Subgrade and Pavement Structure on the Pipeline Crossing the Dike and Construction Method

Abstract

The present invention discloses a roadbed and pavement structure located on a river-crossing pipeline, which relates to the field of road engineering. It includes a roadbed and pavement structure and a river-crossing pipeline; the roadbed and pavement structure is located on the river-crossing pipeline, and the roadbed and pavement structure is divided into four working conditions. Based on different working conditions and according to the principle that the load effect of the river-crossing pipeline structure is the same before and after the construction of a new road, the present invention proposes a roadbed and pavement structure located above the river-crossing pipeline, providing a basis for the load reduction and reinforcement design of existing river-crossing pipelines. The present invention also relates to a construction method of such a roadbed and pavement structure located on the river-crossing pipeline.

Description

Technical Field

[0001] The present invention relates to the field of road engineering, and more specifically, it is a subgrade and pavement structure located on a pipeline passing through a dike. The present invention also relates to a construction method of such a subgrade and pavement structure located on a pipeline passing through a dike. Background Art

[0002] During the construction of riverside roads, it is inevitable to encounter the situation where the proposed road intersects with a pipeline passing through a dike. Since the vast majority of existing pipelines passing through dikes do not consider the working conditions of high-frequency heavy vehicles in the design process, during road construction and later operation, under the action of vehicle loads (especially high-frequency heavy loads), the fill embankment undergoes uneven settlement, resulting in frequent pavement diseases and damage to transverse pipelines passing through the dike. While affecting the normal use of the pipeline, the pavement excavation and repair pose potential safety hazards to the dike.

[0003] The stress situation of pipelines passing through dikes under riverside roads is very complex. At present, there is a lack of a mature theoretical system for the reinforcement design of pipelines under roads. Pipeline reinforcement is mostly based on experience, and in the implementation process, there are often a series of problems such as uneconomical due to overly conservative design, or pavement diseases occurring in the construction and operation stages of the fill embankment section due to improper treatment, affecting normal use and increasing operation and maintenance costs.

[0004] In the subgrade and pavement design codes of our country (the "Code for Design of Highway Asphalt Pavements (JTG D50 - 2006)" and the "Code for Design of Highway Cement Concrete Pavements (JTG D40 - 2011)") and the pipeline structure design code (the "Code for Design of Pipeline Structures in Water Supply and Drainage Engineering (GB 50332 - 2002)"), there are no clear regulations on the special treatment of the subgrade and pavement structure above buried pipelines. In relevant research, pipeline reinforcement treatment measures generally focus on excavating and constructing new load transfer plates. Such measures cause great interference to existing pipelines, have high construction difficulty, and are restricted by the soil cover height above the pipe crown.

[0005] Therefore, it is necessary to develop a subgrade and pavement structure located on a pipeline passing through a dike. Summary of the Invention

[0006] The first object of the present invention is to overcome the deficiencies of the above background art and provide a subgrade and pavement structure located on a pipeline passing through a dike.

[0007] The second object of the present invention is to provide a construction method of such a subgrade and pavement structure located on a pipeline passing through a dike.

[0008] To achieve the above first object, the technical solution of the present invention is: A subgrade and pavement structure located on a pipeline passing through a dike, characterized in that: it includes a subgrade and pavement structure and a pipeline passing through a dike; the subgrade and pavement structure is located on the pipeline passing through a dike, and the subgrade and pavement structure is divided into four working conditions;

[0009] When in the first working condition, the roadbed and pavement structure successively includes the original soil covering the pipe top from bottom to top, the roadbed filling layer, the gravel cushion layer, the first steel wire mesh, the lightweight soil base layer, the second steel wire mesh, the cement concrete base layer and the asphalt concrete surface layer; there is a composite geomembrane in the gravel cushion layer;

[0010] When in the second working condition, the roadbed and pavement structure successively includes the original soil covering the pipe top from bottom to top, the gravel cushion layer, the first steel wire mesh, the lightweight soil base layer, the second steel wire mesh, the cement concrete base layer and the asphalt concrete surface layer; there is a composite geomembrane in the gravel cushion layer;

