Novel roadbed for preventing'pot cover effect 'of airport runway

Abstract

The utility model discloses a novel roadbed for preventing the'pot cover effect 'of an airport runway, and provides a new solution for the problem of diseases caused by the'pot cover effect' of the airport runway. The roadbed structure is composed of a pavement layer, a fiber drainage layer, a wall type blast layer, a cement stabilized macadam layer, a filler layer, a gravel layer and an air isolation layer. The fiber drainage layer is composed of micron-sized drainage fibers and can transversely drain unsaturated water in roadbed soil, and the wall type air blowing layers on the two sides of the drainage ditch can accelerate water evaporation and increase the evaporation speed of the fiber drainage layer. The bottom air insulation layer is used as a defense line of the first'pot cover effect ', can effectively prevent water vapor at the lower part of the roadbed from migrating, and can effectively prevent water from accumulating below the pavement layer by combining with the fiber drainage layer at the lower part of the pavement layer, so that the problem of airport runway diseases caused by the'pot cover effect' is solved.

Description

Technical Field

[0001] This application relates to the technical field of subgrade structures, and specifically to a new type of subgrade for preventing the "pot lid effect" on airport runways. Background Art

[0002] Due to the construction of airport runways, the balance of moisture migration between the original ground surface and the atmosphere has been changed, resulting in the enrichment of moisture in the soil layer below the ground structure, forming the so-called "pot lid effect". The "pot lid effect" is common in cold, dry areas with low water levels, where the compacted asphalt and concrete pavements of airports form an airtight covering layer. Under the influence of freeze-thaw cycles, soil water vapor rises and condenses into water or ice when encountering this covering layer, resulting in water accumulation under the runway. This accumulated water freezes in winter and is difficult to drain when it melts in spring and summer, gradually accumulating and ultimately causing damage to the runway, affecting the safety of aircraft navigation and incurring expensive road maintenance costs. Previous prevention and control methods mainly rely on "passive defense", mainly using methods such as "prevention, drainage, blocking, and interception" for prevention and control. However, the "pot lid effect" is an accumulation phenomenon caused by the long-term migration of moisture at the microscopic level. The above measures can only play a drainage role macroscopically and cannot comprehensively prevent the occurrence of the "pot lid effect".

[0003] To solve the problem of the "pot lid effect", it is necessary to first solve the phenomenon of water vapor migration in the soil, and then set up unsaturated drainage measures at the water accumulation areas to achieve the purpose of combining "prevention" and "drainage". Therefore, providing a new type of subgrade for preventing the "pot lid effect" on airport runways is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0004] The utility model provides a new type of subgrade for preventing the "pot lid effect" on airport runways, which can solve the problem of the "pot lid effect" disease on airports under complex environmental conditions. Specifically, it includes a road surface layer (1), a fiber drainage layer (B1), a wall-type air-blowing layer (B2), a cement stabilized macadam layer (2), a filler layer (3), a gravel layer (4), an air barrier layer (6), a buffer layer (7), and a natural subgrade (5). An air barrier layer (6) is laid on the natural subgrade (5), and the air barrier layer is coated with an anti-corrosion coating on both sides. Above the air barrier layer are successively a buffer cushion layer (7), a gravel layer (4), a filler layer (3), a cement stabilized macadam layer (2), a fiber drainage layer (B1), and a road surface layer (1). The fiber drainage layer extends to the drainage ditch (A) outside the subgrade and is laid downward for a certain distance. A blowing layer (B2) is arranged in the extended part of the fiber drainage layer. The top of the drainage ditch (A) is capped by a concrete slab (A1), and a hole (A2) is opened in the middle of the concrete slab (A1). The top of the concrete slab (A1) is flush with the connection parts on both sides of the road surface layer (1).

[0005] Among them, the moisture barrier layer is located above the natural roadbed (5) and below the buffer cushion layer (7) and the gravel layer (4). The moisture barrier layer (6) is an aluminum-plastic composite film, and the film surface is sprayed with polychlorotrifluoroethylene to enhance the corrosion resistance and durability of the material. Its function is to prevent the upward migration of water vapor in the lower part of the natural roadbed and serve as the first line of defense against the "lid effect".

[0006] The cross slope of the road surface layer is between 1.5% and 2%, and the concrete strength grade of the road surface is above C60.

