar and fiber-reinforced crack-resistant mortar are used to seal the anchors at the ends of the prestressed tendons one by one. Then, a flow-line construction organization is adopted to repeat steps S1 to S7 until all on-site procedures for each construction section of the road project are completed. Finally, the asphalt concrete surface layer is fully paved, and the overall project acceptance and data are archived in a timely manner.

[0011] Compared with the prior art, the beneficial effects of this invention are as follows: 1. This invention employs integrated prefabrication of ribbed piles and double I-beam platforms, combined with a "flat hidden beam" connection system for the wing beam pile heads, forming a synergistic load-bearing structure that can effectively resist concentrated loads. Furthermore, the post-tensioned unbonded prestressed tendons of this invention, combined with bidirectional steel mesh, significantly improve the shear and crack resistance of the road, reducing the risk of uneven settlement of the roadbed.

[0012] 2. This invention employs prefabricated components and utilizes techniques such as steel casing to guide pile driving and fully grouted sleeve connections on-site to ensure construction accuracy. The invention also employs segmented installation of aluminum formwork and a streamlined construction organization, simplifying the installation and dismantling process. Fine aggregate concrete is poured in a single pour without construction joints, improving construction efficiency and project quality.

[0013] 3. This invention employs surface roughening treatment of components and anchor sealing protection to enhance structural integrity and corrosion resistance, extending service life. Furthermore, this invention is adaptable to complex terrain, long-distance roads, and restricted construction sites, and through segmented construction and flexible pile placement, it can meet various working conditions.

[0014] 4. The ribbed pile displacement and pressing pile technology of the present invention can directly strengthen the subgrade soil layer. Combined with the longitudinal and transverse cross support system, it can further improve the overall bearing capacity of the subgrade and reduce later defects. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the road structure of the present invention along the transverse direction of the road; Figure 2 This is a plan view of the road structure of the present invention; Figure 3 This is a schematic diagram of the end ribbed plate of the present invention; Figure 4 This is a schematic diagram of the structure of the central dense rib plate of the present invention; Figure 5 This is a process flow diagram of the construction method of the present invention; Figure 6 This is a structural schematic diagram of the reinforcing cylinder of the present invention and its usage. Detailed Implementation

[0016] This invention discloses a post-tensioned prestressed road supported by reinforced concrete ribbed piles and its construction method. The overall technical solution is based on the principles of "integrated design of ribbed piles and multi-sided wing beam pile heads, steel casing guiding the soil squeezing and static pressure method for pile driving, longitudinal and transverse cross-shaped flat hidden beams for synergistic bearing, full grouting sleeve connection of butt-jointed steel bars, perforated laying of post-tensioned unbonded prestressing tendons, prestressing application and anchoring supported by double I-beam abutments, reinforcement of the road structure pile group bearing effect by steel mesh, rapid installation and dismantling process of aluminum formwork, and full paving of asphalt concrete surface layer".

[0017] See Figure 1 and Figure 2 The overall structure of the road mainly consists of ribbed piles 1, double I-beam bases 12, steel mesh 3, unbonded prestressed tendons 4, anchors 5, fine aggregate concrete layer and asphalt concrete surface layer 6. Ribbed piles 1 are driven along the longitudinal and transverse directions of the roadbed. Each ribbed pile 1 has an integrally formed wing beam pile head 11 and double I-beam base 12 at its top. Reinforcing bars 2 are provided between opposite wing beam pile heads 11. Unbonded pre-reserved holes 9 are provided on the double I-beam base 12. Unbonded prestressed tendons 4 are arranged transversely along the road and pass through the pre-reserved holes 9 on the double I-beam base 12 at the top of each ribbed pile 1. The two ends of the unbonded prestressed tendons 4 are fixed to the outer side of the double I-beam base 12 by anchors 5. Steel mesh 3 is provided at the top of the double I-beam base 12 at the entire elevation of the surface layer. Fine aggregate concrete layer is poured in the ribbed area enclosed by each ribbed pile 1 according to the road design elevation. An asphalt concrete surface layer 6 is also provided on the top of the fine aggregate concrete layer.