[0011] When in the third working condition, the roadbed and pavement structure successively includes the gravel cushion layer, the first steel wire mesh, the lightweight soil base layer, the second steel wire mesh, the reinforced concrete base layer and the asphalt concrete surface layer; there is a composite geomembrane in the gravel cushion layer;

[0012] When in the fourth working condition, the roadbed and pavement structure successively includes the gravel cushion layer, the cement concrete base layer and the asphalt concrete surface layer; there is a composite geomembrane in the gravel cushion layer.

[0013] In the above technical solution, the thickness of the cement concrete base layer is 15 - 25 cm.

[0014] In the above technical solution, the strength grade of the lightweight soil base layer is not lower than CF0.8, and the unit weight grade is not less than W6.

[0015] In the above technical solution, the thickness of the gravel cushion layer is 15 - 30 cm; the thickness of the composite geomembrane is not less than 0.5 mm.

[0016] In the above technical solution, the minimum thickness H 3min of the lightweight soil base layer is:

[0017]

[0018] wherein, H0 is the equivalent soil column height of the vehicle load, γ0 is the gravity density of the soil; H1 is the thickness of the asphalt concrete surface layer; γ1 is the gravity density of the asphalt concrete; H2 is the thickness of the cement concrete base layer, γ2 is the gravity density of the cement concrete, γ3 is the gravity density of the lightweight soil, H4 is the thickness of the gravel cushion layer, γ4 is the gravity density of the gravel cushion layer, H t is the thickness of the roadbed filling layer, γ t is the gravity density of the roadbed filling layer, γ c is the gravity density of the original soil covering the pipe top.

[0019] The maximum thickness H 3max of the lightweight soil base layer is:

[0020] H 3max = H - H1 - H2 - H4.

[0021] In the above technical solution, the calculation formula for the equivalent soil column height of vehicle load is as follows:

[0022]

[0023] where N is the number of vehicles distributed transversely, Q is the total weight of each vehicle, L is the sum of the front and rear axle distances plus the tire contact length, and B is the distance between the outer edges of the tires of the transversely distributed wheels;

[0024] B = Nb + (N - 1)d

[0025] where b is the distance between the outer edges of the tires of each vehicle; d is the clear distance between adjacent vehicles.

[0026] In the above technical solution, if H 3min <H 3max , and H1 + H2 + H 3min + H4 < h, then the roadbed and pavement structure is in the second working condition, where h represents the height of the embankment fill

[0027] If 0.3m ≤ H 3max <H 3min , then the roadbed and pavement structure is in the third working condition, and the thickness of the reinforced concrete base is 20cm.

[0028] If H 3max <H 3min and H 3max < 0.3m, then the roadbed and pavement structure is in the fourth working condition, and the thickness of the reinforced concrete base is 30cm.

[0029] The construction method of the roadbed and pavement structure located on the pipe passing through the dike is characterized in that:

[0030] When the roadbed and pavement structure is in the first working condition, it includes the following steps:

[0031] Step 1.1: Fill the roadbed on the surface of the original soil covering the top of the pipe passing through the dike until the top surface of the roadbed filling layer;

[0032] Step 1.2: Lay a sand-gravel cushion on the surface of the roadbed filling layer, and there is a composite geomembrane in the sand-gravel cushion;

[0033] Step 1.3: Lay the first steel wire mesh and the lightweight soil subbase on the surface of the sand-gravel cushion in sequence;

[0034] Step 1.4: Lay the second steel wire mesh and the cement concrete base on the surface of the lightweight soil subbase in sequence;

[0035] Step 1.5: Lay a prime coat and a tack coat on the surface of the cement concrete base in sequence, and then pave the asphalt concrete surface course;

[0036] When the roadbed and pavement structure is in the second working condition, it includes the following steps:

[0037] Step 2.1: Clear the surface and excavate the original soil covering the top of the cross-dike pipeline to the designated roadbed top elevation;

