A road surface structure and construction method for treating a gradual height difference layer at a road crossing

Abstract

The application relates to the technical field of municipal and highway engineering, and discloses a road surface structure for gradient height difference layered treatment of a road crossing and a construction method, wherein the road surface structure for gradient height difference layered treatment of the road crossing comprises, from bottom to top, a leveling layer, a base layer, a stress absorption layer, an underlayer and an upper layer which are suitable for a fourth subarea, a third subarea and a fourth subarea, a second subarea, a third subarea and a fourth subarea, a second subarea, a third subarea and a fourth subarea and a first subarea, a second subarea, a third subarea and a fourth subarea respectively, wherein the first subarea, the second subarea, the third subarea and the fourth subarea are sequentially smoothly connected and layered and gradually changed, and form the road surface structure for gradient height difference layered treatment of the road crossing. The application is aimed at a gradient height difference of 0-50 cm, designs a targeted treatment scheme according to different height difference ranges, realizes full-scene coverage from a micro height difference to a large height difference, and solves the problem of insufficient adaptation to the gradient height difference.

Description

Technical Field

[0001] This invention relates to the fields of municipal engineering and highways, and more specifically, to a pavement structure and construction method for grade-separated intersections with gradual elevation differences. Background Technology

[0002] In road construction projects, the connection between the new road and the existing road at intersections is a critical aspect of the construction process. Because the existing road surface at the intersection has been in use for a long time, there is often a naturally occurring gradual elevation difference between it and the design elevation of the new road, typically transitioning from 0cm to 50cm. Improper handling of this elevation difference can easily lead to road surface defects such as subsidence, cracking, and bumpy rides at the connection point. This not only affects driving comfort and safety but also shortens the road's lifespan and increases subsequent maintenance costs.

[0003] In existing technologies, the treatment of elevation differences at road intersections often involves either a single thickened surface layer or complete excavation and reconstruction. A single thickened surface layer is prone to cracking due to uneven stress distribution within the structural layers; complete excavation and reconstruction suffers from long construction periods, significant resource waste, and substantial disruption to existing traffic. Furthermore, existing technologies do not design layered, gradual transition structures to accommodate elevation differences ranging from 0 to 50 cm, making it difficult to adapt to the gradual increase in elevation difference, resulting in insufficient stability of the transition section pavement structure and poor connection performance.

[0004] No effective solutions have yet been proposed to address the problems in the relevant technologies. Summary of the Invention

[0005] In response to the problems in related technologies, this invention proposes a pavement structure and construction method for grade level crossings with gradual elevation difference layering, in order to overcome the aforementioned technical problems existing in the existing related technologies.

[0006] Therefore, the specific technical solution adopted by the present invention is as follows: According to one aspect of the present invention, a pavement structure with gradual elevation difference layering at a level crossing is provided, the pavement structure with gradual elevation difference layering at a level crossing comprising, from bottom to top: The leveling layer is suitable for the fourth zone and is used to level the base layer of the old road surface after milling, ensuring the flatness of all subsequent structural layers. The base course, applicable to the third and fourth zones, is used to provide load-bearing support for the pavement structure; Stress-absorbing layers, suitable for the third and fourth zones, are used to reduce the occurrence of reflective cracks; The lower layer, applicable to the second, third and fourth zones, is used to transfer loads in the load-bearing layer; The upper layer, applicable to the first, second, third, and fourth zones, is used to ensure driving comfort and safety; The first, second, third and fourth zones are smoothly connected and gradually change in layers, forming a pavement structure with gradually changing elevation differences at level crossings.

[0007] Furthermore, the height difference in the first partition is greater than 0 cm and less than or equal to 4 cm; the height difference in the second partition is greater than 4 cm and less than or equal to 12 cm; the height difference in the third partition is greater than 12 cm and less than or equal to 30 cm; and the height difference in the fourth partition is greater than 30 cm and less than or equal to 50 cm.

[0008] Furthermore, the leveling layer is paved with cement-stabilized crushed stone material, and the minimum thickness of the leveling layer is greater than or equal to 18cm.

[0009] Furthermore, the base layer is constructed using 18cm thick cement-stabilized crushed stone, with a compaction degree greater than or equal to 98%.