[0018] Ribbed piles 1 are designed as an important means of roadbed reinforcement and also serve as one of the important supporting components for structural load-bearing. Ribbed piles 1 are prefabricated in a precast concrete (PC) factory. The cross-sectional dimensions of ribbed piles 1 are no less than 300mm × 300mm, the design height is no less than 600mm, and the spacing between ribbed piles 1 does not exceed 1600mm. Each ribbed pile 1 has a pile tip at the bottom and a double I-beam pedestal 12 and a wing beam pile head 11 at the top. The double I-beam pedestal 12 is prefabricated as an integrated unit with the ribbed piles 1 during the precast PC factory fabrication. The wing beam pile head 11 at the top of the ribbed pile 1 is divided into three-sided wing beam pile heads and four-sided wing beam pile heads. The ribbed piles 1 with three-sided wing beam pile heads are arranged longitudinally at both ends of the road structure. (See reference...) Figure 3 The closely spaced ribbed piles 1, where the pile heads of the four-sided wing beams are located, are laid out longitudinally along the road in the middle of the road structure. (See reference...) Figure 4The wing beam pile head 11 is also prefabricated as an integral part of the prefabricated PC factory and the closely spaced pile 1. The length of each wing beam pile head 11 extending beyond the closely spaced pile 1 is not less than 450mm and not less than 1.5 times the maximum side length of the cross section of the closely spaced pile 1. The cross section width of the wing beam pile head 11 is equal to the dimension of the corresponding side of the closely spaced pile 1, and its cross section height is not less than 120mm. All surfaces of each wing beam pile head 11 are roughened, with a roughness rate of over 80% as designed.

[0019] To enhance the overall load-bearing capacity of the structure, at least four butt-joint reinforcing bars 2 with a diameter of not less than 16mm are provided at the ends of the wing beam pile heads 11 between two adjacent closely ribbed piles 1. The butt-joint reinforcing bars 2 at the wing beam pile heads 11 between two adjacent closely ribbed piles 1 in the same span are connected by the "full grouting sleeve grouting method". Double rows of butt-joint reinforcing bars 2 are set. The first row of butt-joint reinforcing bars 2 is located 50mm below the top surface of the wing beam pile head 11, and the second row of butt-joint reinforcing bars 2 is located 100mm below the first row of butt-joint reinforcing bars 2. The upper and lower rows of butt-joint reinforcing bars 2 form a "flat hidden beam" between two adjacent closely ribbed piles 1 by adding stirrups. The flat hidden beam consolidates the synergistic load-bearing capacity between each closely ribbed pile 1, thereby improving the road structure's ability to resist large concentrated loads and uneven settlement of the roadbed. To further enhance the overall load-bearing capacity of the structure, a two-way steel mesh 3 is additionally provided on the entire structural surface at the top elevation of the double I-beam platform 12. The diameter of the distributed steel bars used in the steel mesh 3 is not less than 10mm, and the spacing is not more than 150mm. At least two continuous distributed steel bars should be erected perpendicular to the upper part of the double I-beam platform 12. The ends of the continuous distributed steel bars are provided with 180° hooks with the hooks facing downwards.

[0020] To improve the shear bearing capacity of the road structure and meet the technical requirements for unbonded prestressing application and anchoring, a prestressed structure bearing system of ribbed pile-beam-slab is constructed. The top of the ribbed pile 1 is provided with a double I-beam platform 12. The web height of the double I-beam platform 12 is not less than 300mm, the flange width is not less than 40mm, and the thickness of both the web and the flange is not less than 25mm. The cutting length of the double I-beam platform 12 is calculated as the width of the ribbed pile in the same direction + the length of the wing beam pile head × 2-60mm. The cutting length of the double I-beam platform 12 is designed to be continuous along the entire length of the single ribbed pile 1 and the wing beam pile heads 11 at both ends of the ribbed pile 1, thereby improving the shear bearing capacity of the road structure. To better optimize the effectiveness of the unbonded prestressed tendon perforation, tensioning, and anchoring process, the reserved holes 9 on the double I-beam platform 12 are not less than 80mm in diameter, and a working space of not less than 1 / 3 of the cross-sectional length of the ribbed pile and not less than 120mm is left between the two I-beam platforms at the top of the same closely ribbed pile 1.

