A rigid-flexible gradual change integrated structure of a road-bridge transition section and a construction method thereof

Abstract

This invention relates to the field of road and bridge engineering technology, and particularly to an integrated rigid-flexible transition section structure for road-bridge transitions and its construction method. The structure includes a rigid transition section, a wedge-shaped transition body, and a common roadbed arranged sequentially along the driving direction, with the stiffness of the three decreasing sequentially. One side of the rigid transition section, which adheres to the wedge-shaped transition body, is a double-slope concave arc-shaped stepped structure. In this structure, the slope of the lower slope line is greater than that of the upper slope line, and the radius of curvature of the lower concave arc surface corresponding to the lower slope line is smaller than that of the upper concave arc surface corresponding to the upper slope line. This invention solves the problems of stress concentration and easy cracking at the transition section ends caused by abrupt changes in stiffness, achieving continuous and gradual stiffness change, effectively dispersing concentrated stress in the abutment, coordinating settlement differences, and improving the overall structural integrity and driving comfort. It is suitable for road-bridge abutment back-end transition projects for highways and municipal roads at all levels.

Description

Technical Field

[0001] This invention relates to the field of road and bridge engineering technology, and in particular to an integrated rigid-flexible transition section structure for road and bridge and its construction method. Background Technology

[0002] The bridge-road transition section is a critical engineering node connecting rigid bridge abutments and flexible roadbeds, widely used in transportation infrastructure such as highways and railways. Under the combined effects of vehicle dynamic loads, structural self-weight, and environmental factors, this section is prone to structural defects due to significant differences in material properties, stiffness levels, and settlement rates between the abutment and the roadbed. Common connection methods currently include single-step joints, straight-wall butt joints, or structures filled with lightweight filler.

[0003] Taking a single stepped transition structure as an example, it is usually composed of an abutment, a stepped rigid transition section, and a regular roadbed connected in sequence. However, a single stepped structure only achieves connection through the geometric shape of the steps. When the high-rigidity transition section is directly connected to the low-rigidity regular roadbed, the stiffness difference can be 2 to 3 times. This leads to significant stress concentration during load transfer, making the ends of the transition section prone to cracking or damage. Moreover, the settlement rates of the transition section and the regular roadbed are difficult to match, which can easily lead to secondary settlement differences in the later stages. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide an integrated rigid-flexible transition section structure for bridges and roads, which solves problems such as abrupt changes in stiffness between traditional abutments and roadbeds, uneven settlement, and susceptibility to vehicle bumps and structural cracking.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions: In a first aspect, embodiments of the present invention provide a rigid-flexible transition section integrated structure for road and bridge transitions, comprising: a rigid transition section, a wedge-shaped transition body, and a common roadbed arranged sequentially along the driving direction, wherein the stiffness of the three decreases sequentially; the side of the rigid transition section that is attached to the wedge-shaped transition body is a double-slope concave arc-shaped stepped structure, wherein in the double-slope concave arc-shaped stepped structure, the slope of the lower slope line is greater than the slope of the upper slope line, and the radius of curvature of the lower concave arc-shaped surface corresponding to the lower slope line is smaller than the radius of curvature of the upper concave arc-shaped surface corresponding to the upper slope line.

[0006] As a further technical solution, the concave arc surface is concave in the direction of the rigid transition section, and a shear key is provided on the side of the concave arc surface facing the wedge-shaped transition body.

[0007] As a further technical solution, the rigid transition section is integrally cast in place with concrete, and the side of the rigid transition section near the abutment is a vertical end face, which is connected to the abutment by transverse anchoring steel bars.

[0008] As a further technical solution, the shear key is integrally cast with the rigid transition section and embedded in the wedge-shaped transition body to form a fixed engagement.

[0009] As a further technical solution, the wedge-shaped transition body is constructed by layering and compacting cement-modified soil, and the side of the wedge-shaped transition body closest to the ordinary roadbed is set as a gradual step, which connects with the ordinary roadbed.

[0010] As a further technical solution, a base seepage prevention and drainage system is provided at the bottom of the rigid transition section, the wedge-shaped transition body and the ordinary roadbed. The base seepage prevention and drainage system consists of permeable geotextile, drainage pipe, sand cushion layer and seepage prevention geotextile from top to bottom; the sand cushion layer is provided with a drainage slope in the transverse direction.