[0038] Step 2.2: Lay a gravel cushion layer on the surface of the original soil, and there is a composite geomembrane in the gravel cushion layer;

[0039] Step 2.3: Lay the first wire mesh sheet and the lightweight soil subbase on the surface of the gravel cushion layer in sequence;

[0040] Step 2.4: Lay the second wire mesh sheet and the cement concrete base course on the surface of the lightweight soil subbase in sequence;

[0041] Step 2.5: Lay a prime coat and a tack coat on the surface of the cement concrete base course in sequence, and then pave the asphalt concrete surface course;

[0042] When the roadbed and pavement structure is in the third working condition, it includes the following steps:

[0043] Step 3.1: Clear the surface and excavate to the top surface of the cross-dike pipeline;

[0044] Step 3.2: Lay a gravel cushion layer on the surface of the cross-dike pipeline, and there is a composite geomembrane in the gravel cushion layer;

[0045] Step 3.3: Lay the first wire mesh sheet and the lightweight soil subbase on the surface of the gravel cushion layer in sequence;

[0046] Step 3.4: Lay the second wire mesh sheet and the reinforced concrete base course on the surface of the lightweight soil subbase in sequence;

[0047] Step 3.5: Lay a prime coat and a tack coat on the surface of the reinforced concrete base course in sequence, and then pave the asphalt concrete surface course;

[0048] When the roadbed and pavement structure is in the fourth working condition, it includes the following steps:

[0049] Step 4.1: Clear the surface and excavate to the top surface of the cross-dike pipeline;

[0050] Step 4.2: Lay a gravel cushion layer on the surface of the cross-dike pipeline, and there is a composite geomembrane in the gravel cushion layer;

[0051] Step 4.3: Lay the reinforced concrete base course on the gravel cushion layer;

[0052] Step 4.4: Lay a prime coat and a tack coat on the surface of the reinforced concrete base course in sequence, and then pave the asphalt concrete surface course.

[0053] Compared with the prior art, the present invention has the following advantages:

[0054] 1) Based on different working conditions and in accordance with the principle that the load effect of the structure of the pipeline crossing the dike before and after the construction of the new road is the same, the present invention proposes a subgrade and pavement structure located above the pipeline crossing the dike, providing a basis for the load reduction and reinforcement design of the existing pipeline crossing the dike.

[0055] 2) Based on the principle of not disturbing the existing pipeline crossing the dike, the present invention reduces the construction difficulty of the subgrade and pavement above the pipeline, shortens the construction period, makes it easy to ensure the filling quality, reduces the probability of damage to the pipeline crossing the dike and diseases of the subgrade and pavement, and improves the service life of the road and the pipeline crossing the dike. Description of the Drawings

[0056] Figure 1 It is a schematic structural diagram of the present invention when the subgrade and pavement structure is in the first working condition.

[0057] Figure 2 It is a schematic structural diagram of the present invention when the subgrade and pavement structure is in the second working condition.

[0058] Figure 3 It is a schematic structural diagram of the present invention when the subgrade and pavement structure is in the third working condition.

[0059] Figure 4 It is a schematic structural diagram of the present invention when the subgrade and pavement structure is in the fourth working condition. Detailed Description of the Invention

[0060] The following will describe in detail the implementation of the present invention in conjunction with the drawings. However, they do not constitute a limitation to the present invention and are only for illustration purposes. At the same time, the advantages of the present invention will be made clearer and easier to understand through the description.

[0061] Considering the limitations of the existing subgrade and pavement structure on the pipeline crossing the dike and the corresponding reinforcement treatment measures, based on different working conditions, the present invention comprehensively considers the equivalent load effect of the existing pipeline crossing the dike before and after the construction of the road, proposes a subgrade and pavement structure located above the pipeline crossing the dike, adopts reasonable load reduction and reinforcement measures for the existing pipeline, reduces the probability of damage to the pipeline crossing the dike and diseases of the subgrade and pavement, improves the service life of the road, reduces the construction cost, and reduces the construction difficulty.