[0007] The drainage fiber drainage method is one-way (lateral) drainage. The longitudinal fiber is a common reinforcing fiber without drainage capacity. The fiber drainage layer (B1) is laid below the road surface layer (1) and extends 50 cm downward along the drainage ditch externally.

[0008] The width of the drainage ditch (A) is preferably 0.5 m. The top opening is closed by a detachable concrete slab (A1). A hole (A2) is opened in the middle of the concrete slab (A1). The transverse length of the hole is designed according to 80% of the width of the concrete slab (A1), and the longitudinal length is fixed at 4 cm, with an interval of 10 - 15 cm.

[0009] The air-blowing layer (B2) adopts wall-mounted small fans (B3). The air-blowing layer (B2) is located inside the sidewall drainage layer (B1). The switch of the air-blowing layer (B2) is a humidity induction switch. The upper humidity threshold is 70% and the lower threshold is 40%. When the humidity exceeds 70% (proving that the drainage layer starts to work), the switch is automatically turned on to start blowing air, and when the humidity is lower than 40%, the switch is turned off to stop blowing air.

[0010] The beneficial effects of the present utility model are as follows:

[0011] 1. The present utility model provides a method for combining "prevention and drainage" to control the "lid effect" of airport runways. A moisture barrier layer is set to cut off the water vapor migration path from the bottom, and an unsaturated fiber drainage layer is set to drain water from the water accumulation area. While preventing the "lid effect", it can also prevent the frost heave of the roadbed.

[0012] 2. The fiber drainage layer is composed of high-suction drainage fibers. Its one-way capillary drainage ability can suck and drain the water in the unsaturated soil to both exposed ends, and a suction difference is formed under the action of evaporation (or gravity) to form a siphon effect, continuously pumping the saturated (unsaturated) water inside the roadbed out of the roadbed, which can effectively prevent the accumulation of water under the road surface layer to form the "lid effect", and removing the water under the road surface can prevent the occurrence of road frost damage.

[0013] 3. The moisture barrier layer is an aluminum-plastic composite film, which has excellent isolation effect and can effectively prevent the upward migration of water vapor in the lower part, serving as the first bottom line of defense against the "lid effect".

[0014] 4. The construction process of the fiber drainage layer and the gas barrier layer is simple. It only needs to be laid on the basis of the compacted lower structure, and the construction cost is low. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below.

[0016] Figure 1 It is a schematic diagram of the overall structure of a new roadbed for preventing the "pot lid effect" of airport runways in this embodiment;

[0017] Figure 2 It is an enlarged view of the detailed structure of a new roadbed for preventing the "pot lid effect" of airport runways in this embodiment;

[0018] Figure 3 It is a schematic diagram of the shape of the cement cover plate in a new roadbed for preventing the "pot lid effect" of airport runways in this embodiment;

[0019] Reference Signs: 1 - road surface layer; 2 - cement stabilized macadam layer; 3 - filler layer; 4 - gravel layer; 5 - natural roadbed layer; 6 - gas barrier layer; A - drainage ditch; B1 - fiber drainage layer; B2 - wall - type air - blowing layer; B3 - wall - mounted small fan; A1 - concrete slab; A2 - air - permeable and drainage holes of the concrete slab. Detailed Embodiments

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

[0021] The present utility model provides a new roadbed for preventing the "pot lid effect" of airport runways. Through the combination of "prevention" and "drainage", it can effectively solve the problems of the "pot lid effect" disease of airports and the frost heaving problem of airport runways under complex environmental conditions.

[0022] As Figure 1 shown, from top to bottom are the road surface layer (1), fiber drainage layer (B1), wall - type air - blowing layer (B2), cement stabilized macadam layer (2), filler layer (3), gravel layer (4), gas barrier layer (6), buffer cushion layer (7) and natural roadbed (5), as well as the drainage ditches (A) on both sides.

[0023] First, the roadbed is excavated. After leveling the site, the roadbed is compacted at the optimum moisture content, and the degree of compaction is not less than 95%. Subsequently, the gas barrier layer is laid. The main material of the gas barrier layer is aluminum - plastic composite film. Before laying, polytrifluorochloroethylene is sprayed on the surface of the film (the purpose is to enhance the corrosion resistance and durability of the material). After the trifluorochloroethylene condenses firmly, it is then laid on the surface of the natural roadbed.