[0021] Based on the aforementioned road structure, a construction method for post-tensioned prestressed road supported by reinforced concrete ribbed piles is provided. (See reference...) Figure 5 The process flow diagram shown includes the following steps: Step S1: Surveying, setting out, and determining stake positions; roadbed treatment. Step S2: Ribbed piles arrive on site, soil is squeezed and piles are driven in; Step S3: Verify the pile top elevation and adjust the wing beam pile head; Step S4: Adjust the double I-beam platform and grout the steel reinforcement sleeves. Step S5: Install the steel mesh and lay the unbonded prestressed tendons through holes; Step S6: Install aluminum formwork in sections, pour and cure fine aggregate concrete; Step S7: Remove aluminum formwork, tension and anchor unbonded prestressing tendons; Step S8: Repeat steps S1 to S7 until the main structure construction is completed and the asphalt concrete surface layer is fully paved.

[0022] The specific technical solutions for the above construction methods are as follows: Step S1: Measurement, layout, and stakeout; roadbed treatment. According to the technical plan, the roadbed will first be leveled and reinforced, and various obstacles affecting road construction will be cleared. An elevation control line will be set every 3km (one construction section) along the road's driving direction to assist in the leveling and roadbed reinforcement work of each construction section. For complex road conditions such as complex original terrain, road design length exceeding 10km, or limited construction site, a plan of the ribbed pile layout should be drawn in advance. The ribbed piles at each location should be numbered and marked on the plan. The road alignment and the planar position of each ribbed pile should be accurately measured using a total station in sections. The "steel rod driving method" should be used to accurately locate and mark the ribbed pile positions. Work should be carried out in sections, accurately measuring and verifying the overall positional relationship and the relative positional relationship of each ribbed pile position. The longitudinal error within each construction section should be controlled within 20mm, the lateral error within 5mm, and the relative positional error between adjacent pile positions within 2mm. Process acceptance should be carried out thoroughly, with particular emphasis on protecting each pile position. Dedicated personnel should be assigned to this role, and records should be kept.

[0023] Step S2: Ribbed piles arrive on site, soil displacement and pile driving. A continuous construction approach is adopted. Once the pile locations within each construction section are determined, the driving of ribbed piles can begin. Before on-site construction, strict quality control is implemented for all precast ribbed piles upon arrival. Piles damaged, with severe appearance defects, improperly fabricated wing beam pile heads, or insufficient or severely deformed / broken butt reinforcement bars due to improper handling during precast component production, transportation, or storage are strictly prohibited from entering the site. The quality of finished products is rigorously controlled. On-site ribbed pile driving primarily focuses on pile top elevation control, supplemented by soil penetration depth control. A "steel casing guidance + soil squeezing static pressure method" is employed. During hoisting, a steel casing is accurately placed at the ribbed pile location as a guide for soil squeezing and pile driving. The steel casing is made of forged cast iron (e.g., ...). Figure 6 As shown, the steel casing 7 has a wall thickness of not less than 50mm, and its inner diameter is 5mm to 10mm larger than the diameter of the ribbed piles to be driven. The casing 7 is supported by four adjustable-angle hinge bolts 81, with steel supports 82 at the bottom of each support. These supports 82 are driven into the subgrade soil layer via steel anchors 83, ensuring the accuracy of the ribbed pile driving process through the guiding effect of the steel casing 7. The on-site ribbed pile driving process employs a technical solution of "first driving the piles on both sides to control the overall road alignment, then driving the piles in the middle to fully utilize the soil squeezing effect and strengthen the subgrade." Because the ribbed piles are not long, the problem of difficulty in driving the middle piles due to the soil squeezing effect is avoided; instead, the overall bearing capacity of the subgrade soil layer is more effectively strengthened.