[0011] As a further technical solution, a drainage pipe is installed above the sand cushion layer. The drainage pipe is arranged transversely along the road, and both ends of the drainage pipe extend to both sides of the roadbed and connect to the gravel blind ditch.

[0012] As a further technical solution, the top surface of the rigid transition section, the wedge-shaped transition body and the ordinary roadbed is fully paved with a composite reinforcement of bidirectional geogrid and steel mesh, and the composite reinforcement is anchored to the top surface of the rigid transition section.

[0013] As a further technical solution, the composite reinforcement is anchored to the ordinary roadbed by vertical anchoring steel bars.

[0014] Secondly, embodiments of the present invention also provide a construction method for an integrated rigid-flexible transition section structure for road and bridge, comprising the following steps: Construction foundation seepage prevention and drainage system; A rigid transition section of cast-in-place concrete is placed above the base seepage prevention and drainage system and adjacent to the abutment. One side of the rigid transition section is connected to the abutment, and the other side is set as a double-slope concave arc-shaped stepped structure. Shear keys are integrally cast at the step position of the double-slope concave arc-shaped stepped structure. A wedge-shaped transition body is filled between the rigid transition section and the ordinary roadbed. Cement-modified soil is used for layered filling and compaction so that the wedge-shaped transition body fits the double-slope concave arc-shaped stepped structure and wraps the shear key to form an embedded interlocking. The side of the wedge-shaped transition body closest to the ordinary roadbed is set as a gradual step, and the gradual step connects with the ordinary roadbed. A composite reinforcement material of bidirectional geogrid and steel mesh is laid across the entire top surface.

[0015] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: In this invention, the stiffness of the rigid transition section, the wedge-shaped transition body, and the ordinary roadbed decreases sequentially, forming a stress system that gradually transitions from rigid to flexible. Compared to the traditional single-step transition structure where the rigid and flexible sections are directly connected, resulting in a stiffness difference of 2 to 3 times, this structure, by introducing a wedge-shaped transition body and combining it with a double-slope concave arc-shaped stepped structure, extends the stiffness change path and makes stress transmission smoother.

[0016] The steep, low-radius curvature surface on the lower side rapidly diffuses the high stress at the abutment end into the wedge-shaped transition body, preventing stress concentration on a small contact surface. The gentle, high-radius curvature surface on the upper side further smooths the stress transition to the ordinary roadbed, while the gentle slope angle reduces lateral compression on the soil, preventing excessive lateral deformation of the fill material near the rigid transition section of the wedge-shaped transition body. This structure works synergistically from both overall stiffness layout and interface morphology perspectives, solving the problems of stress concentration and easy cracking at the transition section ends caused by abrupt stiffness changes. It achieves continuous and gradual stiffness change, effectively dispersing concentrated stress in the abutment, coordinating settlement differences, and improving structural integrity and driving comfort. It is suitable for bridge abutment back-end transition projects on highways and municipal roads at all levels.

[0017] Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, the dimensions or spacing between the components are exaggerated to show the position of each component, and the schematic diagrams are for illustrative purposes only.

[0019] Figure 1 This is a longitudinal cross-sectional schematic diagram of the overall structure of the road-bridge transition section provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the cross-section of the wedge-shaped transition body provided in an embodiment of the present invention; Figure 3 This is a detailed longitudinal section view of the rigid transition section with two-stage gradual steps provided in an embodiment of the present invention; In the diagram: 1. Bridge abutment; 2. Transverse anchoring reinforcement; 3. Impermeable geotextile; 4. Drainage pipe; 5. Crushed stone blind drain; 6. Rigid transition section; 7. Sand cushion layer; 8. Permeable geotextile; 9. Lower concave arc surface; 10. Composite reinforcement of bidirectional geogrid and steel mesh; 11. Upper concave arc surface; 12. Shear key; 13. Wedge-shaped transition body; 14. Vertical anchoring reinforcement; 15. Ordinary roadbed; 16. Upper slope line; 17. Lower slope line; Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0020] Terminology Explanation: Ordinary roadbed: refers to the roadbed portion that is filled and compacted in layers using natural or conventional roadbed fillers (such as soil, crushed stone, gravel, etc.) in accordance with conventional design requirements and construction specifications. It does not undergo special treatment (such as cement improvement, reinforcement, lightweight replacement, etc.) and has conventional strength, stiffness and consolidation settlement characteristics. It is the most basic and commonly used roadbed type in road engineering.

