Composite roadbed structure and method for constructing a composite roadbed structure

Abstract

The embodiment of the application provides a composite roadbed structure and a composite roadbed structure construction method, relates to the technical field of road and bridge construction in cold regions, and comprises a roadbed unit, a phase change heat preservation unit and a heat pipe unit. The phase change heat preservation unit is arranged in the roadbed unit; the heat pipe unit comprises a heat pipe body and a heat dissipation pipe body, the heat pipe body is embedded in the roadbed unit and located below the phase change heat preservation unit, the heat dissipation pipe body is connected to the heat pipe body, and the heat dissipation pipe body extends out of the roadbed unit. The heat pipe body is used for filling volatile working medium, the volatile working medium is used for volatilizing and flowing to the heat dissipation pipe body when being heated, and condensing and flowing back into the heat pipe body after being cooled at the heat dissipation pipe body. The design of the roadbed structure can effectively improve the long-term thermal stability of the roadbed, avoid the problems of excessive concentration of refrigeration of traditional heat pipes and cavities around the pipes, and realize dynamic cooling and heat preservation of the roadbed throughout the year, thereby providing technical support for high-quality construction and safe operation of road engineering in cold regions.

Description

Technical Field

[0001] This invention relates to the field of road and bridge construction technology in cold regions, and more specifically, to a composite roadbed structure and a construction method for the composite roadbed structure. Background Technology

[0002] When constructing highways and railways in high-altitude and cold regions, special attention must be paid to their thermal sensitivity. In recent years, with my country's rapid economic development, numerous highways and railways have been built in these regions, such as the Qinghai-Tibet Railway, the Qinghai-Tibet Highway, and the Qinghai-Kangding Highway. The success of road construction projects in high-altitude and cold regions hinges on ensuring the thermal stability of the roadbed and the underlying permafrost. In recent years, heat pipe technology has been widely used in road engineering in cold regions. Its excellent heat exchange performance and active cooling characteristics greatly ensure the thermal stability of the roadbed and the underlying permafrost.

[0003] The inventors discovered in their research that existing cold-region roadbed structures have at least the following drawbacks:

[0004] However, existing technologies still struggle to effectively control uneven heat distribution within the roadbed caused by factors such as the yin-yang slope effect, localized snow and sand accumulation on roadbed slopes, leading to frequent differential deformation of the roadbed and affecting road safety and stability. Summary of the Invention

[0005] The objectives of this invention include, for example, providing a composite roadbed structure and a construction method for the composite roadbed structure, which can effectively improve the long-term thermal stability of the roadbed, avoid the problems of excessive centralized cooling and voids around the pipes in traditional heat pipes, and achieve dynamic cooling and insulation of the roadbed throughout the year, providing technical support for high-quality construction and safe operation of road engineering in cold regions.

[0006] The embodiments of the present invention can be implemented as follows:

[0007] In a first aspect, the present invention provides a composite roadbed structure, comprising:

[0008] The roadbed unit, phase change insulation unit, and heat pipe unit are provided; the phase change insulation unit is located inside the roadbed unit; the heat pipe unit includes a heat pipe body and a heat dissipation pipe body, the heat pipe body is buried inside the roadbed unit and located below the phase change insulation unit, and the heat dissipation pipe body is connected to the heat pipe body and extends outside the roadbed unit.

[0009] The heat pipe body is used to fill a volatile working fluid, which evaporates when heated and flows to the heat dissipation tube body, and condenses and flows back to the heat pipe body after being cooled at the heat dissipation tube body.

[0010] In an optional embodiment, the phase change insulation unit includes a substrate and a plurality of phase change capsules, the plurality of phase change capsules being mixed with the raw materials used to prepare the substrate.

[0011] Based on the above scheme, the substrate preparation materials can be concrete, mortar, polystyrene, etc. When preparing the substrate, multiple phase change capsules are first mixed in the raw materials of the substrate. The phase change capsules and raw materials are fully mixed by stirring and other methods to improve the uniformity of the distribution of the phase change capsules. Then, the substrate is prepared by casting at the designated position of the roadbed unit, thereby completing the preparation of the phase change insulation unit. The preparation method is simple and reliable and has high construction efficiency.