[0024] Step S3: Verify pile top elevation and adjust wing beam pile heads. After the ribbed piles are driven in sections, the planar position and top elevation of each driven ribbed pile should be checked promptly and accurately. If significant errors occur in the planar position and top elevation of the ribbed piles, a plan should be developed to adjust the pile positions. Simultaneously, the positional relationship between adjacent ribbed piles should be checked to ensure that the double I-beam platform at the top of each pile is aligned with the direction of travel after driving. Errors in the driving orientation of the ribbed piles due to process planning or human error should be avoided to prevent impacts on subsequent prestressing tendon drilling, tensioning, and anchoring. If a large deviation in the position of a ribbed pile affects subsequent construction procedures, the pile should be pulled out, filled with sand and gravel mixture, and then re-driven. The top elevation of the pile should be checked a second time based on the marked elevation to ensure accurate positioning of each ribbed pile. For the adjustment of the butt reinforcement at the pile head of the wing beam, if improper operation during the production, transportation and stacking of the ribbed piles causes problems such as bending, breakage and rusting of the butt reinforcement at the pile head, it should be straightened before the grouting sleeve is connected. The length of the butt reinforcement joint should be measured to meet the dimensional requirements of the grouting sleeve connection, and the process acceptance and record should be done well.

[0025] Step S4: Adjust the double I-beam platform and grout the steel reinforcement sleeves. According to the technical plan, the double I-beam platforms at the top of the ribbed piles on both sides of the road serve as support points for the tensioning and anchoring of the unbonded prestressing tendons. After the elevation of the top of the ribbed piles in each construction section is verified to be accurate, the double I-beam platforms at the top of the ribbed piles are effectively adjusted to ensure that the double I-beam platforms are intact and without significant deformation. Then, a high-pressure air gun is used to clean the double I-beam platforms at the top of the ribbed piles, focusing on cleaning the cavities between the double I-beam platforms and the reserved holes for the unbonded prestressing tendons to ensure that there are no debris, laitance, or blockages in the reserved holes. After the double I-beam platform at the top of the ribbed piles is adjusted, the double rows of four butt-joint steel bars at the ends of the wing beam pile heads between two adjacent ribbed piles are connected on-site using the full grouting sleeve grouting method. First, all the stirrups are put on the butt-joint steel bars at one end of the wing beam pile head. Then, the full grouting sleeve is installed on the two butt-joint steel bars to be connected. High-strength, low-shrinkage, micro-expansion fiber-reinforced grouting material is used for grouting. After the strength grade of the grouting material reaches more than 85% of the design strength, the stirrups put on the butt-joint steel bars at one end of the wing beam pile head are tied to the double rows of four butt-joint steel bars. This forms a "flat hidden beam steel cage" between the two ribbed piles. Finally, a longitudinal and transverse flat hidden beam cross-connection support system is formed between each ribbed pile. This forms a stress form that improves the overall road structure bearing capacity on the basis of strengthening the subgrade. The hidden works are inspected and recorded.

[0026] Step S5: Install steel mesh and lay unbonded prestressed tendons through holes. After all the butt reinforcement bars between the ribbed piles in each construction section are connected using the sleeve grouting method and a "flat hidden beam reinforcement cage" is formed, the unbonded prestressing tendons can be laid through holes within the lattice area formed by the ribbed piles and the flat hidden beam reinforcement cage. According to the technical plan, the unbonded prestressing tendons are laid on top of the ribbed pile group using the post-tensioning method, and the unbonded prestressing tendons pass through the reserved holes on each double I-beam platform. The laid unbonded prestressing tendons must not interfere with the completed flat hidden beam reinforcement cage. In a cross-flow operation, the installation of the steel mesh can be carried out simultaneously with the laying of the unbonded prestressing tendons. First, the transverse distribution reinforcement bars are laid on the double I-beam platform by spot welding. The contact parts between the transverse distribution reinforcement bars and the double I-beam platform are spot welded one by one. Then, the longitudinal distribution reinforcement bars are laid and additional transverse distribution reinforcement bars are tied using the spot-welded and fixed transverse distribution reinforcement bars on the double I-beam platform as fulcrums, until the on-site laying of all steel mesh in each section is completed.