[0010] Furthermore, the stress-absorbing layer is a rubber asphalt stress-absorbing layer; the lower layer is a precast lower layer with a thickness of 8cm; and the upper layer is a precast upper layer with a thickness of 4cm.

[0011] According to another aspect of the present invention, a construction method for a pavement structure with gradual elevation difference layering at a level crossing is also provided, the method comprising: S1. Conduct a defect detection on the old road surface, remove the defective parts, and obtain a smooth old road surface. S2. Based on the elevation difference distribution, the connection section between the leveled old road surface and the newly built road is divided into four zones: the first zone, the second zone, the third zone, and the fourth zone, and the zoning results are obtained. Based on the zoning results, the leveled old road surface is milled in a targeted manner. S3. After the old road surface has been milled, according to the zoning results, the connecting section is paved in layers based on the leveling layer, base layer, stress absorption layer, lower layer and upper layer to obtain the transition section road surface. S4. After construction is completed, the transition section pavement will be inspected to ensure a smooth connection between the transition section and the leveled old road surface and the newly built road surface.

[0012] Furthermore, the old road surface is inspected for defects, and the damaged sections are removed to obtain a smooth old road surface, including: The old road surface was inspected for defects to determine the types of defects, which included crack defects and loosening defects. When the old road surface has cracks, it is repaired with asphalt crack sealant; when the old road surface has loosening defects, it is filled and leveled with AC-13C asphalt concrete.

[0013] Furthermore, based on the zoning results, targeted milling of the leveled old road surface is carried out, including: When the zoning result is the first zoning, the old road surface is milled and leveled by 0-4cm, and the surface flatness error after milling is less than or equal to 3mm, so that the difference between the elevation of the old road surface after milling and the design elevation of the new road is equal to the thickness of the top layer. When the zoning result is the second zoning, the old road surface is milled and leveled by 0-8cm, and the surface of the old road is leveled. After milling, the surface compaction degree is greater than or equal to 95%. When the zoning result is the third zoning, the old road surface is milled and leveled by 0-18cm, and the aging and weak layers on the old road surface are removed. The elevation error of the top surface of the base layer after milling is less than or equal to 5mm. When the zoning result is the fourth zoning, the old road surface is milled and leveled to the top surface of the base layer, and the minimum milling depth is greater than or equal to 18cm. If the old road surface still cannot meet the structural layer thickness requirements after milling, the old road surface needs to be locally thickened.

[0014] Furthermore, based on the zoning results, and in conjunction with the leveling layer, base layer, stress-absorbing layer, lower layer, and upper layer, the connecting section is paved in layers to obtain the transition section pavement, which includes: S31. In the fourth zone, cement-stabilized crushed stone material is used to pave a leveling layer. The compaction degree of the leveling layer is greater than or equal to 98%, and the flatness error of the top surface after paving is less than or equal to 3mm. S32. In the third and fourth zones, an 18cm thick cement-stabilized crushed stone base course is laid and compacted using a heavy roller, with a compaction degree of 98% or greater. S33. In the third and fourth zones, after cleaning the base layer, spray rubber asphalt and spread single-size crushed stone, with a single-size crushed stone coverage of 85%-90%, and lay a stress-absorbing layer. S34. In the second, third and fourth zones, when the paving temperature is between 150-165℃, an 8cm thick precast lower layer shall be used for paving the lower layer, and the compaction degree of the lower layer after rolling shall be greater than or equal to 96%. S35. In the first, second, third and fourth zones, when the paving temperature is between 160-175℃, a 4cm thick precast surface layer shall be used to pave the surface layer. The compaction degree of the surface layer after rolling shall be greater than or equal to 97%, and the surface texture depth of the surface layer shall be greater than or equal to 0.5mm.

[0015] Furthermore, the thick precast upper layer is AC-13C type asphalt concrete; the thick precast lower layer is AC-20C type asphalt concrete, used as a load-bearing layer to transfer loads.

[0016] The beneficial effects of this invention are as follows: (1) The present invention has strong adaptability. For the gradual height difference of 0-50cm, it designs targeted treatment schemes according to different height difference ranges, realizes full scene coverage from micro height difference to large height difference, and solves the problem of insufficient adaptation of existing technology to gradual height difference.