[0012] In an optional embodiment, the phase change capsule includes a coating layer and a phase change material, wherein the coating layer is wrapped around the phase change material.

[0013] Based on the above scheme, the phase change capsule has a simple structure and is easy to process. By using a coating layer to encapsulate the phase change material, the phase change material is not easily affected by the raw materials of the substrate, resulting in a long service life and good thermal insulation performance of the substrate.

[0014] In an optional embodiment, the heat dissipation tube includes an inner tube and an outer tube, one end of the inner tube is sealed to one end of the outer tube, the other end of the inner tube is connected to the cavity of the outer tube, and a reflux cavity is defined between the outer tube wall of the inner tube and the inner tube wall of the outer tube; one end of the heat pipe body is connected to the inner tube, and the other end of the heat pipe body is connected to the reflux cavity.

[0015] Based on the above scheme, a volatile working fluid is injected into the heat pipe body, with the liquid level of the volatile working fluid not exceeding the top of the inner tube. During operation, when the volatile working fluid is heated, some of it evaporates to form gas, causing a change in the liquid level between the inner tube and the return chamber, creating a pressure difference that drives the volatile working fluid to flow within the heat pipe body. When the gaseous working fluid reaches the location of the heat dissipation tube, it exchanges heat with the external environment, dissipating the heat and condensing back into a liquid state. Under the influence of gravity, it flows along the inner wall of the outer tube back into the heat pipe body. In this way, the volatile working fluid circulates, dissipating excess heat within the roadbed unit and regulating the heat distribution within the roadbed unit, ensuring a uniform heat distribution.

[0016] In an optional embodiment, the reflux cavity is configured as an annular cavity arranged around the inner tube.

[0017] Based on the above scheme, the flow of volatile working fluids is smoother and the heat control efficiency is higher.

[0018] In an optional embodiment, a superhydrophobic coating is provided on the inner wall of the outer tube.

[0019] Based on the above scheme, by setting a superhydrophobic coating on the inner wall of the outer tube, the smoothness of the inner wall of the outer tube can be increased. After the working fluid condenses, it is easy to flow down the inner wall of the outer tube under the action of gravity, and it is not easy to adhere to the inner wall of the outer tube, which shortens the residence time of the working fluid and improves the heat exchange efficiency. Furthermore, since the working fluid is not easy to adhere to the inner wall, the thickness of the working fluid is reduced, the thermal resistance of the outer tube is lower, which is conducive to heat dissipation and further improves the heat exchange efficiency.

[0020] In an optional embodiment, the bottom of the superhydrophobic coating is 3-5 mm higher than the top of the inner tube.

[0021] Based on the above solution, the superhydrophobic coating is not immersed in volatile media, making it less susceptible to corrosion and peeling, thus extending the service life of the superhydrophobic coating.

[0022] In an optional embodiment, the heat pipe body has at least one bent section in its extension direction.

[0023] Based on the above scheme, under the premise that the width of the roadbed unit is fixed, by adding bending pipe sections, the effective length of the heat pipe body can be increased, thereby increasing the coverage area of ​​the heat pipe body, which is conducive to adjusting the heat distribution inside the roadbed unit and improving the uniformity of heat distribution inside the roadbed unit.

[0024] In an optional embodiment, there are multiple heat pipe units, which are arranged at intervals along the extension direction of the roadbed unit; the distance between the heat pipe bodies of adjacent heat pipe units is d, and the effective cooling radius of each heat pipe body is r, where d ≤ 2r.

[0025] Based on the above scheme, the distance between adjacent heat pipe bodies is no greater than the effective cooling radius of two adjacent heat pipe bodies, ensuring that the cooling area of ​​the heat pipe body can completely cover the roadbed unit, making it less likely to have cooling dead zones, resulting in good cooling effect, good temperature control effect, and more uniform heat distribution for the roadbed unit.

