Composite roadbed structure and composite roadbed structure construction method

Abstract

The embodiment of the invention provides a composite roadbed structure and a composite roadbed structure construction method, and relates to the technical field of cold region road and bridge construction, and the composite roadbed structure 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 being filled with a volatile working medium, and the volatile working medium is used for volatilizing when heated, flowing to the heat dissipation pipe body, condensing after being cooled at the position of the heat dissipation pipe body and flowing back into the heat pipe body. According to the design of the roadbed structure, the long-term thermal stability of the roadbed can be effectively improved, the problems of excessive concentrated refrigeration of a traditional heat pipe, cavities around the pipe and the like are solved, annual dynamic cooling and heat preservation of the roadbed are achieved, and technical support is provided for high-quality construction and safe operation of road engineering in the cold region.

Description

Technical Field

[0001] The invention relates to the technical field of cold region road and bridge construction, and in particular to a composite roadbed structure and a composite roadbed structure construction method. Background Art

[0002] When constructing highway and railway projects in high-altitude cold regions, special attention should be paid to their thermal sensitivity and other issues. In recent years, with the rapid development of my country's economy, a large number of highways and railways have been built in high-altitude cold regions, such as the Qinghai-Tibet Railway, the Qinghai-Tibet Highway, and the Qinghai-Kangding Highway. The key to the success or failure of road construction in high-altitude cold regions lies in whether the thermal stability of the roadbed and the underlying frozen soil can be ensured. In recent years, heat pipe technology has been widely used in cold region road projects. Its excellent heat exchange performance and active cooling characteristics have greatly ensured the thermal stability of the roadbed and the underlying frozen soil.

[0003] The inventors found in their research that the existing cold region roadbed structure has at least the following disadvantages:

[0004] However, existing technologies still find it difficult to effectively control the uneven heat distribution inside the roadbed caused by the Yin-Yang slope effect, local snow and sand accumulation on the roadbed slopes, etc., which leads to frequent differential deformation of the roadbed and affects the safety and stability of the road. Summary of the invention

[0005] The purposes of the present invention include, for example, providing a composite roadbed structure and a composite roadbed structure construction method, which can effectively improve the long-term thermal stability of the roadbed, avoid the problems of excessive centralized cooling of traditional heat pipes and voids around the pipes, and realize dynamic cooling and insulation of the roadbed throughout the year, providing technical support for high-quality construction and safe operation of road projects 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] A roadbed unit, a phase change insulation unit and a heat pipe unit; the phase change insulation 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 buried in the roadbed unit and located below the phase change insulation 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;

[0009] The heat pipe body is used to be filled with a volatile working medium, and the volatile working medium is used to volatilize and flow toward the heat dissipation pipe body when heated, and condense and flow back into the heat pipe body after being cooled at the heat dissipation pipe body.

[0010] In an optional embodiment, the phase-change heat preservation unit includes a substrate and a plurality of phase-change capsules, and the plurality of phase-change capsules are mixed with a raw material for preparing the substrate.

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

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

[0013] Based on the above scheme, the structure of the phase change capsule is simple and easy to process. The phase change material is wrapped by the coating layer, the phase change material is not easily affected by the raw material of the substrate, has a long service life, and the thermal insulation effect of the substrate is good.

[0014] In an optional embodiment, the heat dissipation pipe body includes an inner tube and an outer tube, one end of the inner tube is sealedly connected to one end of the outer tube, the other end of the inner tube is connected to the tube 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, and the liquid level of the volatile working fluid is not higher than the top of the inner tube. During operation, when the volatile working fluid is heated, part of the volatile working fluid is heated and evaporated to form gas, causing the liquid level of the inner tube and the liquid level of the reflux chamber to change, forming a pressure difference, and driving the volatile working fluid to flow in the heat pipe body. When the gaseous working fluid flows to the location of the heat dissipation pipe body, it exchanges heat with the external environment, dissipates heat, condenses itself due to cooling, and returns to a liquid working fluid. Under the action of gravity, it flows along the inner tube wall of the outer tube and returns to the heat pipe body. In this way, the volatile working fluid circulates, which can not only dissipate the excess heat inside the roadbed unit, but also regulate the heat inside the roadbed unit to make the heat inside the roadbed unit evenly distributed.