[0021] Example 1 As described in the background section, the road-bridge transition section, as a key engineering node connecting rigid abutments (or the main body of the bridge) and flexible roadbed, is the core area of ​​the transportation line with the most complex stress and the highest concentration of defects. Its structural stability directly determines the ride comfort, structural durability, and operational safety of the line. Under the combined influence of high-frequency dynamic loads from vehicles, structural self-weight, and the natural environment, the significant differences in material properties, stiffness levels, and settlement rates between rigid abutments and flexible roadbeds can easily lead to a series of engineering defects, becoming a long-standing technical challenge in the field of roadbed engineering.

[0022] Existing road-bridge transition sections mostly employ single stepped, straight-walled butt joints, or simple lightweight filler designs. While these can alleviate the problem of abrupt stiffness changes to some extent, they still have many technical shortcomings: (1) Abrupt stiffness transition and significant stress concentration: Traditional single stepped structure only achieves connection through simple geometric transition, without forming a continuous stiffness gradient. The high stiffness transition section is directly connected to the low stiffness ordinary roadbed, with a stiffness difference of 2-3 times, which leads to obvious stress concentration when the load is transferred, and cracks and damage are easy to occur at the end of the transition section.

[0023] (2) Poor overall structural integrity and insufficient anti-slip separation ability: The connecting surface of a single step is mostly a smooth plane, lacking a shear and tensile anti-cooperative locking structure, which makes the step surface prone to slippage.

[0024] (3) Poor settlement coordination. The design of "horizontal length decreasing from top to bottom" of the single step does not take into account the consolidation settlement characteristics of ordinary roadbed. The settlement rate of the transition section is not matched with that of ordinary roadbed, and secondary settlement difference is easily formed in the later stage.

[0025] In one typical embodiment of this disclosure, a rigid-flexible integrated structure for a bridge transition section is provided, which is particularly suitable for the gradual transition of stiffness and control of settlement difference between bridge abutments and roadbeds in highway and railway engineering projects. By optimizing the structural form and material matching of the transition section and the wedge-shaped transition body, a transition system with continuously varying stiffness is constructed, which can effectively disperse the concentrated stress of the bridge abutment, limit the relative displacement of the structure, reduce settlement differences, and improve the overall stability and long-term service performance of the bridge transition section.

[0026] like Figure 1 , Figure 2 , Figure 3 As shown, the integrated rigid-flexible transition structure of the road-bridge transition section includes a rigid transition section 6, a wedge-shaped transition body 13, and a common roadbed 15 arranged sequentially along the driving direction, with the stiffness of the three decreasing sequentially. The side of the rigid transition section 6 that fits into the wedge-shaped transition body 13 is a double-slope concave arc-shaped stepped structure. In this double-slope concave arc-shaped stepped structure, the slope of the lower slope line 17 is greater than the slope of the upper slope line 16, and the radius of curvature of the lower concave arc surface 9 corresponding to the lower slope line 17 is smaller than the radius of curvature of the upper concave arc surface 11 corresponding to the upper slope line 16.

[0027] The double-slope concave arc-shaped stepped structure refers to an interface where the rigid transition section 6 and the wedge-shaped transition body 13 are not a single-slope inclined surface, but rather a stepped curved surface composed of two concave arc surfaces with different slopes. The lower slope line 17, closer to the abutment 1, has a steeper slope and a smaller radius of curvature for the corresponding concave arc surface. The upper slope line 16, closer to the ordinary roadbed 15, has a gentler slope and a larger radius of curvature for the corresponding concave arc surface. This double-slope concave arc-shaped stepped structure can quickly disperse the concentrated stress transmitted from the abutment 1, reducing lateral compression on the wedge-shaped transition body 13 and the ordinary roadbed 15 fill material.

[0028] The rigid transition section 6 is made of cast-in-place concrete, a rigid material. The wedge-shaped transition body 13 is made of cement-modified soil, a medium-rigidity material. The ordinary roadbed 15 uses conventional roadbed fill material, a flexible material. The stiffness of the three decreases sequentially, forming a stress system that gradually transitions from rigid to flexible. Compared to the traditional single-step transition structure where the rigid and flexible sections are directly connected, resulting in a stiffness difference of 2 to 3 times, this structure, by introducing the wedge-shaped transition body 13 and combining it with a double-slope concave arc-shaped stepped structure, extends the stiffness change path and makes stress transfer smoother. The lower steep slope with a small radius of curvature arc surface can quickly diffuse the high stress at the abutment 1 end to the wedge-shaped transition body 13, avoiding stress concentration on a small contact surface. The upper gentle slope with a large radius of curvature arc surface further smooths the stress transition to the ordinary roadbed 15, while the gentle slope angle reduces the lateral compression of the soil, preventing excessive lateral deformation of the fill material on the side of the wedge-shaped transition body 13 near the rigid transition section 6.