[0026] Secondly, the present invention provides a construction method for a composite roadbed structure, applicable to the composite roadbed structure described in any of the foregoing embodiments, the construction method comprising the following steps:

[0027] During the construction of the roadbed unit, a heat pipe unit is installed at the first set height position of the roadbed unit, and then a volatile working fluid is injected into the heat pipe body of the installed heat pipe unit; then the construction of the roadbed unit continues and the heat pipe body is buried; then a phase change insulation unit is installed at the second set height position of the roadbed unit, and then the construction of the roadbed unit is completed.

[0028] The beneficial effects of the embodiments of the present invention include, for example:

[0029] In summary, the composite roadbed structure provided in this embodiment combines a phase change insulation unit and a heat pipe unit within the roadbed unit. When the roadbed unit is heated, the uneven heating on the north and south slopes is mitigated by the phase change insulation unit, preventing most of the heat from being directly transferred to the permafrost area and thus reducing the risk of localized ice melting and roadbed damage due to uneven permafrost thawing. Simultaneously, the heat absorbed by the phase change insulation unit acts on the heat pipe unit, causing the volatile working fluid within the heat pipe to evaporate. The change in the liquid level of the volatile working fluid creates a pressure difference, driving the fluid to flow within the heat pipe. During this flow, excess heat is dissipated through the heat dissipation pipes, and the temperature on the north and south slopes of the roadbed unit tends to be isothermal, resulting in a more uniform temperature distribution within the roadbed unit. This effectively improves the long-term thermal stability of the roadbed unit, avoids the problems of excessive concentrated cooling and surrounding voids associated with traditional heat pipes, and enables dynamic cooling and insulation of the roadbed unit throughout the year, providing technical support for high-quality construction and safe operation of road engineering in cold regions. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a composite roadbed structure according to an embodiment of this application;

[0032] Figure 2 This is a schematic diagram of a heat pipe unit according to an embodiment of this application;

[0033] Figure 3 This is a schematic diagram of the phase change insulation unit according to an embodiment of this application.

[0034] icon:

[0035] 100-Subgrade unit; 110-Subgrade filler layer; 120-Water-stabilized layer; 130-Pavement structure layer; 200-Phase change insulation unit; 210-Substrate; 220-Phase change capsule; 300-Heat pipe unit; 310-Heat pipe body; 320-Heat dissipation pipe body; 321-Inner pipe; 322-Outer pipe; 323-Superhydrophobic coating; 324-Recirculation cavity; 330-Heat dissipation fins. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0038] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0039] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0040] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0041] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0042] It should be understood that permafrost is highly sensitive to temperature changes. Climate warming and engineering construction will cause permafrost to warm and degrade, affecting the stability of the superstructure road. When there is a difference in the absorption of solar radiation on the two slopes of the roadbed, these slopes are called "yin-yang slopes" (slopes with different solar and yin-yang hulls), which will further aggravate permafrost roadbed diseases, induce uneven deformation and longitudinal cracking, and directly affect the service function of the road. Heat pipes have been widely used in the stability maintenance of permafrost roadbeds in some major engineering projects. However, the inventors discovered that the excessive local cooling of traditional heat pipes can lead to problems such as cracks and uneven deformation of the roadbed.

[0043] In view of this, the designers have provided a composite roadbed structure that can not only effectively dissipate excess heat inside the roadbed, but also make the heat distribution inside the roadbed uniform, reducing the impact of temperature differences on the stability of the roadbed.

[0044] Please refer to Figures 1-2 This embodiment provides a composite roadbed structure, including a roadbed unit 100, a phase change insulation unit 200, and a heat pipe unit 300. The phase change insulation unit 200 is disposed within the roadbed unit 100; the heat pipe unit 300 includes a heat pipe body 310 and a heat dissipation pipe body 320. The heat pipe body 310 is embedded within the roadbed unit 100 and located below the phase change insulation unit 200, and the heat dissipation pipe body 320 is connected to the heat pipe body 310 and extends outside the roadbed unit 100. The heat pipe body 310 is used to fill a volatile working fluid, which volatilizes when heated and flows to the heat dissipation pipe body 320, and condenses after being cooled at the heat dissipation pipe body and flows back into the heat pipe body 310.