[0017] (2) The present invention has a stable structure and adopts the design of milling old roads and layered paving. The selection of base and surface materials and the thickness design are scientific and reasonable, ensuring that the bearing capacity of the transition section is consistent with that of existing roads and newly built roads, and effectively avoiding diseases such as subsidence and cracking.

[0018] (3) The present invention is easy to construct, does not require overall excavation and reconstruction, only local milling of the old road surface, short construction period, low resource consumption, little impact on existing traffic, and at the same time reduces construction cost and later maintenance cost.

[0019] (4) The present invention has high construction efficiency. The use of prefabricated surface layer can greatly improve construction efficiency and construction quality. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a diagram of the concrete pavement structure in a road surface structure with a gradual elevation difference layering treatment at a level crossing according to an embodiment of the present invention. Figure 2 This is a flowchart of a construction method for a pavement structure with a gradual elevation difference layering treatment at a level crossing according to an embodiment of the present invention.

[0022] In the picture: 1. New road construction; 2. Existing road surface; 3. Top layer; 4. Bottom layer; 5. Base layer; 6. Leveling layer; 7. Stress-absorbing layer. Detailed Implementation

[0023] To further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0024] According to an embodiment of the present invention, a pavement structure and construction method for grade-separated level crossings with gradual elevation differences are provided.

[0025] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments, such as... Figure 1 As shown, the pavement structure for grade-separated level crossings with gradual elevation differences, according to an embodiment of the present invention, comprises, from bottom to top, the following: Leveling layer 6 is suitable for the fourth zone and is used to level the base layer of the old road surface after milling to ensure the flatness of all subsequent structural layers. Base course 5, applicable to the third and fourth zones, is used to provide load-bearing support for the pavement structure; Stress-absorbing layer 7, applicable to the third and fourth zones, is used to reduce the occurrence of reflective cracks; The lower layer 4 is applicable to the second, third and fourth zones and is used to transfer loads in the load-bearing layer. The upper layer 3, applicable to the first, second, third and fourth zones, is used to ensure driving comfort and safety; The first, second, third and fourth zones are smoothly connected and gradually change in layers, forming a pavement structure with gradually changing elevation differences at level crossings.

[0026] It should be explained that, based on the gradual elevation difference (0-50cm) between the existing intersection road surface (i.e., old road surface 2) and the design elevation of the newly built road 1, the old road is milled and paved in layers. The road structure from bottom to top includes a leveling layer 6, a base layer 5, a stress-absorbing layer 7, a lower layer 4, and an upper layer 3.

[0027] In this optional embodiment, the height difference in the first partition is greater than 0 cm and less than or equal to 4 cm; the height difference in the second partition is greater than 4 cm and less than or equal to 12 cm; the height difference in the third partition is greater than 12 cm and less than or equal to 30 cm; and the height difference in the fourth partition is greater than 30 cm and less than or equal to 50 cm.

[0028] It should be explained that, based on the difference between the design elevation of the new road 1 and the elevation of the old road surface 2 (denoted as H), four scenarios are divided according to the range of H, and corresponding milling and paving schemes are adopted for each scenario: Scenario 1 (i.e., the first zone): 0cm < H ≤ 4cm (slight elevation difference); Scenario 2 (i.e., the second zone): 4cm < H ≤ 12cm (small elevation difference); Scenario 3 (i.e., the third zone): 12cm < H ≤ 30cm (medium elevation difference); Scenario 4 (i.e., the fourth zone): 30cm < H ≤ 50cm (large elevation difference).

[0029] In this optional embodiment, the leveling layer 6 is paved with cement-stabilized crushed stone material, and the minimum thickness of the leveling layer 6 is greater than or equal to 18cm.

[0030] It should be explained that the leveling layer 6 is only applicable to scenario four (30cm < H ≤ 50cm). It is paved with cement-stabilized crushed stone material, and the paving thickness is determined according to the actual height difference. The minimum thickness is not less than 18cm. Its function is to level the base layer of the old road surface 2 after milling to ensure the flatness of the subsequent structural layer paving.

[0031] In this optional embodiment, the base layer 5 is paved with 18cm thick cement-stabilized crushed stone, and the compaction degree of the base layer 5 is greater than or equal to 98%.