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

[0017] Based on the above scheme, the volatile working fluid flows more smoothly and the heat regulation efficiency is high.

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

[0019] Based on the above scheme, by providing a super-liquid-repellent coating on the inner tube wall of the outer tube, the smoothness of the inner tube wall of the outer tube can be increased. After the working fluid is condensed, it is easy to flow downward along the inner tube wall of the outer tube under the action of gravity, and is not easy to adhere to the inner tube wall of the outer tube, thereby shortening the residence time of the working fluid and improving the heat exchange efficiency; and, since the working fluid is not easy to adhere to the inner tube 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 the heat exchange efficiency is further improved.

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

[0021] Based on the above solution, the super-lyophobic coating is not immersed in a volatile medium and is not easily corroded or fallen off, thereby extending the service life of the super-lyophobic coating.

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

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

[0024] In an optional embodiment, there are multiple heat pipe units, and the multiple heat pipe units are arranged at intervals in 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, 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, and there is no cooling dead corner. The cooling effect of the roadbed unit is good, the temperature control effect is good, and the heat distribution is more uniform.

[0026] In a second aspect, the present invention provides a composite roadbed structure construction method, which is applied to the composite roadbed structure described in any one of the aforementioned embodiments, and the construction method comprises the following steps:

[0027] During the construction of the roadbed unit, a heat pipe unit is installed at a 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 roadbed unit is continued to be constructed and the heat pipe body is buried; then a phase change insulation unit is installed at a 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 the phase change insulation unit and the heat pipe unit in the roadbed unit. When the roadbed unit is heated, the positive and negative slopes are heated unevenly, and most of the heat can be blocked by the phase change insulation unit, which is not easy to be directly transferred to the surface frozen soil area, and it is not easy to melt the local ice layer in the surface frozen soil area by heating, and it is not easy to damage the roadbed due to uneven melting of frozen soil. At the same time, the heat absorbed by the phase change insulation unit acts on the heat pipe unit, so that the volatile working fluid in the heat pipe body is heated and evaporated, and the change in the height of the volatile working fluid liquid level produces a pressure difference, driving the volatile working fluid to flow in the heat pipe body. During the flow of the volatile working fluid, the excess heat can be dissipated through the heat dissipation pipe body, and the temperature of the positive and negative slopes of the roadbed unit can be made isothermal, so that the temperature distribution inside the roadbed unit is more uniform, effectively improving the long-term thermal stability of the roadbed unit, avoiding the problems of excessive centralized cooling of traditional heat pipes and the problems of cavities around the pipe, and realizing dynamic cooling and insulation of the roadbed unit throughout the year, providing technical support for high-quality construction and safe operation of cold-region road projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 A schematic diagram of a composite roadbed structure according to an embodiment of the present application;

[0032] Figure 2 A schematic diagram of a heat pipe unit according to an embodiment of the present application;

[0033] Figure 3 Schematic diagram of a phase change insulation unit according to an embodiment of the present application.

[0034] icon:

[0035] 100-roadbed unit; 110-roadbed filling layer; 120-water-stabilizing layer; 130-pavement structure layer; 200-phase change insulation unit; 210-base material; 220-phase change capsule; 300-heat pipe unit; 310-heat pipe body; 320-heat pipe body; 321-inner pipe; 322-outer pipe; 323-super-liquid-repellent coating; 324-reflux chamber; 330-heat fins. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0039] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0040] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0041] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0042] It should be understood that frozen soil is very sensitive to temperature changes. Climate warming and engineering construction will cause frozen soil to warm up and degrade, affecting the stability of the upper road. When there is a difference in the absorption of solar radiation by the slopes on both sides of the roadbed, the slopes on both sides are called yin and yang slopes, which will further aggravate the frozen soil roadbed disease, induce uneven deformation of the roadbed, longitudinal cracking, etc., and directly affect the service function of the road. Heat pipes have been widely used in the stability maintenance of frozen soil roadbeds in some major projects. However, the inventors found that local excessive cooling of traditional heat pipes will cause problems such as cracks in the roadbed and differential deformation of the roadbed.

[0043] In view of this, the designer provides a composite roadbed structure that can not only effectively dissipate excess heat inside the roadbed, but also evenly distribute heat inside the roadbed, reducing the impact of temperature differences on roadbed stability.