[0045] As described above, the working principle of the composite roadbed structure provided in this embodiment is as follows:

[0046] The roadbed unit 100 is combined with the phase change insulation unit 200 and the heat pipe unit 300. When the roadbed unit 100 is heated, the uneven heating of the yin and yang slopes can be blocked by the phase change insulation unit 200. It is not easy to directly transfer heat to the frozen soil area on the ground surface, and it is not easy to cause the local ice layer in the frozen soil area to melt due to heat. It is not easy to cause roadbed damage due to uneven melting of frozen soil. Simultaneously, the heat absorbed by the phase change insulation unit 200 acts on the heat pipe unit 300, causing the volatile working fluid in the heat pipe body 310 to evaporate. The change in the liquid level of the volatile working fluid generates a pressure difference, driving the volatile working fluid to flow in the heat pipe body 310. During the flow of the volatile working fluid, excess heat can be dissipated through the heat dissipation pipe 320. Furthermore, it can make the temperature of the yin and yang slopes of the roadbed unit 100 tend to be isothermal, making the temperature distribution inside the roadbed unit 100 more uniform. This effectively improves the long-term thermal stability of the roadbed unit 100, avoids the problems of excessive concentrated cooling and voids around the pipes in traditional heat pipes, and achieves dynamic cooling and insulation of the roadbed unit 100 throughout the year, providing technical support for the high-quality construction and safe operation of road engineering in cold regions.

[0047] The following embodiments illustrate the details of the composite roadbed structure of this application by way of example.

[0048] Please refer to Figure 1In this embodiment, optionally, the subgrade unit 100 includes a subgrade filler layer 110, a water-stabilized layer 120, and a pavement structure layer 130. The material of the subgrade filler layer 110 can be selected to ensure good load uniformity, which is beneficial to the rationality of the overall load transfer of the subgrade and its long-term thermal stability. After the subgrade filler layer 110 is installed, a groove is provided on the top of the subgrade filler layer 110, and the water-stabilized layer 120 is laid in the groove. Then, the pavement structure layer 130 is laid on top of the water-stabilized layer 120, and the water-stabilized layer 120 and the pavement structure layer 130 fill the groove. The materials of the water-stabilized layer 120 and the pavement structure layer 130 are selected as needed, ensuring safe service.

[0049] It should be understood that the path filler layer can be set as an isosceles trapezoidal structure to reduce the effect of uneven slopes and facilitate the uniform distribution of heat inside the roadbed unit 100.

[0050] Please refer to Figure 1 and Figure 3 In this embodiment, optionally, the phase change insulation unit 200 includes a substrate 210 and multiple phase change capsules 220. The multiple phase change capsules 220 are mixed together with the raw materials required to prepare the substrate 210. Specifically, the substrate 210 can be made of materials such as concrete, mortar, and polystyrene, and can be cast into the roadbed filler layer 110. When preparing the substrate 210, multiple phase change capsules 220 can be mixed into the raw materials of the substrate 210 first, and the phase change capsules 220 can be thoroughly mixed with the raw materials through stirring or other methods to improve the uniformity of the distribution of the phase change capsules 220. Then, the substrate 210 is cast into the designated position of the roadbed unit 100 to complete the preparation of the phase change insulation unit 200. The preparation method is simple, reliable, and has high construction efficiency.

[0051] It should be understood that the substrate 210 can be constructed by laying it continuously in the extension direction of the subgrade unit 100. The width of the substrate 210 is smaller than the width of the subgrade unit 100 to avoid the substrate 210 being directly exposed to the subgrade filler layer 110, thereby extending the service life of the substrate 210. It also avoids the substrate 210 being directly exposed to sunlight, reducing the absorption of heat from the external environment by the substrate 210 and lowering the internal temperature of the subgrade filler layer 110.

[0052] In addition, the number of substrates 210 can also be set to multiple, and multiple substrates 210 are arranged adjacent to each other in the extension direction of the roadbed unit 100. Adjacent substrates 210 can be connected or have a set distance.