[0032] It should be explained that base course 5 is applicable to scenario 3 (12cm < H ≤ 30cm) and scenario 4 (30cm < H ≤ 50cm). It is paved with 18cm thick cement-stabilized crushed stone. The compaction degree of base course 5 is not less than 98%, and it has high strength and high stability, providing load-bearing support for the road structure.

[0033] In this optional embodiment, the stress-absorbing layer 7 is a rubber asphalt stress-absorbing layer; the lower layer 4 is a precast lower layer with a thickness of 8 cm; and the upper layer 3 is a precast upper layer with a thickness of 4 cm.

[0034] It should be explained that stress-absorbing layer 7 is applicable to scenario 3 (12cm < H ≤ 30cm) and scenario 4 (30cm < H ≤ 50cm). A rubber asphalt stress-absorbing layer (SAMI) is laid on top of the base layer 5 to reduce the occurrence of reflective cracks.

[0035] The lower layer 4 is suitable for scenario 2 (4cm < H ≤ 12cm), scenario 3 (12cm < H ≤ 30cm), and scenario 4 (30cm < H ≤ 50cm). It is paved with an 8cm thick precast lower layer (AC-20C type asphalt concrete). AC-20C asphalt concrete has good high temperature stability and shear resistance, and serves as a load-bearing layer to transfer loads. The top layer 3 is suitable for all scenarios. It is paved with a 4cm thick precast top layer (AC-13C type asphalt concrete). AC-13C asphalt concrete has good flatness and anti-skid performance, ensuring driving comfort and safety.

[0036] According to one embodiment of the present invention, such as Figure 2 As shown, a construction method for a pavement structure with gradual elevation difference layering at a level crossing is also provided. This method includes: S1. Conduct a defect detection on the old road surface 2, remove the defective parts, and obtain a smooth old road surface; S2. Based on the elevation difference distribution, the connection section between the leveled old road surface and the newly built road 1 is divided into the first zone, the second zone, the third zone and the fourth zone to obtain the zoning results; the leveled old road surface is milled in a targeted manner according to the zoning results. S3. After the old road surface has been milled, according to the zoning results, the connecting section is paved in layers according to the leveling layer 6, base layer 5, stress absorption layer 7, lower layer 4 and upper layer 3 to obtain the transition section road surface. S4. After construction is completed, the transition section pavement will be inspected to ensure a smooth connection between the transition section and the leveled old road surface and the newly built road surface.

[0037] In this optional embodiment, the old road surface 2 is inspected for defects, and the defective parts are removed to obtain a smooth old road surface, including: The old road surface 2 was inspected for defects, and the types of defects were obtained. The types of defects included cracks and loosening. When the type of damage to the old road surface 2 is cracking, asphalt crack sealant is used for repair; when the type of damage to the old road surface 2 is loosening, AC-13C asphalt concrete is used for filling and leveling.

[0038] It should be explained that, firstly, the old road surface 2 should be inspected for defects, and loose and damaged parts should be removed to ensure that the load-bearing capacity of the old road surface 2 base layer meets the design requirements; if there are defects such as subsidence or cracks in the old road surface 2, they should be repaired before subsequent work can be carried out.

[0039] In this optional embodiment, targeted milling of the leveled old road surface based on the zoning results includes: When the zoning result is the first zoning, the old road surface is milled and leveled by 0-4cm, and the surface flatness error after milling is less than or equal to 3mm, so that the difference between the elevation of the old road surface after milling and the design elevation of the new road is equal to the thickness of the top layer. When the zoning result is the second zoning, the old road surface is milled and leveled by 0-8cm, and the surface of the old road is leveled. After milling, the surface compaction degree is greater than or equal to 95%. When the zoning result is the third zoning, the old road surface is milled and leveled by 0-18cm, and the aging and weak layers on the old road surface are removed. The elevation error of the top surface of the base layer after milling is less than or equal to 5mm. When the zoning result is the fourth zoning, the old road surface is milled and leveled to the top surface of the base layer, and the minimum milling depth is greater than or equal to 18cm. If the old road surface still cannot meet the structural layer thickness requirements after milling, the old road surface needs to be locally thickened.