[0029] In one optional embodiment, the lower slope of the rigid transition section 6 is 1:2.5, corresponding to a concave arc surface curvature radius of 5.25m; the upper slope of the rigid transition section 6 is 1:3.0, corresponding to a concave arc surface curvature radius of 6.3m.

[0030] In some further specific examples of this disclosure, the concave arc surface is concave in the direction of the rigid transition section 6, and a shear key 12 is provided on the side of the concave arc surface facing the wedge-shaped transition body 13.

[0031] The concave arc surface towards the rigid transition section 6 means that, viewed in longitudinal section, the arc surface is a curved surface that is carved inward from the outer contour line of the rigid transition section 6, rather than a curved surface that bulges outward. During the casting of the rigid transition section 6, a pit-like surface is formed. The wedge-shaped transition body 13 is filled into this pit during construction, increasing the contact area and the degree of interlocking between the two materials. Shear keys 12 are located at stepped positions and are key-like structures that further bulge from the concave arc surface. When the wedge-shaped transition body is layered, it completely encloses the shear keys 12, forming a mechanical interlock after hardening. The concave arc surface provides surface contact and curved transition, while the shear keys 12 provide point-like or block-like localized locking. Combined, the rigid transition section 6 and the wedge-shaped transition body 13 not only have curved surface contact but also multiple embedded shear-resistant structures. When a vehicle load passes over them, the shear force, tensile force, and potential relative slippage between the transition section and the transition body are resisted by these shear keys 12 and the concave arc surface. Compared to the smooth stepped surface of a traditional single staircase, which is prone to slippage and separation under long-term loads, this structure enhances the overall integrity of the structure and improves its anti-slip capability through the combination of the concave arc surface and shear key 12.

[0032] In one alternative embodiment, the shear key 12 can be 0.15m in length and 0.1m in width. The longitudinal section of the shear key 12 can be tapered, and the cross-sectional shape can be rectangular, trapezoidal, or semi-circular, as long as it can form an interlocking engagement.

[0033] In some other specific examples of this disclosure, the rigid transition section 6 is integrally cast in place with concrete, and the side of the rigid transition section 6 closest to the abutment 1 has a vertical end face, which is connected to the abutment 1 by transverse anchoring steel bars 2.

[0034] The vertical end face design allows the rigid transition section 6 to fit tightly against the abutment 1. One end of the transverse anchoring steel bar 2 is pre-embedded in the abutment 1, and the other end is anchored into the rigid transition section 6. After the concrete hardens, the two are connected into a whole. This rigid connection method allows the load on the abutment 1 to be directly transferred to the rigid transition section 6, avoiding relative misalignment at the connection point.

[0035] In some further specific examples of this disclosure, the shear key 12 is integrally cast with the rigid transition section 6 and embedded within the wedge-shaped transition body 13 to form a secure interlocking structure. Integral casting means that the shear key 12 and the rigid transition section 6 are part of the same concrete component, with no interface between them and consistent strength. The shear key 12 protrudes from a concave arc surface, and the wedge-shaped transition body 13 is compacted around the shear key 12 during filling. After hardening, the wedge-shaped transition body 13 forms a groove complementary to the shear key 12. When subjected to horizontal loads such as vehicle braking forces or earthquakes, the shear key 12 experiences shear force. Because the shear key 12 is embedded within the wedge-shaped transition body 13, this shear force is dispersed throughout the surrounding backfill of the wedge-shaped transition body 13, rather than concentrated at the root of the rigid transition section 6. Simultaneously, when subjected to vertical settlement differences, the shear key 12 can limit the relative vertical displacement between the rigid transition section 6 and the wedge-shaped transition body 13.

[0036] In some other specific examples of this disclosure, the wedge-shaped transition body 13 is constructed and compacted in layers using cement-modified soil, and the side of the wedge-shaped transition body 13 closest to the ordinary roadbed 15 is set as a gradual step, which connects with the ordinary roadbed 15.