[0062] Referring to the drawings, it can be seen that the subgrade and pavement structure located on the pipeline crossing the dike is characterized in that it includes a subgrade and pavement structure 1 and a pipeline crossing the dike 2; the subgrade and pavement structure 1 is located on the pipeline crossing the dike 2, and the subgrade and pavement structure 1 is divided into four working conditions;

[0063] When in the first working condition, the subgrade and pavement structure 1 successively includes the original soil layer 11 covering the top of the pipe, the subgrade filling layer 12, the gravel cushion layer 13, the first wire mesh 14, the lightweight soil base layer 15, the second wire mesh 16, the cement concrete base layer 171 and the asphalt concrete surface layer 18 from bottom to top; there is a composite geomembrane 19 in the gravel cushion layer 13;

[0064] Under the second working condition, the roadbed and pavement structure 1 from bottom to top successively includes the original soil 11 covering the pipe top, the sand gravel cushion layer 13, the first steel wire mesh 14, the lightweight soil subbase 15, the second steel wire mesh 16, the cement concrete base layer 171 and the asphalt concrete surface layer 18; there is a composite geomembrane 19 in the sand gravel cushion layer 13;

[0065] Under the third working condition, the roadbed and pavement structure 1 from bottom to top successively includes the sand gravel cushion layer 13, the first steel wire mesh 14, the lightweight soil subbase 15, the second steel wire mesh 16, the reinforced concrete base layer 172 and the asphalt concrete surface layer 18; there is a composite geomembrane 19 in the sand gravel cushion layer 13;

[0066] Under the fourth working condition, the roadbed and pavement structure 1 from bottom to top successively includes the sand gravel cushion layer 13, the cement concrete base layer 171 and the asphalt concrete surface layer 18; there is a composite geomembrane 19 in the sand gravel cushion layer 13.

[0067] The thickness of the cement concrete base layer 171 is 15 - 25 cm, and the flexural tensile strength shall meet the requirements of the current "Design Code for Highway Cement Concrete Pavement (JTG D40 - 2011)".

[0068] The strength grade of the lightweight soil subbase 15 is not lower than CF0.8, and the bulk density grade is not less than W6. The bulk density grade and allowable deviation range of the material, and the strength grade shall meet the "Technical Specification for Filling Engineering with Aerated Mixed Lightweight Soil" (CJJ / T 177 - 2012).

[0069] The thickness of the sand gravel cushion layer 13 is 15 - 30 cm; the thickness of the composite geomembrane 19 is not less than 0.5 mm.

[0070] The minimum thickness H of the lightweight soil subbase 15 3min is:

[0071]

[0072] wherein, H0 is the equivalent soil column height of the vehicle load, γ0 is the gravity density of the soil; H1 is the thickness of the asphalt concrete surface layer 18; γ1 is the gravity density of the asphalt concrete; H2 is the thickness of the cement concrete base layer 171, γ2 is the gravity density of the cement concrete, γ3 is the gravity density of the lightweight soil, H4 is the thickness of the sand gravel cushion layer 13, γ4 is the gravity density of the sand gravel cushion layer 13, H t is the thickness of the roadbed filling layer 12, γ t is the gravity density of the roadbed filling layer 12, γ c is the gravity density of the original soil 11 covering the pipe top.

[0073] The maximum thickness H of the lightweight soil subbase 15 3max is:

[0074] H3max = H - H1 - H2 - H4。

[0075] The calculation formula for the equivalent soil column height of vehicle load is as follows:

[0076]

[0077] Wherein, N is the number of vehicles distributed transversely, Q is the total weight of each vehicle, L is the sum of the front and rear axle distances plus the tire contact length, and B is the distance between the outer edges of the tires of the transversely distributed wheels;

[0078] B = Nb + (N - 1)d

[0079] Wherein, b is the distance between the outer edges of the tires of each vehicle; d is the clear distance between adjacent vehicles; N, Q, L, b, and d are taken according to the relevant requirements of the "Technical Standard for Highway Engineering" (JTG B01-2014).