[0040] It should be noted that, depending on the different elevation differences, the existing road surface will be milled accordingly, and the milling depth will be performed according to the following requirements: In Scenario 1 (0cm<H≤4cm), the old road surface is milled to a thickness of 0-4cm, so that the difference between the elevation of the old road surface after milling and the design elevation of the new road is equal to the thickness of the top layer. In Scenario 2 (4cm<H≤12cm), the old road surface is milled to a depth of 0-8cm to smooth the surface and provide a foundation for layered paving. In Scenario 3 (12cm<H≤30cm), the old road surface is milled and leveled from 0-18cm to completely remove the aging and weak layers on the old road surface, ensuring a good bond with the newly paved base layer. In Scenario 4 (30cm < H ≤ 50cm), the old road surface is milled and leveled to the top surface of the stable base layer (the milling depth is adjusted according to the actual height difference, and the minimum milling depth is not less than 18cm). If the thickness requirement of the structural layer cannot be met after milling, the base layer of the old road surface needs to be locally thickened.

[0041] In this optional embodiment, based on the zoning results, and in conjunction with the leveling layer 6, base layer 5, stress-absorbing layer 7, lower layer 4, and upper layer 3, the connecting section is paved in layers to obtain the transition section pavement, which includes: S31. In the fourth zone, cement-stabilized crushed stone material is used to lay leveling layer 6. The compaction degree of leveling layer 6 is greater than or equal to 98%, and the flatness error of the top surface after laying is less than or equal to 3mm. S32. In the third and fourth zones, 18cm thick cement-stabilized crushed stone is used and compacted with a heavy roller to pave base course 5. The compaction degree of base course 5 is greater than or equal to 98%. S33. In the third and fourth zones, after cleaning the base layer 5, spray rubber asphalt and spread single-size crushed stone, with a single-size crushed stone coverage rate of 85%-90%, and lay stress-absorbing layer 7. S34. In the second, third and fourth zones, when the paving temperature is between 150-165℃, an 8cm thick precast lower layer is used to pave the lower layer 4. The compaction degree of the lower layer 4 after rolling is greater than or equal to 96%. S35. In the first, second, third and fourth zones, when the paving temperature is between 160-175℃, a 4cm thick precast surface layer shall be used to pave surface layer 3. After compaction, surface layer 3 shall have a compaction degree greater than or equal to 97% and a surface texture depth greater than or equal to 0.5mm.

[0042] In this optional embodiment, the thick precast upper layer is AC-13C type asphalt concrete; the thick precast lower layer is AC-20C type asphalt concrete, used as a load-bearing layer to transfer loads.

[0043] The following detailed description, with reference to specific embodiments, illustrates the construction method of the pavement structure for the gradual elevation difference layering treatment at level crossings provided by the present invention.

[0044] (1) Project Overview: A newly constructed road connects to an existing road at a junction, with a total length of 15m. The existing road surface at the junction is asphalt concrete with a service life of 8 years, and the load-bearing capacity of base course 5 has been tested and meets the design requirements. The elevation difference between the design elevation of the new road 1 and the old road surface 2 gradually changes from 0cm at the starting point to 50cm at the ending point. The design speed is 60km / h, and a transition section pavement structure needs to be constructed.

[0045] (2) Construction steps: 1) Disease treatment.

[0046] A comprehensive inspection of the existing road surface at the intersection was conducted. For crack-type defects, asphalt crack sealant was used for repair; for loose defects, AC-13C asphalt concrete was used for filling and leveling.

[0047] 2) Segmented milling.

[0048] Based on the elevation difference distribution, the connecting section is divided into 4 zones. In Zone 1 (0-3m), H=0-4cm, the old road surface is milled and leveled by 0-4cm, and the surface flatness error after milling is ≤3mm. In Zone 2 (3-7m), H=4-12cm, the old road surface is milled and leveled by 0-8cm, and the surface compaction degree after milling is ≥95%. In Zone 3 (7-12m), H=12-30cm, the old road surface is milled and leveled by 0-18cm, and the elevation error of the top surface of the base layer after milling is ≤5mm. In Zone 4 (12-15m), H=30-50cm, the old road surface is milled and leveled by 20cm (to the top surface of the stable base layer), and the surface is flat and free of looseness after milling.

[0049] 3) Layered paving.