[0037] Cement-modified soil is a geotextile material with medium stiffness formed by adding a certain proportion of cement to the subgrade fill material, mixing it evenly, and then compacting it. Layered filling and compaction are used to ensure the compaction degree of each layer, making the wedge-shaped transition body 13 uniform overall and free of weak interlayers. The gradual step design refers to filling the wedge-shaped transition body 13 in a stepped shape on the side closest to the ordinary subgrade 15. Compared to direct inclined or vertical contact, the stepped overlap increases the contact area between the wedge-shaped transition body 13 and the ordinary subgrade 15, making the transition from medium stiffness to flexible stiffness smoother and avoiding new stiffness jumps at the interface between the wedge-shaped transition body 13 and the ordinary subgrade 15.

[0038] Specifically, the wedge-shaped transition body 13 is constructed by layering and compacting 6%~8% (by weight) cement-modified soil. It is a long, wedge-shaped structure extending longitudinally along the route, with an isosceles trapezoidal cross-section to ensure uniform lateral stress. The newly added trapezoidal structure extends the transition path by more than three times, prolonging the load transfer time and fully absorbing impact loads. The right side of the wedge-shaped transition body 13 is in concave-convex contact with the double-level continuous concave arc surface on the left side of the rigid transition section 6, tightly wrapping the entire left arc surface of the rigid transition section 6 and the shear key 12, forming a mechanical engagement with the shear key 12 to achieve seamless connection between the transition section and the transition body. The left side is set as a gradually changing step with a 1:3.0 slope, seamlessly connecting with the ordinary roadbed 15. The gradually changing step is merely a step-like filling in form, used to maintain the slope and achieve a smooth transition in stiffness.

[0039] In some other specific examples of this disclosure, a base seepage prevention and drainage system is provided at the bottom of the rigid transition section 6, the wedge-shaped transition body 13 and the ordinary roadbed 15. The base seepage prevention and drainage system consists of a permeable geotextile 8, a drainage pipe 4, a sand cushion layer 7 and a seepage prevention geotextile 3 from top to bottom. The sand cushion layer 7 is provided with a drainage slope in the transverse direction.

[0040] The impermeable geotextile 3 is laid on the top surface of the foundation to block capillary water rise and prevent groundwater from seeping into the roadbed fill material, thus avoiding water softening of the fill material and resulting in a decrease in strength. The sand cushion layer 7 is laid on top of the impermeable geotextile 3; the pores between the sand particles form drainage channels, and the transverse drainage slope allows water to flow to both sides of the roadbed. Drainage pipes 4 are installed above or inside the sand cushion layer 7 to collect and drain interlayer water. The permeable geotextile 8 is laid on top, allowing water to pass through while blocking soil particles, preventing fill material particles from entering the drainage pipes 4 and the sand cushion layer 7 and causing blockages.

[0041] The various layers of the seepage-proof drainage system function independently yet work together: the impermeable geotextile 3 cuts off the water source from the bottom, the sand cushion layer 7 provides surface drainage, the drainage pipe 4 provides linear rapid drainage, and the permeable geotextile 8 protects the drainage channels from blockage. This three-dimensional drainage system solves the problem of water accumulation at the bottom of the transition section softening the fill material, ensuring long-term stability.

[0042] In one optional embodiment, the drainage pipe 4 is made of PVC with a diameter of 100mm. The pipe is arranged transversely along the roadbed and has an outward drainage slope of not less than 2%, with a longitudinal spacing of 4 to 5m. The sand cushion layer 7 is laid on top of the impermeable geotextile 3 with a thickness of 0.2m and has an outward drainage slope of not less than 2% in the transverse direction. It is used to collect and drain interlayer seepage water, while uniformly transferring the upper load, leveling the foundation, and improving the overall stability of the structure.

[0043] In some further specific examples of this disclosure, the drainage pipe 4 is arranged transversely along the road, with both ends extending to both sides of the roadbed and connecting to the gravel blind ditch 5. Transverse arrangement means that the drainage pipe 4 runs from one side of the roadbed across the entire bottom of the transition section to the other side, with both ends extending beyond the roadbed slope. The gravel blind ditch 5 is a trench filled with gravel and arranged longitudinally along the roadbed, serving both water storage and drainage functions. Water collected by the drainage pipe 4 flows into the gravel blind ditch 5 by gravity, and the blind ditch then discharges the water to drainage facilities outside the roadbed. The transverse drainage pipe 4 and the longitudinal gravel blind ditch 5 form a complete drainage network.