[0044] Please refer to Figure 1-Figure 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 arranged in 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 in the roadbed unit 100 and is located below the phase change insulation unit 200, the heat dissipation pipe body 320 is connected to the heat pipe body 310, and the heat dissipation pipe body 320 extends out of the roadbed unit 100. The heat pipe body 310 is used to fill a volatile working medium, and the volatile working medium is used to volatilize and flow to the heat dissipation pipe body 320 when heated, and condense and flow back into the heat pipe body 310 after being cooled at the heat dissipation pipe body.

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

[0046] The phase change insulation unit 200 and the heat pipe unit 300 are combined in the roadbed unit 100. When the roadbed unit 100 is heated, the positive and negative slopes are heated unevenly, and most of the heat can be blocked by the phase change insulation unit 200, which is not easy to be directly transmitted to the surface frozen soil area, and it is not easy to melt the local ice layer in the surface frozen soil area due to heat, and it is not easy to damage the roadbed due to uneven melting of frozen soil. At the same time, 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 due to the heat, and the change in the liquid level of the volatile working fluid produces a pressure difference, driving the volatile working fluid to flow in the heat pipe body 310. During the flow of the volatile working fluid, the excess heat can be dissipated through the heat dissipation pipe body 320, and the temperatures of the positive and negative slopes of the roadbed unit 100 can be made isothermal, making the temperature distribution inside the roadbed unit 100 more uniform, effectively improving the long-term thermal stability of the roadbed unit 100, avoiding the problems of excessive centralized cooling and voids around the pipes of traditional heat pipes, and realizing dynamic cooling and insulation of the roadbed unit 100 throughout the year, providing technical support for high-quality construction and safe operation of road projects in cold regions.

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

[0048] Please refer to Figure 1In this embodiment, optionally, the roadbed unit 100 includes a roadbed filling layer 110, a water-stable layer 120 and a pavement structure layer 130. The material of the roadbed filling layer 110 can be selected from materials with good uniformity of load transfer, which is beneficial to the rationality of the overall load transfer of the roadbed and the long-term thermal stability of the roadbed. After the roadbed filling layer 110 is set, a groove is set on the top of the roadbed filling layer 110, and the water-stable layer 120 is laid in the groove, and then the pavement structure layer 130 is laid on the top of the water-stable layer 120, and the water-stable layer 120 and the pavement structure layer 130 fill the groove. Among them, the materials of the water-stable layer 120 and the pavement structure layer 130 are selected as needed to ensure safe service.

[0049] It should be understood that the path filler layer can be set to a structure with an isosceles trapezoidal cross-section to reduce the yin-yang slope effect and facilitate uniform heat distribution 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 a plurality of phase change capsules 220. The plurality of phase change capsules 220 are mixed with the raw materials required for preparing the substrate 210. Specifically, the preparation material of the substrate 210 may be concrete, mortar, polystyrene, etc., and the substrate 210 may be formed inside the roadbed filling layer 110 by casting. When preparing the substrate 210, a plurality of phase change capsules 220 may be first mixed in the raw materials of the substrate 210, and the phase change capsules 220 and the raw materials may be fully mixed by stirring or the like, thereby improving the distribution uniformity of the phase change capsules 220, and then, the substrate 210 may be prepared by casting at a set position of the roadbed unit 100, thereby completing the preparation of the phase change insulation unit 200, and the preparation method is simple and reliable, and the construction efficiency is high.

[0051] It should be understood that the substrate 210 can be constructed by paving in the extension direction of the roadbed unit 100. The width of the substrate 210 is smaller than the width of the roadbed unit 100, so as to avoid the substrate 210 being directly exposed to the roadbed filling layer 110, thereby extending the service life of the substrate 210, and also preventing the substrate 210 from being directly exposed to sunlight, thereby reducing the heat absorbed by the substrate 210 from the external environment and lowering the internal temperature of the roadbed filling layer 110.

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

[0053] It should be understood that when preparing the phase change capsule 220, the phase change capsule 220 includes a coating layer and a phase change material, and the coating layer is wrapped around the phase change material. The method of wrapping the coating layer around the phase change material can be physical, chemical, or physical and chemical, and can be selected as needed. By wrapping the phase change material with the coating layer, the phase change material is not easily affected by the raw material of the substrate 210, has a long service life, and has a good thermal insulation effect of the substrate 210.