[0050] Section 4 is paved with a leveling layer 6, using cement-stabilized crushed stone material, with a paving thickness of 22cm (determined based on elevation difference calculations), a compaction degree ≥98%, and a top surface flatness error ≤3mm after paving. Sections 3 and 4 are paved with a base course 5, consisting of 18cm thick cement-stabilized crushed stone, compacted with a heavy roller, with a compaction degree ≥98%, and subsequent work can proceed after 7 days of curing. Sections 3 and 4 are paved with a stress-absorbing layer 7, using rubber asphalt + 9.5-13.2mm single-size crushed stone, and asphalt (1.8-2) is sprayed after cleaning the base course 5. 2kg / m²), simultaneously spread crushed stone (coverage rate 85%-90%), statically compacted; pave the lower layer 4 in zones 2, 3, and 4, paving an 8cm thick precast lower layer (AC-20C asphalt concrete), with paving temperature controlled at 150-165℃, and compaction degree ≥96% after rolling; pave the upper layer 3 in all zones, paving a 4cm thick precast upper layer (AC-13C asphalt concrete), with paving temperature controlled at 160-175℃, compaction degree ≥97% after rolling, and surface texture depth ≥0.5mm.

[0051] (3) Quality inspection: After construction was completed, the transition section of the road surface was tested: the road surface smoothness (IRI) was ≤2.0m / km, the compaction degree met the design requirements, there was no vehicle bouncing, and the transition section was smoothly connected to the old road surface 2 and the newly built road 1, meeting the usage requirements.

[0052] In summary, by utilizing the above-mentioned technical solutions of this invention, the invention exhibits strong adaptability. For gradual elevation differences of 0-50cm, it designs targeted solutions according to different elevation difference ranges, achieving full-scene coverage from micro to large elevation differences, thus solving the problem of insufficient adaptability of existing technologies to gradual elevation differences. The invention boasts a stable structure, employing a design of milling existing roads and layered paving. The selection and thickness design of base and surface layer materials are scientifically reasonable, ensuring that the bearing capacity of the transition section is consistent with existing and newly constructed roads, effectively avoiding subsidence, cracking, and other defects. The invention is convenient to construct, requiring no overall excavation and reconstruction, only partial milling of the existing road surface. This results in a short construction period, low resource consumption, minimal impact on existing traffic, and reduced construction and maintenance costs. Furthermore, the invention offers high construction efficiency; the use of prefabricated surface layers greatly improves construction efficiency and quality.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pavement structure for grade-separated intersections with gradually changing elevation differences, characterized in that, The transition section between the leveled old road surface and the newly constructed road is divided into four zones: Zone 1, Zone 2, Zone 3, and Zone 4. The resulting zoning structure of the grade-separated intersection with its gradual elevation change, from bottom to top, includes: The leveling layer, applicable to the fourth zone, is used to level the base layer of the old road surface after milling, ensuring the flatness of all subsequent structural layers. The leveling layer is paved with cement-stabilized crushed stone material. The base course, applicable to the third and fourth zones, is used to provide load-bearing support for the pavement structure. The base course is paved with 18cm thick cement-stabilized crushed stone. A stress-absorbing layer, applicable to the third and fourth zones, is used to reduce the occurrence of reflective cracks. The stress-absorbing layer is made of rubber asphalt stress-absorbing layer. The lower layer, applicable to the second, third and fourth zones, is used to transfer loads in the load-bearing layer. The lower layer is AC-20C type asphalt concrete. The upper layer, applicable to the first, second, third and fourth zones, is used to ensure driving comfort and safety. The upper layer is AC-13C type asphalt concrete. The first, second, third and fourth zones are smoothly connected and gradually change in layers, forming a pavement structure with gradually changing elevation differences at level crossings.

2. The pavement structure for grade-separated level crossings with gradual elevation differences according to claim 1, characterized in that, The height difference in the first partition is greater than 0 cm and less than or equal to 4 cm; the height difference in the second partition is greater than 4 cm and less than or equal to 12 cm; the height difference in the third partition is greater than 12 cm and less than or equal to 30 cm; and the height difference in the fourth partition is greater than 30 cm and less than or equal to 50 cm.

3. The pavement structure for grade-separated level crossings with gradual elevation differences according to claim 2, characterized in that, The leveling layer is constructed using cement-stabilized crushed stone material, and the minimum thickness of the leveling layer is greater than or equal to 18cm.