[0024] After the gas barrier layer (6) is laid, a 10-cm buffer cushion layer (7) needs to be laid above it to prevent the gravel layer from squeezing and damaging the gas barrier layer. The buffer cushion layer can be made of materials such as coarse sand, and waterproof concrete is selected for the part in contact with the drainage ditch. Above the gas barrier layer (6) is the gravel layer (4), which is composed of gravel with a particle size between 20 and 40 cm. The purpose of laying this layer of material is to prevent the rise of capillary water. After the gravel layer (4) is compacted, the filler layer (3) is laid, and the filler layer is selected as crushed stone soil with a low fine-grained content. After the filler layer (3) is laid and compacted, the cement-stabilized crushed stone layer (2) is laid. When its unconfined compressive strength for 7 days reaches more than 5 MPa, the air-blowing layer (B2) is laid. The wall-mounted small fan (B3) used in the air-blowing layer (B2) is connected by rivets. Subsequently, the fiber drainage layer (B1) is laid. After the laying is completed, the road surface layer (1) is laid, and the concrete grade of the road surface layer is not lower than C60. Finally, the drainage ditch (A) is built, and the drainage ditch is built with waterproof concrete.

[0025] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A new type of roadbed for preventing the "pot lid effect" on airport runways, comprising a road surface layer (1), a fiber drainage layer (B1), a wall - type air - blowing layer (B2), a cement - stabilized macadam layer (2), a filler layer (3), a gravel layer (4), an air - isolating layer (6), and a buffer cushion layer (7), characterized in that: An air barrier layer (6) is laid on the natural roadbed (5), and successively above the air barrier layer are a buffer cushion layer (7), a gravel layer (4), a filling layer (3), a cement stabilized macadam layer (2), a fiber drainage layer (B1), and a road surface layer (1).

2. The novel roadbed for preventing the "pot lid effect" on the airport runway according to claim 1, wherein: The fiber drainage layer (B1) extends to the drainage ditch (A) outside the roadbed and is laid downward for a certain distance. A blowing layer (B2) is arranged inside the extended part. The top of the drainage ditch (A) is capped by a concrete slab (A1). An opening (A2) is formed in the middle of the concrete slab (A1). The top of the concrete slab (A1) is flush with the joints on both sides of the road surface layer (1).

3. The novel roadbed for preventing the "pot lid effect" on the airport runway according to claim 1 is characterized in that: The cross slope of the road surface layer is between 1.5% and 2%, and the concrete strength grade of the road surface is above C60.

4. A novel roadbed for preventing the "pot lid effect" on airport runways according to claim 1, characterized in that: The drainage method of the fiber drainage layer is one-way drainage. The longitudinal fibers are ordinary reinforced fibers without drainage capacity. The fiber drainage layer (B1) is laid below the road surface layer (1) and extends downward along the drainage ditch for 50 cm outside.

5. The novel roadbed for preventing the "pot cover effect" on the airport runway according to claim 1 is characterized in that: The width of the drainage ditch (A) is preferably 0.5 m. The top opening is closed by a detachable concrete slab (A1). An opening (A2) is formed in the middle of the concrete slab (A1). The transverse length of the pore channel is designed according to 80% of the width of the concrete slab (A1), and the longitudinal length is fixed at 4 cm, with an interval of 10 - 15 cm.

6. The novel roadbed for preventing the "pot lid effect" on the airport runway according to claim 1, wherein: The blowing layer (B2) adopts a wall-mounted small fan (B3). The blowing layer (B2) is located inside the side wall drainage layer (B1), and the switch is controlled by a humidity induction switch.

7. The novel roadbed for preventing the "pot cover effect" on the airport runway according to claim 1 is characterized in that: The power supply switch is controlled by a humidity induction switch. The upper humidity threshold is 70%, and the lower threshold is 40%. When the humidity exceeds 70%, the switch is automatically turned on to start blowing, and when the humidity is lower than 40%, the switch is turned off to stop blowing.

8. A new roadbed for preventing the "lid effect" of airport runways according to claim 1, characterized in that: The air barrier layer is located above the natural roadbed (5) and below the gravel layer (4) and the buffer cushion layer (7). The air barrier layer (6) is an aluminum-plastic composite film, and the surface of the film is sprayed with polychlorotrifluoroethylene to enhance the corrosion resistance and durability of the material.

9. The novel roadbed for preventing the "pot lid effect" on airport runways according to claim 1 is characterized in that: A 10-cm buffer cushion layer (7) is laid on the air barrier layer (6) as a buffer zone between the air barrier layer (6) and the gravel layer (4) to prevent the air barrier layer from being punctured by the gravel layer.

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