[0054] In addition, after the phase change capsules 220 are prepared, the phase change capsules 220 may be spherical particles, which is convenient for mixing with the raw materials of the substrate 210 .

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

[0056] Please refer to Figure 1-Figure 2 In this embodiment, optionally, the heat pipe body 310 can also be called an evaporation pipe, and the heat pipe body 310 is horizontally arranged in the roadbed filling layer 110. The heat pipe body 310 can be set as a split structure, and the heat pipe body 310 can include multiple pipe sections, and adjacent pipe sections are butt-jointed by joints to reduce the difficulty of processing. In addition, the heat pipe body 310 can be set as a bent pipe, or the heat pipe body 310 has at least one bent pipe section in its extension direction. In this way, under the premise that the width of the roadbed unit 100 is certain, by adding the bent pipe section, 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 conducive to adjusting the heat distribution inside the roadbed unit 100 and improving the uniformity of the heat distribution inside the roadbed unit 100.

[0057] Optionally, the heat dissipation pipe body 320 can also be called a condenser pipe, and the heat dissipation pipe body 320 includes an inner pipe 321 and an outer pipe 322. One end of the inner pipe 321 is sealed and connected to one end of the outer pipe 322, and the other end of the inner pipe 321 is connected to the tube cavity of the outer pipe 322. A reflux chamber 324 is defined between the outer pipe 322 wall of the inner pipe 321 and the inner pipe 321 wall of the outer pipe 322. The inner pipe 321 can be arranged coaxially with the outer pipe 322, so that the reflux chamber 324 defined between the inner pipe 321 and the outer pipe 322 is an annular chamber, and the annular chamber 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 reflux chamber 324. The position where the heat pipe body 310 is connected to the reflux chamber 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, and 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. In this way, when the volatile working fluid is evaporated by heat, a height difference is generated between the liquid level of the reflux chamber 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] It should be noted that during the service of the composite roadbed structure, when the volatile working fluid is heated, part of the volatile working fluid is heated and evaporated to form gas, causing the liquid level of the inner tube 321 and the liquid level of the reflux chamber 324 to change, forming a pressure difference, and driving 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 body 320, it exchanges heat with the external environment, dissipates heat, and condenses itself by cooling, recovering to a liquid working fluid, and flows along the wall of the inner tube 321 of the outer tube 322 under the action of gravity, and returns to the heat pipe body 310. In this way, the volatile working fluid circulates, which can not only dissipate the excess heat inside the roadbed unit 100, but also realize the regulation of the internal heat of the roadbed unit 100, so that the internal heat of the roadbed unit 100 is evenly distributed.

[0060] Furthermore, since the reflux chamber 324 is configured as an annular chamber, the volatile working fluid flows more smoothly and the heat regulation efficiency is high.

[0061] Furthermore, a super-liquid-repellent coating 323 is provided on the wall of the inner tube 321 of the outer tube 322, which can increase the smoothness of the wall of the inner tube 321 of the outer tube 322. After the working fluid is condensed, it is easy to flow downward along the wall of the inner tube 321 of the outer tube 322 under the action of gravity, and is not easy to adhere to the wall of the inner tube 321 of the outer tube 322, thereby shortening the residence time of the working fluid and improving the heat exchange efficiency; and since the working fluid is not easy to adhere to the wall of the inner tube 321, 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 the heat exchange efficiency is further improved.

[0062] Optionally, the bottom of the super-liquid-repellent coating 323 is 3-5 mm higher than the top of the inner tube 321. For example, the bottom of the super-liquid-repellent coating 323 is 3 mm, 4 mm or 5 mm higher than the top of the inner tube 321. With such a design, the super-liquid-repellent coating 323 is not immersed in a volatile medium, is not easily corroded and falls off, and the service life of the super-liquid-repellent coating 323 is extended.

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

[0064] It should be noted that the super-lyophobic coating 323 can be set as a silicone super-lyophobic coating 323, and the stable contact angle of the condensed liquid volatile working fluid on the super-lyophobic coating 323 is not less than 150°. In this way, the probability of the liquid working fluid adhering to the wall of the inner tube 321 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 super-liquid-repellent coating 323 can be formed on the raw steel coil of the outer tube 322 by a spraying process before the outer tube 322 is formed, which is convenient for processing and has high molding quality.