[0053] It should be understood that in the preparation of phase change capsule 220, phase change capsule 220 includes a coating layer and a phase change material, with the coating layer covering the phase change material. The method for wrapping the coating layer around the phase change material can be a physical method, a chemical method, or a physicochemical method, selected as needed. By using the coating layer to encapsulate the phase change material, the phase change material is less susceptible to the influence of the raw materials of the substrate 210, resulting in a longer service life and better thermal insulation performance of the substrate 210.

[0054] Furthermore, once the phase change capsule 220 is prepared, the phase change capsule 220 can be spherical particles, which facilitates mixing with the raw materials in the substrate 210.

[0055] In one embodiment, optionally, the phase change material may be paraffin wax, and the coating material may be a resin material.

[0056] Please refer to Figures 1-2 In this embodiment, optionally, the heat pipe body 310 can also be referred to as an evaporator pipe, and the heat pipe body 310 is horizontally arranged within the roadbed filler layer 110. The heat pipe body 310 can be configured as a split structure, and the heat pipe body 310 can include multiple pipe segments, with adjacent pipe segments connected by joints, reducing processing difficulty. In addition, the heat pipe body 310 can be configured as a bent pipe, or the heat pipe body 310 has at least one bent pipe segment in its extension direction. In this way, given a fixed width of the roadbed unit 100, by increasing the bent pipe segment, the effective length of the heat pipe body 310 can be increased, thereby increasing the coverage area of ​​the heat pipe body 310, which is beneficial for adjusting the heat distribution inside the roadbed unit 100 and improving the uniformity of heat distribution inside the roadbed unit 100.

[0057] Optionally, the heat pipe body 320 can also be called a condenser pipe. The heat pipe body 320 includes an inner pipe 321 and an outer pipe 322. One end of the inner pipe 321 is sealed to one end of the outer pipe 322, and the other end of the inner pipe 321 is connected to the cavity of the outer pipe 322. A return cavity 324 is defined between the wall of the outer pipe 322 and the wall of the inner pipe 321. The inner pipe 321 and the outer pipe 322 can be arranged coaxially. In this way, the return cavity 324 defined between the inner pipe 321 and the outer pipe 322 is an annular cavity, which is arranged around the inner pipe 321. One end of the heat pipe body 310 is connected to the inner pipe 321, and the other end of the heat pipe body 310 is connected to the return cavity 324. The position of the heat pipe body 310 connected to the return cavity 324 is lower than the top port of the inner pipe 321.

[0058] It should be understood that both the inner tube 321 and the outer tube 322 can be circular tubes. There is a gap between the top of the inner tube 321 and the top of the outer tube 322. When the volatile working fluid is injected, the liquid level of the volatile working fluid is lower than the top port of the inner tube 321. Thus, when the volatile working fluid is heated and evaporates, a height difference is generated between the liquid level of the return cavity 324 and the inner tube 321, forming a pressure difference, which can drive the volatile working fluid to flow in the heat pipe body 310.

[0059] The instruction manual explains that during the service of the composite roadbed structure, when the volatile working fluid is heated, some of it evaporates into gas, causing a change in the liquid level in the inner tube 321 and the return chamber 324, creating a pressure difference that drives the volatile working fluid to flow in the heat pipe body 310. When the gaseous working fluid flows to the location of the heat dissipation pipe 320, it exchanges heat with the external environment, dissipates the heat, and condenses back into a liquid state. Under the influence of gravity, it flows along the wall of the inner tube 321 of the outer tube 322 back into the heat pipe body 310. In this way, the volatile working fluid circulates, which not only dissipates excess heat inside the roadbed unit 100 but also regulates the heat inside the roadbed unit 100, ensuring a uniform heat distribution.

[0060] Furthermore, by setting the reflux chamber 324 as an annular chamber, the flow of volatile working fluid is smoother, resulting in high heat control efficiency.