[0027] Step S6: Segmented installation of aluminum formwork, pouring and curing of fine aggregate concrete. According to the technical plan, after the unbonded prestressed tendons in each construction section are laid, the fine aggregate concrete layer can be poured. Before pouring the fine aggregate concrete, aluminum formwork is used to install the side formwork around each construction section on-site. The aluminum formwork is installed using a direct tightening method with internal threads, eliminating the need for additional supports and facilitating installation and dismantling. To prevent grout leakage during fine aggregate concrete pouring, a 3mm thick flexible asphalt membrane strip is installed between the aluminum formwork and the positioning piles, with a width of not less than 100mm. After the aluminum formwork in each construction section is installed, the fine aggregate concrete is poured immediately within the grid area formed by the ribbed piles and the flat hidden beam reinforcement cage. The strength grade of the fine aggregate concrete is not lower than C30. The fine aggregate concrete layer in each construction section is poured in one go without any construction joints. Special attention is paid to the concrete pouring at the pile heads of the three-sided and four-sided wing beams at the top of the ribbed piles, with enhanced vibration and curing. Since the technical solution adopts the post-tensioned unbonded prestressed technology, the cavity in the middle of the double I-beam platform at the top of the ribbed pile should be poured together with the fine stone concrete layer, and the vibration and curing should be strengthened, and the process acceptance and recording should be done well.

[0028] Step S7: Remove aluminum formwork, tension and anchor unbonded prestressing tendons. According to the technical plan, the requirements for removing the aluminum formwork as a side formwork are relatively low; it is sufficient to ensure the appearance of the road concrete remains intact after the aluminum formwork is removed. Construction is organized in sections, and once the poured fine aggregate concrete has cured to 100% of its design strength, the tensioning and anchoring of the unbonded prestressed tendons can begin. The anchoring ends of the unbonded prestressed tendons are located on the outer side web of the double I-beam platform at the top of each ribbed pile, providing ample working space and facilitating construction. The on-site tensioning of the unbonded prestressed tendons adopts a technical scheme of "each construction section completed independently, tensioning sequentially from the middle to the ends of the construction section, symmetrical tensioning, and immediate anchoring after tensioning." The prestressed tendons are over-tensioned to 1.05σcon, and proper acceptance and recording of concealed works are ensured.

[0029] Step S8: Repeat steps S1 to S7 until the main structure construction is completed and the asphalt concrete surface layer is fully paved. According to the technical plan, after the unbonded prestressed tendons are tensioned and the anchors are installed in each construction section, the anchors at the ends of the prestressed tendons are first sealed one by one using sulfur mortar and fiber-reinforced crack-resistant mortar. Then, the construction is carried out in a continuous flow manner, repeating steps S1 to S7 until all on-site procedures for each construction section of the road project are completed. Finally, the asphalt concrete surface layer is fully paved, and the overall project is inspected and the data is archived in a timely manner.

[0030] In summary, this invention can improve the load-bearing capacity of road structures, enhance stability and durability, while optimizing construction efficiency and reducing subsequent maintenance costs.

[0031] 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. Reinforced concrete stiffened ribbed pile supported post-tensioned prestressed road, characterized in that: The ribbed pile, double I-beam pedestal, steel mesh and unbonded prestressed tendon are provided along the longitudinal and transverse direction of the road embankment, the top of each ribbed pile is provided with a wing beam pile head and a double I-beam pedestal which are integrally formed, the butt joint steel bars are arranged between the opposite wing beam pile heads, the unbonded prestressed tendon is arranged on the double I-beam pedestal and the two ends of the unbonded prestressed tendon are fixed to the outer side of the double I-beam pedestal by the anchor, the steel mesh is arranged on the top of the double I-beam pedestal, the fine stone concrete layer is poured in the ribbed area surrounded by the ribbed piles according to the design elevation of the road, and the asphalt concrete surface layer is further arranged on the upper part of the fine stone concrete layer.

2. The roadway according to claim 1, characterized in that: The ribbed pile is prefabricated in the fabricated PC factory, the cross section design size of the ribbed pile is not less than 300mm*300mm, the design height is not less than 600mm, and the distance between the ribbed piles is not more than 1600mm, the bottom of the ribbed pile is provided with a pile tip, and the top of the ribbed pile is provided with the double I-beam pedestal and the wing beam pile head.