[0066] It should be understood that in this embodiment, the number of heat pipe units can be multiple, and the multiple heat pipe units are arranged at intervals in 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, 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, and there is no cooling dead corner, the roadbed unit has a good cooling effect, a good temperature control effect, and a more uniform heat distribution.

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

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

[0069] During the construction of the roadbed unit 100, the heat pipe unit 300 is installed at a 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 roadbed unit 100 is continued to be constructed and the heat pipe body 310 is buried; then the phase change insulation unit 200 is installed at a second set height position of the roadbed unit 100, and then the construction of the roadbed unit 100 is completed.

[0070] Specifically, the specific form of the required composite roadbed structure is determined according to the construction design drawing and relevant specifications. Depending on the specific project needs, a cushion layer that meets the requirements of the specifications can be first filled on the foundation soil and compacted, and the heat pipe body 310 is placed horizontally on the cushion layer. To facilitate the construction of the heat pipe body 310, the heat pipe body 310 can be designed as a segmented structure, and adjacent pipe sections can be connected by connectors, and the connectors must be corrosion-resistant and liquid-proof.

[0071] The roadbed unit 100 should be well drained, and asphalt can be laid on the 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. The volatile working fluid is injected into the heat pipe body 310 through the reserved injection port on the heat dissipation pipe body 320, and then all the air in the pipe is extracted through the injection port again, and the injection port is sealed after completion. After splicing, the heat pipe body 310 should be checked to see if it can work normally. It should be noted that the placement form and geometric shape of the pressure-driven ultra-long uniformly distributed heat pipe and phase change insulation structure with super-liquid-repellent coating 323 in the composite roadbed structure in this embodiment to enhance heat transfer are not unique.

[0072] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A composite roadbed structure, characterized in that: include: A roadbed unit (100), a phase-change heat preservation unit (200) and a heat pipe unit (300); the phase-change heat preservation unit (200) is arranged in the roadbed unit (100); the heat pipe unit (300) comprises a heat pipe body (310) and a heat dissipation pipe body (320); the heat pipe body (310) is buried in the roadbed unit (100) and is located below the phase-change heat preservation unit (200); the heat dissipation pipe body (320) is connected to the heat pipe body (310); and the heat dissipation pipe body (320) extends out of the roadbed unit (100); The heat pipe body (310) is used to be filled with a volatile working medium, and the volatile working medium is used to volatilize and flow toward the heat dissipation pipe body (320) when heated, and condense and flow back into the heat pipe body (310) after being cooled at the heat dissipation pipe body.

2. The composite roadbed structure according to claim 1, characterized in that: The phase-change heat preservation unit (200) comprises a substrate (210) and a plurality of phase-change capsules (220), wherein the plurality of phase-change capsules (220) are mixed with a raw material for preparing the substrate (210).

3. The composite roadbed structure according to claim 2, characterized in that: The phase change capsule (220) comprises 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 heat dissipation pipe body (320) comprises an inner pipe (321) and an outer pipe (322); one end of the inner pipe (321) is sealedly connected to one end of the outer pipe (322); the other end of the inner pipe (321) is connected to the tube cavity of the outer pipe (322); a reflux cavity (324) is defined between the outer pipe (322) wall of the inner pipe (321) and the inner pipe (321) wall of the outer pipe (322); one end of the heat pipe body (310) is connected to the inner pipe (321); the other end of the heat pipe body (310) is connected to the reflux cavity (324).

5. The composite roadbed structure according to claim 4, characterized in that: The reflux chamber (324) is configured as an annular chamber arranged around the inner tube (321).

6. The composite roadbed structure according to claim 4, characterized in that: A super-liquid-repellent coating (323) is provided on the wall of the inner tube (321) of the outer tube (322).

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

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

9. The composite roadbed structure according to claim 1, characterized in that: The number of the 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.

10. A composite roadbed structure construction method, characterized in that: Applied to the composite roadbed structure according to any one of claims 1 to 9, the construction method comprises the following steps: During the construction of a roadbed unit (100), a heat pipe unit (300) is installed at a 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 roadbed unit (100) is continued to be constructed and the heat pipe body (310) is buried; then a phase change insulation unit (200) is installed at a second set height position of the roadbed unit (100), and then the construction of the roadbed unit (100) is completed.

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