[0080] If H 3min <H 3max , and H1 + H2 + H 3min + H4 < h, then the subgrade and pavement structure 1 is in the second working condition, where h represents the height of the embankment fill.

[0081] If 0.3m ≤ H 3max <H 3min , then the subgrade and pavement structure 1 is in the third working condition, and the thickness of the reinforced concrete base layer 172 is 20cm.

[0082] If H 3max <H 3min and H 3max < 0.3m, then the subgrade and pavement structure 1 is in the fourth working condition, and the thickness of the reinforced concrete base layer 172 is 30cm.

[0083] The construction method of the subgrade and pavement structure located on the pipeline crossing the dike is characterized in that:

[0084] When the subgrade and pavement structure 1 is in the first working condition, it includes the following steps:

[0085] Step 1.1: Fill the subgrade on the surface of the original soil 11 on the top of the pipeline crossing the dike 2 until the top surface of the subgrade filling layer 12;

[0086] Step 1.2: Lay a gravel cushion layer 13 on the surface of the subgrade filling layer 12, and there is a composite geomembrane 19 in the gravel cushion layer 13;

[0087] Step 1.3: Lay a first wire mesh 14 and a lightweight soil subbase 15 on the surface of the gravel cushion layer 13 in sequence;

[0088] Step 1.4: Lay a second wire mesh 16 and a cement concrete base layer 171 on the surface of the lightweight soil subbase 15 in sequence;

[0089] Step 1.5: Lay a prime coat and a tack coat on the surface of the cement concrete base course 171 in sequence, and then lay the asphalt concrete surface course 18.

[0090] When the roadbed and pavement structure 1 is in the second working condition, it includes the following steps:

[0091] Step 2.1: Clear the surface and excavate the original soil 11 on the top of the cross-dike pipeline 2 to the specified roadbed top elevation.

[0092] Step 2.2: Lay a gravel cushion layer 13 on the surface of the original soil 11, and there is a composite geomembrane 19 in the gravel cushion layer 13.

[0093] Step 2.3: Lay the first wire mesh sheet 14 and the lightweight soil base course 15 on the surface of the gravel cushion layer 13 in sequence.

[0094] Step 2.4: Lay the second wire mesh sheet 16 and the cement concrete base course 171 on the surface of the lightweight soil base course 15 in sequence.

[0095] Step 2.5: Lay a prime coat and a tack coat on the surface of the cement concrete base course 171 in sequence, and then lay the asphalt concrete surface course 18.

[0096] When the roadbed and pavement structure 1 is in the third working condition, it includes the following steps:

[0097] Step 3.1: Clear the surface and excavate to the top surface of the cross-dike pipeline 2.

[0098] Step 3.2: Lay a gravel cushion layer 13 on the surface of the cross-dike pipeline 2, and there is a composite geomembrane 19 in the gravel cushion layer 13.

[0099] Step 3.3: Lay the first wire mesh sheet 14 and the lightweight soil base course 15 on the surface of the gravel cushion layer 13 in sequence.

[0100] Step 3.4: Lay the second wire mesh sheet 16 and the reinforced concrete base course 172 on the surface of the lightweight soil base course 15 in sequence.

[0101] Step 3.5: Lay a prime coat and a tack coat on the surface of the reinforced concrete base course 172 in sequence, and then lay the asphalt concrete surface course 18.

[0102] When the roadbed and pavement structure 1 is in the fourth working condition, it includes the following steps:

[0103] Step 4.1: Clear the surface and excavate to the top surface of the cross-dike pipeline 2.

[0104] Step 4.2: Lay a gravel cushion layer 13 on the surface of the cross-dike pipeline 2, and there is a composite geomembrane 19 in the gravel cushion layer 13.

[0105] Step 4.3: Lay the reinforced concrete base course 172 on the gravel cushion layer 13.

[0106] Step 4.4: Lay a prime coat and a tack coat successively on the surface of the reinforced concrete base course 172, and then pave the bituminous concrete surface course 18.