3. The roadway of claim 2, wherein: The wing beam pile head at the top of the ribbed pile is divided into three-edge wing beam pile head and four-edge wing beam pile head, the ribbed pile with the three-edge wing beam pile head is arranged at the two ends of the road structure along the longitudinal direction of the road, and the ribbed pile with the four-edge wing beam pile head is arranged at the middle part of the road structure along the longitudinal direction of the road, the length of each wing beam pile head extending out of the ribbed pile is not less than 450mm and not less than 1.5 times of the maximum side length of the cross section design of the ribbed pile, the cross section width of the wing beam pile head is equal to the size of the corresponding side of the ribbed pile, the cross section height is not less than 120mm, and all the surfaces of each wing beam pile head are roughened with a roughness of more than 80%.

4. The roadway of claim 3, wherein: The end of the wing beam pile head between the two adjacent ribbed piles is provided with at least four butt joint steel bars with a diameter of not less than 16mm, the butt joint steel bars at the wing beam pile head between the two adjacent ribbed piles in the same span are connected by the full grouting sleeve grouting method, the four butt joint steel bars are divided into two rows, the first row of butt joint steel bars is located at 50mm below the top surface of the wing beam pile head, the second row of butt joint steel bars is located at 100mm below the first row of butt joint steel bars, and the upper and lower rows of butt joint steel bars form a flat hidden beam between the two adjacent ribbed piles by increasing the stirrup.

5. The roadway of claim 2, wherein: The web height of the double I-beam pedestal is not less than 300mm, the flange width is not less than 40mm, the web and flange thicknesses are both not less than 25mm, and the blanking length of the double I-beam pedestal is calculated according to the width of the ribbed pile in the same direction+length of the wing beam pile head*2-60mm, the diameter of the reserved hole arranged on the double I-beam pedestal is not less than 60mm, and the working space between the two double I-beam pedestals on the top of the same ribbed pile is not less than 1 / 3 of the cross section length of the ribbed pile and not less than 120mm.

6. The roadway of claim 1, wherein: The steel mesh is a longitudinal and transverse double-direction structure, the distribution steel bar has a diameter of not less than 10mm and a spacing of not more than 150mm, at least two full-length distribution steel bars are arranged vertically on the upper part of the double I-beam pedestal, the end of the full-length distribution steel bar is provided with a 180° hook and the hook direction is downward.

7. A method of construction of a post-tensioned prestressed road supported by reinforced concrete stiffened rib piles, characterised in that, The method comprises the following steps: S1, measuring the stake position of the line and treating the embankment; S2, ribbed pile access, soil compaction and pile pressing; S3, pile top elevation review, wing beam pile head adjustment; Step S4, double I-beam pedestal adjustment, steel sleeve grouting connection; Step S5, steel mesh installation, non-bonded prestressed tendon perforation laying; Step S6, aluminum mold segmented installation, fine stone concrete pouring and curing; Step S7, aluminum mold removal, non-bonded prestressed tendon tensioning and anchoring; Step S8, repeat steps S1~S7 until the completion of the main structure construction, and the overall paving of the asphalt concrete surface.