[0061] Furthermore, a superhydrophobic coating 323 is provided on the inner tube 321 wall of the outer tube 322, which can increase the smoothness of the inner tube 321 wall of the outer tube 322. After the working fluid condenses, it is easy to flow downward along the inner tube 321 wall of the outer tube 322 under the action of gravity, and it is not easy to adhere to the inner tube 321 wall of the outer tube 322, which shortens the residence time of the working fluid and improves the heat exchange efficiency. In addition, since the working fluid is not easy to adhere to the inner tube 321 wall, the thickness of the working fluid is reduced, the thermal resistance of the outer tube 322 is lower, which is conducive to heat dissipation and further improves the heat exchange efficiency.

[0062] Optionally, the bottom of the superhydrophobic coating 323 is 3-5 mm higher than the top of the inner tube 321. For example, the bottom of the superhydrophobic coating 323 is 3 mm, 4 mm, or 5 mm higher than the top of the inner tube 321. With this design, the superhydrophobic coating 323 is not immersed in volatile media, making it less susceptible to corrosion and peeling, thus extending the service life of the superhydrophobic coating 323.

[0063] In other embodiments, optionally, heat dissipation fins 330 are installed on the wall of the outer tube 322. The heat dissipation fins 330 are located outside the roadbed filler layer 110, with a large contact area with air, high heat exchange efficiency, which is conducive to cooling the gaseous working fluid, shortening the time required for the internal temperature balance of the roadbed, and further reducing the damage to the roadbed caused by uneven heat distribution.

[0064] It should be noted that the superhydrophobic coating 323 can be set as an organosilicon-based superhydrophobic coating 323, and the stable contact angle of the condensed liquid volatile working fluid on the superhydrophobic coating 323 is not less than 150°. In this way, the probability of the liquid working fluid adhering to the inner tube 321 wall of the outer tube 322 is further reduced, which is conducive to the reflux of the liquid working fluid.

[0065] When preparing the outer tube 322, a superhydrophobic coating 323 can be formed on the raw steel coil of the outer tube 322 by spraying before the outer tube 322 is formed. This process is convenient and the forming quality is high.

[0066] It should be understood that in this embodiment, there can be multiple heat pipe units, which are arranged at intervals along the extension direction of the roadbed unit. The distance between the heat pipe bodies of adjacent heat pipe units is d, and the effective cooling radius of each heat pipe body is r, where d ≤ 2r. The distance between adjacent heat pipe bodies is not greater than the effective cooling radius of two adjacent heat pipe bodies, ensuring that the cooling area of ​​the heat pipe body can completely cover the roadbed unit, minimizing cooling dead zones, resulting in good cooling effect, good temperature control, and more uniform heat distribution in the roadbed unit.

[0067] The composite roadbed structure provided in this embodiment effectively improves the long-term thermal stability of the roadbed by combining a phase change insulation unit 200 and a heat pipe unit 300 within the roadbed unit 100. It avoids the problems of excessive centralized cooling and voids around the pipes in traditional heat pipes, and achieves dynamic cooling and insulation of the roadbed throughout the year, providing technical support for high-quality construction and safe operation of road engineering in cold regions.

[0068] This embodiment also provides a construction method for a composite roadbed structure, including the following steps:

[0069] During the construction of the roadbed unit 100, a heat pipe unit 300 is installed at the first set height position of the roadbed unit 100, and then a volatile working fluid is injected into the heat pipe body 310 of the installed heat pipe unit 300; then the construction of the roadbed unit 100 continues and the heat pipe body 310 is buried; then the phase change insulation unit 200 is installed at the second set height position of the roadbed unit 100, and then the construction of the roadbed unit 100 is completed.

[0070] Specifically, the required composite subgrade structure should first be determined based on the construction design drawings and relevant specifications. Depending on the specific project requirements, a subbase layer conforming to the specifications can be first filled and compacted on the foundation soil, and then the heat pipe body 310 can be placed horizontally on this subbase layer. To facilitate the construction of the heat pipe body 310, it can be designed as a segmented structure, with adjacent pipe segments connected by connectors, ensuring that these connectors are corrosion-resistant and liquid-proof.