[0107] In actual use, in the third working condition, the thickness of the reinforced concrete base course 172 is 20 cm, and the steel bars in the X and Y directions are φ12@10;

[0108] In the fourth working condition, the thickness of the reinforced concrete base course 172 is 30 cm, and the steel bars in the X and Y directions are φ14@10;

[0109] Other parts not described belong to the prior art.

Claims

1. Construction method of subgrade and pavement structure on the pipeline passing through the dike, characterized in that: It includes a roadbed and pavement structure (1) and a pipe crossing the dike (2); the roadbed and pavement structure (1) is located on the pipe crossing the dike (2). According to the principle that the load effect before and after the construction of the new road on the pipe crossing the dike structure is the same, the roadbed and pavement structure (1) is divided into four working conditions; In the first working condition, the roadbed and pavement structure (1) successively includes the original soil covering on the top of the pipe (11), the roadbed filling layer (12), the sand-gravel cushion layer (13), the first wire mesh (14), the lightweight soil subbase (15), the second wire mesh (16), the cement concrete base (171) and the asphalt concrete surface layer (18) from bottom to top; there is a composite geomembrane (19) in the sand-gravel cushion layer (13); In the second working condition, the roadbed and pavement structure (1) successively includes the original soil covering on the top of the pipe (11), the sand-gravel cushion layer (13), the first wire mesh (14), the lightweight soil subbase (15), the second wire mesh (16), the cement concrete base (171) and the asphalt concrete surface layer (18) from bottom to top; there is a composite geomembrane (19) in the sand-gravel cushion layer (13); In the third working condition, the roadbed and pavement structure (1) successively includes the sand-gravel cushion layer (13), the first wire mesh (14), the lightweight soil subbase (15), the second wire mesh (16), the reinforced concrete base (172) and the asphalt concrete surface layer (18) from bottom to top; there is a composite geomembrane (19) in the sand-gravel cushion layer (13); In the fourth working condition, the roadbed and pavement structure (1) successively includes the sand-gravel cushion layer (13), the cement concrete base (171) and the asphalt concrete surface layer (18) from bottom to top; there is a composite geomembrane (19) in the sand-gravel cushion layer (13); The minimum thickness H of the light soil subbase (15) 3min is as follows: Among them, H0 is the equivalent soil column height of the vehicle load, and γ0 is the unit weight of soil; H1 is the thickness of the asphalt concrete surface layer (18), and γ1 is the unit weight of asphalt concrete; H2 is the thickness of the cement concrete base layer (171), γ2 is the unit weight of cement concrete, γ3 is the unit weight of lightweight soil, H4 is the thickness of the gravel cushion layer (13), γ4 is the unit weight of the gravel cushion layer (13), H t is the thickness of the subgrade filling layer (12), γ t is the unit weight of the subgrade filling layer (12), γ c is the unit weight of the original soil covering the pipe (11); The maximum thickness H of the lightweight soil subbase (15) 3max is as follows: H 3max = H - H1 - H2 - H4; H is the distance from the edge of the roadbed and pavement structure to the top surface of the pipe crossing the dike; If H 3min <H 3max , and H1 + H2 + H 3min + H4 < h, then the roadbed and pavement structure (1) is in the second working condition, where h represents the height of the embankment fill; If 0.3m ≤ H 3max <H 3min , then the roadbed and pavement structure (1) is in the third working condition, and the thickness of the reinforced concrete base layer (172) is 20 cm; If H 3max <H 3min and H 3max <0.3 m, then the roadbed and pavement structure (1) is in the fourth working condition, and the thickness of the reinforced concrete base (172) is 30 cm.

2. The construction method of the roadbed and pavement structure on the culvert-piercing pipeline according to claim 1, characterized in that: The thickness of the cement concrete base (171) is 15 - 25 cm.

3. The construction method of the roadbed and pavement structure on the culvert-piercing pipeline according to claim 2, characterized in that: The strength grade of the lightweight soil subbase (15) is not lower than CF0.8, and the unit weight grade is not less than W6.