[0044] In some other specific examples of this disclosure, the top surfaces of the rigid transition section 6, the wedge-shaped transition body 13 and the ordinary roadbed 15 are fully covered with a two-way geogrid and steel mesh composite reinforcement 10, which is anchored to the top surface of the rigid transition section 6.

[0045] Bidirectional geogrid is a geosynthetic material with a mesh structure, providing tensile strength in both longitudinal and transverse directions. The reinforcing mesh is a welded or tied steel skeleton with high tensile strength and resistance to deformation. Together, they form a reinforced layer laid on top of the subgrade. Traffic loads act directly on the pavement structure above the reinforced layer, which distributes the load over a larger area, reducing the compressive stress on the underlying fill material. Simultaneously, when uneven settlement occurs in the subgrade, the reinforced layer can withstand tensile deformation without fracturing, limiting the development of differential settlement. The composite reinforcement is anchored to the top surface of the rigid transition section 6, connecting the reinforced layer to the rigid transition section 6 and preventing the reinforced layer from detaching at the end of the rigid transition section 6.

[0046] In other specific examples of this disclosure, the composite reinforcement is anchored to the ordinary subgrade 15 via vertical anchoring bars 14. The bottom end of the vertical anchoring bars 14 is embedded inside the ordinary subgrade 15, and the top end is connected to or hooked to the composite reinforcement. When the composite reinforcement is subjected to tensile force, the vertical anchoring bars 14 transfer the tensile force to the deeper soil layer, relying on the soil layer's bond force to provide anchorage. Without the vertical anchoring bars 14, the composite reinforcement is simply laid on the top surface of the subgrade, connected to the subgrade only by friction, and is prone to slippage and detachment under large tensile forces. The installation of the vertical anchoring bars 14 ensures that the reinforcement layer can share the load with the subgrade, and that tensile loads can be effectively transferred and distributed.

[0047] In summary, this structure, through a layered combination of a rigid concrete transition section, a medium-stiffness wedge-shaped transition body 13, and a flexible ordinary roadbed 15, combined with a smooth transition design of the double-slope concave arc surface of the transition section, stepped interlocking, shear keys 12, and overall reinforcement, avoids abrupt changes in stiffness between the abutment 1 and the roadbed, significantly disperses the concentrated stress transmitted by the abutment 1, and fundamentally reduces defects such as misalignment and cracking in the transition section. The wedge-shaped transition body 13 extends the rigid-flexible transition path by more than three times compared to traditional structures, serving as a medium-stiffness buffer layer to achieve a continuous and gradual change in stiffness. This effectively disperses the concentrated stress of the abutment 1, coordinates settlement differences, and improves the overall structural integrity and driving comfort, making it suitable for bridge-to-road abutment transition projects on highways and municipal roads at all levels.

[0048] Example 2 This embodiment provides a construction method for an integrated rigid-flexible transition structure for road and bridge sections. The method first involves constructing a base waterproofing and drainage system, including laying waterproof geotextile 3, setting a sand cushion layer 7, arranging drainage pipes 4, and permeable geotextile 8, etc.

[0049] A cast-in-place rigid concrete transition section 6 is located above the base seepage prevention and drainage system and adjacent to abutment 1. One side of the rigid transition section 6 is connected to abutment 1, and the other side is set as a double-slope concave arc-shaped stepped structure, with shear keys 12 integrally cast at the stepped position.

[0050] A wedge-shaped transition body 13 is constructed between the rigid transition section 6 and the ordinary roadbed 15. Cement-modified soil is used for layered filling and compaction, so that the wedge-shaped transition body 13 fits the double-slope concave arc-shaped stepped structure and wraps the shear key 12 to form a fixed interlocking. At the same time, the side of the wedge-shaped transition body 13 closest to the ordinary roadbed 15 is set as a gradual step to connect with the ordinary roadbed 15.

[0051] Finally, a composite reinforcement layer of bidirectional geogrid and steel mesh is laid across the entire top surface. This top reinforcement layer is laid after all the fill material has been filled and compacted, and it can hold down the fill material below and provide overall tensile restraint.

[0052] Among them, the ordinary roadbed 15 is filled in layers with conventional roadbed filler and smoothly connected with the wedge-shaped transition body 13.

[0053] Rigid transition section 6 is integrally cast in place using C30 concrete.