8. The construction method according to claim 7, characterized in that, The specific technical solutions are as follows: Step S1: measurement and line laying, roadbed treatment: First, the roadbed is leveled and reinforced, and various obstacles affecting road construction are cleaned. Every 3km along the driving direction of the road, an elevation control line is set up to assist the leveling and roadbed reinforcement work of each construction section. For complex road original terrain, road design length of more than 10km or complex construction site conditions, etc., a dense rib pile plan layout is drawn in advance. The dense rib piles at each point are numbered and marked on the dense rib pile plan layout. The road line direction and the plan position of each dense rib pile are accurately measured and set by using a total station. The dense rib pile position points are accurately positioned and marked by using the "steel drill method". The overall position relationship and mutual position relationship of each dense rib pile position point are accurately measured and accurately checked. The longitudinal error in each construction section is controlled within 20mm, the transverse error is controlled within 5mm, and the mutual position error of adjacent two pile position points is controlled within 2mm. Process acceptance work is done well, and the protection of each pile position point is strengthened. Special positions are left with records; Step S2: dense rib pile into the field, soil extrusion and pile pressing: Using a flow construction organization method, after the pile position points in each construction section are determined, the dense rib pile sinking operation can be arranged. Before the on-site construction, the quality of each precast dense rib pile is strictly controlled. If the dense rib pile is damaged due to improper process operation such as precast component production, transportation, storage, etc., serious appearance quality, improper wing beam pile head, insufficient length of butt joint steel bar or serious deformation, fracture, etc., it is not allowed to enter the field. The quality of finished products is strictly controlled. The on-site dense rib pile sinking work is mainly controlled by the pile top elevation and supplemented by the soil extrusion depth. The "steel casing guidance + soil extrusion static pressing method" is adopted. That is, the steel casing is accurately placed at the dense rib pile position point as the operation guide for soil extrusion and pile pressing during hoisting. The steel casing is made of cast iron and forged. The wall thickness of the steel casing is not less than 50mm. The inner diameter of the steel casing is 5mm~10mm larger than the diameter of the dense rib pile to be sunk. The steel casing body is provided with four adjustable angle hinge screw supports. The hinge screw support bottom is provided with a steel support. The steel support is punched into the roadbed soil layer by steel anchor nails to ensure the accuracy of the dense rib pile sinking by soil extrusion and pile pressing. The on-site dense rib pile soil extrusion and pile pressing construction is carried out by "sinking the two side pile bodies first to control the overall road line type, and then sinking the middle pile body to fully play the soil extrusion effect to strengthen the roadbed"; Step S3: pile top elevation review, wing beam pile head adjustment: After the segmental dense rib pile is settled, the planar position relationship and the pile top elevation of the settled dense rib pile are checked in time and accurately. When there is a large error in the planar position relationship and the pile top elevation of the dense rib pile, a scheme is formulated to adjust the pile position, and the position relationship between the adjacent dense rib piles is checked to ensure that the double I-beam pedestal at the top of the dense rib pile is consistent with the driving direction after the dense rib pile is settled. When the position deviation of the dense rib pile is large and affects the construction of the subsequent process, the method of pulling out the pile and filling the sand and gravel mixture is used to adjust and recheck the pile top elevation according to the in-place elevation marked on the pile top to ensure that the dense rib pile is accurately positioned. For the adjustment of the butt joint steel bars at the wing beam pile head, the butt joint steel bars are bent, broken, rusted and other problems caused by improper process operations such as production, transportation and storage of the dense rib pile. The straightening treatment is performed before the butt joint steel bars are connected by the grouting sleeve, and the length of the butt joint steel bar joint is measured to meet the size requirement of the grouting sleeve connection, and the process acceptance and record are completed. Step S4: double I-beam pedestal adjustment and steel sleeve grouting connection: The double I-beam pedestal at the top of the dense rib pile on both sides of the road is used as the supporting point for the unbonded prestressed tendon tensioning and anchoring. After the pile top elevation of the dense rib pile in each construction section is accurately checked, the double I-beam pedestal at the top of the dense rib pile is effectively adjusted to ensure that the double I-beam pedestal is intact and has no large deformation, and then the double I-beam pedestal at the top of the dense rib pile is cleaned by using a high-pressure air gun, and the cavities between the double I-beam pedestals and the reserved holes for the unbonded prestressed tendon are cleaned to ensure that there are no impurities, floating slurry, and reserved hole plugging problems. After the double I-beam pedestal at the top of the dense rib pile is adjusted, the double-row four butt joint steel bars provided