4. The pavement structure for grade-separated level crossings with gradual elevation differences according to claim 3, characterized in that, The base layer is constructed using 18cm thick cement-stabilized crushed stone, and the compaction degree of the base layer is greater than or equal to 98%.

5. The pavement structure for grade-separated level crossings with gradual elevation differences according to claim 4, characterized in that, The stress-absorbing layer is made of rubber asphalt; the lower layer is paved with an 8cm thick precast lower layer; and the upper layer is paved with a 4cm thick precast upper layer.

6. A construction method for a pavement structure with gradual elevation difference layering at a level crossing, used to implement the construction of the pavement structure with gradual elevation difference layering at a level crossing as described in claim 5, characterized in that, The method includes: S1. Conduct a defect detection on the old road surface, remove the defective parts, and obtain a smooth old road surface. S2. Based on the elevation difference distribution, the connection section between the leveled old road surface and the newly built road is divided into four zones: the first zone, the second zone, the third zone, and the fourth zone, and the zoning results are obtained. Based on the zoning results, the leveled old road surface is milled in a targeted manner. S3. After the old road surface has been milled, according to the zoning results, the connecting section is paved in layers based on the leveling layer, base layer, stress absorption layer, lower layer and upper layer to obtain the transition section road surface. S4. After construction is completed, the transition section pavement will be inspected to ensure a smooth connection between the transition section and the leveled old road surface and the newly built road surface.

7. The construction method for a pavement structure with gradual elevation difference layering at a level crossing according to claim 6, characterized in that, The process of detecting and removing defects in the old road surface to obtain a smooth old road surface includes: The old road surface was inspected for defects to determine the types of defects, which included crack defects and loosening defects. When the old road surface has cracks, it is repaired with asphalt crack sealant; when the old road surface has loosening defects, it is filled and leveled with AC-13C asphalt concrete.

8. A construction method for a pavement structure with gradual elevation difference layering at a level crossing according to claim 6, characterized in that, The targeted milling of the old road surface based on the zoning results includes: When the zoning result is the first zoning, the old road surface is milled and leveled by 0-4cm, and the surface flatness error after milling is less than or equal to 3mm, so that the difference between the elevation of the old road surface after milling and the design elevation of the new road is equal to the thickness of the top layer. When the zoning result is the second zoning, the old road surface is milled and leveled by 0-8cm, and the surface of the old road is leveled. After milling, the surface compaction degree is greater than or equal to 95%. When the zoning result is the third zoning, the old road surface is milled and leveled by 0-18cm, and the aging and weak layers on the old road surface are removed. The elevation error of the top surface of the base layer after milling is less than or equal to 5mm. When the zoning result is the fourth zoning, the old road surface is milled and leveled to the top surface of the base layer, and the minimum milling depth is greater than or equal to 18cm. If the old road surface still cannot meet the structural layer thickness requirements after milling, the old road surface needs to be locally thickened.

9. A construction method for a pavement structure with gradual elevation difference layering at a level crossing according to claim 6, characterized in that, Based on the zoning results, and in conjunction with the leveling layer, base layer, stress-absorbing layer, lower layer, and upper layer, the connecting section is paved in layers to obtain the transition section pavement, which includes: S31. In the fourth zone, cement-stabilized crushed stone material is used to pave a leveling layer. The compaction degree of the leveling layer is greater than or equal to 98%, and the flatness error of the top surface after paving is less than or equal to 3mm. S32. In the third and fourth zones, an 18cm thick cement-stabilized crushed stone base course is laid and compacted using a heavy roller, with a compaction degree of 98% or greater. S33. In the third and fourth zones, after cleaning the base layer, spray rubber asphalt and spread single-size crushed stone, with a single-size crushed stone coverage of 85%-90%, and lay a stress-absorbing layer. S34. In the second, third and fourth zones, when the paving temperature is between 150-165℃, an 8cm thick precast lower layer shall be used for paving the lower layer, and the compaction degree of the lower layer after rolling shall be greater than or equal to 96%. S35. In the first, second, third and fourth zones, when the paving temperature is between 160-175℃, a 4cm thick precast surface layer shall be used to pave the surface layer. The compaction degree of the surface layer after rolling shall be greater than or equal to 97%, and the surface texture depth of the surface layer shall be greater than or equal to 0.5mm.

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