4. The construction method of the roadbed and pavement structure on the culvert pipe passing through the dike according to claim 3, characterized in that: The thickness of the sand-gravel cushion layer (13) is 15 - 30 cm; the thickness of the composite geomembrane (19) is not less than 0.5 mm.

5. The construction method of the roadbed and pavement structure located on the pipeline crossing the dike according to claim 4, characterized in that: The calculation formula for the equivalent soil column height of the vehicle load is: Among them, N is the number of vehicles distributed horizontally, Q is the total weight of each vehicle, L is the sum of the front and rear axle distances and the tire contact length, and B is the distance between the outer edges of the tires of the horizontally distributed wheels; B = Nb + (N - 1)d; Among them, b is the distance between the outer edges of the tires of each vehicle; d is the net distance between adjacent vehicles.

6. The construction method of the roadbed and pavement structure located on the pipe crossing the dike according to any one of claims 1 - 5, characterized in that: When the roadbed and pavement structure (1) is in the first working condition, it includes the following steps: Step 1.1: Fill the roadbed on the surface of the original soil (11) covering the top of the pipe crossing the dike (2) to the top surface of the roadbed filling layer (12); Step 1.2: Lay the sand-gravel cushion layer (13) on the surface of the roadbed filling layer (12), and there is a composite geomembrane (19) in the sand-gravel cushion layer (13); Step 1.3: Lay the first wire mesh (14) and the lightweight soil subbase (15) successively on the surface of the sand-gravel cushion layer (13); Step 1.4: Lay the second wire mesh sheet (16) and the cement concrete base course (171) successively on the surface of the lightweight soil subbase (15); Step 1.5: Lay the prime coat and tack coat successively on the surface of the cement concrete base course (171), and then pave the bituminous concrete surface course (18); When the roadbed and pavement structure (1) is in the second working condition, it includes the following steps: Step 2.1: Clear the surface and excavate the original soil (11) on top of the cross - embankment pipeline (2) to the specified roadbed top elevation; Step 2.2: Lay the gravel cushion layer (13) on the surface of the original soil (11), and there is a composite geomembrane (19) in the gravel cushion layer (13); Step 2.3: Lay the first wire mesh sheet (14) and the lightweight soil subbase (15) successively on the surface of the gravel cushion layer (13); Step 2.4: Lay the second wire mesh sheet (16) and the cement concrete base course (171) successively on the surface of the lightweight soil subbase (15); Step 2.5: Lay the prime coat and tack coat successively on the surface of the cement concrete base course (171), and then pave the bituminous concrete surface course (18); When the roadbed and pavement structure (1) is in the third working condition, it includes the following steps: Step 3.1: Clear the surface and excavate to the top surface of the cross - embankment pipeline (2); Step 3.2: Lay the gravel cushion layer (13) on the surface of the cross - embankment pipeline (2), and there is a composite geomembrane (19) in the gravel cushion layer (13); Step 3.3: Lay the first wire mesh sheet (14) and the lightweight soil subbase (15) successively on the surface of the gravel cushion layer (13); Step 3.4: Lay the second wire mesh sheet (16) and the reinforced concrete base course (172) successively on the surface of the lightweight soil subbase (15); Step 3.5: Lay the prime coat and tack coat successively on the surface of the reinforced concrete base course (172), and then pave the bituminous concrete surface course (18); When the roadbed and pavement structure (1) is in the fourth working condition, it includes the following steps: Step 4.1: Clear the surface and excavate to the top surface of the cross - embankment pipeline (2); Step 4.2: Lay the gravel cushion layer (13) on the surface of the cross - embankment pipeline (2), and there is a composite geomembrane (19) in the gravel cushion layer (13); Step 4.3: Lay the reinforced concrete base course (172) on the gravel cushion layer (13); Step 4.4: Lay the prime coat and tack coat successively on the surface of the reinforced concrete base course (172), and then pave the bituminous concrete surface course (18).

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