at the end of the wing beam pile head between the two adjacent dense rib piles are connected on site by using the full grouting sleeve grouting method, that is, the stirrups are first sleeved on the butt joint steel bars at one end of the wing beam pile head, and then the full grouting sleeve is installed on the two butt joint steel bars to be connected. High-strength low-shrinkage micro-expansion fiber reinforced grouting material is used for grouting construction. After the strength grade of the grouting material reaches more than 85% of the design strength, the stirrups sleeved on the butt joint steel bars at one end of the wing beam pile head are bound on the double-row four butt joint steel bars to form a "flat concealed beam steel cage" between the two dense rib piles. Finally, a longitudinal and transverse flat concealed beam cross connection support system is formed between the dense rib piles to form a stress form that enhances the bearing capacity of the overall road structure on the basis of the reinforced roadbed. The concealed engineering acceptance and record are completed. Step S5: steel mesh installation and unbonded prestressed tendon perforation laying: After the butt joint steel bars between the dense rib piles in each construction section are connected by the sleeve grouting method and the "flat hidden beam steel cage" is formed, the unbonded prestressed tendon can be laid in the lattice interval formed by the dense rib piles and the flat hidden beam steel cage; the field unbonded prestressed tendon is laid on the top of the dense rib pile group by the post-tensioning method, and the unbonded prestressed tendon passes through the reserved hole on each double I-beam pedestal, and the unbonded prestressed tendon laying process cannot interfere with the completed flat hidden beam steel cage; cross-flow operation is performed, and the installation of the steel mesh is performed at the same time as the unbonded prestressed tendon laying, that is, the horizontal distribution steel bars are laid on the double I-beam pedestal by spot welding, the horizontal distribution steel bars are spot welded in contact with the double I-beam pedestal, then the horizontal distribution steel bars fixed by spot welding on the double I-beam pedestal are used as fulcrums to lay the longitudinal distribution steel bars and supplement the binding of other horizontal distribution steel bars, until the field laying of all steel meshes in each section is completed; Step S6: aluminum mold segmented installation, fine stone concrete pouring and curing: After the unbonded prestressed tendon in each construction section is laid, the fine stone concrete layer can be poured; before pouring the fine stone concrete, the aluminum mold is used to install the side mold of each construction section on site, the aluminum mold is installed by directly screwing and fixing with internal thread sleeve, without the need for additional support, and is convenient to install and disassemble; a 3mm thick flexible asphalt roll adhesive tape is arranged between the aluminum mold and the positioning pile, and the width of the flexible asphalt roll adhesive tape is not less than 100mm; after the aluminum mold in each construction section is installed, the fine stone concrete is immediately poured in the lattice interval formed by the dense rib piles and the flat hidden beam steel cage, the strength grade of the fine stone concrete is not less than C30, the fine stone concrete layer in each construction section is poured at one time and cannot have construction joints, and the concrete pouring work at the top of the three-edge wing beam pile head and the four-edge wing beam pile head of the dense rib pile is highlighted, and the vibration and curing are strengthened; the post-tensioning unbonded prestressed tendon technology is used, the cavity in the middle of the double I-beam pedestal at the top of the dense rib pile is poured with the fine stone concrete layer, the vibration and curing are strengthened, and the process acceptance and record are well done; Step S7: aluminum mold disassembly, unbonded prestressed tendon tensioning and anchoring: The aluminum mold as the side mold requires relatively low disassembly, as long as the road concrete appearance after the aluminum mold is disassembled is good; the unbonded prestressed tendon tensioning and anchoring work can be performed after the poured fine stone concrete is cured to 100% of the design strength by segmented and water-flow construction, the anchoring end of the field unbonded prestressed tendon is located on the outer side web plate of the double I-beam pedestal at the top of each dense rib pile, the anchoring end has a large operation space, and the construction is convenient; the field unbonded prestressed tendon tensioning adopts the method of "independent completion of each construction section, tensioning from the middle to the end of the construction section in sequence, and tensioning and anchoring simultaneously", the prestressed tendon is tensioned by 1.05σcon, and the concealed engineering acceptance and record are well done; Step S8: repeat steps S1 to S7 until the main structure construction is completed, and the asphalt concrete surface layer is fully paved: After the unbonded prestressed tendon tensioning and anchor rod are completed in each construction section, firstly, the anchor of the prestressed tendon end is sealed one by one by using sulfur cement + fiber reinforced anti-cracking mortar, and then the repeated steps S1~S7 are adopted by using the flow construction organization form until all the construction section field process operations of the road engineering are completed, and finally the asphalt concrete surface layer is fully paved, and the engineering overall acceptance and data are timely archived.

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