[0071] The roadbed unit 100 should have proper drainage measures. Asphalt can be laid on top of the roadbed unit 100 for easy passage. During the construction of the roadbed filler layer 110 of the roadbed unit 100, the heat pipe body 310 and the heat dissipation pipe body 320 are assembled. A volatile working fluid is injected into the heat pipe body 310 through the pre-reserved injection port on the heat dissipation pipe body 320. Then, all air inside the pipe is extracted again through the injection port, and the injection port is sealed afterward. After assembly, the heat pipe body 310 should be checked to ensure it functions normally. It should be noted that the placement and geometry of the superhydrophobic coating 323 enhancing heat transfer pressure-driven ultra-long uniformly distributed heat pipe and the phase change insulation structure in the composite roadbed structure of this embodiment are not unique.

[0072] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A composite roadbed structure, characterized by, include: The roadbed unit (100), the phase change insulation unit (200), and the heat pipe unit (300) are provided inside the roadbed unit (100). The heat pipe unit (300) includes a heat pipe body (310) and a heat dissipation pipe body (320). The heat pipe body (310) is buried inside the roadbed unit (100) and located below the phase change insulation unit (200). The heat dissipation pipe body (320) is connected to the heat pipe body (310) and extends outside the roadbed unit (100). The heat pipe body (310) is used to fill a volatile working fluid, which is used to evaporate when heated and flow to the heat dissipation pipe body (320), and condense and flow back into the heat pipe body (310) after being cooled at the heat dissipation pipe body. The heat dissipation tube (320) includes an inner tube (321) and an outer tube (322). One end of the inner tube (321) is sealed to one end of the outer tube (322). The other end of the inner tube (321) is connected to the cavity of the outer tube (322). A reflux cavity (324) is defined between the outer wall of the inner tube (321) and the inner wall of the outer tube (322). One end of the heat pipe body (310) is connected to the inner tube (321), and the other end of the heat pipe body (310) is connected to the reflux cavity (324). The position of the heat pipe body (310) connected to the reflux cavity (324) is lower than the top port of the inner tube (321). The top of the inner tube (321) and the top of the outer tube (322) are spaced apart.

2. The composite roadbed structure according to claim 1, characterized in that: The phase change insulation unit (200) includes a substrate (210) and a plurality of phase change capsules (220), wherein the plurality of phase change capsules (220) are mixed with the raw materials used to prepare the substrate (210).

3. The composite roadbed structure according to claim 2, characterized in that: The phase change capsule (220) includes a coating layer and a phase change material, wherein the coating layer is wrapped around the phase change material.

4. The composite roadbed structure according to claim 1, characterized in that: The reflux cavity (324) is configured as an annular cavity surrounding the inner tube (321).

5. The composite roadbed structure according to claim 1, characterized in that: The inner tube (321) wall of the outer tube (322) is provided with a superhydrophobic coating (323).

6. The composite roadbed structure according to claim 5, characterized in that: The bottom of the superhydrophobic coating (323) is 3-5 mm higher than the top of the inner tube (321).

7. The composite roadbed structure according to claim 1, characterized in that: The heat pipe body (310) has at least one bent section in its extension direction.

8. The composite roadbed structure according to claim 1, characterized in that: The number of heat pipe units (300) is multiple, and the multiple heat pipe units (300) are arranged at intervals in the extension direction of the roadbed unit; the distance between the heat pipe bodies (310) of adjacent heat pipe units (300) is d, and the effective cooling radius of each heat pipe body (310) is r, d≤2r.

9. A method of constructing a composite roadbed structure, characterized by The construction method, applicable to the composite roadbed structure according to any one of claims 1-8, comprises the following steps: During the construction of the roadbed unit (100), a heat pipe unit (300) is installed at the first set height position of the roadbed unit (100), and then a volatile working fluid is injected into the heat pipe body (310) of the installed heat pipe unit (300); then the construction of the roadbed unit (100) continues and the heat pipe body (310) is buried; then a phase change insulation unit (200) is installed at the second set height position of the roadbed unit (100), and then the construction of the roadbed unit (100) is completed.

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