[0054] The wedge-shaped transition body 13 is a full-width cross-sectional structure, which is filled between the rigid transition section 6 and the ordinary roadbed 15. It is filled and compacted in layers with cement-modified soil at a weight ratio of 6% to 8%, with each layer being about 0.2m thick and the compaction degree being no less than 96%.

[0055] After the overall construction is completed, the slopes of the wedge-shaped transition body 13 and the ordinary roadbed 15 are smoothed at a ratio of 1:1.5 and slope protection is carried out to prevent rainwater from washing away the fill material and to ensure the long-term stability of the structure.

[0056] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A rigid-flexible transition section integrated structure for road and bridge sections, characterized in that, include: The rigid transition section, wedge-shaped transition body and ordinary roadbed are set in sequence along the direction of traffic, and the stiffness of the three decreases in sequence. The rigid transition section is attached to one side of the wedge-shaped transition body, which is a double-slope concave arc-shaped stepped structure. In the double-slope concave arc-shaped stepped structure, the slope of the lower slope line is greater than that of the upper slope line, and the radius of curvature of the lower concave arc surface corresponding to the lower slope line is smaller than that of the upper concave arc surface corresponding to the upper slope line.

2. The integrated rigid-flexible transition section structure for road and bridge as described in claim 1, characterized in that, The concave arc surface is concave in the direction of the rigid transition section, and a shear key is provided on the side of the concave arc surface facing the wedge-shaped transition body.

3. The integrated rigid-flexible transition section structure for road and bridge as described in claim 1, characterized in that, The rigid transition section is integrally cast in place with concrete. The side of the rigid transition section closest to the abutment is a vertical end face, which is connected to the abutment by transverse anchoring steel bars.

4. The integrated rigid-flexible transition section structure for road and bridge as described in claim 2, characterized in that, The shear key is integrally cast with the rigid transition section and embedded in the wedge-shaped transition body to form a fixed engagement.

5. The integrated rigid-flexible transition section structure for road and bridge as described in claim 1, characterized in that, The wedge-shaped transition body is constructed by layering and compacting cement-modified soil. The side of the wedge-shaped transition body closest to the ordinary roadbed is set as a gradual step, and the gradual step connects with the ordinary roadbed.

6. The integrated rigid-flexible transition section structure for road and bridge as described in claim 1, characterized in that, The rigid transition section, wedge-shaped transition body, and ordinary roadbed are equipped with a base seepage prevention and drainage system. The base seepage prevention and drainage system consists of permeable geotextile, drainage pipe, sand cushion layer, and seepage prevention geotextile from top to bottom. The sand cushion layer is provided with a drainage slope in the transverse direction.

7. The integrated rigid-flexible transition section structure for road and bridge as described in claim 6, characterized in that, A drainage pipe is installed above the sand cushion layer. The drainage pipe runs horizontally along the road and extends to both ends of the roadbed and connects to the gravel blind ditch.

8. The integrated rigid-flexible transition section structure for road and bridge as described in claim 1, characterized in that, The top surface of the rigid transition section, the wedge-shaped transition body, and the ordinary roadbed is fully paved with a composite reinforcement of bidirectional geogrid and steel mesh, and the composite reinforcement is anchored to the top surface of the rigid transition section.

9. The integrated rigid-flexible transition section structure for road and bridge as described in claim 8, characterized in that, The composite reinforcement is anchored to the ordinary roadbed by vertical anchoring steel bars.

10. A construction method for an integrated rigid-flexible transition section structure for road and bridge bridges, characterized in that, Includes the following steps: Construction foundation seepage prevention and drainage system; A rigid transition section of cast-in-place concrete is placed above the base seepage prevention and drainage system and adjacent to the abutment. One side of the rigid transition section is connected to the abutment, and the other side is set as a double-slope concave arc-shaped stepped structure. Shear keys are integrally cast at the step position of the double-slope concave arc-shaped stepped structure. A wedge-shaped transition body is filled between the rigid transition section and the ordinary roadbed. Cement-modified soil is used for layered filling and compaction so that the wedge-shaped transition body fits the double-slope concave arc-shaped stepped structure and wraps the shear key to form an embedded interlocking. The side of the wedge-shaped transition body closest to the ordinary roadbed is set as a gradual step, and the gradual step connects with the ordinary roadbed. A composite reinforcement material of bidirectional geogrid and steel mesh is laid across the entire top surface.

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